Document admin_reloadPlugin API

[bgravenorst]

Providing a new RPC method admin_reloadPlugin to dynamically (without the need to restart Besu) reload plugin config (this required a new reloadConfiguration method in Besu plugin api as it’s available for all plugins) see hyperledger/besu#261

[NicolasMassart]

The method seems not to be called admin_reloadPlugin as indicated in #261 but looking at the code is seems to be plugins_reloadPluginConfig and have parameters. I think Parameters may be the name of the plugin that should be reloaded, but I still have to make sure as my last try was not working.

[MadelineMurray]

@NicolasMassart - once you get this working could you paste a working example into here Bryon can use.

[MadelineMurray]

Was there a CLI option related to this?

[NicolasMassart]

No, only the RPC. No need for a CLI as it would mean that you stop and start Besu to run it, and if you do so, it reloads plugins. SO the only reason you need to reload is when you don't want to restart Besu, hence the RPC method. Will provide the method syntax here asap.

[NicolasMassart]

In theory, a sample request to reload a Kafka plugin config using RPC would be :
{"jsonrpc":"2.0","method":"plugins_reloadPluginConfig","params":["tech.pegasys.plus.plugin.kafka.KafkaPlugin"],"id":1} with the plugin name being the fully qualified java name of the plugin class.
But I'm having issues with internal error when trying this so I will add more details once I'm sure it works.

[NicolasMassart]

The issue on this Kafka example is related to some changes in the Event stream plugin (see private Jira https://pegasys1.atlassian.net/browse/PIE-2292).
Also I wonder, as the Kafka plugin is not open source, if we should use it as an example. But we have no open source plugins, so we may use a fake plugin name in our example request.
It would then be something like: {"jsonrpc":"2.0","method":"plugins_reloadPluginConfig","params":["com.example.SamplePlugin"],"id":1}