add details for implementing SBI

After the server stubs have been generated (see [Server stubs](#server-stubs)), the folder stucture will be something like the structure shown below:

```

meep-<MEC identifier>

meep-<mec-identifier>

     |

     \____ main.go

     |

3. **Create the service handler file**

   Create a `server/<service-name>.go` file. This will contain all the handler functions for endpoints and the emulation logic for the service.

   Create a `server/<mec-identifier>.go` file. This will contain all the handler functions for endpoints and the emulation logic for the service.

4. **Implement handler function for unsupported endpoints**

   In the `server/api_unsupported.go` file (if it exists), for each of the handler functions, replace the previous code with `notImplemented(w, r)` and add this function in the `server/<service-name>.go` as follows:

   In the `server/api_unsupported.go` file (if it exists), for each of the handler functions, replace the previous code with `notImplemented(w, r)` and add this function in the `server/<mec-identifier>.go` as follows:

   ```go

   func notImplemented(w http.ResponseWriter, r *http.Request) {

5. **Separate handler function(s) for the endpoints**

   Remove the previous code in each of the `server/api_<api_tag>.go` file and replace it with a handler function. Implement all those handler functions in the `server/<service-name>.go` file.

   Remove the previous code in each of the `server/api_<api_tag>.go` file and replace it with a handler function. Implement all those handler functions in the `server/<mec-identifier>.go` file.

6. **Implement SBI Communication Logic**

   Create a `server/sbi` folder and create a `<service-name>.go` file in it. Implement all the communication and initialization related logic of SBI in this file.

   The new MEC service will need to communicate with South Bound services to, for example, get updated scenario information. To do this, create a `server/sbi` folder and create a `<mec-identifier>-sbi.go` file in it. Implement all the communication and initialization related logic of SBI (South Bound Interface) in this file. This will include communication with the message queue and Redis cache from where it will obtain the necessary information.

   Also, for the service to communicate with the SBI and pass parameters to and receive them from SBIs, implement that logic in the `server/<service-name>.go` file.

   Instances of the necessary SBIs will then be created and their initilization triggering logic implmented in the `server/<mec-identifier>.go` file for the service to communicate with and receive information from them.

7. **Creating _go.mod_ and _go.sum_ files**

   Run the following commands to create the _go.mod_ and _go.sum_ files:

   ```sh

   go mod init github.com/InterDigitalInc/AdvantEDGE/go-apps/meep-<service-name>

   go get github.com/InterDigitalInc/AdvantEDGE/go-apps/meep-<service-name>

   go mod init github.com/InterDigitalInc/AdvantEDGE/go-apps/meep-<mec-identifier>

   go get github.com/InterDigitalInc/AdvantEDGE/go-apps/meep-<mec-identifier>

   ```

After doing the above steps, the files will look something like the file/folder structure shown below:

```

meep-<MEC identifier>

meep-<mec-identifier>

     |

     \____ main.go

     |

     |

     \____ sbi

     |      |

     |      \____ <service-name>.go

     |      \____ <mec-identifier>-sbi.go

     |

     \____ server

            |

            |

            \____ routers.go

            |

            \____ <service-name>.go

            \____ <mec-identifier>.go

```

### Client-side

```

go-packages

     |

     \____ meep-<MEC identifier>-client

     \____ meep-<mec-identifier>-client

                    |

                    \____ .swagger-codegen

                    |      |

                    \____ README.md

```

The tag `<MEC identifier>` identifies the MEC API implemented by the micro-service. For instance, for the MEC-030 micro-service,the tag is 'vis'. The client microservice is named mee-vis-client.

The tag `<mec-identifier>` identifies the MEC API implemented by the micro-service. For instance, for the MEC-030 micro-service,the tag is 'vis'. The client microservice is named mee-vis-client.

There may be multiple files for `api_<api_tag>` and `model_<model_name>` depending on the tags and component schemas in the OAS file used to generate the server stubs.

   Rename the client package generated by [Swagger Codegen](https://github.com/swagger-api/swagger-codegen) is a package named 'swagger'. This package name shall be renamed into 'client' using the following command:

   ```sh

   $ cd go-packages/meep-<MEC identifier>-client

   $ cd go-packages/meep-<mec-identifier>-client

   $ find . -name "*.go" -exec sed --in-place 's/swagger/client/g' {} \;

   ```

   Run the following commands to create the _go.mod_ and _go.sum_ files:

   ```sh

   go mod init github.com/InterDigitalInc/AdvantEDGE/go-packages/meep-<MEC identifier>-client

   go get github.com/InterDigitalInc/AdvantEDGE/go-apps/meep-<MEC identifier>-client

   go mod init github.com/InterDigitalInc/AdvantEDGE/go-packages/meep-<mec-identifier>-client

   go get github.com/InterDigitalInc/AdvantEDGE/go-apps/meep-<mec-identifier>-client

   ```

After doing the above steps, the files will look something like the file/folder structure shown below:

```

meep-<MEC identifier>

meep-<mec-identifier>

     |

     \____ api_<MEC identifier>.go

     \____ api_<mec-identifier>.go

     |

     \____ client.go

     |

     |

     \____ response.go

     |

     \____ <service-name>.go

     \____ <mec-identifier>.go

```

## Unit tests for the new micro-service

1. **Create a testing file**

   Create a file named <service-name>_Test.go

   Create a file named <mec-identifier>_Test.go

   The files will look something like the file/folder structure shown below:

```

meep-<MEC identifier>

meep-<mec-identifier>

     |

     \____ ...

     |

            |

            \____ routers.go

            |

            \____ <service-name>.go

            \____ <mec-identifier>.go

            |

            \____ <service-name>_Test.go

            \____ <mec-identifier>_Test.go

```

2. **Implement tests for unimplemented methods**

done

# Start service

exec /meep-<MEC identifier>

exec /meep-<mec-identifier>

```

**NOTE**: Replace `meep-<MEC identifier>` in the last line with the service name. For example, for V2X Information service, it will become `meep-vis`.

**NOTE**: Replace `meep-<mec-identifier>` in the last line with the service name. For example, for V2X Information service, it will become `meep-vis`.

The updated directory tree will look like this:

```

meep-<MEC identifier>

meep-<mec-identifier>

     |

     \____ main.go

     |

     |

     \____ sbi

     |      |

     |      \____ <service-name>.go

     |      \____ <mec-identifier>.go

     |

     \____ server

            |

            |

            \____ routers.go

            |

            \____ <service-name>.go

            \____ <mec-identifier>.go

```

As a next step, code include in the directory structure above will be added into AdvantEDGE repository of fork. See [Code Integration](./backend-integration.md#code-integration) for more details.