在ansible1.9的時(shí)候，API是一個(gè)非常簡(jiǎn)單的東西。官方說“it's pretty simple”，真是又pretty又simple。

import ansible.runner

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

到了ansible2.0以后，是“a bit more complicated”，Oh my，簡(jiǎn)直讓人難受。

簡(jiǎn)潔和靈活是魚和熊掌。

ansible2.0 API怎么用？

ansible2.0更貼近于ansible cli的常用命令執(zhí)行方式，不同于上一版本只能發(fā)送單個(gè)命令或playbook；而更推薦用戶在調(diào)用ansibleAPI的時(shí)候，將playbook的每個(gè)task拆分出來，獲取每個(gè)task的結(jié)果。能夠跟靈活處理在執(zhí)行批量作業(yè)過程中的各種反饋。

• 將執(zhí)行操作的隊(duì)列模型，包含各類環(huán)境參數(shù)設(shè)置，歸結(jié)到“ansible.executor.task_queue_manager”類中
• 將執(zhí)行過程中的各個(gè)task的設(shè)置，或者說playbook中的編排內(nèi)容，歸結(jié)到“ansible.playbook.play”中

上述兩個(gè)東西，幾乎囊括了可以在執(zhí)行過程中設(shè)置的所有參數(shù)，足夠靈活，也讓人抓狂，相當(dāng)于需要自己寫一個(gè)1.9版本中的runner。
他們的確也都是原生類，并非專用于外部調(diào)用。

ansible.executor.task_queue_manager

這是ansible的一個(gè)內(nèi)部模塊（ansible/executor/task_queue_manager.py）。初始化的源碼如下：

class TaskQueueManager:

    '''
    This class handles the multiprocessing requirements of Ansible by
    creating a pool of worker forks, a result handler fork, and a
    manager object with shared datastructures/queues for coordinating
    work between all processes.

    The queue manager is responsible for loading the play strategy plugin,
    which dispatches the Play's tasks to hosts.
    '''

    def __init__(self, inventory, variable_manager, loader, options, passwords, stdout_callback=None, run_additional_callbacks=True, run_tree=False):

        self._inventory        = inventory
        self._variable_manager = variable_manager
        self._loader           = loader
        self._options          = options
        self._stats            = AggregateStats()
        self.passwords         = passwords
        self._stdout_callback  = stdout_callback
        self._run_additional_callbacks = run_additional_callbacks
        self._run_tree         = run_tree

        self._callbacks_loaded = False
        self._callback_plugins = []
        self._start_at_done    = False
        self._result_prc       = None

        ……

創(chuàng)建時(shí)，需要的主要參數(shù)包括：

• inventory --> 由ansible.inventory模塊創(chuàng)建，用于導(dǎo)入inventory文件
• variable_manager --> 由ansible.vars模塊創(chuàng)建，用于存儲(chǔ)各類變量信息
• loader --> 由ansible.parsing.dataloader模塊創(chuàng)建，用于數(shù)據(jù)解析
• options --> 存放各類配置信息的數(shù)據(jù)字典
• passwords --> 登錄密碼，可設(shè)置加密信息
• stdout_callback --> 回調(diào)函數(shù)

ansible.playbook.play

ansible.playbook是一個(gè)原生模塊，既用于CLI也用于API。從源碼可以看出來：

try:
    from __main__ import display
except ImportError:
    from ansible.utils.display import Display
    display = Display()

ansible.playbook.play（ansible/playbook/play.py）。初始化源碼的介紹如下：

__all__ = ['Play']


class Play(Base, Taggable, Become):

    """
    A play is a language feature that represents a list of roles and/or
    task/handler blocks to execute on a given set of hosts.

    Usage:

       Play.load(datastructure) -> Play
       Play.something(...)
    """

• 最后，用task_queue_manager(play)來執(zhí)行，老規(guī)矩，源碼的官方解釋。

def run(self, play):
        '''
        Iterates over the roles/tasks in a play, using the given (or default)
        strategy for queueing tasks. The default is the linear strategy, which
        operates like classic Ansible by keeping all hosts in lock-step with
        a given task (meaning no hosts move on to the next task until all hosts
        are done with the current task).
        '''

一個(gè)完整的例子

# -*- coding:utf-8 -*-
# !/usr/bin/env python
#
# Author: Shawn.T
# Email: shawntai.ds@gmail.com
#
# this is the Interface package of Ansible2 API
#

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 tempfile import NamedTemporaryFile
import os

class AnsibleTask(object):
    def __init__(self, targetHost):
        Options = namedtuple(
                          'Options', [
                              'listtags', 'listtasks', 'listhosts', 'syntax', '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
        self.variable_manager = VariableManager()

        self.options = Options(
                          listtags=False, listtasks=False, listhosts=False, syntax=False, connection='smart',
                          module_path='/usr/lib/python2.7/site-packages/ansible/modules', forks=100,
                          remote_user='root', private_key_file=None, ssh_common_args=None, ssh_extra_args=None,
                          sftp_extra_args=None, scp_extra_args=None, become=False, become_method=None, become_user='root',
                          verbosity=None, check=False
                      )
        self.passwords = dict(vault_pass='secret')
        self.loader = DataLoader()

        # create inventory and pass to var manager
        self.hostsFile = NamedTemporaryFile(delete=False)
        self.hostsFile.write(targetHost)
        self.hostsFile.close()
        self.inventory = Inventory(loader=self.loader, variable_manager=self.variable_manager, host_list=self.hostsFile.name)
        self.variable_manager.set_inventory(self.inventory)

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

        # run it
        tqm = None
        try:
            tqm = TaskQueueManager(
                      inventory=self.inventory,
                      variable_manager=self.variable_manager,
                      loader=self.loader,
                      options=self.options,
                      passwords=self.passwords,
                      stdout_callback='default',
                  )
            result = tqm.run(play)
        finally:
        # print result
            if tqm is not None:
                tqm.cleanup()
                os.remove(self.hostsFile.name)
                self.inventory.clear_pattern_cache()
            return result

寫一個(gè)ansibleTask類，創(chuàng)建了上述的各類必要的配置信息對(duì)象，最后使用ansibleTask.ansiblePlay()函數(shù)執(zhí)行。

• inventory文件的動(dòng)態(tài)生成

寫上面的代碼的過程中，碰到一個(gè)問題：inventory對(duì)象創(chuàng)建時(shí)需要一個(gè)實(shí)體的hosts文件，而文件需要?jiǎng)討B(tài)生成。
生成的方法參考了這篇牛逼閃閃的文章。使用tempfile.NamedTemporaryFile這個(gè)方法來創(chuàng)建一個(gè)有名稱的臨時(shí)文件，可以選擇關(guān)閉后刪除或保留。上面的處理辦法是：不刪除，在執(zhí)行完畢之后，通過os.remove(self.hostsFile.name)進(jìn)行刪除。

ps.經(jīng)YiChenWang指出，inventory的創(chuàng)建參數(shù)host_list可以使列表。使用以下方式創(chuàng)建inventory也是可以的：

self.inventory = Inventory(loader=self.loader, variable_manager=self.variable_manager, host_list=['xx.xx.xx.xx', 'xx.xx.xx.xx'])

不過，源碼中指出，采用list格式參數(shù)是無法加載inventory data的。如果需要加載，還是得使用臨時(shí)文件的辦法。