Yarn: Allow for ENVVAR specification of YARN cache directory location

[ryanmt]

Do you want to request a _feature_ or report a _bug_?
Feature request

What is the current behavior?
The cache location is mapped relative to the user home directory across OSs.

If the current behavior is a bug, please provide the steps to reproduce.
NA

What is the expected behavior?
To be able to specify by an environment variable or cli setting a yarn config path. For many docker users, this would allow a mounted location to be used for the cache, or to specify a network path for a shared cache in automated build systems, etc.

Please mention your node.js, yarn and operating system version.
Ubuntu 16.04 (docker), node version 6.1.0, yarn version 0.16.0.

[mmerickel]

I'm experiencing the same problem. I wanted to set the cache folder location via yarn config but looking at the Config.init(...) bootstrapping process, it's only possible to set it from the --cache-folder option on the cli at this time.

[samccone]

Thanks for the issue @ryanmt and follow up @mmerickel
This would make for a really great first PR into yarn.

Thanks

[bengummer]

This would be really handy for running yarn inside AWS lambda. The user home directory on lambda is read-only which causes a lambda fs permission error to be thrown at https://github.com/yarnpkg/yarn/blob/553e55f146a465a4e773b53b0a93752163c4b039/bin/yarn.js#L10

[rattrayalex]

My usecase is docker; during development, I want docker to read from (and write to) a project-specific cache which I can access by running yarn add within my project on the host machine (my laptop).

[victornoel]

@ryanmt no PR? :)

[valscion]

I suppose that yarn 0.18.0 released with PR #2046 makes this issue fixed, and this could be closed?

[wyze]

This landed in v0.18.0.

[nervo]

I'm sorry, but i don't get it :)
Is there somewhere a way to pass the yarn config dir as an environment variable ?
I don't see such a thing in https://github.com/yarnpkg/yarn/pull/2046

[valscion]

I'm sorry, but i don't get it :)
Is there somewhere a way to pass the yarn config dir as an environment variable ?
I don't see such a thing in #2046

The original PR description had this text in it:

To be able to specify by an environment variable or cli setting a yarn config path

So I'd say this requirement is fulfilled and thus this issue was closed as fixed.

Maybe open a new issue with a thorough use case explaining why you need to be able to use an environment variable and why the config option is not enough for you?

[nervo]

The original title of this issue was "Allow for ENVVAR specification of YARN cache directory location" (though the expected behavior mentions also a cli setting), and as it was closed by https://github.com/yarnpkg/yarn/pull/2046, i was hoping that there were a kind of hidden magic allowing to define setting by environment variable mapping, just like npm does (see: https://docs.npmjs.com/misc/config#environment-variables).

It does not appear to be the case :) (or not ?)

I'm curious, @ryanmt how do you handle this with docker ?
For my part, I am used to define COMPOSER_CACHE_DIR and NPM_CONFIG_CACHE environment variable pointing to a shared volume.

[colinodell]

@nervo I have opened #3208 specifically for environment variable support.