Initial "Telemetry Frontend" client code

src/telemetry_frontend/client/TelemetryFrontendClient.py

+# Copyright 2022-2023 ETSI TeraFlowSDN - TFS OSG (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 grpc, logging
+from common.Constants import ServiceNameEnum
+from common.Settings import get_service_host, get_service_port_grpc
+
+from common.proto.context_pb2 import Empty
+from common.tools.grpc.Tools import grpc_message_to_json_string
+from common.tools.client.RetryDecorator import retry, delay_exponential
+from common.proto.telemetry_frontend_pb2_grpc import TelemetryFrontendServiceStub
+from comment.proto.telemetry_frontend_pb2 import Collector, CollectorId, CollectorFilter, CollectorList
+
+LOGGER = logging.getLogger(__name__)
+MAX_RETRIES = 10
+DELAY_FUNCTION = delay_exponential(initial=0.01, increment=2.0, maximum=5.0)
+RETRY_DECORATOR = retry(max_retries=MAX_RETRIES, delay_function=DELAY_FUNCTION, prepare_method_name='connect')
+
+class TelemetryFrontendClient:
+    def __init__(self, host=None, port=None):
+        if not host: host = get_service_host(ServiceNameEnum.TELEMETRYFRONTEND)
+        if not port: port = get_service_port_grpc(ServiceNameEnum.TELEMETRYFRONTEND)
+        self.endpoint = '{:s}:{:s}'.format(str(host), str(port))
+        LOGGER.debug('Creating channel to {:s}...'.format(str(self.endpoint)))
+        self.channel = None
+        self.stub = None
+        self.connect()
+        LOGGER.debug('Channel created')        
+
+    def connect(self):
+        self.channel = grpc.insecure_channel(self.endpoint)
+        self.stub = TelemetryFrontendServiceStub(self.channel)
+
+    def close(self):
+        if self.channel is not None: self.channel.close()
+        self.channel = None
+        self.stub = None
+
+    @RETRY_DECORATOR
+    def StartCollector(self, request : Collector) --> CollectorId:
+        LOGGER.debug('StartCollector: {:s}'.format(grpc_message_to_json_string(request)))
+        response = self.stub.StartCollector(request)
+        LOGGER.debug('StartCollector result: {:s}'.format(grpc_message_to_json_string(response)))
+        return response
+
+    @RETRY_DECORATOR
+    def StopCollector(self, request : CollectorId) --> Empty:
+        LOGGER.debug('StopCollector: {:s}'.format(grpc_message_to_json_string(request)))
+        response = self.stub.StopCollector(request)
+        LOGGER.debug('StopCollector result: {:s}'.format(grpc_message_to_json_string(response)))
+        return response
+
+    @RETRY_DECORATOR
+    def SelectCollectors(self, request : CollectorFilter) --> CollectorList:
+        LOGGER.debug('SelectCollectors: {:s}'.format(grpc_message_to_json_string(request)))
+        response = self.stub.SelectCollectors(request)
+        LOGGER.debug('SelectCollectors result: {:s}'.format(grpc_message_to_json_string(response)))
+        return response
+