pdb本地调试¶
Ansible是用Python编写的，用于调试本地代码执行的工具是Python调试器 pdb 。这个工具允许我们在Ansys中插入断点代码和交互式地逐行执行代码。
调试 ansible 代码¶
找到ansible的运行文件
[root@master ~]# whereis ansible
ansible: /usr/bin/ansible /etc/ansible /usr/share/man/man1/ansible.1.gz
在/usr/bin/ansible文件开始处加入
57 if __name__ == '__main__':
58
59 import pdb; pdb.set_trace()
60 display = LastResort()
61
62 try: # bad ANSIBLE_CONFIG or config options can force ugly stacktrace
63 import ansible.constants as C
64 from ansible.utils.display import Display
65 except AnsibleOptionsError as e:
66 display.error(to_text(e), wrap_text=False)
67 sys.exit(5)
然后运行ansible命令，就进入了pdb调试状态
# ansible localhost -m ping
> /usr/bin/ansible(60)<module>()
-> display = LastResort()
(Pdb)
pdb常用命令¶
输入 help 查看帮助信息
(Pdb) help
Documented commands (type help <topic>):
========================================
EOF bt cont enable jump pp run unt
a c continue exit l q s until
alias cl d h list quit step up
args clear debug help n r tbreak w
b commands disable ignore next restart u whatis
break condition down j p return unalias where
Miscellaneous help topics:
==========================
exec pdb
Undocumented commands:
======================
retval rv
输入n(next)，让程序运行下一行，如果当前语句有一个函数调用，用n是不会进入被调用的函数体中的
(Pdb) n
> /usr/bin/ansible(62)<module>()
-> try: # bad ANSIBLE_CONFIG or config options can force ugly stacktrace
(Pdb)
输入l(list)，查看代码片段
(Pdb) l
57 if __name__ == '__main__':
58
59 import pdb; pdb.set_trace()
60 display = LastResort()
61
62 -> try: # bad ANSIBLE_CONFIG or config options can force ugly stacktrace
63 import ansible.constants as C
64 from ansible.utils.display import Display
65 except AnsibleOptionsError as e:
66 display.error(to_text(e), wrap_text=False)
67 sys.exit(5)
(Pdb)
输入p(pp) 查看变量的值
(Pdb) pp display
<__main__.LastResort object at 0xbe3410>
(Pdb) p display
<__main__.LastResort object at 0xbe3410>
(Pdb)
输入s(step into) 跟n相似，但是如果当前有一个函数调用，那么s会进入被调用的函数体中
(Pdb) s
> /usr/bin/ansible(63)<module>()
-> import ansible.constants as C
(Pdb)
输入r(return) 执行代码直到从当前函数返回
(Pdb) r
--Call--
> /usr/lib/python2.7/site-packages/ansible/module_utils/six/__init__.py(193)find_module()
-> def find_module(self, fullname, path=None):
(Pdb)
输入b 设置断点，例如 "b 78"，就是在当前脚本的78行打上断点，还能输入函数名作为参数，断点就打到具体的函数入口，如果只敲b，会显示现有的全部断点
(Pdb) b 194
Breakpoint 1 at /usr/lib/python2.7/site-packages/ansible/module_utils/six/__init__.py:194
(Pdb) b
Num Type Disp Enb Where
1 breakpoint keep yes at /usr/lib/python2.7/site-packages/ansible/module_utils/six/__init__.py:194
(Pdb)
输入a(rgs)，打印当前函数的参数
(Pdb) a
self = <ansible.module_utils.six._SixMetaPathImporter object at 0xb016d0>
fullname = ansible.constants
path = ['/usr/lib/python2.7/site-packages/ansible']
(Pdb)
输入bt(w) 打印堆栈跟踪，最下面的帧位于底部。箭头表示"当前帧"，它决定了大多数命令的上下文。
(Pdb) bt
/usr/bin/ansible(63)<module>()
-> import ansible.constants as C
> /usr/lib/python2.7/site-packages/ansible/module_utils/six/__init__.py(193)find_module()
-> def find_module(self, fullname, path=None):
(Pdb)
输入c (continue) 停止 debug 继续执行程序,直到下一个断点。
(Pdb) c
> /usr/lib/python2.7/site-packages/ansible/module_utils/six/__init__.py(194)find_module()
-> if fullname in self.known_modules:
(Pdb)
输入q(uit)，退出调试
有时候我们只是想调试某一部分代码，如果从命令入口开始调试则很难找到相应的代码，这样就需要在某一模块的入口上添加调试点就可以了。
调试 Playbook 代码¶
Playbook负责加载，解析，执行yml文件的playbook。
palybook的主要入口在playbook/__init__.py文件的Playbook类，这个文件在linux下通常存在/usr/lib/python2.7/site-packages/ansible/playbook/__init__.py.
下面是在__init__()方法中添加了断点
38 class Playbook:
39
40 def __init__(self, loader):
41 import pdb; pdb.set_trace()
42 # Entries in the datastructure of a playbook may
43 # be either a play or an include statement
44 self._entries = []
45 self._basedir = to_text(os.getcwd(), errors='surrogate_or_strict')
46 self._loader = loader
47 self._file_name = None
# ansible-playbook debuger.yaml
> /usr/lib/python2.7/site-packages/ansible/playbook/__init__.py(44)__init__()
-> self._entries = []
(Pdb) l
39
40 def __init__(self, loader):
41 import pdb; pdb.set_trace()
42 # Entries in the datastructure of a playbook may
43 # be either a play or an include statement
44 -> self._entries = []
45 self._basedir = to_text(os.getcwd(), errors='surrogate_or_strict')
46 self._loader = loader
47 self._file_name = None
48
49 @staticmethod
(Pdb)
调试 Inventory 代码¶
inventory负责发现，解析，加载主机清单。
inventory的主要入口在inventory/manager.py文件中的InventoryManager类，这个文件在linux下通常存在/usr/lib/python2.7/site-packages/ansible/inventory/manager.py，如果不知道自己的ansible路径在哪里，可以使用python -c "import ansible; print(ansible)"命令查看。 下面是在__init__()方法中添加了断点
136 class InventoryManager(object):
137 ''' Creates and manages inventory '''
138
139 def __init__(self, loader, sources=None):
140 import pdb; pdb.set_trace()
141
142 # base objects
143 self._loader = loader
144 self._inventory = InventoryData()
# ansible localhost -m ping
> /usr/lib/python2.7/site-packages/ansible/inventory/manager.py(143)__init__()
-> self._loader = loader
(Pdb) l
138
139 def __init__(self, loader, sources=None):
140 import pdb; pdb.set_trace()
141
142 # base objects
143 -> self._loader = loader
144 self._inventory = InventoryData()
145
146 # a list of host(names) to contain current inquiries to
147 self._restriction = None
148 self._subset = None
(Pdb)
调试 Plugins 代码¶
plugins 相关的代码是在控制节点中执行的，可以使用本地调试。下列以callback/default 插件代码为测试
文件/usr/lib/python2.7/site-packages/ansible/plugins/callback/default.py
63 class CallbackModule(CallbackBase):
64
65 '''
66 This is the default callback interface, which simply prints messages
67 to stdout when new callback events are received.
68 '''
69
70 CALLBACK_VERSION = 2.0
71 CALLBACK_TYPE = 'stdout'
72 CALLBACK_NAME = 'default'
73
74 def __init__(self):
75
76 import pdb; pdb.set_trace()
可以更进一步的调试callback回调接口
95 def v2_runner_on_failed(self, result, ignore_errors=False):
96
97 import pdb; pdb.set_trace()
98 delegated_vars = result._result.get('_ansible_delegated_vars', None)
99 self._clean_results(result._result, result._task.action)
122 def v2_runner_on_ok(self, result):
123 import pdb; pdb.set_trace()
124
125 delegated_vars = result._result.get('_ansible_delegated_vars', None)
126
127 if isinstance(result._task, TaskInclude):
运行命令
# ansible-playbook debuger.yaml
> /usr/lib/python2.7/site-packages/ansible/plugins/callback/default.py(77)__init__()
-> self._play = None
(Pdb) l
72 CALLBACK_NAME = 'default'
73
74 def __init__(self):
75
76 import pdb; pdb.set_trace()
77 -> self._play = None
78 self._last_task_banner = None
79 self._last_task_name = None
80 self._task_type_cache = {}
81 super(CallbackModule, self).__init__()
82
Info
module 模块代码是在远端执行的，所以不能使用pdb本地调试
本地运行模块¶
python -m pdb ./my_new_test_module.py ./args.json
最后更新: 2020-12-03 08:40:01