Add file_cache_path support for Chef

[patcon]

Forked issue from #12

[fgrehm]

@patcon Just checking, would be possible (at least in theory) to have file_cache_path supported for :chef_solo? I can try to make it a PR for vagrant itself if it is ;)

[patcon]

Oh. Shit. I just checked. I thought chef-solo defaulted to /var/chef/cache :/

[fgrehm]

@patcon I think you can shortcut this to compat_provisioners.any? ;)

[patcon]

Actually, this is going to be ugly for chef_solo, since Vagrant currently uses the provisioning_path as the file_cache_path in the solo.rb template, which already has the synced_folders for the cookbooks and roles within it. vagrant-cachier's approach is to delete a non-symlink cache bucket like /tmp/vagrant-chef-1, which would mess things up since it has syned_folders within.

Seems that vagrant's chef_solo provisioner needs to start making the file_cache_path separately configurable (rather than using provisioning_path in its solo.rb template) before vagrant-cachier can work for it. Would be great if both :chef_solo and :chef_client defaulted to /var/chef/cache, otherwise caching will remain messy or will require custom config by end-user.

cc: @mitchellh Thoughts?

[patcon]

My second and final commit doesn't work, by the way.

[patcon]

Still blocked, but awaiting review of the above vagrant core PR that allows use to move forward.

[fgrehm]

@patcon the Vagrant PR has been merged \o/ I'm thinking about converting some puppet manifests I've got to chef cookbooks to find out the impact of having this in place, so if I can be of any help just let me know ;)

[patcon]

Working on this now, btw :)

[patcon]

OK, this should work. My connection is mega-slow since I'm tethering (and chef omnibus still seems to take forever), so I've only tested on the ubuntu test box.

The java cookbook that I added to the development vagrantfile run has a big 75MB download placed in file_cache_path, and it showed up fine.

[patcon]

Note, that we might need to move the lockfile (a setting in solo.rb and client.rb), which is the file that chef drops into place to prevent itself from having two processes trying to modify the system:
http://docs.opscode.com/config_rb_solo.html

By default, this is placed in file_cache_path, but this is not recommended for NF mounts, as the links explains.

No issue so far, but might rear it's head later. Will likely require that we add lockfile support to the chef_solo and chef_client provisioners in vagrant core. I'll open a new issue for later.

[fgrehm]

@patcon AWESOME! I think I'm gonna be able to try it out before the weekend :)

[patcon]

I'm also starting to doubt whether this will be useful right away.

The remote_file resource has two main actions in chef: :create and :create_if_missing:

• Using :create_if_missing on a file stored in file_cache_path would work right away, but people don't tend to use it much because it can lead to non-idempotent situations (I believe). In fact, it would probably be bad and tough for users to debug.
• Using :create doesn't checks the remote modification date unless you do some gymnastics:
  http://docs.opscode.com/resource_remote_file.html#examples

So this might not actually do much right away, except for the rare place where someone has used http_request magic and stored the file in file_cache_path.

What we really need is a new core chef action for remote_file that uses http_request and makes the above simpler -- something like :create_if_modified.

cc: @jtimberman @schisamo Thoughts?

[fgrehm]

@patcon it might not be useful for everything but my idea is to use for my own stuff like this and this :)

[patcon]

👍

[fgrehm]

@patcon I'm giving this a go right now but before I forget, we need to update the current docs and let everyone knows that this is only going to work with vagrant 1.2.4+ :)

[fgrehm]

@patcon this is awesome man! 👍 Looking forward to the docs so we can merge this one in. Would you also be able to rebase / merge this branch against current master? tks!

[patcon]

Awesome. Added some docs and merged

[fgrehm]

@patcon 👍

[dergachev]

@patcon 👍

[mrjcleaver]

@patcon 👍