Very nice proposal, Magesh. I like the approach and the new concepts and interfaces, but I do have a few comments/suggestions about some specific details:
1. In the "Motivation" section, perhaps it makes sense to briefly describe one or two somewhat concrete examples of how this is useful. 2. Maybe in the "Public Interfaces" section you could briefly describe each of the interfaces, what they represent, and which are implemented by the framework vs implemented by an extension. I think it'd help to explain that only the `ConnectRestPlugin` needs to be implemented, and the rest will be provided by the framework. I know the next section goes into it a bit, but it'd be useful in this section when first talking about the new interfaces. 3. Also in the "Public Interfaces" section: I don't think we should introduce a "rest.plugins" configuration property. Instead, can we not just instantiate and call all of the ConnectRestPlugins that we find on the plugin path? Besides, it seems too close to the `plugin.path` configuration property. 4. Why would the implementation register Connect resources *after* the plugins, if Jersey currently registers only the first one? The "Rejected Alternatives" mentions why, but this section should be explicit about why. For example, "The plugin's would be registered in the RestServer.start(Herder herder) method before registering the default Connect resources, which ensures that plugins cannot remove Connect resources." 5. "Hence, it is recommended that the plugins don't re-register the default Connect Resources. This could potentially lead to unexpected errors." First, we should not say "recommended" and should just say plugins should not register any resources that conflict with the built-in Connect resources. Second, if the worker does find conflicts, can we just remove them before adding the built-in Connect resources? 6. Is it possible for implementations to check whether resources already exist before registering their own? If so, we should recommend that implementations do this and log any problems. 7. We should be explicit that the "Service Provider" is Java's Service Provider API. We also need to be explicit that an implementation must provide a `META-INF/services/org.apache.kafka.connect.ConnectRestPlugin` file (or whatever the package name of the `ConnectRestPlugin` will be) with the fully-qualified name of the implementation class(es). 8. The example should include the META-INF file required by the Service Provider API. Again, overall this is really great! Best regards, Randall On Wed, Apr 11, 2018 at 12:14 AM, Magesh Nandakumar <mage...@confluent.io> wrote: > Hi, > > We have posted KIP-285: Connect Rest Extension Plugin to add the ability to > provide Rest Extensions to Connect Rest API. > > https://cwiki.apache.org/confluence/display/KAFKA/KIP- > 285%3A+Connect+Rest+Extension+Plugin > > Please take a look. Your feedback is appreciated. > > Thanks, > > Magesh >
