Combining Ansible and Fabric

Both Ansible and Fabric are great tools, but they truly shine when used together.

A common pattern for this is that a playbook is used to set up a state against which then a fabric script is (repeatedly) executed.

For example an initial setup of an application, where a playbook takes care that all required directories are created with the proper permissions and into which then a fabric script performs an upload of the application code.

Sharing variables between playbooks and fabric scripts

For such a collaboration both fabric and ansible need to know where all of this should take place, for instance. I.e. fabric has to know the location of the directory that the playbook has created.

You can either define variables directly in ploy.conf or in group or host variables such as group_vars/all.yml or group_vars/webserver.yml.

To create key/value pairs in ploy.conf that are visible to ansible, you must prefix them with ansible-.

For example, you could create an entry in ploy.conf like so:

ansible-frontend_path = /opt/foo

And then use the following snippet in a playbook:

- name: ensure the www data directory exists
  file: path={{frontend_path}} state=directory mode=775

Applying the playbook will then create the application directory as expected:

ploy configure webserver
PLAY [jailhost-webserver] *****************************************************

GATHERING FACTS ***************************************************************
ok: [jailhost-webserver]

TASK: [ensure the www data directory exists] **********************************
changed: [jailhost-webserver]

Now let’s create a fabric task that uploads the contents of that website:

def upload_website():
    ansible_vars = fab.env.instance.get_ansible_variables()
    fab.put('dist/*', ansible_vars['frontend_path'] + '/')

Notice, how we’re accessing the ansible variables via Fabrics’ env where ploy_fabrics has conveniently placed a ploy instance of our host.

Let’s run that:

# ploy do webserver upload_website
[root@jailhost-webserver] put: dist/index.html -> /opt/foo/index.html

Putting variables that you want to share between fabric and ansible into your ploy.conf is the recommended way, as it upholds the configuration file as the canonical place for all of your configuration.

However, until ploy learns how to deal with multi-line variable definitions, dealing with such requires setting them in group_vars/all.yml.