Attempting to connect to pubsub emulator from a docker container throws connection refused

Question

I have a container running a java application that attempts to connect to pubsub emulator and returns this error com.google.api.gax.rpc.UnavailableException: io.grpc.StatusRuntimeException: UNAVAILABLE: io exception . I run the docker with this command:

docker run --name projectx \
    --network=host \
    -e PUBSUB_EMULATOR_HOST=localhost:8085 \
    -e BIGTABLE_EMULATOR_HOST=localhost:8086 \
    -e GCP_PROJECT_ID=project12345678 \
    image:latest \

The container attempts to start the java application, but fails when trying to connect to pubsub. The command for starting pubsub is as follows:

gcloud beta emulators pubsub start --project=project12345678 --host-port=0.0.0.0:8085

The stack trace returned can be seen below:

Exception in thread "main" com.google.api.gax.rpc.UnavailableException: io.grpc.StatusRuntimeException: UNAVAILABLE: io exception
    at com.google.api.gax.rpc.ApiExceptionFactory.createException(ApiExceptionFactory.java:112)
    at com.google.api.gax.rpc.ApiExceptionFactory.createException(ApiExceptionFactory.java:41)
    at com.google.api.gax.grpc.GrpcApiExceptionFactory.create(GrpcApiExceptionFactory.java:86)
    at com.google.api.gax.grpc.GrpcApiExceptionFactory.create(GrpcApiExceptionFactory.java:66)
    at com.google.api.gax.grpc.GrpcExceptionCallable$ExceptionTransformingFuture.onFailure(GrpcExceptionCallable.java:97)
    at com.google.api.core.ApiFutures$1.onFailure(ApiFutures.java:84)
    at com.google.common.util.concurrent.Futures$CallbackListener.run(Futures.java:1132)
    at com.google.common.util.concurrent.DirectExecutor.execute(DirectExecutor.java:31)
    at com.google.common.util.concurrent.AbstractFuture.executeListener(AbstractFuture.java:1270)
    at com.google.common.util.concurrent.AbstractFuture.complete(AbstractFuture.java:1038)
    at com.google.common.util.concurrent.AbstractFuture.setException(AbstractFuture.java:808)
    at io.grpc.stub.ClientCalls$GrpcFuture.setException(ClientCalls.java:578)
    at io.grpc.stub.ClientCalls$UnaryStreamToFuture.onClose(ClientCalls.java:548)
    at io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)
    at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)
    at io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)
    at io.grpc.census.CensusStatsModule$StatsClientInterceptor$1$1.onClose(CensusStatsModule.java:814)
    at io.grpc.PartialForwardingClientCallListener.onClose(PartialForwardingClientCallListener.java:39)
    at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:23)
    at io.grpc.ForwardingClientCallListener$SimpleForwardingClientCallListener.onClose(ForwardingClientCallListener.java:40)
    at io.grpc.census.CensusTracingModule$TracingClientInterceptor$1$1.onClose(CensusTracingModule.java:494)
    at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:567)
    at io.grpc.internal.ClientCallImpl.access$300(ClientCallImpl.java:71)
    at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:735)
    at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:716)
    at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
    at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:829)
    Suppressed: com.google.api.gax.rpc.AsyncTaskException: Asynchronous task failed
        at com.google.api.gax.rpc.ApiExceptions.callAndTranslateApiException(ApiExceptions.java:57)
        at com.google.api.gax.rpc.UnaryCallable.call(UnaryCallable.java:112)
        at com.google.cloud.pubsub.v1.SubscriptionAdminClient.seek(SubscriptionAdminClient.java:3341)
Caused by: io.grpc.StatusRuntimeException: UNAVAILABLE: io exception
    at io.grpc.Status.asRuntimeException(Status.java:539)
    ... 18 more
Caused by: io.grpc.netty.shaded.io.netty.channel.AbstractChannel$AnnotatedConnectException: finishConnect(..) failed: Connection refused: localhost/0:0:0:0:0:0:0:1:8085
Caused by: java.net.ConnectException: finishConnect(..) failed: Connection refused
    at io.grpc.netty.shaded.io.netty.channel.unix.Errors.newConnectException0(Errors.java:155)
    at io.grpc.netty.shaded.io.netty.channel.unix.Errors.handleConnectErrno(Errors.java:128)
    at io.grpc.netty.shaded.io.netty.channel.unix.Socket.finishConnect(Socket.java:359)
    at io.grpc.netty.shaded.io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.doFinishConnect(AbstractEpollChannel.java:710)
    at io.grpc.netty.shaded.io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.finishConnect(AbstractEpollChannel.java:687)
    at io.grpc.netty.shaded.io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.epollOutReady(AbstractEpollChannel.java:567)
    at io.grpc.netty.shaded.io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:489)
    at io.grpc.netty.shaded.io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:397)
    at io.grpc.netty.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
    at io.grpc.netty.shaded.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.grpc.netty.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.base/java.lang.Thread.run(Thread.java:829)

Can anyone help please

i have attempted changing the host from 127.0.0.1 to localhost and 0.0.0.0 but no joy. I expect the container to connect to pubsub.