glcli: Large responses are rejected

[cdecker]

The new rust-based glcli appears to be enforcing the 4MB response size limit:

Error, message length too large: found 4362728 bytes, the limit is: 4194304 bytes

@nepet: if I remember correctly there was a parameter we could pass to the stub to configure that limit. Since we trust the server when it comes to responses, we can lift that limit, to 32MB for example.

[YusukeShimizu]

I looked into it a bit, so I'd like to share my findings.
I think we can adjust the decoding message size limit.
It defaults to 4MB, so it looks like the default setting is currently in effect.

[cdecker]

Indeed, we have encountered this in the past, when syncing the gossip internally. We could just lift the maximum size the client accepts, since we have control over the server-side, and don't need to worry about DoS (a client asking for too large a response is just hammering their own node, not affecting others). And the client is likely in the best position to judge whether it can cache and process large responses, and should set limits accordingly.

[nepet]

I think this is more an issue on gl-client as glcli uses scheduler.node() to get a grpc client from gl-client. As @YusukeShimizu proposed this should be fixable by setting a bigger size limit when constructing the grpc clients.

If you want to have a take on this @YusukeShimizu, you can find them here:

greenlight/libs/gl-client/src/node/mod.rs

Lines 39 to 55 in ed1f18b

	impl GrpcClient for Client {
	fn new_with_inner(inner: service::AuthService) -> Self {
	Client::new(inner)
	}
	}
	impl GrpcClient for GClient {
	fn new_with_inner(inner: service::AuthService) -> Self {
	GenericClient::new(inner)
	}
	}
	impl GrpcClient for ClnClient {
	fn new_with_inner(inner: service::AuthService) -> Self {
	ClnClient::new(inner)
	}
	}

We may want to consider to make this a configurable option (maybe via something like scheduler.node(max_size) or an env var with a sane default.

[cdecker]

Addressed by #599