panic: proto: file "egress.proto" is already registered

[kieron-dev]

Since some protobuf libraries have been updated, go-log-cache now panics when included in a project.

For example, running this main.go:

package main

import logcachev1 "code.cloudfoundry.org/go-log-cache"

func main() {
    logcachev1.NewClient("foo")
}

panics with:

❯ go run main.go
panic: proto: file "egress.proto" is already registered
See https://developers.google.com/protocol-buffers/docs/reference/go/faq#namespace-conflict


goroutine 1 [running]:
google.golang.org/protobuf/reflect/protoregistry.glob..func1({0x9ade40, 0x9c6cf8}, {0x9ade40, 0xc00016aa00})
        /home/vagrant/go/pkg/mod/google.golang.org/[email protected]/reflect/protoregistry/registry.go:54 +0x1f4
google.golang.org/protobuf/reflect/protoregistry.(*Files).RegisterFile(0xc00000e0c0, {0x9c6cf8, 0xc00017f340})
        /home/vagrant/go/pkg/mod/google.golang.org/[email protected]/reflect/protoregistry/registry.go:128 +0x399
google.golang.org/protobuf/internal/filedesc.Builder.Build({{0x0, 0x0}, {0xc0000c7800, 0x3e3, 0x400}, 0x1, 0x6, 0x0, 0x1, {0x9b7c50, ...}, ...})
        /home/vagrant/go/pkg/mod/google.golang.org/[email protected]/internal/filedesc/build.go:113 +0x1d6
github.com/golang/protobuf/proto.RegisterFile({0x913777, 0xc}, {0xcb6540, 0x24d, 0x14})
        /home/vagrant/go/pkg/mod/github.com/golang/[email protected]/proto/registry.go:48 +0x127
code.cloudfoundry.org/go-log-cache/rpc/logcache_v1.init.1()
        /home/vagrant/go/pkg/mod/code.cloudfoundry.org/[email protected]/rpc/logcache_v1/egress.pb.go:353 +0x3a
exit status 2

Investigation has shown this is because go-log-cache imports go-loggregator, and both go-log-cache and go-loggregator have compiled gprc .proto files called 'ingress.proto' and 'egress.proto'. This went from being ignored, to being a warning, and now panics with the up to date protobuf libraries.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. Unfortunately, the Pivotal Tracker project is private so you may be unable to view the contents of the story.

The labels on this github issue will be updated when the story is started.

[geofffranks]

Resolved by merging #31