grpc: Unavailable response when gRPC server run in Docker

[noahdietz]

My code (written in Go, which just creates a Bucket via gRPC) succeeds when the storage_testbench server is run directly in a virtualenv, but fails when the server is running inside of a Docker container. The error reads rpc error: code = Unavailable desc = connection closed before server preface received.

The container was started with the following command:
docker run --name storage_testbench --rm -d -p 9000:9000 -p 8888:8888 gcr.io/cloud-devrel-public-resources/storage-testbench

The gRPC server was started with the following command:
curl -s "http://localhost:9000/start_grpc?port=8888"

[noahdietz]

docker ps produces the following:

CONTAINER ID   IMAGE                                                    COMMAND                  CREATED         STATUS        PORTS                                            NAMES
2759b71c6cff   gcr.io/cloud-devrel-public-resources/storage-testbench   "gunicorn --bind 0.0…"   2 seconds ago   Up 1 second   0.0.0.0:8888->8888/tcp, 0.0.0.0:9000->9000/tcp   storage_testbench

[noahdietz]

Worth noting, I am testing on macOS

[BenWhitehead]

After a bit of diagnostics on a linux host I've found the following:

Run the image

docker run -it --rm --net=host gcr.io/cloud-devrel-public-resources/storage-testbench:v0.15.0

Start grpc

curl http://localhost:9000/start_grpc?port=9001

List bound ports:

$ sudo netstat -ntplv | grep '900'
tcp        0      0 0.0.0.0:9000            0.0.0.0:*               LISTEN      4008468/python3     
tcp6       0      0 ::1:9001                :::*                    LISTEN      4008484/python3     
tcp6       0      0 127.0.0.1:9001          :::*                    LISTEN      4008484/python3 

The grpc server being started by gunicorn is only listening on localhost. We'll need to figure out some way to get it to use the same interface it's started with via --bind so that the server will be accessible from the Docker bridge network.

[coryan]

Maybe we should just replace localhost here:

storage-testbench/testbench/grpc_server.py

Line 697 in a521716

port = server.add_insecure_port("localhost:%d" % port)

With the wildcard address [::]:%d' % port