Yo uso la biblioteca experimental gloud-java. Después de la actualización de hoy, se produjo un error. Ejecute el ejemplo desde la biblioteca local (este error aparece automáticamente en el motor flexible de Google Cloud, aunque la implementación no se produjo durante una semana)

public class PullTest {
private static final transient Logger logger = Logger.getLogger(MethodHandles.lookup().lookupClass().getName());

public static void main(String... args) throws Exception {
    try (PubSub pubsub = PubSubOptions.defaultInstance().service()) {
        String subscriptionName = "subscription-segment";
        Subscription subscription = pubsub.getSubscription(subscriptionName);
    }
}
}

lanzar excepción

Aug 10, 2016 2:19:08 AM io.grpc.internal.ManagedChannelImpl <init>
INFO: [ManagedChannelImpl@131ef10] Created with target pubsub-experimental.googleapis.com:443
Aug 10, 2016 2:19:08 AM io.grpc.internal.ManagedChannelImpl <init>
INFO: [ManagedChannelImpl@394df057] Created with target pubsub-experimental.googleapis.com:443
Aug 10, 2016 2:19:10 AM io.grpc.internal.ManagedChannelImpl maybeTerminateChannel
INFO: [ManagedChannelImpl@131ef10] Terminated
Exception in thread "main" com.google.cloud.pubsub.PubSubException: io.grpc.StatusRuntimeException: PERMISSION_DENIED: Google Cloud Pub/Sub API (Experimental) has not been used in project google.com:cloudsdktool before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/pubsub-experimental.googleapis.com/overview?project=google.com:cloudsdktool then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry.
at com.google.cloud.pubsub.spi.DefaultPubSubRpc$1.apply(DefaultPubSubRpc.java:183)
at com.google.cloud.pubsub.spi.DefaultPubSubRpc$1.apply(DefaultPubSubRpc.java:177)
at com.google.common.util.concurrent.Futures$CatchingFuture.doFallback(Futures.java:842)
at com.google.common.util.concurrent.Futures$CatchingFuture.doFallback(Futures.java:834)
at com.google.common.util.concurrent.Futures$AbstractCatchingFuture.run(Futures.java:789)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:456)
at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:817)
at com.google.common.util.concurrent.AbstractFuture.complete(AbstractFuture.java:753)
at com.google.common.util.concurrent.AbstractFuture.setException(AbstractFuture.java:634)
at com.google.common.util.concurrent.SettableFuture.setException(SettableFuture.java:53)
at com.google.api.gax.grpc.RetryingCallable$Retryer$1.onFailure(RetryingCallable.java:139)
at com.google.common.util.concurrent.Futures$6.run(Futures.java:1764)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:456)
at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:817)
at com.google.common.util.concurrent.AbstractFuture.complete(AbstractFuture.java:753)
at com.google.common.util.concurrent.AbstractFuture.setException(AbstractFuture.java:634)
at com.google.common.util.concurrent.SettableFuture.setException(SettableFuture.java:53)
at com.google.api.gax.grpc.ExceptionTransformingCallable$1.onFailure(ExceptionTransformingCallable.java:90)
at com.google.common.util.concurrent.Futures$6.run(Futures.java:1764)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:456)
at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:817)
at com.google.common.util.concurrent.AbstractFuture.complete(AbstractFuture.java:753)
at com.google.common.util.concurrent.AbstractFuture.setException(AbstractFuture.java:634)
at io.grpc.stub.ClientCalls$GrpcFuture.setException(ClientCalls.java:331)
at io.grpc.stub.ClientCalls$UnaryStreamToFuture.onClose(ClientCalls.java:307)
at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$3.runInContext(ClientCallImpl.java:462)
at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:54)
at io.grpc.internal.SerializingExecutor$TaskRunner.run(SerializingExecutor.java:154)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.google.api.gax.grpc.ApiException: io.grpc.StatusRuntimeException: PERMISSION_DENIED: Google Cloud Pub/Sub API (Experimental) has not been used in project google.com:cloudsdktool before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/pubsub-experimental.googleapis.com/overview?project=google.com:cloudsdktool then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry.
... 18 more
Caused by: io.grpc.StatusRuntimeException: PERMISSION_DENIED: Google Cloud Pub/Sub API (Experimental) has not been used in project google.com:cloudsdktool before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/pubsub-experimental.googleapis.com/overview?project=google.com:cloudsdktool then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry.
at io.grpc.Status.asRuntimeException(Status.java:503)
... 11 more
Aug 10, 2016 2:19:10 AM io.grpc.internal.ManagedChannelImpl maybeTerminateChannel
INFO: [ManagedChannelImpl@394df057] Terminated

¿Cómo solucionar este problema? El problema surgió de la nada. En la mañana funcionó :)

PD.

$ gcloud info

muestra la información correcta

$ gcloud auth login

no ayudó