Ansible Playbook使用Python API重试逻辑

时间:2018-04-13 19:26:36

标签: python ansible ansible-2.x

使用Ansible 2 Python API我能够运行playbooks并使用自定义回调处理程序处理结果(感谢this question)。一切都运作良好,但现在我想为PlaybookExecutor实现一个简单的重试循环。

我所有的回调处理程序都在填充数组中任何失败的任务,如果我发现该数组不是空的,则将其视为失败并重试。

我有另一个python模块,它使用这个脚本启动剧本。对run_playbook的调用嵌套在try / except块中,我喜欢冒泡的异常,所以我可以正确处理失败。

我想让我的剧本尝试3次尝试,如果全部失败则提出异常。

这是我的代码:

#! /usr/bin/python
# -*- coding: utf-8 -*-

from __future__ import print_function
import logging
import os
from collections import namedtuple
from ansible.parsing.dataloader import DataLoader
from ansible.vars.manager import VariableManager
from ansible.inventory.manager import InventoryManager
from ansible.executor.playbook_executor import PlaybookExecutor
from ansible.plugins.callback import CallbackBase

class ResultsCallback(CallbackBase):
    """ A callback plugin used for performing an action as results come in """
    def __init__(self):
        super(ResultsCallback, self).__init__()
        # Store all failed results
        self.failed = []

    def v2_runner_on_failed(self, result, ignore_errors=False):
        if ignore_errors:
            self._display.display("...ignoring", color=C.COLOR_SKIP)
        host = result._host
        self.failed.append(result.task_name)


def create_inventory_file(hostnames):
    inv_file = 'ansible_hosts.{0}'.format(os.getppid())
    logging.print('\nCreating Ansible host file: {0}/{1}'.format(os.path.join(os.path.expanduser('~')), inv_file))
    with open(os.path.join(os.path.expanduser('~'), inv_file), 'w') as host_file:
        # If ec2, stuff into an '[ec2]' group.
        # Otherwise don't use a group header
        if 'ec2' in hostnames[0]:
            host_file.write('[ec2]\n')
        for host in hostnames:
            host_file.write('{0}\n'.format(host))

    return os.path.join(os.path.expanduser('~'), inv_file)


def run_playbook(hostnames, playbook, playbook_arguments, host_file=False):
    # If user passes in the optional arg host_file, then just use that one.
    if not host_file:                                                                                                                                                                                          
        host_file = create_inventory_file(hostnames)
    if not os.path.isfile(host_file):
        logging.critical('Host file does not exist. Make sure absolute path is correct.\nInventory: {0}'.format(host_file))
        raise RuntimeError('Host file does not exist')

    loader = DataLoader()
    inventory = InventoryManager(loader=loader, sources=host_file)
    variable_manager = VariableManager(loader=loader, inventory=inventory)

    # Add extra variables to use in playbook like so:
    # variable_manager.extra_vars = {'name': 'value'}
    if playbook_arguments:
        variable_manager.extra_vars = playbook_arguments

    Options = namedtuple('Options', ['listtags', 'listtasks', 'listhosts', 'syntax', 'connection','module_path', 'forks', 'remote_user', 'become', 'become_method', 'become_user', 'verbosity', 'check', 'diff', 'ask_sudo_pass'])

    if 'superuser' in playbook_arguments:
        remote_user = playbook_arguments['superuser']
    else:
        remote_user = 'ec2-user'

    options = Options(listtags=None, listtasks=None, listhosts=None, syntax=None, connection='smart', module_path=None, forks=100, remote_user=remote_user,  become=None, become_method='sudo', become_user='root', verbosity=None, check=False, diff=False, ask_sudo_pass=None)

    pbex = PlaybookExecutor(playbooks=[playbook], inventory=inventory, variable_manager=variable_manager, loader=loader, options=options, passwords={})

    callback = ResultsCallback()
    pbex._tqm._stdout_callback = callback

    logging.print('Provisioning cluster with Ansible...')
    attempts = 3
    for i in range(attempts):
        try:
            pbex.run()
            failed = callback.failed
            if failed:
                logging.critical('Playbook failed!')
                raise RuntimeError('{0} tasks failed'.format(len(failed)))
            break
        except:
            if i < attempts - 1:
                logging.critical('Attempting to re-try playbook')
                continue
            else:
                raise

    logging.print('\nRemoving Ansible Inventory file {0}'.format(host_file))
    try:
        os.remove(host_file)
    except OSError:
        pass

但是,当我使用保证失败的playbook测试上面的代码时,它会失败,并带有以下回溯:

Creating Ansible host file: /home/someuser/ansible_hosts.18600
Provisioning cluster with Ansible...
Playbook failed!
Attempting to re-try playbook
Exception during setup; tearing down all created instances
Traceback (most recent call last):
  File "./manage_aws.py", line 486, in cmd_ec2_create
    manage_ansible.run_playbook(hostnames, playbook, playbook_arguments)
  File "/home/someuser/manage_ansible.py", line 88, in run_playbook
    break
  File "/usr/local/lib/python2.7/dist-packages/ansible/executor/playbook_executor.py", line 159, in run
    result = self._tqm.run(play=play)
  File "/usr/local/lib/python2.7/dist-packages/ansible/executor/task_queue_manager.py", line 296, in run
    strategy.cleanup()
  File "/usr/local/lib/python2.7/dist-packages/ansible/plugins/strategy/__init__.py", line 223, in cleanup
    self._final_q.put(_sentinel)
  File "/usr/lib/python2.7/multiprocessing/queues.py", line 100, in put
    assert not self._closed
AssertionError

您会注意到异常在调用脚本manage_aws.py中被正确捕获(&#34;安装期间出现异常;拆除所有已创建的实例&#34;)我们将拆除实例。这很棒,但我想在决定之前正确地重新尝试剧本。

我没有Python大师,所以如果有人有任何提示,或者已经完成了类似的事情,那么我非常感谢你的建议。

提前致谢!

1 个答案:

答案 0 :(得分:0)

我找到了一个解决方案,虽然它并不像我希望的那样优雅。

我遇到的问题似乎与重新运行相同的PlaybokExecutor对象有关,而不会让生成的线程正常清理。

我做的是修复它只是在我注意到第一个失败的时候初始化一个新的PlaybookExecutor对象。目前的实现只允许一次重试,这很好,但我很可能会根据需要调整它以做更多。

这是我改编的重试逻辑:

    pbex = PlaybookExecutor(playbooks=[playbook], inventory=inventory, variable_manager=variable_manager, loader=loader, options=options, passwords={})

    callback = ResultsCallback()
    pbex._tqm._stdout_callback = callback

    logging.print('Provisioning cluster with Ansible...')
    pbex.run()
    failed = callback.failed
    if failed:
        logging.critical('Playbook failed! Attempting retry...')
        pbex_retry = PlaybookExecutor(playbooks=[playbook], inventory=inventory, variable_manager=variable_manager, loader=loader, options=options, passwords={})
        callback_retry = ResultsCallback()
        pbex_retry._tqm._stdout_callback = callback_retry
        pbex_retry.run()
        failed_retry = callback_retry.failed
        if failed_retry:
            logging.critical('Playbook failed again! Failed on task:\n{0}'.format(failed_retry[0]))
            remove_inventory_file(host_file)
            raise RuntimeError('Playbook failed to successfully configure the cluster.')

    remove_inventory_file(host_file)

超级简单的解决方案,但遗憾的是我的初步尝试没有达到预期效果。也许我会重新访问它并尝试在失败时正确清理执行程序。