Support Pub/Sub Emulator

It seems right now google-cloud-pubsub doesn’t support gcloud emulator. At least I’m not able to configure it for Pub/Sub even though I managed to use an emulator with google-cloud-datastore. I think it is related to https://github.com/GoogleCloudPlatform/google-cloud-datastore/issues/114.

Anyways, when I’m trying to create a subscriber using a channel provider with no credentials. Here are some snippets in Kotlin of how I create a SubscriptionAdminClient:

val channelProvider = InstantiatingChannelProvider.newBuilder()
        .setEndpoint("localhost:$port")
        .setCredentialsProvider(FixedCredentialsProvider.create(NoCredentials.getInstance()))
        .build()

protected fun getSubscriptionAdminClient(): SubscriptionAdminClient {
  val adminSettings = SubscriptionAdminSettings.defaultBuilder()
    .setChannelProvider(channelProvider)
    .build()
  return SubscriptionAdminClient.create(adminSettings)
}

When I’m trying to call com.google.cloud.pubsub.spi.v1.SubscriptionAdminClient#createSubscription I’m getting:

com.google.api.gax.grpc.ApiException: io.grpc.StatusRuntimeException: UNKNOWN
	at com.google.api.gax.grpc.ExceptionTransformingCallable$ExceptionTransformingFuture.onFailure(ExceptionTransformingCallable.java:109)
	at com.google.api.gax.core.ApiFutures$1.onFailure(ApiFutures.java:53)
	at com.google.common.util.concurrent.Futures$4.run(Futures.java:1126)
	at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
	at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:902)
	at com.google.common.util.concurrent.AbstractFuture.addListener(AbstractFuture.java:636)
	at com.google.common.util.concurrent.ForwardingListenableFuture.addListener(ForwardingListenableFuture.java:45)
	at com.google.api.gax.core.internal.ApiFutureToListenableFuture.addListener(ApiFutureToListenableFuture.java:53)
	at com.google.common.util.concurrent.Futures.addCallback(Futures.java:1138)
	at com.google.common.util.concurrent.Futures.addCallback(Futures.java:1076)
	at com.google.api.gax.core.ApiFutures.addCallback(ApiFutures.java:48)
	at com.google.api.gax.grpc.ExceptionTransformingCallable.futureCall(ExceptionTransformingCallable.java:65)
	at com.google.api.gax.grpc.RetryingCallable$GrpcRetryCallable.call(RetryingCallable.java:139)
	at com.google.api.gax.grpc.RetryingCallable.futureCall(RetryingCallable.java:84)
	at com.google.api.gax.grpc.UnaryCallable.futureCall(UnaryCallable.java:219)
	at com.google.api.gax.grpc.UnaryCallable.futureCall(UnaryCallable.java:230)
	at com.google.api.gax.grpc.UnaryCallable.call(UnaryCallable.java:258)
	at com.google.cloud.pubsub.spi.v1.SubscriptionAdminClient.createSubscription(SubscriptionAdminClient.java:339)
	at com.google.cloud.pubsub.spi.v1.SubscriptionAdminClient.createSubscription(SubscriptionAdminClient.java:307)
	at com.fkorotkov.gcloud.pubsub.PubSubImpl.registerSubscriber(PubSubImpl.kt:72)
Caused by: io.grpc.StatusRuntimeException: UNKNOWN
	at io.grpc.Status.asRuntimeException(Status.java:540)
	at io.grpc.stub.ClientCalls$UnaryStreamToFuture.onClose(ClientCalls.java:439)
	at io.grpc.ClientInterceptors$CheckedForwardingClientCall.start(ClientInterceptors.java:202)
	at io.grpc.ForwardingClientCall.start(ForwardingClientCall.java:47)
	at com.google.api.gax.grpc.HeaderInterceptor$1.start(HeaderInterceptor.java:62)
	at io.grpc.stub.ClientCalls.startCall(ClientCalls.java:270)
	at io.grpc.stub.ClientCalls.asyncUnaryRequestCall(ClientCalls.java:249)
	at io.grpc.stub.ClientCalls.futureUnaryCall(ClientCalls.java:186)
	at com.google.api.gax.grpc.DirectCallable.futureCall(DirectCallable.java:59)
	at com.google.api.gax.grpc.ExceptionTransformingCallable.futureCall(ExceptionTransformingCallable.java:62)
	... 55 more
Caused by: java.lang.IllegalStateException: OAuth2Credentials instance does not support refreshing the access token. An instance with a new access token should be used, or a derived type that supports refreshing.
	at com.google.auth.oauth2.OAuth2Credentials.refreshAccessToken(OAuth2Credentials.java:182)
	at com.google.auth.oauth2.OAuth2Credentials.refresh(OAuth2Credentials.java:149)
	at com.google.auth.oauth2.OAuth2Credentials.getRequestMetadata(OAuth2Credentials.java:135)
	at io.grpc.auth.ClientAuthInterceptor.getRequestMetadata(ClientAuthInterceptor.java:148)
	at io.grpc.auth.ClientAuthInterceptor.access$100(ClientAuthInterceptor.java:62)
	at io.grpc.auth.ClientAuthInterceptor$1.checkedStart(ClientAuthInterceptor.java:94)
	at io.grpc.ClientInterceptors$CheckedForwardingClientCall.start(ClientInterceptors.java:194)
	... 62 more

As I mentioned above I’m able to use Datastore emulator when I run it with --no-legacy flag and by creating a Datastore service like this:

DatastoreOptions.newBuilder()
      .setProjectId("unit-testing")
      .setHost("localhost:$port")
      .setCredentials(NoCredentials.getInstance())
      .build()
      .getService()

I’m using the latest available version of the libraries at the moment:

{
  "group": "com.google.cloud",
  "name": "google-cloud-datastore",
  "version": "0.13.0-beta"
},
{
  "group": "com.google.cloud",
  "name": "google-cloud-pubsub",
  "version": "0.13.0-alpha"
}

[omrihq]

Interesting, is there an updated example of a PubSub emulator then? Ex: https://github.com/GoogleCloudPlatform/google-cloud-java/blob/master/TESTING.md#testing-code-that-uses-pubsub seems to use old code

[garrettjonesgoogle]

The class name is now InstantiatingGrpcChannelProvider and it is present in gax-grpc.