NethVoice: Allow the instances in the cluster to be discoverable

[Amygos]

Currently, there is no built-in way to list all NethVoice instances within the
cluster. This makes it difficult for other modules to automatically detect and
configure these instances, complicating integrations such as with NethVoice
Proxy. Enabling service discovery will streamline integrations and
configuration across modules.

Proposed Solution

Store each NethVoice instance’s address and port as entries under a dedicated
srv key in Redis. Other modules can then use the standard NS8 service
discovery approach to retrieve this information and dynamically discover
available NethVoice instances for configuration and integration purposes.

Alternative Solutions

• Manual entry of instance details in each module (labor-intensive and
  error-prone).

Additional Context

This functionality would benefit use cases like integrating with NethVoice
Proxy and could be useful for any future modules requiring cluster/node wide
instance awareness.

[Amygos]

Test Case 1: Service Discovery on Fresh Installation

1. Install the NethVoice module (testing version) on one cluster node.
2. Complete the initial NethVoice module configuration and ensure the service is running.
3. Get the NethVoice SIP port, eg:

   runagent -m nethvoice1 env  | grep ASTERISK_SIP_PORT

4. From a terminal as the root user, execute eg:

  api-cli run module/nethvoice1/list-service-providers -d '{"service":"sip","transport":"udp","filter":{"module_id":"nethvoice1"}}'  | jq

5. Observe and review the JSON output.

• Expected Results:
  • The output contains a single entry representing the installed NethVoice instance.
  • The entry includes: node_address, node_id, port, module_uuid, node, transport, module_id, and ui_name.
  • The port value matches the SIP UDP port as configured within the NethVoice instance.

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Test Case 2: Service Discovery After Updating NethVoice Module

1. On an installation of NethVoice that is already configured.
2. Get the NethVoice SIP port, .eg:

   runagent -m nethvoice1 env  | grep ASTERISK_SIP_PORT

3. Upgrade the NethVoice module from stable to the testing version.
4. From a terminal as the root user, execute eg:

  api-cli run module/nethvoice1/list-service-providers -d '{"service":"sip","transport":"udp","filter":{"module_id":"nethvoice1"}}'  | jq

5. Observe and review the JSON output.

• Expected Results:
  • The output contains a single entry representing the installed NethVoice instance.
  • The entry includes: node_address, node_id, port, module_uuid, node, transport, module_id, and ui_name.
  • The port value matches the SIP UDP port as configured within the NethVoice instance.