chore: enable rest plugin only if in config or if --rest-http-port is set

[gabrik]

Currently the rest plugin is enabled by default for zenohd, which means that its a required dependency when running a simple zenoh router without configuration.

This PR changes the behaviour by enabling the rest plugin only if the --rest-http-port is passed.

[github-actions]

PR missing one of the required labels: {'bug', 'breaking-change', 'enhancement', 'internal', 'documentation', 'dependencies', 'new feature'}

[OlivierHecart]

Should be:

    // apply '--rest-http-port' to config only if explicitly set (overwriting config)
    // or if no config file is set (to apply its default value)
    if args.rest_http_port.is_some() || args.config.is_none() {
        match args.rest_http_port.as_deref() {
            Some(value) => {
                if !value.eq_ignore_ascii_case("none") {
                    config
                        .insert_json5("plugins/rest/http_port", &format!(r#""{value}""#))
                        .unwrap();
                    config
                        .insert_json5("plugins/rest/__required__", "true")
                        .unwrap();
                }
            }
            None => {
                config
                    .insert_json5("plugins/rest/http_port", "8000")
                    .unwrap();
            }
        }
    }

[gabrik]

shouldn't the || args.config.is_none() be removed to load only if the argument passed?

[OlivierHecart]

shouldn't the || args.config.is_none() be removed to load only if the argument passed?

Well the point is that we want rest to start on port 8000 by default if nothing is specified.

[gabrik]

shouldn't the || args.config.is_none() be removed to load only if the argument passed?

Well the point is that we want rest to start on port 8000 by default if nothing is specified.

the point of my PR is not not have it unless --rest-http-port is specified

[OlivierHecart]

shouldn't the || args.config.is_none() be removed to load only if the argument passed?

Well the point is that we want rest to start on port 8000 by default if nothing is specified.

the point of my PR is not not have it unless --rest-http-port is specified

I believed the point of the PR was to not fail if rest was not available but still start it on port 8000 by default if available.

[Mallets]

I agree with this PR and not having unnecessary services running if not specified.
Moreover, with current status it's impossible to compile and run zenohd without forcing the compilation of the rest plugin, which is quite annoying tbh.
The PR should also include updates to the README to explicitly set the --http-port parameter when needed.

[Mallets]

• Documentation to be updated: https://zenoh.io/docs/manual/configuration/ Explicit mention zenohd --http-rest-port in documentation atolab/zenoh-web#88

Update:
Dockerfile to be updated: https://github.com/eclipse-zenoh/ci/blob/7cbe301bce9b932eea7ffea2b463890ab712f97e/publish-crates-docker/Dockerfile#L14
Current Dockerfile already passes all CLI arguments to the inner zenohd. So no new changes are expected.

@gabrik this PR is complete from PoV. Anything else?

[gabrik]

• Documentation to be updated: https://zenoh.io/docs/manual/configuration/ Explicit mention zenohd --http-rest-port in documentation atolab/zenoh-web#88

Update: Dockerfile to be updated: https://github.com/eclipse-zenoh/ci/blob/7cbe301bce9b932eea7ffea2b463890ab712f97e/publish-crates-docker/Dockerfile#L14 Current Dockerfile already passes all CLI arguments to the inner zenohd. So no new changes are expected.

@gabrik this PR is complete from PoV. Anything else?

Looks good to me, but I cannot approve as I commited here.

[JEnoch]

We have examples of REST API usage in backends READMEs that shall be updated with the correct zenohd command line for REST plugin activation:

• https://github.com/eclipse-zenoh/zenoh-backend-influxdb?tab=readme-ov-file#setup-at-runtime-via-curl-commands-on-the-admin-space
• https://github.com/eclipse-zenoh/zenoh-backend-rocksdb?tab=readme-ov-file#setup-at-runtime-via-curl-commands-on-the-admin-space
• https://github.com/eclipse-zenoh/zenoh-backend-filesystem?tab=readme-ov-file#setup-at-runtime-via-curl-commands-on-the-admin-space