Support to output the true command execute on the sandbox.

[hackrole]

Hi, I am stuck into pants now.

I have python project using pants.
It have following structure, as I think this is the most common structure pattern on python project.

We write test with pytest, and using pytest-dotenv to setup some environment for pytest to work, for example MYSQL_DB_HOST.

My agent/build file look like this:

resources(name="test_env", sources=[".test.env"])

poetry_requirements(name="poetry_deps")

python_sources(name="agent", sources=["app/**/*.py"], dependencies=[":poetry_deps"])

python_sources(name="test_agent", sources=["tests/**/*.py"])

python_tests(name="tests", sources=["tests/**/test_*.py"], dependencies=[":agent", ":test_agent", ":test_env"])

But current the .test.env seems not load. I have save and enter the sandbox diretory. Run pytest in the sandbox with virtualenv is working. But the pants complains about the MYSQL_DB_HOST not defined. I am guess the problem is that pants run command in wrong directory or with wrong paramters. But I have no idea to figure out what exactly the pants run. This add too much difficulty on debug and fix issues.

I am sorry If I miss somthing in the doc. But I checkout the pants document without ways to do such things.

It will be nice to be able to see what the pants really execute.

[benjyw]

Are you trying to run manually with ./__run.sh in the sandbox? And that works?

The only difference between ./__run.sh and what Pants actually runs should be that ./__run.sh doesn't scrub env vars. So either things work because MYSQL_DB_HOST happens to also be set in your environment when you ./__run.sh? Or there is some other interaction with the environment that isn't available when Pants runs the process but is when you run it in the sandbox manually.

What is loading .test.env? Does the test fail because it can't find that file or because it doesn't apply it, somehow?

[benjyw]

So the env is explicitly set in __run.sh, and that command is the same as the one Pants runs. So that is all a red herring.

The real issue, as you've figured out, is the CWD

[benjyw]

Pants expects to run from the repo root. Even if it runs subsets of tests, it does so based on the arguments passed to it, not based on the cwd.

[benjyw]

So your question "each sub project should still be tested/built as a single project within its own sub directory. Is not this correctly?" - this is not how Pants is designed.

I wonder if you can change the working dir in the test, before pytest-dotenv kicks in. There are some configuration options for pytest-dotenv that may be useful.

Also, do things work if you pass the env file explicitly? pants test path/to/test.py -- --envfile=path/to/.env ? I'm not suggesting this is a long-term solution, but it would be instructive to know if it works (it at least means your .env files are properly wrapped in resource or file targets and properly depended on).

[hackrole]

I make it work be using extra_env_vars

python_tests(
    name="tests",
    sources=["tests/**/test_*.py"],
    dependencies=[":hello"],
    extra_env_vars=[
        "CONTEXT_URL=http://127.0.0.1/",
        "DEBUG=True",
        "ENV=test",
    ],
)

[benjyw]

Cool, so we can close this?