Vagrant Unison 2 Plugin

This is a Vagrant 1.7+ plugin that syncs files over SSH from a local folder to your Vagrant VM (local or on AWS). Under the covers it uses Unison

NOTE: This plugin requires Vagrant 1.7+,

• Unisoned folder support via unison over ssh -> will work with any vagrant provider, eg Virtualbox or AWS, though it's most tested on a local VM via Virtualbox.

1. You must already have Unison installed on your path on your host and guest machines, and it must be the same version of Unison on both.

   • On Mac you can install this with Homebrew: brew install unison
     • This will install unison 2.48.3
   • On Ubuntu:
     • Xenial (16.04): sudo apt-get install unison
     • Ubuntu Trusty (14.04):
       • sudo add-apt-repository ppa:eugenesan/ppa
       • sudo apt-get update
       • sudo apt-get install unison=2.48.3-1ubuntu1.02~eugenesan~trusty2
   • Other 64-bit Linux:
     • Install package from http://ftp5.gwdg.de/pub/linux/archlinux/extra/os/x86_64/unison-2.48.3-2-x86_64.pkg.tar.xz. (Install at your own risk, this is a plain http link. If someone knows of a signed version, checksum, or https host let me know so I can update it).
   • On Windows, download [2.48.3](http://www.pps.univ-paris-diderot.fr/~vouillon/unison/unison 2.48.3.zip), unzip, rename unison-2.48.3 text.exe to unison.exe and copy to somewhere in your path. Alternatively, install using Chocolatey.

2. Install using standard Vagrant 1.1+ plugin installation methods.

   • vagrant plugin install vagrant-unison2

3. Configure unison in your Vagrantfile, as shown below.

4. Start your vagrant box as normal (eg: vagrant up)

Vagrant.configure("2") do |config|
  config.vm.box = "dummy"

  # Required configs
  config.unison.host_folder = "src/"  #relative to the folder your Vagrantfile is in
  config.unison.guest_folder = "src/" #relative to the vagrant home folder (e.g. /home/vagrant)

  # Optional configs
  # File patterns to ignore when syncing. Ensure you don't have spaces between the commas!
  config.unison.ignore = "Name {.DS_Store,.git,node_modules}" # Default: none

  # SSH connection details for Vagrant to communicate with VM.
  config.unison.ssh_host = "10.0.0.1" # Default: '127.0.0.1'
  config.unison.ssh_port = 22 # Default: 2222
  config.unison.ssh_user = "deploy" # Default: 'vagrant'
  config.unison.perms = 0 # if you get "properties changed on both sides" error 

  # `vagrant unison-sync-polling` command will restart unison in VM if memory
  # usage gets above this threshold (in MB).
  config.unison.mem_cap_mb = 500 # Default: 200

  # Change polling interval (in seconds) at which to sync changes
  config.unison.repeat = 5 # Default: 1
end

Run vagrant unison-sync-once to run a single, non-interactive sync and then exit.

Run vagrant unison-sync-polling to start in bidirect monitor (repeat) mode - every second unison checks for changes on either side and syncs them.

Run vagrant unison-sync to sync then start watching the local_folder for changes, and syncing these to your vagrang VM.

This uses the watch ruby gem and runs a one-off unison sync when it gets change events.

For some reason, this does not always get all the events immediately which can be frustrating. Since the polling mode (unison repeat mode) is not too resource intensive, I recommend that instead.

Run vagrant unison-sync-interactive to start in interactive mode. The first time it will ask what to do for every top-level file & directory, otherwise is asks about changes. It allows solving conflicts in various ways. Press "?" in interactive mode to see options for resolving.

This is a useful tool when the automatic sync sees a change in a file on both sides and skips it.

Run vagrant unison-cleanup to clear the unison metadata from ~/Library/Application Support/Unison/ as well as all files.

When you get

Fatal error: Warning: inconsistent state.  
The archive file is missing on some hosts.
For safety, the remaining copies should be deleted.
  Archive arb126d8de1ef26a835b94cf51975c530f on host blablabla.local should be DELETED
  Archive arbc6a36f85b3d1473c55565dd220acf68 on host blablabla is MISSING
Please delete archive files as appropriate and try again
or invoke Unison with -ignorearchives flag.

You should run a unison-cleanup

Running Unison with -ignorearchives flag is a bad idea, since it will produce conflicts.

The error is:

Unison failed: Uncaught exception Failure("input_value: bad bigarray kind")

This is caused when the unison on your host and guest were compiled with different versions of ocaml. To fix ensure that both are compiled with the same ocaml version. More Info Here

This is most often caused in my experience by files that get changed by different users with different permissions.

For instance, if you're running an Ubuntu VM then the unison process is running as the vagrant user. If you have the unison synced folder loaded as a volume in a docker container and a new file gets created in the container, the vagrant user in the VM won't own that file and this can keep unison from being able to sync the file. (I'm looking for a way to fix this particular error case).

Running a unison-cleanup should fix this state.

The error is:

Synchronization complete at 13:00:33  (0 item transferred, 1 skipped, 0 failed)
  skipped:  (properties changed on both sides)
props    <-?-> props      /

This can be caused by file permissions being synced. If you get this error set the perms arg to 0 as in the example configuration.

See perms documentation for more info.

To work on the vagrant-unison plugin, clone this repository out, and use Bundler to get the dependencies:

$ bundle

Once you have the dependencies, verify the unit tests pass with rake:

$ bundle exec rake

If those pass, you're ready to start developing the plugin. You can test the plugin without installing it into your Vagrant environment by just creating a Vagrantfile in the top level of this directory (it is gitignored) that uses it, and uses bundler to execute Vagrant:

$ bundle exec vagrant up
$ bundle exec vagrant unison-sync

Or, install the plugin from your local build to use with an existing project's Vagrantfile on your machine.

Build the plugin with

rake build

Now you'll see the built gem in a pkg directory. Install it with

vagrant plugin install pkg/vagrant-unison-VERSION.gem