Implement support for passing a .env file to corerun to easily set environment variables for stress testing.

[jkoritzinsky]

Introduce support into corerun for providing a "dotenv" file based on the format supported by python-dotenv that corerun will use to set environment variables before loading CoreCLR.

This can be used to set various different stress modes by just editing a text file with a single format instead of having to edit a script which you then have to run.

The file can be provided to corerun with the -e or --env flags.

For example, diagnosing #57915 took setting and regularly changing 5+ environment variables, which was error prone.

TODO:

• Docs
• Update the bash/batch scripts for tests to support dotenv files.
• Investigation into updating "scenario" Helix runs for corerun-based testing to use this.

[ghost]

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Issue Details

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Introduce support into corerun for providing a "dotenv" file based on the format supported by python-dotenv that corerun will use to set environment variables before loading CoreCLR.

This can be used to set various different stress modes by just editing a text file with a single format instead of having to edit a script which you then have to run.

The file can be provided to corerun with the -e or --env flags.

TODO:

• Docs
• Update the bash/batch scripts for tests to support dotenv files.
• Investigation into updating "scenario" Helix runs for corerun-based testing to use this.

Author:	jkoritzinsky
Assignees:	-
Labels:	area-Host
Milestone:	-

[jkoritzinsky]

Also, another fun feature that comes with this: GCStress can now be enabled when testing with WinDbgNext without having to use child process debugging through a batch file!

[am11]

format supported by python-dotenv that corerun will use to set environment variables before loading CoreCLR.

dotenv is a specific format that allows extra stuff, which typically is not allowed in the shell. e.g. spaces before/after =.
Is it the full implementation of dotenv format, or just to the extent we need, i.e. dotenv-like? If it is partial support, do we know what are the limitations? If it is a full implementation does -st pass, e.g., these conformance tests: https://github.com/motdotla/dotenv/tree/master/tests?

[jkoritzinsky]

It's meant to support the same level of dotenv support that the python-dotenv project provides (trimming spaces around the equals, comments, quoting and multi-line support, etc). I've seen various different rules for the format between python, nodejs, Ruby, etc. implementations, so I picked one to use as my base.

[jkoritzinsky]

Skimming through those tests, the only case that I don't already test (and doesn't work) is '\r'-only line ending parsing.

[AaronRobinsonMSFT]

We should also update the doc on corerun usage - https://github.com/dotnet/runtime/blob/57bfe474518ab5b7cfe6bf7424a79ce3af9d6657/docs/workflow/testing/using-corerun.md

[AaronRobinsonMSFT]

Instead of string_t value, why not const char_t* value?

[jkoritzinsky]

I used string_t here for parity with pal::getenv which returns a string_t.

[am11]

dotenv support that the python-dotenv project provides

Nice. It includes variable expansion https://pypi.org/project/python-dotenv/#variable-expansion as well?
I was just thinking whether it is too much to add a full blown dotenv format support, when all we really need is reading a .txt file line-by-line with KEY=VALUE pair (plus some error handling).

[jkoritzinsky]

Yep it has variable expansion too! It first looks in env vars previously specified in the file. If it's not found there, then it looks in the environment. If it's not defined anywhere, it substitutes with an empty string.

[jkoritzinsky]

cc: @elinor-fung

[jkoritzinsky]

Only test failure is the xunit test harness collection issue.

[AaronRobinsonMSFT]

Thanks!

[ghost]

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