Expose ContractReader and ChainWriter of relayer in relayerSet

[kidambisrinivas]

Updates

• Implement ContractReader and ChainWriter in relayerset
  • Relayerset does not start gRPC service for relayer and mount it on-demand
  • So we had to expose ContractReader and ChainWriter of relayer from relayerset client itself

Testing

$ go test -count=1 -v ./pkg/loop/internal/relayerset
=== RUN   Test_RelayerSet
2024-09-04T16:02:42.491+0100 [DEBUG] accepting initial connection: addr=/var/folders/1b/byq7w64n1x7gmp5cp9__vp_r0000gn/T/plugin2829362114
2024-09-04T16:02:42.492+0100 [DEBUG] stdio EOF, exiting copy loop
2024-09-04T16:02:42.492+0100 [DEBUG] stdio EOF, exiting copy loop
2024-09-04T16:02:42.493+0100 [DEBUG] making new client mux initial connection: addr=/var/folders/1b/byq7w64n1x7gmp5cp9__vp_r0000gn/T/plugin2829362114
2024-09-04T16:02:42.493+0100 [DEBUG] initial server connection accepted: addr=/var/folders/1b/byq7w64n1x7gmp5cp9__vp_r0000gn/T/plugin2829362114
2024-09-04T16:02:42.494+0100 [DEBUG] client muxer connected: addr=/var/folders/1b/byq7w64n1x7gmp5cp9__vp_r0000gn/T/plugin2829362114
2024-09-04T16:02:42.494+0100 [DEBUG] sending conn to default listener
2024-09-04T16:02:42.497+0100 [DEBUG] sending conn to default listener
2024-09-04T16:02:42.497+0100 [DEBUG] stdio: received EOF, stopping recv loop: err="rpc error: code = Unavailable desc = error reading from server: EOF"
--- PASS: Test_RelayerSet (0.01s)
PASS
ok      github.com/smartcontractkit/chainlink-common/pkg/loop/internal/relayerset       0.408s

[jmank88]

Is this PR part of a set? If so, please link them together from the descriptions.

[patrickhuie19]

I don't follow - relayerset is supposed to serve relayers, which then hold a Chain Reader and Chain Writer. What does defining a Chain Reader and Chain Writer on a relayerset mean?

[cedric-cordenier]

I don't follow - relayerset is supposed to serve relayers, which then hold a Chain Reader and Chain Writer. What does defining a Chain Reader and Chain Writer on a relayerset mean?

@patrickhuie19 This is just a way to save us from instantiating an extra server for the relayer.

The calls we would make normally are:
RelayerSet.Get -> Relayer
and then
Relayer.NewChainReader -> ChainReader

We could translate this to the GRPC world by having each call to RelayerSet.Get wrap the returned relayer in a server and register that to the GRPC server. However this is actually pretty inefficient since a relayer object on its own is useless; users will always want to use the relayer to instantiate eg. a chainreader or chainwriter.

So we can avoid the intermediate server for the relayer by just storing a reference to the relayerSet client and the relayer we want to fetch.

I.e. the calls described above instead would become:

RelayerSet.Get -> RelayerClient (i.e. a RelayerSetClient + relayerID) -- effectively this call just acts as a check that the relayer exists
RelayerClient.NewChainReader -> this is a call to RelayerSet.NewChainReader with (relayerID, []chainReaderConfig); the implementation will then fetch the relayer and call NewChainReader on it

[patrickhuie19]

I don't follow - relayerset is supposed to serve relayers, which then hold a Chain Reader and Chain Writer. What does defining a Chain Reader and Chain Writer on a relayerset mean?

@patrickhuie19 This is just a way to save us from instantiating an extra server for the relayer.

The calls we would make normally are: RelayerSet.Get -> Relayer and then Relayer.NewChainReader -> ChainReader

We could translate this to the GRPC world by having each call to RelayerSet.Get wrap the returned relayer in a server and register that to the GRPC server. However this is actually pretty inefficient since a relayer object on its own is useless; users will always want to use the relayer to instantiate eg. a chainreader or chainwriter.

So we can avoid the intermediate server for the relayer by just storing a reference to the relayerSet client and the relayer we want to fetch.

I.e. the calls described above instead would become:

RelayerSet.Get -> RelayerClient (i.e. a RelayerSetClient + relayerID) -- effectively this call just acts as a check that the relayer exists RelayerClient.NewChainReader -> this is a call to RelayerSet.NewChainReader with (relayerID, []chainReaderConfig); the implementation will then fetch the relayer and call NewChainReader on it

That makes sense to me. Can we document that @kidambisrinivas ?

[kidambisrinivas]

@patrickhuie19 Documented this