google cloud dataflow cross project access for big table - google-bigquery

Question

I want to run dataflow job to migrate data from google-project-1-table to google-project-2-table. (Read from one and write to another). I am getting permission issue while doing that. I have set "GOOGLE_APPLICATION_CREDENTIALS" to point to my credential file for project-1. In project-2 below are the permissions/roles for project-1. 1) service-account (role - Editor) 2) -compute#developer.gserviceaccount.com (role - Editor) 3) #cloudservices.gserviceaccount.com(role - Editor).
Is there anything else I need to do to run the job?
Caused by: com.google.bigtable.repackaged.com.google.cloud.grpc.io.IOExceptionWithStatus: Error in response stream
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.ResultQueueEntry$ExceptionResultQueueEntry.getResponseOrThrow(ResultQueueEntry.java:66)
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.ResponseQueueReader.getNextMergedRow(ResponseQueueReader.java:55)
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.StreamingBigtableResultScanner.next(StreamingBigtableResultScanner.java:42)
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.StreamingBigtableResultScanner.next(StreamingBigtableResultScanner.java:27)
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.ResumingStreamingResultScanner.next(ResumingStreamingResultScanner.java:89)
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.ResumingStreamingResultScanner.next(ResumingStreamingResultScanner.java:45)
at com.google.cloud.bigtable.dataflow.CloudBigtableIO$1.next(CloudBigtableIO.java:221)
at com.google.cloud.bigtable.dataflow.CloudBigtableIO$1.next(CloudBigtableIO.java:216)
at com.google.cloud.bigtable.dataflow.CloudBigtableIO$Reader.advance(CloudBigtableIO.java:775)
at com.google.cloud.bigtable.dataflow.CloudBigtableIO$Reader.start(CloudBigtableIO.java:799)
at com.google.cloud.dataflow.sdk.io.Read$Bounded$1.evaluateReadHelper(Read.java:178)
... 18 more
Caused by: com.google.bigtable.repackaged.io.grpc.StatusRuntimeException: PERMISSION_DENIED: User can't access project: project-2
at com.google.bigtable.repackaged.io.grpc.Status.asRuntimeException(Status.java:431)
at com.google.bigtable.repackaged.com.google.cloud.grpc.scanner.StreamObserverAdapter.onClose(StreamObserverAdapter.java:48)
at com.google.bigtable.repackaged.io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$3.runInContext(ClientCallImpl.java:462)
at com.google.bigtable.repackaged.io.grpc.internal.ContextRunnable.run(ContextRunnable.java:54)
at com.google.bigtable.repackaged.io.grpc.internal.SerializingExecutor$TaskRunner.run(SerializingExecutor.java:154)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
... 1 more

Answer 1

There are some instructions for this in the section "Accessing Cloud Platform Resources Across Multiple Cloud Platform Projects" of the Dataflow Security and Permissions guide.
Since that guide does not explicitly address Cloud BigTable, I will try to write up the requirements clearly here in terms of your question.
Using fake project id numbers, it seems you have:
A project project-1 with id 12345.
A project project-2 with id 9876
A Bigtable google-project-1-table in project-1
A Bigtable google-project-2-table in project-2
A Dataflow pipeline that will run in project-1, which you want to:
read from google-project-1-table
write to google-project-2-table
Is that accurate?
Your Dataflow workers that write to Bigtable run as the compute engine service account. That is 12345-compute#developer.gserviceaccount.com. This account will need to be able to access project-2 and write to google-project-2-table.
Your error message implies that the permissions failure occurs at the coarsest granularity - the account cannot access project-2 at all.