Connect to docker daemon from a test on MacOS

[perrydunn]

Is there a way to connect to locally running docker daemon from a test target?

Example

gentest(
    name = "example",
    test_cmd = "docker info",
)

Please version 17.17.0

[chrisnovakovic]

This should work as-is, provided the user running Please has permission to read dockerd's socket file (e.g. /var/run/docker.sock) and the directory containing the socket file is visible from within the sandbox - i.e., .plzconfig doesn't contain

[Sandbox]
Dir=/var/run

If you want the target to be able to invoke the local Docker daemon even when remote execution is enabled, you can add local = True to the gentest parameter list.

[perrydunn]

Thanks for the speedy response Chris!

I haven't excluded the socket file. I'm running Docker from Docker Desktop for Mac (Big Sur 11.7.10 Intel).

➜  ~ docker context ls
NAME                TYPE                DESCRIPTION                               DOCKER ENDPOINT                                       KUBERNETES ENDPOINT   ORCHESTRATOR
default             moby                Current DOCKER_HOST based configuration   unix:///var/run/docker.sock
desktop-linux *     moby                Docker Desktop                            unix:///Users/peregrinedunn/.docker/run/docker.sock

Running a test target produces ERROR: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? whereas plz run (non-test) works fine.

[chrisnovakovic]

On Ubuntu, with

gentest(
    name = "example",
    test_cmd = "docker context ls",
    local = True,
)

I get

$ plz test --shell //:example
Temp directories prepared, total time 10ms:
  //:example: /tmp/please_test/plz-out/tmp/example._test/run_1
    Command: docker context ls

bash-5.1$ docker context ls
NAME        DESCRIPTION                               DOCKER ENDPOINT               ERROR
default *   Current DOCKER_HOST based configuration   unix:///var/run/docker.sock
bash-5.1$

and docker info works as expected, so perhaps this is a macOS-specific thing. Are you trying to connect to the default context or to desktop-linux?

[perrydunn]

docker context ls
NAME                TYPE                DESCRIPTION                               DOCKER ENDPOINT                                       KUBERNETES ENDPOINT   ORCHESTRATOR
default             moby                Current DOCKER_HOST based configuration   unix:///var/run/docker.sock
desktop-linux *     moby                Docker Desktop                            unix:///Users/peregrinedunn/.docker/run/docker.sock

with

gentest(
    name = "example",
    test_cmd = "docker context ls",
)

plz test :example produces

Standard output:
NAME                TYPE                DESCRIPTION                               DOCKER ENDPOINT               KUBERNETES ENDPOINT   ORCHESTRATOR
default *           moby                Current DOCKER_HOST based configuration   unix:///var/run/docker.sock

similarly when running interactively with --shell

so, yeah, looks like that is the issue

[chrisnovakovic]

If you're trying to connect to desktop-linux, the problem here is that contexts are configured in ~/.docker/contexts/, and the HOME environment variable is set to a transient value in the Please sandbox. You could bypass the sandbox for tests that need to use that Docker context (sandbox = False), although I'm squeamish about any test that depends on state stored in the home directory of the user that runs the test...