Merge branch 'develop' of ssh://gifrerenom_labs.etsi.org/tfs/controller into...

Merge branch 'develop' of ssh://gifrerenom_labs.etsi.org/tfs/controller into feat/130-opt-sbi-for-qkd-nodes

src/dlt/gateway/dltApp/package.json

+{
+    "name": "dlt_gateway",
+    "version": "1.0.0",
+    "description": "A DLT application that record and manages network related data as JSON, implemented in typeScript using HLF fabric-gateway",
+    "main": "dist/index.js",
+    "typings": "dist/index.d.ts",
+    "engines": {
+        "node": ">=18"
+    },
+    "scripts": {
+        "build": "tsc",
+        "build:watch": "tsc -w",
+        "lint": "eslint . --ext .ts",
+        "prepare": "npm run build",
+        "pretest": "npm run lint",
+        "start": "node dist/dlt_gateway.js"
+    },
+    "engineStrict": true,
+    "author": "Javier Jose Diaz (CTTC)",
+    "license": "Apache-2.0",
+    "dependencies": {
+        "@grpc/grpc-js": "^1.10.8",
+        "@grpc/proto-loader": "^0.7.13",
+        "@hyperledger/fabric-gateway": "~1.4.0",
+        "dotenv": "^16.4.5",
+        "grpc-tools": "^1.12.4",
+        "protobufjs": "^7.3.0",
+        "uuid": "^9.0.1"
+    },
+    "devDependencies": {
+        "@tsconfig/node18": "^18.2.2",
+        "@types/node": "^18.18.6",
+        "@typescript-eslint/eslint-plugin": "^6.9.0",
+        "@typescript-eslint/parser": "^6.9.0",
+        "eslint": "^8.52.0",
+        "typescript": "~5.2.2"
+    }
+}

src/dlt/gateway/dltApp/src/dltGateway.js

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+const grpc = require('@grpc/grpc-js');
+const protoLoader = require('@grpc/proto-loader');
+const path = require('path');
+const { connectToNetwork } = require('../dist/fabricConnect');
+const utf8Decoder = new TextDecoder();
+
+// Load the protocol buffer definitions
+const PROTO_PATH = path.resolve(__dirname, '../proto/dlt_gateway.proto');
+const packageDefinition = protoLoader.loadSync(PROTO_PATH, {
+  keepCase: true,
+  longs: String,
+  enums: String,
+  defaults: true,
+  oneofs: true,
+});
+const dltProto = grpc.loadPackageDefinition(packageDefinition).dlt;
+
+// Create a gRPC server instance
+const server = new grpc.Server();
+let contractInstance = null;
+let closeConnection = null;
+let events = null; // To store the events iterable
+
+const clients = new Set(); // Set to keep track of active client streams
+
+
+
+// Initialize connection to the chaincode
+
+async function initChaincodeConnection() {
+  try {
+    const networkResources = await connectToNetwork();
+    contractInstance = networkResources.contract;
+    events = networkResources.events; // Initiate event listening
+    closeConnection = networkResources.close;
+
+    //console.log("DEBUG", events)
+    console.log("Chaincode connection established successfully.");
+  } catch (error) {
+    console.error('Failed to establish chaincode connection:', error);
+    process.exit(1); // Exit if the connection cannot be established
+  }
+}
+
+// gRPC method to handle recording data to the DLT
+async function recordToDlt(call, callback) {
+  if (!contractInstance) {
+    callback({
+      code: grpc.status.UNAVAILABLE,
+      details: "Chaincode connection is not established."
+    });
+    return;
+  }
+  const { record_id, operation, data_json } = call.request;
+  try {
+
+
+    console.log(`Operation requested: ${operation}`);
+
+    switch (operation) {
+      case 'DLTRECORDOPERATION_ADD':
+        await contractInstance.submitTransaction('StoreRecord', JSON.stringify(record_id), data_json);
+        break;
+      case 'DLTRECORDOPERATION_UPDATE':
+        await contractInstance.submitTransaction('UpdateRecord', JSON.stringify(record_id), data_json);
+        break;
+      case 'DLTRECORDOPERATION_DELETE':
+        await contractInstance.submitTransaction('DeleteRecord', JSON.stringify(record_id));
+        break;
+      default:
+        throw new Error('Invalid operation');
+    }
+    // Send success response
+    callback(null, { record_id, status: 'DLTRECORDSTATUS_SUCCEEDED' });
+  } catch (error) {
+    // Send failure response with error message
+    console.log("ERRROR", error)
+    callback(null, { record_id, status: 'DLTRECORDSTATUS_FAILED', error_message: error.message });
+  }
+}
+
+// gRPC method to fetch data from the DLT
+async function getFromDlt(call, callback) {
+
+  if (!contractInstance) {
+    callback({
+      code: grpc.status.UNAVAILABLE,
+      details: "Chaincode connection is not established."
+    });
+    return;
+  }
+
+  try {
+
+    console.log("RECEIVED CALL REQUEST:", call.request);
+    //const { record_id, operation, data_json } = call.request;
+    const resultBytes = await contractInstance.evaluateTransaction('RetrieveRecord', JSON.stringify(call.request));
+    // Decode and parse the result
+    const resultJson = utf8Decoder.decode(resultBytes);
+    const result = JSON.parse(resultJson);
+
+    // Send the response with the formatted JSON data
+    callback(null, { record_id: call.request, operation: result.operation, data_json: result.data_json });
+  } catch (error) {   
+   if (error.message.includes("data not found for key")) {
+    // Return an empty response when no record is found
+    console.log("REQUEST ERROR:", error);
+    const emptyRecordId = {
+      domain_uuid: { uuid: "" },
+      type: 'DLTRECORDTYPE_UNDEFINED',
+      record_uuid: { uuid: "" }
+    };
+    callback(null, { record_id: emptyRecordId, data_json: "" });
+  } else {
+    // Send failure response with error message
+    callback({
+      code: grpc.status.UNKNOWN,
+      details: error.message
+    });
+   }
+  }
+}
+
+// Implement subscription to DLT events
+
+const eventNameToEventTypeEnum = {
+  'StoreRecord': 'EVENTTYPE_CREATE',
+  'UpdateRecord': 'EVENTTYPE_UPDATE',
+  'DeleteRecord': 'EVENTTYPE_REMOVE'
+};
+
+function subscribeToDlt(call) {
+  if (!events) {
+    call.emit('error', {
+      code: grpc.status.UNAVAILABLE,
+      details: "Event listener is not established."
+    });
+    return;
+  }
+
+  // Add the client to the set of active clients
+  clients.add(call);
+  console.log(`Client connected. Total clients: ${clients.size}`);
+
+  // Clean up when the client disconnects
+  call.on('cancelled', () => {
+    clients.delete(call);
+    console.log(`Client disconnected (cancelled). Total clients: ${clients.size}`);
+
+  });
+  call.on('error', (err) => {
+    clients.delete(call);
+    console.log(`Client disconnected (error: ${err.message}). Total clients: ${clients.size}`);
+
+  });
+  call.on('end', () => {
+    clients.delete(call);
+    console.log(`Client disconnected (end). Total clients: ${clients.size}`);
+
+  });
+
+  (async () => {
+    try {
+      for await (const event of events) {
+        const eventPayload = event.payload;
+        //console.log("Raw event payload:", eventPayload);
+        const resultJson = utf8Decoder.decode(eventPayload);
+        const eventJson = JSON.parse(resultJson);
+
+        console.log("Writing event to stream:", eventJson.record_id);
+
+        const eventType = eventNameToEventTypeEnum[event.eventName] || 'EVENTTYPE_UNDEFINED';
+
+        for (const client of clients) {
+          const writeSuccessful = client.write({
+            event: {
+              timestamp: { timestamp: Math.floor(Date.now() / 1000) },
+              event_type: eventType // Set appropriate event type
+            },
+            record_id: {
+              domain_uuid: { uuid: eventJson.record_id.domain_uuid.uuid },
+              type: eventJson.record_id.type || 'DLTRECORDTYPE_UNDEFINED',
+              record_uuid: { uuid: eventJson.record_id.record_uuid.uuid }
+            }
+          });
+          
+          // Check if the internal buffer is full
+          if (!writeSuccessful) {
+            // Wait for the 'drain' event before continuing
+            await new Promise((resolve) => client.once('drain', resolve));
+          }
+        }
+      }
+
+      //call.end();
+
+    } catch (error) {
+      for (const client of clients) {
+        client.emit('error', {
+          code: grpc.status.UNKNOWN,
+          details: `Error processing event: ${error.message}`
+        });
+
+      }
+    }
+  })();
+}
+
+// Placeholder
+function getDltStatus(call, callback) {
+  // Implement status fetching logic here
+  // Not implemented for simplicity
+}
+
+// Placeholder
+function getDltPeers(call, callback) {
+  // Implement peers fetching logic here
+  // Not implemented for simplicity
+}
+
+// Add the service to the server
+server.addService(dltProto.DltGatewayService.service, {
+  RecordToDlt: recordToDlt,
+  GetFromDlt: getFromDlt,
+  SubscribeToDlt: subscribeToDlt,
+  GetDltStatus: getDltStatus,
+  GetDltPeers: getDltPeers,
+});
+
+// Start the server
+const PORT = process.env.GRPC_PORT || '50051';
+server.bindAsync(`0.0.0.0:${PORT}`, grpc.ServerCredentials.createInsecure(), async (error) => {
+  if (error) {
+    console.error('Failed to bind server:', error);
+    return;
+  }
+  console.log(`gRPC server running at http://0.0.0.0:${PORT}`);
+  await initChaincodeConnection();  //Connects to the chaincode and 
+  server;
+});
+
+// Handle shutdown gracefully
+process.on('SIGINT', async () => {
+  console.log('Shutting down...');
+  await closeConnection();
+  server.forceShutdown();
+});
\ No newline at end of file

src/dlt/gateway/dltApp/src/fabricConnect.ts

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import * as grpc from '@grpc/grpc-js';
+import { connect, Contract, Identity, Signer, signers, Network, CloseableAsyncIterable, ChaincodeEvent, GatewayError } from '@hyperledger/fabric-gateway';
+import * as crypto from 'crypto';
+import { promises as fs } from 'fs';
+import * as path from 'path';
+import { TextDecoder } from 'util';
+import * as dotenv from 'dotenv';
+
+dotenv.config({ path: path.resolve(__dirname, '..', '.env') });
+const channelName = getEnvVar('CHANNEL_NAME');
+const chaincodeName = getEnvVar('CHAINCODE_NAME');
+const mspId = getEnvVar('MSP_ID');
+
+
+// Path to user private key directory.
+const keyDirectoryPath = getEnvVar('KEY_DIRECTORY_PATH');
+
+// Path to user certificate directory.
+const certDirectoryPath = getEnvVar('CERT_DIRECTORY_PATH');
+
+// Path to peer tls certificate.
+const tlsCertPath = getEnvVar('TLS_CERT_PATH');
+
+// Gateway peer endpoint.
+const peerEndpoint = getEnvVar('PEER_ENDPOINT');
+
+// Gateway peer SSL host name override.
+const peerHostAlias = getEnvVar('PEER_HOST_ALIAS');
+
+const utf8Decoder = new TextDecoder();
+const assetId = `asset${Date.now()}`;
+
+export async function connectToNetwork(): Promise<{ contract: Contract, events: CloseableAsyncIterable<ChaincodeEvent>, close: () => Promise<void> }> {
+
+    await displayInputParameters();
+
+    // The gRPC client connection should be shared by all Gateway connections to this endpoint.
+
+    const client = await newGrpcConnection();
+
+    const gateway = connect({
+        client,
+        identity: await newIdentity(),
+        signer: await newSigner(),
+        // Default timeouts for different gRPC calls
+        evaluateOptions: () => {
+            return { deadline: Date.now() + 5000 }; // 5 seconds
+        },
+        endorseOptions: () => {
+            return { deadline: Date.now() + 15000 }; // 15 seconds
+        },
+        submitOptions: () => {
+            return { deadline: Date.now() + 5000 }; // 5 seconds
+        },
+        commitStatusOptions: () => {
+            return { deadline: Date.now() + 60000 }; // 1 minute
+        },
+    });
+
+    let events: CloseableAsyncIterable<ChaincodeEvent> | undefined;
+
+
+    // Get a network instance representing the channel where the smart contract is deployed.
+    const network = gateway.getNetwork(channelName);
+
+    // Get the smart contract from the network.
+    const contract = network.getContract(chaincodeName);
+
+    //Listen for events emitted by transactions
+    //events = await startEventListening(network);
+    events = await network.getChaincodeEvents(chaincodeName);
+
+    // Initialize the ledger.
+    await initLedger(contract);
+
+    console.log(Date.now())
+
+    return {
+        contract: contract,
+        events: events,
+        close: async function () {
+            if (events) events.close();
+            gateway.close();
+            client.close();
+        }
+    };
+
+
+}
+
+async function newGrpcConnection(): Promise<grpc.Client> {
+    const tlsRootCert = await fs.readFile(tlsCertPath);
+    const tlsCredentials = grpc.credentials.createSsl(tlsRootCert);
+    return new grpc.Client(peerEndpoint, tlsCredentials, {
+        'grpc.ssl_target_name_override': peerHostAlias,
+    });
+}
+
+async function newIdentity(): Promise<Identity> {
+    //const certPath = await getFirstDirFileName(certDirectoryPath);
+    //console.log("DEBUG", certDirectoryPath);
+    const credentials = await fs.readFile(certDirectoryPath);
+    return { mspId, credentials };
+}
+
+
+async function newSigner(): Promise<Signer> {
+    //const keyPath = await getFirstDirFileName(keyDirectoryPath);
+    //console.log("DEBUG2", keyDirectoryPath);
+    const privateKeyPem = await fs.readFile(keyDirectoryPath);
+    const privateKey = crypto.createPrivateKey(privateKeyPem);
+    return signers.newPrivateKeySigner(privateKey);
+}
+
+/**
+ * This type of transaction would typically only be run once by an application the first time it was started after its
+ * initial deployment. A new version of the chaincode deployed later would likely not need to run an "init" function.
+ */
+async function initLedger(contract: Contract): Promise<void> {
+    try {
+        console.log('\n--> Submit Transaction: InitLedger, function activates the chaincode');
+
+        await contract.submitTransaction('InitLedger');
+
+        console.log('*** Transaction committed successfully');
+    } catch (error) {
+        console.error('Failed to submit InitLedger transaction:', error);
+        throw error;
+    }
+}
+
+
+
+/**
+ * getEnvVar() will return the value of an environment variable.
+ */
+function getEnvVar(varName: string): string {
+    const value = process.env[varName];
+    if (!value) {
+        throw new Error(`Environment variable ${varName} is not set`);
+    }
+    return value;
+}
+
+/**
+ * displayInputParameters() will print the global scope parameters used by the main driver routine.
+ */
+async function displayInputParameters(): Promise<void> {
+    console.log(`channelName:       ${channelName}`);
+    console.log(`chaincodeName:     ${chaincodeName}`);
+    console.log(`mspId:             ${mspId}`);
+    console.log(`keyDirectoryPath:  ${keyDirectoryPath}`);
+    console.log(`certDirectoryPath: ${certDirectoryPath}`);
+    console.log(`tlsCertPath:       ${tlsCertPath}`);
+    console.log(`peerEndpoint:      ${peerEndpoint}`);
+    console.log(`peerHostAlias:     ${peerHostAlias}`);
+}
+
+/**
+ * startEventListening() will initiate the event listener for chaincode events.
+ */
+async function startEventListening(network: Network): Promise<CloseableAsyncIterable<ChaincodeEvent>> {
+    console.log('\n*** Start chaincode event listening');
+
+    const events = await network.getChaincodeEvents(chaincodeName);
+
+    void readEvents(events); // Don't await - run asynchronously
+    return events;
+}
+
+/**
+ * readEvents() format and display the events as a JSON.
+ */
+async function readEvents(events: CloseableAsyncIterable<ChaincodeEvent>): Promise<void> {
+    try {
+        for await (const event of events) {
+            const payload = parseJson(event.payload);
+            console.log(`\n<-- Chaincode event received: ${event.eventName} -`, payload);
+        }
+    } catch (error: unknown) {
+        // Ignore the read error when events.close() is called explicitly
+        if (!(error instanceof GatewayError) || error.code !== grpc.status.CANCELLED.valueOf()) {
+            throw error;
+        }
+    }
+}
+
+/**
+ * parseJson() formats a JSON.
+ */
+function parseJson(jsonBytes: Uint8Array): unknown {
+    const json = utf8Decoder.decode(jsonBytes);
+    return JSON.parse(json);
+}
+

src/dlt/gateway/dltApp/tsconfig.json

+{
+    "extends":"@tsconfig/node18/tsconfig.json",
+    "compilerOptions": {
+        "experimentalDecorators": true,
+        "emitDecoratorMetadata": true,
+        "outDir": "dist",
+        "declaration": true,
+        "sourceMap": true,
+        "noImplicitAny": true
+    },
+    "include": [
+        "./src/**/*"   ],
+    "exclude": [
+        "./src/**/*.spec.ts"
+    ]
+ }
+ 
\ No newline at end of file

src/dlt/gateway/keys/.gitignore

+ca.crt
+cert.pem
+priv_sk

src/dlt/gateway/samples/sampleTopo.json

+{
+    "name": "Network A",
+    "nodes": [
+        {
+            "id": "node1",
+            "type": "switch",
+            "status": "active",
+            "connections": [
+                "node2",
+                "node3"
+            ]
+        },
+        {
+            "id": "node2",
+            "type": "router",
+            "status": "inactive",
+            "connections": [
+                "node1"
+            ]
+        },
+        {
+            "id": "node3",
+            "type": "server",
+            "status": "active",
+            "connections": [
+                "node1"
+            ]
+        }
+    ]
+}

src/dlt/gateway/samples/topo1.json

+{
+    "contexts": [
+        {"context_id": {"context_uuid": {"uuid": "admin"}}}
+    ],
+    "topologies": [
+        {"topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}}
+    ],
+    "devices": [
+        {
+            "device_id": {"device_uuid": {"uuid": "DC1"}}, "device_type": "emu-datacenter", "device_drivers": [0],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"uuid": "eth1", "type": "copper"}, {"uuid": "eth2", "type": "copper"}, {"uuid": "int", "type": "copper"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "DC2"}}, "device_type": "emu-datacenter", "device_drivers": [0],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"uuid": "eth1", "type": "copper"}, {"uuid": "eth2", "type": "copper"}, {"uuid": "int", "type": "copper"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "SRL1"}}, "device_type": "packet-router", "device_drivers": [8],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "172.100.100.101"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "57400"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {
+                    "username": "admin", "password": "NokiaSrl1!", "use_tls": true
+                }}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "SRL2"}}, "device_type": "packet-router", "device_drivers": [8],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "172.100.100.102"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "57400"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {
+                    "username": "admin", "password": "NokiaSrl1!", "use_tls": true
+                }}}
+            ]}
+        }
+    ],
+    "links": [
+        {
+            "link_id": {"link_uuid": {"uuid": "DC1/eth1==SRL1/ethernet-1/2"}},
+            "link_endpoint_ids": [
+                {"device_id": {"device_uuid": {"uuid": "DC1"}}, "endpoint_uuid": {"uuid": "eth1"}},
+                {"device_id": {"device_uuid": {"uuid": "SRL1"}}, "endpoint_uuid": {"uuid": "ethernet-1/2"}}
+            ]
+        },
+        {
+            "link_id": {"link_uuid": {"uuid": "SRL1/ethernet-1/2==DC1/eth1"}},
+            "link_endpoint_ids": [
+                {"device_id": {"device_uuid": {"uuid": "SRL1"}}, "endpoint_uuid": {"uuid": "ethernet-1/2"}},
+                {"device_id": {"device_uuid": {"uuid": "DC1"}}, "endpoint_uuid": {"uuid": "eth1"}}
+            ]
+        },
+
+        {
+            "link_id": {"link_uuid": {"uuid": "SRL1/ethernet-1/1==SRL2/ethernet-1/1"}},
+            "link_endpoint_ids": [
+                {"device_id": {"device_uuid": {"uuid": "SRL1"}}, "endpoint_uuid": {"uuid": "ethernet-1/1"}},
+                {"device_id": {"device_uuid": {"uuid": "SRL2"}}, "endpoint_uuid": {"uuid": "ethernet-1/1"}}
+            ]
+        },
+        {
+            "link_id": {"link_uuid": {"uuid": "SRL2/ethernet-1/1==SRL1/ethernet-1/1"}},
+            "link_endpoint_ids": [
+                {"device_id": {"device_uuid": {"uuid": "SRL2"}}, "endpoint_uuid": {"uuid": "ethernet-1/1"}},
+                {"device_id": {"device_uuid": {"uuid": "SRL1"}}, "endpoint_uuid": {"uuid": "ethernet-1/1"}}
+            ]
+        },
+
+        {
+            "link_id": {"link_uuid": {"uuid": "DC2/eth1==SRL2/ethernet-1/2"}},
+            "link_endpoint_ids": [
+                {"device_id": {"device_uuid": {"uuid": "DC2"}}, "endpoint_uuid": {"uuid": "eth1"}},
+                {"device_id": {"device_uuid": {"uuid": "SRL2"}}, "endpoint_uuid": {"uuid": "ethernet-1/2"}}
+            ]
+        },
+        {
+            "link_id": {"link_uuid": {"uuid": "SRL2/ethernet-1/2==DC2/eth1"}},
+            "link_endpoint_ids": [
+                {"device_id": {"device_uuid": {"uuid": "SRL2"}}, "endpoint_uuid": {"uuid": "ethernet-1/2"}},
+                {"device_id": {"device_uuid": {"uuid": "DC2"}}, "endpoint_uuid": {"uuid": "eth1"}}
+            ]
+        }
+    ]
+}

src/dlt/gateway/samples/topo2.json

+{
+    "contexts": [
+        {"context_id": {"context_uuid": {"uuid": "admin"}}}
+    ],
+    "topologies": [
+        {"topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}}
+    ],
+    "devices": [
+        {
+            "device_id": {"device_uuid": {"uuid": "R1"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/6"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R2"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/6"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R3"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/6"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R4"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/6"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R5"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/6"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R6"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/6"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"}
+                ]}}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R7"}}, "device_type": "emu-packet-router", "device_drivers": [0],
+            "device_endpoints": [], "device_operational_status": 1, "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "1/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/1"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/2"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/3"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/4"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/5"},
+                    {"sample_types": [101, 102, 201, 202], "type": "copper", "uuid": "2/6"}
+                ]}}}
+            ]}
+        }
+    ],
+    "links": [
+        {"link_id": {"link_uuid": {"uuid": "R1==R2"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "2/2"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R1==R6"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2/2"}},
+            {"device_id": {"device_uuid": {"uuid": "R6"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R1==R7"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2/3"}},
+            {"device_id": {"device_uuid": {"uuid": "R7"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R2==R1"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "2/2"}},
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R2==R3"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R3"}}, "endpoint_uuid": {"uuid": "2/2"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R3==R2"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R3"}}, "endpoint_uuid": {"uuid": "2/2"}},
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R3==R4"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R3"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R4"}}, "endpoint_uuid": {"uuid": "2/2"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R3==R7"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R3"}}, "endpoint_uuid": {"uuid": "2/3"}},
+            {"device_id": {"device_uuid": {"uuid": "R7"}}, "endpoint_uuid": {"uuid": "2/3"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R4==R3"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R4"}}, "endpoint_uuid": {"uuid": "2/2"}},
+            {"device_id": {"device_uuid": {"uuid": "R3"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R4==R5"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R4"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R5"}}, "endpoint_uuid": {"uuid": "2/2"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R5==R4"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R5"}}, "endpoint_uuid": {"uuid": "2/2"}},
+            {"device_id": {"device_uuid": {"uuid": "R4"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R5==R6"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R5"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R6"}}, "endpoint_uuid": {"uuid": "2/2"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R5==R7"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R5"}}, "endpoint_uuid": {"uuid": "2/3"}},
+            {"device_id": {"device_uuid": {"uuid": "R7"}}, "endpoint_uuid": {"uuid": "2/5"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R6==R1"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R6"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2/2"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R6==R5"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R6"}}, "endpoint_uuid": {"uuid": "2/2"}},
+            {"device_id": {"device_uuid": {"uuid": "R5"}}, "endpoint_uuid": {"uuid": "2/1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R7==R1"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R7"}}, "endpoint_uuid": {"uuid": "2/1"}},
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2/3"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R7==R3"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R7"}}, "endpoint_uuid": {"uuid": "2/3"}},
+            {"device_id": {"device_uuid": {"uuid": "R3"}}, "endpoint_uuid": {"uuid": "2/3"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R7==R5"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R7"}}, "endpoint_uuid": {"uuid": "2/5"}},
+            {"device_id": {"device_uuid": {"uuid": "R5"}}, "endpoint_uuid": {"uuid": "2/3"}}
+        ]}
+    ]
+}

src/dlt/gateway/samples/topo3.json

+{
+    "contexts": [
+        {"context_id": {"context_uuid": {"uuid": "admin"}}, "name": "admin"}
+    ],
+    "topologies": [
+        {"topology_id": {"topology_uuid": {"uuid": "admin"}, "context_id": {"context_uuid": {"uuid": "admin"}}}, "name": "admin"}
+    ],
+    "devices": [
+        {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "be1.be", "type": "copper"}, {"uuid": "pt1.pt", "type": "copper"}, {"uuid": "uk1.uk", "type": "copper"},
+                {"uuid": "es1.es", "type": "copper"}, {"uuid": "it1.it", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "de1.de", "type": "copper"}, {"uuid": "gr1.gr", "type": "copper"}, {"uuid": "uk1.uk", "type": "copper"},
+                {"uuid": "fr1.fr", "type": "copper"}, {"uuid": "it1.it", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "de1.de", "type": "copper"}, {"uuid": "fr1.fr", "type": "copper"}, {"uuid": "be1.be", "type": "copper"},
+                {"uuid": "pt1.pt", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "uk1.uk", "type": "copper"}, {"uuid": "be1.be", "type": "copper"}, {"uuid": "gr1.gr", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "uk1.uk", "type": "copper"}, {"uuid": "fr1.fr", "type": "copper"}, {"uuid": "es1.es", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "it1.it", "type": "copper"}, {"uuid": "fr1.fr", "type": "copper"}, {"uuid": "pt1.pt", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "es1.es", "type": "copper"}, {"uuid": "fr1.fr", "type": "copper"}, {"uuid": "be1.be", "type": "copper"},
+                {"uuid": "gr1.gr", "type": "copper"}
+            ]}}}
+        ]}},
+        {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "device_type": "emu-packet-router", "device_operational_status": 1, "device_drivers": [0], "device_config": {"config_rules": [
+            {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "127.0.0.1"}},
+            {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "0"}},
+            {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {"endpoints": [
+                {"uuid": "client:1", "type": "copper"}, {"uuid": "client:2", "type": "copper"}, {"uuid": "client:3", "type": "copper"},
+                {"uuid": "it1.it", "type": "copper"}, {"uuid": "de1.de", "type": "copper"}, {"uuid": "be1.be", "type": "copper"}
+            ]}}}
+        ]}}
+    ],
+    "links": [
+        {"link_id": {"link_uuid": {"uuid": "fr1.fr_be1.be"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 4.804849}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "be1.be"}},
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "fr1.fr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "uk1.uk_fr1.fr"}}, "attributes": {"total_capacity_gbps": 300, "used_capacity_gbps": 55.182499}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "fr1.fr"}},
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "uk1.uk"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "uk1.uk_de1.de"}}, "attributes": {"total_capacity_gbps": 600, "used_capacity_gbps": 199.272255}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "de1.de"}},
+            {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "endpoint_uuid": {"uuid": "uk1.uk"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "uk1.uk_be1.be"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 14.334868}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "be1.be"}},
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "uk1.uk"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "pt1.pt_uk1.uk"}}, "attributes": {"total_capacity_gbps": 400, "used_capacity_gbps": 51.415678}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "endpoint_uuid": {"uuid": "uk1.uk"}},
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "pt1.pt"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "pt1.pt_fr1.fr"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 3.733925}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "endpoint_uuid": {"uuid": "fr1.fr"}},
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "pt1.pt"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "pt1.pt_es1.es"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 13.32428}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "endpoint_uuid": {"uuid": "es1.es"}},
+            {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "endpoint_uuid": {"uuid": "pt1.pt"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "it1.it_gr1.gr"}}, "attributes": {"total_capacity_gbps": 800, "used_capacity_gbps": 1.593313}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "gr1.gr"}},
+            {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "endpoint_uuid": {"uuid": "it1.it"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "it1.it_fr1.fr"}}, "attributes": {"total_capacity_gbps": 200, "used_capacity_gbps": 98.574706}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "fr1.fr"}},
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "it1.it"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "it1.it_es1.es"}}, "attributes": {"total_capacity_gbps": 300, "used_capacity_gbps": 18.97108}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "es1.es"}},
+            {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "endpoint_uuid": {"uuid": "it1.it"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "it1.it_be1.be"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 10.327772}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "be1.be"}},
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "it1.it"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "gr1.gr_it1.it"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 7.983659}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "endpoint_uuid": {"uuid": "it1.it"}},
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "gr1.gr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "gr1.gr_de1.de"}}, "attributes": {"total_capacity_gbps": 5000, "used_capacity_gbps": 4930.897339}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "endpoint_uuid": {"uuid": "de1.de"}},
+            {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "endpoint_uuid": {"uuid": "gr1.gr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "gr1.gr_be1.be"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 0.895539}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "endpoint_uuid": {"uuid": "be1.be"}},
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "gr1.gr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "fr1.fr_uk1.uk"}}, "attributes": {"total_capacity_gbps": 200, "used_capacity_gbps": 28.144199}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "uk1.uk"}},
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "fr1.fr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "fr1.fr_pt1.pt"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 1.916587}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "pt1.pt"}},
+            {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "endpoint_uuid": {"uuid": "fr1.fr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "fr1.fr_it1.it"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 3.330747}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "it1.it"}},
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "fr1.fr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "fr1.fr_es1.es"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 96.682749}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "es1.es"}},
+            {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "endpoint_uuid": {"uuid": "fr1.fr"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "es1.es_pt1.pt"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 5.643483}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "endpoint_uuid": {"uuid": "pt1.pt"}},
+            {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "endpoint_uuid": {"uuid": "es1.es"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "es1.es_it1.it"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 15.353667}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "endpoint_uuid": {"uuid": "it1.it"}},
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "es1.es"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "es1.es_fr1.fr"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 20.517778}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "es1.es"}}, "endpoint_uuid": {"uuid": "fr1.fr"}},
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "es1.es"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "de1.de_uk1.uk"}}, "attributes": {"total_capacity_gbps": 600, "used_capacity_gbps": 239.446965}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "endpoint_uuid": {"uuid": "uk1.uk"}},
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "de1.de"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "de1.de_gr1.gr"}}, "attributes": {"total_capacity_gbps": 2100, "used_capacity_gbps": 110.602237}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "endpoint_uuid": {"uuid": "gr1.gr"}},
+            {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "endpoint_uuid": {"uuid": "de1.de"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "de1.de_be1.be"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 57.709307}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "endpoint_uuid": {"uuid": "be1.be"}},
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "de1.de"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "uk1.uk_pt1.pt"}}, "attributes": {"total_capacity_gbps": 800, "used_capacity_gbps": 652.70225}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "pt1.pt"}},
+            {"device_id": {"device_uuid": {"uuid": "pt1.pt"}}, "endpoint_uuid": {"uuid": "uk1.uk"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "be1.be_uk1.uk"}}, "attributes": {"total_capacity_gbps": 200, "used_capacity_gbps": 8.252107}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "uk1.uk"}},
+            {"device_id": {"device_uuid": {"uuid": "uk1.uk"}}, "endpoint_uuid": {"uuid": "be1.be"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "be1.be_it1.it"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 0.357069}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "it1.it"}},
+            {"device_id": {"device_uuid": {"uuid": "it1.it"}}, "endpoint_uuid": {"uuid": "be1.be"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "be1.be_de1.de"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 20.400142}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "de1.de"}},
+            {"device_id": {"device_uuid": {"uuid": "de1.de"}}, "endpoint_uuid": {"uuid": "be1.be"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "be1.be_fr1.fr"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 31.346514}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "fr1.fr"}},
+            {"device_id": {"device_uuid": {"uuid": "fr1.fr"}}, "endpoint_uuid": {"uuid": "be1.be"}}
+        ]}, 
+        {"link_id": {"link_uuid": {"uuid": "be1.be_gr1.gr"}}, "attributes": {"total_capacity_gbps": 100, "used_capacity_gbps": 0.026822}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "be1.be"}}, "endpoint_uuid": {"uuid": "gr1.gr"}},
+            {"device_id": {"device_uuid": {"uuid": "gr1.gr"}}, "endpoint_uuid": {"uuid": "be1.be"}}
+        ]}
+    ]
+}

src/dlt/gateway/samples/topo4.json

+{
+    "contexts": [
+        {"context_id": {"context_uuid": {"uuid": "admin"}}}
+    ],
+    "topologies": [
+        {"topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}}
+    ],
+    "devices": [
+        {
+            "device_id": {"device_uuid": {"uuid": "T1"}}, "device_type": "optical-transponder", "device_drivers": [11],
+            "device_operational_status": 1,
+            "device_endpoints": [
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "T1"}}, "endpoint_uuid": {"uuid": "1"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }}
+            ],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "172.254.253.101"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "2022"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {
+                    "username": "admin", "password": "admin", "force_running": false, "hostkey_verify": false,
+                    "look_for_keys": false, "allow_agent": false, "commit_per_rule": false,
+                    "device_params": {"name": "default"}, "manager_params": {"timeout": 120},
+                    "endpoints": [{"uuid": "1", "type": "optical", "sample_types": [101, 102, 201, 202]}]
+                }}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "T2"}}, "device_type": "optical-transponder", "device_drivers": [11],
+            "device_operational_status": 1,
+            "device_endpoints": [
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "T2"}}, "endpoint_uuid": {"uuid": "6"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }}
+            ],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "172.254.253.102"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "2022"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {
+                    "username": "admin", "password": "admin", "force_running": false, "hostkey_verify": false,
+                    "look_for_keys": false, "allow_agent": false, "commit_per_rule": false,
+                    "device_params": {"name": "default"}, "manager_params": {"timeout": 120},
+                    "endpoints": [{"uuid": "6", "type": "optical", "sample_types": [101, 102, 201, 202]}]
+                }}}
+            ]}
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R1"}}, "device_type": "optical-roadm", "device_drivers": [11],
+            "device_operational_status": 1,
+            "device_endpoints": [
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }},
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "3"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }},
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "12"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }},
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "13"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }}
+            ],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "172.254.253.201"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "2022"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {
+                    "username": "admin", "password": "admin", "force_running": false, "hostkey_verify": false,
+                    "look_for_keys": false, "allow_agent": false, "commit_per_rule": false,
+                    "device_params": {"name": "default"}, "manager_params": {"timeout": 120},
+                    "endpoints": [
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "2"},
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "3"},
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "12"},
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "13"}
+                    ]}
+                }}]
+            }
+        },
+        {
+            "device_id": {"device_uuid": {"uuid": "R2"}}, "device_type": "optical-roadm", "device_drivers": [11],
+            "device_operational_status": 1,
+            "device_endpoints": [
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "4"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }},
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "5"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }},
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "14"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }},
+                {"endpoint_id": {
+                    "device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "15"},
+                    "topology_id": {"context_id": {"context_uuid": {"uuid": "admin"}}, "topology_uuid": {"uuid": "admin"}}
+                }}
+            ],
+            "device_config": {"config_rules": [
+                {"action": 1, "custom": {"resource_key": "_connect/address", "resource_value": "172.254.253.202"}},
+                {"action": 1, "custom": {"resource_key": "_connect/port", "resource_value": "2022"}},
+                {"action": 1, "custom": {"resource_key": "_connect/settings", "resource_value": {
+                    "username": "admin", "password": "admin", "force_running": false, "hostkey_verify": false,
+                    "look_for_keys": false, "allow_agent": false, "commit_per_rule": false,
+                    "device_params": {"name": "default"}, "manager_params": {"timeout": 120},
+                    "endpoints": [
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "4"},
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "5"},
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "14"},
+                        {"sample_types": [101, 102, 201, 202], "type": "optical", "uuid": "15"}
+                    ]
+                }}}
+            ]}
+        }
+    ],
+    "links": [
+        {"link_id": {"link_uuid": {"uuid": "T1->R1"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "T1"}}, "endpoint_uuid": {"uuid": "1"}},
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "12"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R1->T1"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "2"}},
+            {"device_id": {"device_uuid": {"uuid": "T1"}}, "endpoint_uuid": {"uuid": "1"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R1->R2"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "3"}},
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "14"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R2->R1"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "4"}},
+            {"device_id": {"device_uuid": {"uuid": "R1"}}, "endpoint_uuid": {"uuid": "13"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "T2->R2"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "T2"}}, "endpoint_uuid": {"uuid": "6"}},
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "15"}}
+        ]},
+        {"link_id": {"link_uuid": {"uuid": "R2->T2"}}, "link_endpoint_ids": [
+            {"device_id": {"device_uuid": {"uuid": "R2"}}, "endpoint_uuid": {"uuid": "5"}},
+            {"device_id": {"device_uuid": {"uuid": "T2"}}, "endpoint_uuid": {"uuid": "6"}}
+        ]}
+    ]
+}

src/dlt/gateway/samples/updatedTopo.json

+{
+    "name": "Updated Network",
+    "nodes": [
+        {
+            "id": "node1",
+            "type": "switch",
+            "status": "active",
+            "connections": ["node2"]
+        },
+        {
+            "id": "node2",
+            "type": "router",
+            "status": "inactive",
+            "connections": ["node1"]
+        }
+    ]
+}

src/dlt/gateway/tests/perfTest.js

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+const { connectToNetwork } = require('../dltApp/dist/fabricConnect');
+const fsp = require('fs').promises;
+const fs = require('fs');
+const util = require('util');
+
+const utf8Decoder = new TextDecoder();
+const topoDirectory = '../samples/';
+const topologies = ['topo1.json', 'topo2.json', 'topo3.json', 'topo4.json'];
+//const topologies = ['topo4.json'];
+
+const iterations = 1000;
+
+async function main() {
+    try {
+        const { contract, close } = await connectToNetwork();
+        for (const topoFile of topologies) {
+            const logFilePath = `./operation_times_${topoFile.split('.')[0]}.txt`; // Creates a separate logfile for each topology
+            const appendFile = util.promisify(fs.appendFile.bind(fs, logFilePath)); 
+            
+            console.log(`Starting tests for ${topoFile}`);
+            for (let i = 0; i < iterations; i++) {
+                console.log(`Iteration ${i + 1} for ${topoFile}`);
+                await runBlockchainOperations(contract, topoFile, appendFile); 
+            }
+        }
+                await close(); // Clean up the connection
+    } catch (error) {
+        console.error('An error occurred:', error);
+    }
+}
+
+async function runBlockchainOperations(contract, topoFile, appendFile) {
+    const assetId = `asset${Date.now()}`;
+    const jsonData = await readJsonData(`${topoDirectory}${topoFile}`);
+
+    // Define operations
+    const operations = [
+        { type: 'STORE', jsonData },
+        { type: 'UPDATE', jsonData },
+        { type: 'FETCH', jsonData: null },
+        { type: 'DELETE', jsonData: null },
+        { type: 'FETCH_ALL', jsonData: null }
+    ];
+
+    for (let op of operations) {
+        await executeOperation(contract, op.type, assetId, op.jsonData, appendFile);
+    }
+}
+
+async function readJsonData(filePath) {
+    try {
+        return await fsp.readFile(filePath, 'utf8');
+    } catch (error) {
+        console.error(`Failed to read file: ${filePath}`, error);
+        return '{}';
+    }
+}
+
+async function executeOperation(contract, operationType, assetId, jsonData, appendFile) {
+    const startTime = process.hrtime.bigint();
+    try {
+        let result;
+        switch (operationType) {
+            case 'STORE':
+                result = await contract.submitTransaction('StoreTopoData', assetId, jsonData);
+                break;
+            case 'UPDATE':
+                result = await contract.submitTransaction('UpdateTopoData', assetId, jsonData);
+                break;
+            case 'FETCH':
+                result = await contract.evaluateTransaction('RetrieveTopoData', assetId);
+                break;
+            case 'DELETE':
+                result = await contract.submitTransaction('DeleteTopo', assetId);
+                break;
+            case 'FETCH_ALL':
+                result = await contract.evaluateTransaction('GetAllInfo');
+                break;
+        }
+        result = utf8Decoder.decode(result);
+        const operationTime = recordOperationTime(startTime);
+        await logOperationTime(operationTime, operationType, appendFile);
+        console.log(`${operationType} Result:`, result);
+    } catch (error) {
+        console.error(`Error during ${operationType}:`, error);
+    }
+}
+
+function recordOperationTime(startTime) {
+    const endTime = process.hrtime.bigint();
+    const operationTime = Number(endTime - startTime) / 1e6;
+    return operationTime;
+}
+
+async function logOperationTime(operationTime, operationType, appendFile) {
+    const timestamp = Date.now();
+    const logEntry = `${timestamp} - ${operationType} - Execution time: ${operationTime.toFixed(3)} ms\n`;
+    try {
+        await appendFile(logEntry);
+    } catch (error) {
+        console, error('Error writing to log file:', error);
+    }
+}
+
+main();

src/dlt/gateway/tests/rateTest.js

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+const { connectToNetwork } = require('../dltApp/dist/fabricConnect');
+const fs = require('fs');
+const util = require('util');
+const appendFile = util.promisify(fs.appendFile);
+const logFilePath = './transaction_times_TPS_TOPO3.txt';
+const utf8Decoder = new TextDecoder();
+const topoDirectory = '../samples/';
+
+async function main() {
+    const { contract, close } = await connectToNetwork();
+    try {
+        const rates = [10, 50, 250, 500]; // Transactions per second
+        for (let i = 0; i < 1000; i++) {
+                for (let rate of rates) {
+                    console.log(`Testing at ${rate} TPS`);
+                    await performLoadTest(contract, 1000, rate);
+            }
+    }
+    } finally {
+        await close(); // Ensure to close the network connection
+    }
+}
+
+async function performLoadTest(contract, totalTransactions, rate) {
+    const interval = 1000 / rate; // Calculate interval in milliseconds
+    let promises = [];
+    const startTime = Date.now();
+
+    for (let i = 0; i < totalTransactions; i++) {
+        // Queue a transaction promise
+        promises.push(sendTransaction(contract, `asset${Date.now() + i}`));
+
+        // Process in batches according to the rate
+        if ((i + 1) % rate === 0 || i === totalTransactions - 1) {
+            await Promise.all(promises); // Send a batch of transactions
+            promises = []; // Reset for the next batch
+            if (i < totalTransactions - 1) {
+                await new Promise(resolve => setTimeout(resolve, interval)); // Throttle the transaction sending
+            }
+        }
+    }
+
+    const endTime = Date.now();
+    const totalTime = endTime - startTime;
+    const actualRate = totalTransactions / (totalTime / 1000);
+    console.log(`Total time for ${totalTransactions} transactions at target ${rate} TPS: ${totalTime} ms`);
+    console.log(`Actual rate achieved: ${actualRate.toFixed(2)} TPS`);
+    await appendFile(logFilePath, `Target Rate: ${rate} TPS, Total Time: ${totalTime} ms, Actual Rate: ${actualRate.toFixed(2)} TPS\n`);
+}
+
+async function sendTransaction(contract, assetId) {
+    try {
+        const jsonData = await readJsonData(`${topoDirectory}topo3.json`);
+        const result = await contract.submitTransaction('StoreTopoData', assetId, jsonData);
+        return utf8Decoder.decode(result);
+    } catch (error) {
+        console.error('Transaction failed:', error);
+        return null;
+    }
+}
+
+async function readJsonData(filePath) {
+    try {
+        return await fs.promises.readFile(filePath, 'utf8');
+    } catch (error) {
+        console.error(`Failed to read file: ${filePath}`, error);
+        return '{}';
+    }
+}
+
+main().catch(console.error);

src/dlt/gateway/tests/simpleTest.js

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+const { connectToNetwork } = require('../dltApp/dist/fabricConnect');
+const fs = require('fs');
+const util = require('util');
+const appendFile = util.promisify(fs.appendFile);
+const logFilePath = './transaction_times_TPS2.txt';
+const utf8Decoder = new TextDecoder();
+const topoDirectory = '../samples/';
+
+async function main() {
+    const { contract, close } = await connectToNetwork();
+    try {
+        console.log('Testing with 8 consecutive transactions');
+        await performLoadTest(contract);
+    } finally {
+        await close(); // Ensure to close the network connection
+    }
+}
+
+async function performLoadTest(contract) {
+    const totalTransactions = 500;
+    const promises = [];
+    const startTime = Date.now();
+
+    for (let i = 0; i < totalTransactions; i++) {
+        // Queue a transaction promise
+        promises.push(sendTransaction(contract, `asset${startTime}_${i}`));
+    }
+
+    await Promise.all(promises); // Send all transactions
+
+    const endTime = Date.now();
+    const totalTime = endTime - startTime;
+    const actualRate = totalTransactions / (totalTime / 1000);
+    console.log(`Total time for ${totalTransactions} transactions: ${totalTime} ms`);
+    console.log(`Actual rate achieved: ${actualRate.toFixed(2)} TPS`);
+    await appendFile(logFilePath, `Total Transactions: ${totalTransactions}, Total Time: ${totalTime} ms, Actual Rate: ${actualRate.toFixed(2)} TPS\n`);
+}
+
+async function sendTransaction(contract, assetId) {
+    try {
+        const jsonData = await readJsonData(`${topoDirectory}topo4.json`);
+        //const jsonData = JSON.stringify({ data: `Data for ${assetId}`});
+        const result = await contract.submitTransaction('StoreTopoData', assetId, jsonData);
+        return utf8Decoder.decode(result);
+    } catch (error) {
+        console.error('Transaction failed:', error);
+        return null;
+    }
+}
+
+async function readJsonData(filePath) {
+    try {
+        return await fs.promises.readFile(filePath, 'utf8');
+    } catch (error) {
+        console.error(`Failed to read file: ${filePath}`, error);
+        return '{}';
+    }
+}
+
+main().catch(console.error);

src/dlt/gateway/tests/testEvents.js

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+const grpc = require('@grpc/grpc-js');
+const protoLoader = require('@grpc/proto-loader');
+const path = require('path');
+
+const PROTO_PATH = path.resolve(__dirname, '../../../../proto/dlt_gateway.proto');
+const packageDefinition = protoLoader.loadSync(PROTO_PATH, {
+  keepCase: true,
+  longs: String,
+  enums: String,
+  defaults: true,
+  oneofs: true,
+});
+const dltProto = grpc.loadPackageDefinition(packageDefinition).dlt;
+
+const client = new dltProto.DltGatewayService(
+  '127.0.0.1:32001', // Replace with TFS server IP_ADDRESS
+  grpc.credentials.createInsecure()
+);
+
+function subscribeToDlt() {
+  const request = {
+    // Define any necessary subscription filters here if applicable
+  };
+
+  const call = client.SubscribeToDlt(request);
+
+  call.on('data', (event) => {
+    console.log('Received event:', event);
+  });
+
+  call.on('error', (error) => {
+    console.error('Error:', error.message);
+  });
+
+  call.on('end', () => {
+    console.log('Stream ended.');
+  });
+
+  // Optionally, you can cancel the subscription after a certain time or condition
+  setTimeout(() => {
+    console.log('Cancelling subscription...');
+    call.cancel();
+  }, 600000); // Cancel after 1 minute for demonstration purposes
+}
+
+function runTests() {
+  console.log("Testing subscription to DLT events");
+  subscribeToDlt();
+}
+
+runTests();

src/dlt/gateway/tests/testGateway.js

+// Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+
+const grpc = require('@grpc/grpc-js');
+const protoLoader = require('@grpc/proto-loader');
+const path = require('path');
+const fs = require('fs').promises;
+const { v4: uuidv4 } = require('uuid'); // Import the UUID library
+
+
+const PROTO_PATH = path.resolve(__dirname, '../../../../proto/dlt_gateway.proto');
+const packageDefinition = protoLoader.loadSync(PROTO_PATH, {
+    keepCase: true,
+    longs: String,
+    enums: String,
+    defaults: true,
+    oneofs: true,
+});
+const dltProto = grpc.loadPackageDefinition(packageDefinition).dlt;
+
+const client = new dltProto.DltGatewayService(
+    '127.0.0.1:32001', // Replace with TFS server IP_ADDRESS
+    grpc.credentials.createInsecure()
+);
+
+const assetId = `asset-${Date.now()}`;
+const domainUuid = `domain-${uuidv4()}`; // Generate a pretty domain UUID
+
+async function getTopoData(filename) {
+    try {
+        const data = await fs.readFile(`../samples/${filename}`, 'utf8');
+        return data;
+    } catch (error) {
+        console.error('Failed to read file:', filename, error);
+        return '{}'; // Empty JSON if error
+    }
+}
+
+async function processTopoData(operation, assetId, jsonFilename) {
+    let jsonData = '{}';
+    if (jsonFilename) {
+        jsonData = await getTopoData(jsonFilename);
+    }
+
+    const request = {
+        record_id: {
+            domain_uuid: { uuid: domainUuid },  // Replace "domain-uuid" with actual domain UUID if needed
+            type: 'DLTRECORDTYPE_TOPOLOGY',  // Use the appropriate type if needed
+            record_uuid: { uuid: assetId }
+        },
+        operation,
+        data_json: jsonData
+    };
+
+    return new Promise((resolve, reject) => {
+        client.RecordToDlt(request, (error, response) => {
+            if (error) {
+                console.error('Error:', error.message);
+                reject(error);
+            } else {
+                console.log('Response:', response);
+                resolve(response);
+            }
+        });
+    });
+}
+
+async function getDLTData(assetId) {
+
+    const request = {
+        domain_uuid: { uuid: domainUuid },  // Replace "domain-uuid" with actual domain UUID if needed
+        type: 'DLTRECORDTYPE_TOPOLOGY',  // Use the appropriate type if needed
+        record_uuid: { uuid: assetId }
+    };
+
+    return new Promise((resolve, reject) => {
+        client.GetFromDlt(request, (error, response) => {
+            if (error) {
+                console.error('Error:', error.message);
+                reject(error);
+            } else {
+                console.log('Response:', response);
+                resolve(response);
+            }
+        });
+    });
+}
+
+async function runTests() {
+    console.log("Testing Store Operation");
+    await processTopoData('DLTRECORDOPERATION_ADD', assetId, 'topo2.json');
+
+    console.log("Testing Update Operation");
+    await processTopoData('DLTRECORDOPERATION_UPDATE', assetId, 'topo3.json');
+
+    console.log("Testing Fetch Operation");
+    await getDLTData(assetId);
+
+
+    console.log("Testing Delete Operation");
+    await processTopoData('DLTRECORDOPERATION_DELETE', assetId);
+
+    console.log("Testing Fetch All Operation");
+    // This part assumes you have a GetAllInfo method implemented in your chaincode and corresponding gRPC service.
+    // client.GetAllInfo({}, (error, response) => {
+    //   if (error) {
+    //     console.error('Error:', error.message);
+    //   } else {
+    //     console.log('All Data:', response);
+    //   }
+    // });
+}
+
+runTests().catch(console.error);

src/interdomain/Config.py

@@ -15,6 +15,7 @@
 from common.Settings import get_setting
 
 SETTING_NAME_TOPOLOGY_ABSTRACTOR = 'TOPOLOGY_ABSTRACTOR'
+SETTING_NAME_DLT_INTEGRATION = 'DLT_INTEGRATION'
 TRUE_VALUES = {'Y', 'YES', 'TRUE', 'T', 'E', 'ENABLE', 'ENABLED'}
 
 def is_topology_abstractor_enabled() -> bool:
@@ -22,3 +23,9 @@ def is_topology_abstractor_enabled() -> bool:
     if is_enabled is None: return False
     str_is_enabled = str(is_enabled).upper()
     return str_is_enabled in TRUE_VALUES
+
+def is_dlt_enabled() -> bool:
+    is_enabled = get_setting(SETTING_NAME_DLT_INTEGRATION, default=None)
+    if is_enabled is None: return False
+    str_is_enabled = str(is_enabled).upper()
+    return str_is_enabled in TRUE_VALUES

src/interdomain/service/InterdomainServiceServicerImpl.py

@@ -34,7 +34,7 @@ from common.tools.object_factory.Device import json_device_id
 from common.tools.object_factory.EndPoint import json_endpoint_id
 from common.tools.object_factory.Topology import json_topology_id
 from context.client.ContextClient import ContextClient
-from dlt.connector.client.DltConnectorClient import DltConnectorClient
+from dlt.connector.client.DltConnectorClientAsync import DltConnectorClientAsync
 from pathcomp.frontend.client.PathCompClient import PathCompClient
 from service.client.ServiceClient import ServiceClient
 from slice.client.SliceClient import SliceClient
@@ -88,7 +88,7 @@ class InterdomainServiceServicerImpl(InterdomainServiceServicer):
         ])
         if len(env_vars) == 2:
             # DLT available
-            dlt_connector_client = DltConnectorClient()
+            dlt_connector_client = DltConnectorClientAsync()
             dlt_connector_client.connect()
         else:
             dlt_connector_client = None

src/interdomain/service/__main__.py

@@ -18,8 +18,9 @@ from common.Constants import ServiceNameEnum
 from common.Settings import (
     ENVVAR_SUFIX_SERVICE_HOST, ENVVAR_SUFIX_SERVICE_PORT_GRPC, get_env_var_name, get_log_level, get_metrics_port,
     wait_for_environment_variables)
-from interdomain.Config import is_topology_abstractor_enabled
+from interdomain.Config import is_dlt_enabled, is_topology_abstractor_enabled
 from .topology_abstractor.TopologyAbstractor import TopologyAbstractor
+from .topology_abstractor.DltRecorder import DLTRecorder
 from .InterdomainService import InterdomainService
 from .RemoteDomainClients import RemoteDomainClients
 
@@ -69,12 +70,21 @@ def main():
         topology_abstractor = TopologyAbstractor()
         topology_abstractor.start()
 
+    # Subscribe to Context Events
+    dlt_enabled = is_dlt_enabled()
+    if dlt_enabled:
+        LOGGER.info('Starting DLT functionality...')
+        dlt_recorder = DLTRecorder()
+        dlt_recorder.start()
+
     # Wait for Ctrl+C or termination signal
     while not terminate.wait(timeout=1.0): pass
 
     LOGGER.info('Terminating...')
     if topology_abstractor_enabled:
         topology_abstractor.stop()
+    if dlt_enabled:
+         dlt_recorder.stop()
     grpc_service.stop()
     remote_domain_clients.stop()