ansible/docsite/rst/developing_api.rst

Python API

Topics

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 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/python2

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

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

# 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='debug', args=dict(msg='Hello Galaxy!'))) ]
    )
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='default',
          )
    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 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/).

developing_inventory

Developing dynamic inventory integrations

developing_modules

How to develop modules

developing_plugins

How to develop plugins

Development Mailing List

Mailing list for development topics

irc.freenode.net

#ansible IRC chat channel