Add gRPC endpoints for querying txs, TxsByEvents, tx/broadcast

[anilcse]

• Currently there are only legacy REST endpoints for querying TxsByEvents and for querying TxByHash. Having gRPC methods/endpoints would be handy for applications that uses gRPC alone.

cc @aaronc @amaurymartiny @alexanderbez

[aaronc]

It seems like clients could use tendermint JSON RPC directly without needing gRPC, and that gRPC would just be a very thin wrapper over tendermint. What benefits would this bring?

/cc @marbar3778

[alexanderbez]

The idea I think is that it's one less service to have to interface with if the client doesn't actually need Tendermint's JSON RPC.

[aaronc]

Yeah that's reasonable. We should also wrap broadcast (and maybe some other tendermint methods) if we do this.

[aaronc]

Yeah that's reasonable. We should also wrap broadcast (and maybe some other tendermint methods) if we do this.

[anilcse]

The idea I think is that it's one less service to have to interface with if the client doesn't actually need Tendermint's JSON RPC.

Correct @alexanderbez , and the less services to interface for clients, the better UX.

Yeah that's reasonable. We should also wrap broadcast (and maybe some other tendermint methods) if we do this.

+1

[sahith-narahari]

@anilcse @clevinson this should be addressed for 0.40 right, or is there a change of plan I missed

[amaury1093]

In reading Tendermint's v1.0 roadmap, I saw they were evaluating using gRPC instead of their own RPC layer. If that happens, I guess this issue is not relevant anymore?

The 2 gRPC servers will be on 2 different ports, if clients want everything on one single port, maybe there's a workaround to combine them under one port?

[anilcse]

We can address this after 0.40 as well, not a blocker. @amaurymartiny as this would be a small rework even after updating the TM side changes, I suggest to address this now. Wdyt?

[aaronc]

In reading Tendermint's v1.0 roadmap, I saw they were evaluating using gRPC instead of their own RPC layer. If that happens, I guess this issue is not relevant anymore?

Exactly.

But it's small enough (hopefully) that it's not a problem to add it in the meantime.

Not a blocker for 0.40.