Overview

The ploy_fabric plugin provides integration of Fabric with ploy.

Installation

ploy_fabric is best installed with easy_install, pip or with zc.recipe.egg in a buildout.

Once installed, it's functionality is immediately usable with ploy.

Commands

The plugin adds the following commands to ploy.

do

Runs a Fabric task with simplified syntax for arguments. You can just put positional arguments on the command line behind the task name. For keyword arguments user the name=value syntax. For example:

ploy do something arg key=value

fab

Runs a Fabric task and passes on command line options to Fabric. This basically reflects the fab script of Fabric.

Options

Instances only get the new fabfile option to specify which file to look in for tasks. The location is relative to ploy.conf.

Instance methods

For the Python side, each instance gains the do(task, *args, **kwargs) method. The task argument is the name of a task from the Fabric script which should be run. The remaining arguments are passed on to that task.

Another helper added to each instance is a context manager accessible via the fabric attribute on instances. With that you can switch to a new ssh connection with a different user in your Fabric tasks:

from fabric.api import env, run


def sometask():
    run("whoami")  # prints the default user (root)
    with env.instance.fabric(user='foo'):
      run("whoami")  # prints 'foo' if the connection worked
    run("whoami")  # prints the default user (root)

All changes to the Fabric environment are reverted when the context manager exits.

Fabric task decorator

With ploy_fabric.context you can decorate a task to use a specific user with a separate connection. All changes to the Fabric environment are reverted when the context manager exits. This is useful if you want to run a task from inside another task.

from fabric.api import env, run
from ploy_fabric import context


@context  # always run with the default user
def sometask():
    run("whoami")  # prints the default user (root)


@context(user=None)  # always run with the default user (alternate syntax)
def someothertask():
    env.forward_agent = True
    run("whoami")  # prints the default user (root)


@context(user='foo')  # always run as foo user
def anothertask():
    env.forward_agent = False
    run("whoami")  # prints the default user (user)
    someothertask()
    assert env.forward_agent == False

Fabric environment

The Fabric environment has the following settings by default.

reject_unknown_hosts

Always set to True, ssh connections are handled by this plugin and ploy.

disable_known_hosts

Always set to True, handled by ploy.

host_string

The unique id of the current instance, only manipulate if you know what you do!

known_hosts

Path to the known_hosts file managed by ploy.

instances

Dictionary allowing access to the other instances to get variables or call methods on.

instance

The current instance to access variables from the config attribute or other things and methods.

config_base

The directory of ploy.conf.

Any option of the instance starting with fabric- is stripped of the fabric- prefix and overwrites settings in the environment with that name.