django-syncmedia

syncmedia is a Django application to keep uploaded files in sync between multiple instances of a Django website deployed on different machines.

The basic idea is to call a syncronization backend anytime a registered Model is being saved, so that che configured Storage for a FileField in the said Model is syncronized with other hosts. The hosts to syncronize with are not necessay running syncmedia nor even Django, unless we need a two way syncronization, but of course the syncronization backend must be available on every host involved.

Syncronizations backends

At the moment only rsync is suported and implemented, but we have plans to implement a backend using git (possibly with git-annex https://github.com/joeyh/git-annex).

Configuration

Models configuration

To start using syncmedia you need to specify MODEL_SYNC variable in your settings.py, this has to be a dictionary shaped like this:

MODEL_SYNC = {
    my_app.models.MyModelClass: {
        'sycdirs': ['path/to/my/media/dir/', 'path/to/my/other/dir/'],
        'exclude': '<file names to exclude pattern>'
        }
    }

Such a configuration will enable the call of a post_save callback for each configured Model class that will sync the specified directories.

Hosts configuration

For syncmedia to be able to push and pull files to and from each host, the hosts needs to be able to connecto to each others. syncmedia provides a management command to initialize each host a make it register itself inside the database (as well as forcing a push or pull operation, which can be userfull in a cron job).

By calling the folowing command, the host will put itself inside the Host table, providing its FQDN as the connection url, a unique name to identify the host, a username and a rsa public key.

python manage.py sync_media init

Since, for now, the sync is made over ssh you’ll need to make sure each host includes other’s hosts rsa public keys among it’s authorized_keys. By default the path to rsa public kes is $HOME/.ssh/id_rsa.pub, but you can specify a different one by setting PATH_RSA in your settings.py.