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Added a short section about "Setting Environment Variables for Processes" #10983

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Added a short section about "Setting Environment Variables for Processes" #10983

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Added a short section about "Setting Environment Variables for Proces…
javiereguiluz Feb 11, 2019
6954744
Fixes after the reviewers review
javiereguiluz Feb 20, 2019
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22 changes: 22 additions & 0 deletions components/process.rst
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Expand Up @@ -128,6 +128,28 @@ environment variables using the second argument of the ``run()``,
// On both Unix-like and Windows
$process->run(null, ['MESSAGE' => 'Something to output']);

Setting Environment Variables for Processes
-------------------------------------------

The constructor of the :class:`Symfony\\Component\\Process\\Process` class and
all its methods related to executing processes (``run()``, ``mustRun()``,
``start()``, etc.) allow passing an array of environment variables to set before
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Suggested change
``start()``, etc.) allow passing an array of environment variables to set before
``start()``, etc.), allow passing an array of environment variables to set before

running the process::

$process = new Process(['...'], null, ['ENV_VAR_NAME' => 'value']);
$process = Process::fromShellCommandline('...', null, ['ENV_VAR_NAME' => 'value']);
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do we need both lines?

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Here we're trying to display multiple different ways to set up env vars. Thats's why we have several lines.

$process->run(null, ['ENV_VAR_NAME' => 'value']);
// ...
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imo this is only noise


These environment variables are automatically inherited by child processes. You
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These environment variables and the already existing environment variables bound to the current process are inherited by child processes. You can hide an environment variable from child processes by setting it to false:

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I need some help trying to understand this in practice. Imagine this command:

$process = new Process(['foo'], null, ['APP_ENV' => 'test']);

foo command is run with APP_ENV=test and if foo starts new processes or runs commands, they will use APP_ENV=test too. OK.

But here we are saying, if you want to prevent that, set the env var to false:

$process = new Process(['foo'], null, ['APP_ENV' => false]);

OK, so child processes now don't use APP_ENV=test ... but the main foo command doesn't either, right?

Question: how can I define an env var for a command ... and prevent defining it for its child processes? Thanks.

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@nicolas-grekas nicolas-grekas Feb 19, 2019 •
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A running Process instance is a child process. We don't make a difference between a child process and its sub-children. That's not our responsibility at all.

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Now I understand. Thanks!

can prevent that setting the following env vars to ``false``::

// ...
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imo this is only noise

$process = new Process(['...'], null, [
'APP_ENV' => false,
'SYMFONY_DOTENV_VARS' => false
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If you keep this, you should add this:

Suggested change
'SYMFONY_DOTENV_VARS' => false
'SYMFONY_DOTENV_VARS' => false,

]);

Getting real-time Process Output
--------------------------------

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