Dynamically adding and removing a service

Let’s imagine an API gateway with some schema validation where each route has its own schema for its request body. The list of routes and schemas are retrieved in runtime from some centralized registry. The route and schema can be added, removed or updated.

For Armeria to support this scenario, we need the following updates:

• Provide a way to add and remove a Service from a Server without restarting a Server.
  • Service will need additional life cycle callbacks.
• Provide a way to add and remove a gRPC and Thrift service from GrpcService and THttpService.
• Improve DocService to reconfigure itself on server configuration changes.
  • ServerListener will need additional life cycle callbacks, e.g. routeAdded, routeRemoved.

Related conversation: https://line-armeria.slack.com/archives/C1NGPBUH2/p1598973931015200

[aio64]

Magic thanks, will pull, integrate and explore the TLS caveat and report anything that may be noteworthy.

[trustin]

@amitvc’s PR has been merged. This means, you can update the service bindings without restarting a server, with some limitations:

• TLS settings cannot be changed without restarting a server yet; and
• the services being removed will not be notified of removal, which may cause a problem to a service that performs an action when the server stops, such as TomcatService and JettyService.

The next step would be to address the above limitations.