GSoC Weekly Check-In (Week 9-10)

What Did I do last week?

The plan for the last couple of weeks was to facilitate fetching plugin code from github repository, but due to some unexpected roadblocks, we had to delay fetching external plugins. There were a couple of changes in the existing implementation:

1. Since we decided not to go with hot reloading, there was no need for plugin flags. So instead of using a boolean flag to differentiate b/w in-memory plugins and runtime plugins, I used a simple regex check to get the job done. We simply load the plugin from the registry if the configuration contains only characters ranging from [a-z][0-9], else we call the loader to load plugins at runtime. Ex:

# Loading plugin from registry
[grpc.services.userprovider]
driver = "json"

# Loading runtime plugin (contains the path)
[grpc.services.userprovider]
driver = "./json"

2. Second issues was to pass context. A lot of Reva plugins would not work if we do not pass context to plugins, and the problem that we faced was that Golang RPC package does not support passing context via RPC. Our entire plugin architecture was based off of RPC, which meant that this was pretty big deal! We had to find a way to pass context data through RPC, else some of the plugins would be rendered useless.

We solved this issues by pulling values out of the context data and storing it into a map[interface{}]interface{} data structure before sending out the RPCs. This map[interface{}]interface{} was sent as an RPC argument and then was again added to context on the server side. My mentor, Ishank came up with smart way of pulling context data out into map[interface{}]interface{} by using reflection. Check it out!

What will I do next week?

Now that we are almost done with the basic plugin architecture and we have a working implementation of plugin package, which supports both compiling the plugins and the existing in-memory plugin, the next step is to facilitate plugins from external repository.

Any hiccups?

Yes! There were a couple of roadblocks for me. I struggled to come up with an efficient way to pass context data via RPC. But with the help of my mentors we were able to get over the hump and complete the implementation.