Represents the "configuration" part of the "init" message during
plugin initialization.
Changelog-Added: cln_plugin: persist cln configuration from init msg
We now have ternary outcomes for `Builder.configure()` and
`Builder.start()`:
- Ok(Some(p)) means we were configured correctly, and can continue
with our work normally
- Ok(None) means that `lightningd` was invoked with `--help`, we
weren't configured (which is not an error since the `lightningd` just
implicitly told us to shut down) and user code should clean up and
exit as well
- Err(e) something went wrong, user code may report an error and exit.
Mostly comments and docs: some places are actually paths, which
I have avoided changing. We may migrate them slowly, particularly
when they're user-visible.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
For now hooks are treated identically to rpcmethods, with the
exception of not being returned in the `getmanifest` call. Later on we
can add typed handlers as well.
We wrap emitted messages into a JSON-RPC notification envelope and
write them to stdout. We use an indirection over an mpsc channel in
order to avoid deadlocks if we emit logs while holding the writer lock
on stdout.