Problem you have encountered:

Cannot create a Pubsub avro schema using PubSub Emulator.

We are using gcr.io/google.com/cloudsdktool/cloud-sdk:emulators image and golang pubsub library "cloud.google.com/go/pubsub"

We have no issues creating topics and subscriptions using client.CreateTopic(ctx, topicID)

But if doing

	config := pubsub.SchemaConfig{
		Type:       pubsub.SchemaAvro,
		Definition: string(avscSource),
	}
	s, err := schemaClient.CreateSchema(ctx, schemaID, config)

We are getting

 failed to create schema: rpc error: code = Unauthenticated desc = transport: per-RPC creds failed due to error: Post "https://oauth2.googleapis.com/token": no responder found

What you expected to happen:

I would expect schema to be crated in the emulator.

Steps to reproduce:

1. Start a container: gcr.io/google.com/cloudsdktool/cloud-sdk:emulators
2. Run the emulator gcloud beta emulators pubsub start --host-port=0.0.0.0:8085
3. Set PUBSUB_EMULATOR_HOST env variable to localhost:8085
4. Start go with

       client, err := pubsub.NewClient(ctx, projectID)
       client.CreateTopic(ctx, topicID)

	schemaClient, err := pubsub.NewSchemaClient(ctx, projectID)
	config := pubsub.SchemaConfig{
		Type:       pubsub.SchemaAvro,
		Definition: string(avscSource),
	}
	s, err := schemaClient.CreateSchema(ctx, schemaID, config)

Other information (workarounds you have tried, documentation consulted, etc):

Tried schemaClient, err := pubsub.NewSchemaClient(ctx, projectID, option.WithEndpoint("localhost:8085")) but I am getting a timeout in such case when pubsub client goes gRPC call to execute the schema creation

Docs

• https://cloud.google.com/pubsub/docs/create-schemas#go
• https://cloud.google.com/pubsub/docs/emulator