support "v1" of the reflection protocol, not just "v1alpha"

[jhump]

The server reflection service has a v1:
https://github.com/grpc/grpc/blob/master/src/proto/grpc/reflection/v1/reflection.proto

But this repo still only uses the v1alpha version.

Ideally, the implementation in the reflection sub-package would register implementations for both (or at least accept an option to do so). That would support a transition to the v1 API while still supporting clients that continue to use the v1alpha version.

[dfawley]

@ejona86 @markdroth What is happening in grpc-java/c++ here? Do you support both versions? v1 was added to the grpc-proto repo 4 years ago, but we never picked it up in grpc-go.

[ejona86]

To my knowledge, no language is using v1. Carl added the v1 version, but nothing else happened with it.

It's one of those "how is nobody complaining about this" things, while simultaneously being "things work fine." I do expect this will be painful in many languages, as the API used to register the service commonly only supports a single service.

[ejona86]

See also: grpc/grpc-java#6724

[buzzsurfr]

Requesting to take this one as a first-time contributor (in code) to grpc-go. (Still pumped from KubeCon NA 2022)

[dfawley]

@buzzsurfr SGTM, I think we can go ahead and support both v1 and v1alpha.

[easwars]

As part of this change, it would also be good to fix our script which compiles the proto files. Currently we have a copy of this proto file in our repo. We are trying to get rid of this approach where we have a copy of the proto file in our repo, but instead want the regenerate.sh to pull protos from their canonical sources and only store the generated pb.gos in our repo.

[buzzsurfr]

@easwars Looking at the script, what's the difference between legacy sources (Generates sources without the embed requirement) and sources (Generates only the new gRPC Service symbols). What's the "embed requirement"?

grpc-go/regenerate.sh

Lines 53 to 74 in 7f23df0

	# Generates sources without the embed requirement
	LEGACY_SOURCES=(
	${WORKDIR}/grpc-proto/grpc/binlog/v1/binarylog.proto
	${WORKDIR}/grpc-proto/grpc/channelz/v1/channelz.proto
	${WORKDIR}/grpc-proto/grpc/health/v1/health.proto
	${WORKDIR}/grpc-proto/grpc/lb/v1/load_balancer.proto
	profiling/proto/service.proto
	reflection/grpc_reflection_v1alpha/reflection.proto
	)
	# Generates only the new gRPC Service symbols
	SOURCES=(
	$(git ls-files --exclude-standard --cached --others "*.proto" | grep -v '^\(profiling/proto/service.proto\|reflection/grpc_reflection_v1alpha/reflection.proto\)$')
	${WORKDIR}/grpc-proto/grpc/gcp/altscontext.proto
	${WORKDIR}/grpc-proto/grpc/gcp/handshaker.proto
	${WORKDIR}/grpc-proto/grpc/gcp/transport_security_common.proto
	${WORKDIR}/grpc-proto/grpc/lookup/v1/rls.proto
	${WORKDIR}/grpc-proto/grpc/lookup/v1/rls_config.proto
	${WORKDIR}/grpc-proto/grpc/testing/*.proto
	${WORKDIR}/grpc-proto/grpc/core/*.proto
	)

[buzzsurfr]

I did try moving v1alpha to use the protobuf from grpc-proto/grpc/reflection/v1alpha but it's missing a go_package directive.

WARNING: Missing 'go_package' option in "grpc/reflection/v1alpha/reflection.proto"

I see that v1 has it--should I open a separate PR to add a similar line to v1alpha?

[easwars]

I see that v1 has it--should I open a separate PR to add a similar line to v1alpha?

That would be cool if you could do it. Thank you so much.