PubSub client not working with emulator

[yassenb]

Environment details

• OS: Linux
• Ruby version: 3.4
• Gem name and version: google-cloud-pubsub 3.0.2

Steps to reproduce

See the code samples. Everything was working fine with the PubSub emulator in version 2.x. Version 3.x has broken it and trying the following snippet results in a timeout.

Code example

# Code for 2.23 that works
pubsub = Google::Cloud::PubSub.new(emulator_host: "localhost:8681", project_id: ENV.fetch("GOOGLE_CLOUD_PROJECT_ID"))
puts pubsub.topics.map { it.name }

# Code for 3.0.2 that doesn't work
pubsub = Google::Cloud::PubSub.new(emulator_host: "localhost:8681", project_id: ENV.fetch("GOOGLE_CLOUD_PROJECT_ID"))
puts pubsub.topic_admin.list_topics(project: ENV.fetch("GOOGLE_CLOUD_PROJECT_ID"))

Full backtrace

/home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/google-cloud-pubsub-v1-1.14.0/lib/google/cloud/pubsub/v1/topic_admin/client.rb:738:in 'Google::Cloud::PubSub::V1::TopicAdmin::Client#list_topics': 4:4:Deadline Exceeded. debug_error_string:{DEADLINE_EXCEEDED:Deadline Exceeded {grpc_status:4}} (Google::Cloud::DeadlineExceededError)
	from ./bin/local_subscribe.rb:24:in '<main>'
/home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/gapic-common-1.2.0/lib/gapic/grpc/service_stub/rpc_call.rb:138:in 'Gapic::ServiceStub::RpcCall#call': 4:4:Deadline Exceeded. debug_error_string:{DEADLINE_EXCEEDED:Deadline Exceeded {grpc_status:4}} (Gapic::GRPC::DeadlineExceededError)
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/gapic-common-1.2.0/lib/gapic/grpc/service_stub.rb:217:in 'Gapic::ServiceStub#call_rpc'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/google-cloud-pubsub-v1-1.14.0/lib/google/cloud/pubsub/v1/topic_admin/client.rb:732:in 'Google::Cloud::PubSub::V1::TopicAdmin::Client#list_topics'
	from ./bin/local_subscribe.rb:24:in '<main>'
/home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/grpc-1.75.0-x86_64-linux-gnu/src/ruby/lib/grpc/generic/active_call.rb:29:in 'Struct::BatchResult#check_status': 4:Deadline Exceeded. debug_error_string:{DEADLINE_EXCEEDED:Deadline Exceeded {grpc_status:4}} (GRPC::DeadlineExceeded)
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/grpc-1.75.0-x86_64-linux-gnu/src/ruby/lib/grpc/generic/active_call.rb:189:in 'GRPC::ActiveCall#attach_status_results_and_complete_call'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/grpc-1.75.0-x86_64-linux-gnu/src/ruby/lib/grpc/generic/active_call.rb:383:in 'GRPC::ActiveCall#request_response'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/grpc-1.75.0-x86_64-linux-gnu/src/ruby/lib/grpc/generic/client_stub.rb:174:in 'block (2 levels) in request_response'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/grpc-1.75.0-x86_64-linux-gnu/src/ruby/lib/grpc/generic/interceptors.rb:170:in 'GRPC::InterceptionContext#intercept!'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/grpc-1.75.0-x86_64-linux-gnu/src/ruby/lib/grpc/generic/client_stub.rb:173:in 'block in request_response'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/gapic-common-1.2.0/lib/gapic/grpc/service_stub/rpc_call.rb:130:in 'Gapic::ServiceStub::RpcCall#call'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/gapic-common-1.2.0/lib/gapic/grpc/service_stub.rb:217:in 'Gapic::ServiceStub#call_rpc'
	from /home/yassen/.asdf/installs/ruby/3.4.4/lib/ruby/gems/3.4.0/gems/google-cloud-pubsub-v1-1.14.0/lib/google/cloud/pubsub/v1/topic_admin/client.rb:732:in 'Google::Cloud::PubSub::V1::TopicAdmin::Client#list_topics'
	from ./bin/local_subscribe.rb:24:in '<main>'

[cy-yun]

Thank you for raising the issue!

Could you please provide the logs that are printed out when you run gcloud beta emulators pubsub start --project=<YOUR-PROJECT> ?

It should look something like:

[pubsub] This is the Google Pub/Sub fake.
[pubsub] Implementation may be incomplete or differ from the real system.
.
.
.

I'm using google-cloud-pubsub 3.0.3 and google-cloud-pubsub-v1-1.11.1 . I cannot reproduce the DeadlineExceeded error when I call topic_admin.list_topics .

[yassenb]

I am running a docker image in docker compose, using google/cloud-sdk:latest as the image. At the start of the logs there's

pubsub-1  | Executing: /usr/lib/google-cloud-sdk/platform/pubsub-emulator/bin/cloud-pubsub-emulator --host=0.0.0.0 --port=8681
pubsub-1  | [pubsub] This is the Google Pub/Sub fake.
pubsub-1  | [pubsub] Implementation may be incomplete or differ from the real system.

When running the problematic 3.0.3 version I get multiple errors like this:

pubsub-1  | [pubsub] Nov 06, 2025 8:49:20 AM io.grpc.internal.SerializingExecutor run
pubsub-1  | [pubsub] SEVERE: Exception while executing runnable io.grpc.internal.ServerImpl$JumpToApplicationThreadServerStreamListener$1HalfClosed@47858489
pubsub-1  | [pubsub] java.lang.IllegalArgumentException
pubsub-1  | [pubsub] 	at com.google.common.base.Preconditions.checkArgument(Preconditions.java:129)
pubsub-1  | [pubsub] 	at com.google.cloud.pubsub.testing.v1.FakePubsubServer.getProjectPolicy(FakePubsubServer.java:2644)
pubsub-1  | [pubsub] 	at com.google.cloud.pubsub.testing.v1.FakePubsubServer.listTopics(FakePubsubServer.java:536)
pubsub-1  | [pubsub] 	at com.google.cloud.pubsub.testing.v1.PubsubGrpcServerAdapter$1.listTopics(PubsubGrpcServerAdapter.java:163)
pubsub-1  | [pubsub] 	at com.google.pubsub.v1.PublisherGrpc$MethodHandlers.invoke(PublisherGrpc.java:1306)
pubsub-1  | [pubsub] 	at io.grpc.stub.ServerCalls$UnaryServerCallHandler$UnaryServerCallListener.onHalfClose(ServerCalls.java:182)
pubsub-1  | [pubsub] 	at io.grpc.PartialForwardingServerCallListener.onHalfClose(PartialForwardingServerCallListener.java:35)
pubsub-1  | [pubsub] 	at io.grpc.ForwardingServerCallListener.onHalfClose(ForwardingServerCallListener.java:23)
pubsub-1  | [pubsub] 	at io.grpc.ForwardingServerCallListener$SimpleForwardingServerCallListener.onHalfClose(ForwardingServerCallListener.java:40)
pubsub-1  | [pubsub] 	at io.grpc.Contexts$ContextualizedServerCallListener.onHalfClose(Contexts.java:86)
pubsub-1  | [pubsub] 	at io.grpc.internal.ServerCallImpl$ServerStreamListenerImpl.halfClosed(ServerCallImpl.java:356)
pubsub-1  | [pubsub] 	at io.grpc.internal.ServerImpl$JumpToApplicationThreadServerStreamListener$1HalfClosed.runInContext(ServerImpl.java:861)
pubsub-1  | [pubsub] 	at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
pubsub-1  | [pubsub] 	at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
pubsub-1  | [pubsub] 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
pubsub-1  | [pubsub] 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
pubsub-1  | [pubsub] 	at java.base/java.lang.Thread.run(Thread.java:840)