Access to environment variables in Unit config about unit HOT 6 OPEN

Hi, our thoughts on it:

1. Users can now use a config template to maintain the "environment" options.
2. We agree it's more convenient to provide native variables for the application options like working_directory and environment. Now we are on the 1.32 version and we'll try it when we start the 1.33 version.

Thanks.

from unit.

If we consider that envsubst(1) and similar tools provides a reasonable workaround today, how useful would it be to "pass through" specific environment variables to the application's environment?

{
  "applications": {
    "foo": {
      "type": "external",
      "working_directory": "/path/to/thing",
      "executable": "app",
      "environment_passthrough": ["SOME_ENV_VAR", "OTHER_ENV_VAR"],
      "environment": {
        "HOME": "/path/to/thing"
      }
    }
  }
}

Would this be a worthwhile feature in its own right? Or is full access to env vars, across the entire configuration scope the main thing? If so, we might also consider environment variable substitution a function that the unitc CLI tool can provide.

from unit.

Yup, same here. Here's what one of our configs looks like and how we use ENV vars in our config:

"applications": {
    "sinatra": {
      "type": "ruby",
      "processes": {{ NUM_WORKERS }},
      "threads": {{ WORKER_THREADS_MAX }},
      "script": "{{ HOME }}/workspace/app/config.ru",
      "hooks": "{{ HOME }}/workspace/app/config/unit/hooks.rb",
      "working_directory": "{{ HOME}}/workspace/app/",
      "limits": {
        "timeout": 30
      }
    }
  }

from unit.

Oooooh, this is a good one. I use envtpl right now to get this functionality in my configs but would love to drop it as a dependency!

from unit.

Hi,
There are a few separate functions here.

1. Unit supports variables and njs/JS for options like pass, share, etc.
   https://unit.nginx.org/scripting/
2. It's able to access environment variables with njs.
   https://nginx.org/en/docs/njs/reference.html#process
3. The variables and JS only work on the runtime phase.

But the option environment in the application is applied when the proto process starts, it's a different phase than the runtime phase which runs for the http request.

To make it short, the feature is about whether Unit provides variable engine in the application starting phase.
We'll discuss it with the team, and any thoughts are welcome.

from unit.

Our use-case would be to configure number of processes, options for applications (like memory_limit), etc. Thank you!

from unit.