grpc vs json-rpc

[etienne-napoleone]

Hey guys,

Wondering what's the value running grpc instead of json rpc?

Afaik json-rpc is:

• widely understood
• has a super large tooling
• best practices have been known for a while
• super easy to query
• super easy to serve/proxy
• super easy to rate-limit
• super easy to cache
• super easy to write clients for
• probably wouldn't be the performance bottleneck anyway

It seems to me like using grpc (not even going to talk about amino hrmm) makes the learning curve steeper for new devs to join in. The depreciation of native standardised restful and rpc APIs seems like a disaster for the ecosystem approachability. Would be interested to hear the arguments in favor

[amaury1093]

Each node exposes a Tendermint endpoint which talks JSON-RPC: https://docs.cosmos.network/main/core/grpc_rest.html#tendermint-rpc. So it's not "instead", but both can run together, or you can configure your node to run only one.

2 advantages that gRPC has in my opinion:

1. More performant over-the-wire: it's Protobuf binary sent with gRPC, instead of JSON with JSON-RPC
2. Possibility to generate server and client code: we write the definitions once in Protobuf, and a lot of client/server code can be generated in Golang, Rust and JS.

[etienne-napoleone]

I agree on the performance benefit of grpc, but have to disagree on point 2.
any type of software you write that needs to access blockchain data needs to be dependent on grpc, protobuf definitions that need to be compiled etc.
not convenient in most cases imo

[aaronc]

I think most of the points you listed apply equal well to the way we use gRPC if not better. Also, we have types so client code can be generated. We're using protobuf for storage so gRPC is an obvious choice and is more performant. I'm also not sure all the points you made even apply to json-rpc (unless things have changed significantly recently), sounds more like REST/OpenAPI which we support via grpc-gateway.

[etienne-napoleone]

is grpc-gateway what's "powering" lcd? or is it something different? tbh the doc is kinda confusing and not explicit
kindly disagree on the rest

[alexanderbez]

LCD isn't a thing. There's the gRPC service and then there's the gRPC-gateway service which is an HTTP wrapper around the gRPC service. There's also a web thing, but idk what that is really...