Channel ManagedChannelImpl{logId=589, target=vision.googleapis.com:443} was not terminated properly #3912
Description
In a concurrent environment, the Vision API client will occasionally log the following error:
Nov 06, 2018 8:07:35 AM io.grpc.internal.ManagedChannelOrphanWrapper$ManagedChannelReference cleanQueue
SEVERE: *~*~*~ Channel ManagedChannelImpl{logId=589, target=vision.googleapis.com:443} was not terminated properly!!! ~*~*~*
Make sure to call shutdown()/shutdownNow() and wait until awaitTermination() returns true.
java.lang.RuntimeException: ManagedChannel allocation site
at io.grpc.internal.ManagedChannelOrphanWrapper$ManagedChannelReference.<init>(ManagedChannelOrphanWrapper.java:103)
at io.grpc.internal.ManagedChannelOrphanWrapper.<init>(ManagedChannelOrphanWrapper.java:53)
at io.grpc.internal.ManagedChannelOrphanWrapper.<init>(ManagedChannelOrphanWrapper.java:44)
at io.grpc.internal.AbstractManagedChannelImplBuilder.build(AbstractManagedChannelImplBuilder.java:410)
at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.createSingleChannel(InstantiatingGrpcChannelProvider.java:206)
at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.createChannel(InstantiatingGrpcChannelProvider.java:157)
at com.google.api.gax.grpc.InstantiatingGrpcChannelProvider.getTransportChannel(InstantiatingGrpcChannelProvider.java:149)
at com.google.api.gax.rpc.ClientContext.create(ClientContext.java:149)
at com.google.cloud.vision.v1.stub.GrpcImageAnnotatorStub.create(GrpcImageAnnotatorStub.java:84)
at com.google.cloud.vision.v1.stub.ImageAnnotatorStubSettings.createStub(ImageAnnotatorStubSettings.java:120)
at com.google.cloud.vision.v1.ImageAnnotatorClient.<init>(ImageAnnotatorClient.java:136)
at com.google.cloud.vision.v1.ImageAnnotatorClient.create(ImageAnnotatorClient.java:117)
at com.google.cloud.vision.v1.ImageAnnotatorClient.create(ImageAnnotatorClient.java:108)
at com.acme.vision.support.VisionTerminationErrorTest.executeOcrRequest(VisionTerminationErrorTest.java:60)
at com.acme.vision.support.VisionTerminationErrorTest.lambda$ocrImage$0(VisionTerminationErrorTest.java:28)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
No error is actually thrown, just logged. I'm attaching a sample project to replicate the condition. Since it doesn't actually throw an exception, I cannot fail the test. You'll need to inspect the log output. You may also need to tweak the number of threads to replicate on your system.