Documentation

Python API

Note

This document is out of date: ‘ansible.parsing.dataloader’ and ‘ansible.runner’ are not available in the current version of Ansible.

Please note that while we make this API available it is not intended for direct consumption, it is here for the support of the Ansible command line tools. We try not to make breaking changes but we reserve the right to do so at any time if it makes sense for the Ansible toolset.

The following documentation is provided for those that still want to use the API directly, but be mindful this is not something the Ansible team supports.

There are several interesting ways to use Ansible from an API perspective. You can use the Ansible python API to control nodes, you can extend Ansible to respond to various python events, you can write various plugins, and you can plug in inventory data from external data sources. This document covers the execution and Playbook API at a basic level.

If you are looking to use Ansible programmatically from something other than Python, trigger events asynchronously, or have access control and logging demands, take a look at Ansible Tower as it has a very nice REST API that provides all of these things at a higher level.

Ansible is written in its own API so you have a considerable amount of power across the board. This chapter discusses the Python API.

The Python API is very powerful, and is how the all the ansible CLI tools are implemented. In version 2.0 the core ansible got rewritten and the API was mostly rewritten.

Note

Ansible relies on forking processes, as such the API is not thread safe.

Python API 2.0

In 2.0 things get a bit more complicated to start, but you end up with much more discrete and readable classes:

#!/usr/bin/env python

import json
from collections import namedtuple
from ansible.parsing.dataloader import DataLoader
from ansible.vars import VariableManager
from ansible.inventory import Inventory
from ansible.playbook.play import Play
from ansible.executor.task_queue_manager import TaskQueueManager
from ansible.plugins.callback import CallbackBase

class ResultCallback(CallbackBase):
    """A sample callback plugin used for performing an action as results come in

    If you want to collect all results into a single object for processing at
    the end of the execution, look into utilizing the ``json`` callback plugin
    or writing your own custom callback plugin
    """
    def v2_runner_on_ok(self, result, **kwargs):
        """Print a json representation of the result

        This method could store the result in an instance attribute for retrieval later
        """
        host = result._host
        print json.dumps({host.name: result._result}, indent=4)

Options = namedtuple('Options', ['connection', 'module_path', 'forks', 'become', 'become_method', 'become_user', 'check'])
# initialize needed objects
variable_manager = VariableManager()
loader = DataLoader()
options = Options(connection='local', module_path='/path/to/mymodules', forks=100, become=None, become_method=None, become_user=None, check=False)
passwords = dict(vault_pass='secret')

# Instantiate our ResultCallback for handling results as they come in
results_callback = ResultCallback()

# create inventory and pass to var manager
inventory = Inventory(loader=loader, variable_manager=variable_manager, host_list='localhost')
variable_manager.set_inventory(inventory)

# create play with tasks
play_source =  dict(
        name = "Ansible Play",
        hosts = 'localhost',
        gather_facts = 'no',
        tasks = [
            dict(action=dict(module='shell', args='ls'), register='shell_out'),
            dict(action=dict(module='debug', args=dict(msg='{{shell_out.stdout}}')))
         ]
    )
play = Play().load(play_source, variable_manager=variable_manager, loader=loader)

# actually run it
tqm = None
try:
    tqm = TaskQueueManager(
              inventory=inventory,
              variable_manager=variable_manager,
              loader=loader,
              options=options,
              passwords=passwords,
              stdout_callback=results_callback,  # Use our custom callback instead of the ``default`` callback plugin
          )
    result = tqm.run(play)
finally:
    if tqm is not None:
        tqm.cleanup()

Python API pre 2.0

It’s pretty simple:

import ansible.runner

runner = ansible.runner.Runner(
   module_name='ping',
   module_args='',
   pattern='web*',
   forks=10
)
datastructure = runner.run()

The run method returns results per host, grouped by whether they could be contacted or not. Return types are module specific, as expressed in the About Modules documentation.:

{
    "dark" : {
       "web1.example.com" : "failure message"
    },
    "contacted" : {
       "web2.example.com" : 1
    }
}

A module can return any type of JSON data it wants, so Ansible can be used as a framework to rapidly build powerful applications and scripts.

Detailed API Example

The following script prints out the uptime information for all hosts:

#!/usr/bin/python

import ansible.runner
import sys

# construct the ansible runner and execute on all hosts
results = ansible.runner.Runner(
    pattern='*', forks=10,
    module_name='command', module_args='/usr/bin/uptime',
).run()

if results is None:
   print "No hosts found"
   sys.exit(1)

print "UP ***********"
for (hostname, result) in results['contacted'].items():
    if not 'failed' in result:
        print "%s >>> %s" % (hostname, result['stdout'])

print "FAILED *******"
for (hostname, result) in results['contacted'].items():
    if 'failed' in result:
        print "%s >>> %s" % (hostname, result['msg'])

print "DOWN *********"
for (hostname, result) in results['dark'].items():
    print "%s >>> %s" % (hostname, result)

Advanced programmers may also wish to read the source to ansible itself, for it uses the API (with all available options) to implement the ansible command line tools (lib/ansible/cli/).

See also

Developing Dynamic Inventory Sources
Developing dynamic inventory integrations
Developing Modules
How to develop modules
Developing Plugins
How to develop plugins
Development Mailing List
Mailing list for development topics
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