Trying to package my project’s Docker image but I get this error about

--test-extra-env-var

, which seems completely unrelated

% pants --no-pantsd package src/my-project:docker-base-image
01:51:15.56 [ERROR] 1 Exception encountered:

Engine traceback:
  in `package` goal

ValueError: An invalid variable was requested via the --test-extra-env-var mechanism: {PIP_EXTRA_INDEX_URL:

Relevant sections from the

pants.toml

file:

[docker]
build_verbose = "True"
env_vars = [
  "HOME",
  "DOCKER_CONFIG=%(homedir)s/.docker",
  "DOCKER_CONTEXT=default",
  "NEXUS_USER",
  "NEXUS_PWD",
]
tools = ["docker-credential-ecr-login", "sh"]

[docker.registries.my-company-aws]
address = "<AWS ECR URL>"

[docker.build_args]
PIP_EXTRA_INDEX_URL = "<INTERNAL NEXUS REPO URL>"

Sorry for the trouble. That does seem unrelated... Have you configured anything in the

[test]

subsection? And/or are there any other search results for

PIP_EXTRA_INDEX_URL

in your configuration/repository?

The

test

subsections in

pants.toml

looks like this

[test]
output = "all"
use_coverage = true

[coverage-py]
report = ["console", "xml", "html"]

and

PIP_EXTRA_INDEX_URL

appears in my project’s BUILD file as

docker_image(
    name="docker-base-image",
    repository="my-project-base",
    source="docker/base/Dockerfile",
    context_root="./",
    dependencies=[
        ":files",
    ],
    extra_build_args=["PIP_EXTRA_INDEX_URL"],
    registries=[
        "@my-company-aws",
    ],
    image_tags=["latest"],
)

and in the

Dockerfile

as

...
ARG PIP_EXTRA_INDEX_URL
...

Ah hm. This definitely sounds peculiar. Can you create a standalone reduced reproduction that you can share?

A minimal reproducible example here - https://github.com/narayanacharya6/pants-package-Docker-issue.

Thanks, I can reproduce with

NEXUS_USER=a NEXUS_PWD=b pants package src/my-project:docker-base-image

. If you have time, reducing it even further would be useful, to remove everything except what is required to reproduce the problem (e.g. it seems like a bunch of the env var configuration in

pants.toml

could be removed or simplified). Also, it'd be good to try it with the latest versions of pants (

2.21.0

is the latest stable, and

2.22.0a0

is the latest dev release): maybe they have fixed the problem or improved the error message!

I’ve tried with 2.21 and get the same result. I’ll try to further cleanup but I doubt I’ll get a different result because it doesn’t look like they contribute to the issue, for or otherwise (I might be wrong, I hope I am wrong 😛 because I’m stuck with this for days now 😞 ).

Yeah, the goal is to keep the error as it is, but get to a minimal reproducer with no "distracting"/"irrelevant" elements. That is, focus on exactly the problem, so we can help you debug more easily. (Btw, did you try 2.22.0a0 too?)

Haven’t tried 2.22.0a0. I’ll give that a shot too.

Ah, I think

[docker].build_args

expects a list, not key/value pairs. https://www.pantsbuild.org/2.21/reference/subsystems/docker#build_args So, the error message was very bad, and is now merely just quite bad. Does this work?

[docker]
...
build_args = ["PIP_EXTRA_INDEX_URL=<SOME_URL_HERE>"]

Yes, this works! (in the example repo at least) Let me try this in my actual project and report back 🙂

Nice one. Yeah, an issue about "list" options having bad error messages when used like a "dict" would be good, with this as a motivating example

Created one here - https://github.com/pantsbuild/pants/issues/21052

Thank you!