Environmental variables not available during '--preload' application start up

[tshlabs]

Environmental variables set through Gunicorn via the '-e' CLI flag or the 'raw_env' configuration setting are not available during application start up when the application uses the '--preload' flag.

An example program to demonstrate this (using Flask 0.10.1 and Gunicorn 18.0) is here:

https://gist.github.com/tshlabs/eb59186648fd003bf28c

The output from this is the following:

$ gunicorn -b localhost:8000 --preload -e FOO=bar test:application
This is the bootstrap. FOO = None
2014-05-05 20:56:14 [2575] [INFO] Starting gunicorn 18.0
2014-05-05 20:56:14 [2575] [INFO] Listening at: http://127.0.0.1:8000 (2575)
2014-05-05 20:56:14 [2575] [INFO] Using worker: sync
2014-05-05 20:56:14 [2584] [INFO] Booting worker with pid: 2584

However, when the '--preload' flag isn't used the environmental variable is available during application start up.

$ gunicorn -b localhost:8000 -e FOO=bar test:application
2014-05-05 21:06:00 [18244] [INFO] Starting gunicorn 18.0
2014-05-05 21:06:00 [18244] [INFO] Listening at: http://127.0.0.1:8000 (18244)
2014-05-05 21:06:00 [18244] [INFO] Using worker: sync
2014-05-05 21:06:00 [18249] [INFO] Booting worker with pid: 18249
This is the bootstrap. FOO = bar

When visiting 'localhost:8000' in a browser in both cases, the value of the 'FOO' variable is 'bar'.

$ curl http://localhost:8000/
The is the worker. FOO = bar

Is it expected behavior that environmental variables are not available during application start up when using the --preload flag?

[tilgovi]

I'm not aware of any good reason why it's this way.
@benoitc could we move the # set environments variables block in Arbiter.start into Arbiter.setup?

[benoitc]

@tilgovi I don't see any reason coming to my mind actually... It's probably good to set it in the setup function.

[tshlabs]

@tilgovi @benoitc Awesome. Thank you. Would you like a pull request?

[tilgovi]

@tshlabs 👍 ⛵