Playbook Debugger
=================
.. contents :: Topics
In 2.1 we added a `` debug `` strategy. This strategy enables you to invoke a debugger when a task has
failed. You have access to all of the features of the debugger in the context of the failed task. You can then, for example, check or set the value of variables, update module arguments, and re-run the failed task with the new variables and arguments to help resolve the cause of the failure.
To use the `` debug `` strategy, change the `` strategy `` attribute like this::
- hosts: test
strategy: debug
tasks:
...
For example, run the playbook below::
- hosts: test
strategy: debug
gather_facts: no
vars:
var1: value1
tasks:
- name: wrong variable
ping: data={{ wrong_var }}
The debugger is invoked since the *wrong_var* variable is undefined.
Let's change the module's arguments and run the task again
.. code-block :: none
PLAY ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** *****
TASK [wrong variable] ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***
fatal: [192.0.2.10]: FAILED! => {"failed": true, "msg": "ERROR! 'wrong_var' is undefined"}
Debugger invoked
(debug) p result
{'msg': u"ERROR! 'wrong_var' is undefined", 'failed': True}
(debug) p task.args
{u'data': u'{{ wrong_var }}'}
(debug) task.args['data'] = '{{ var1 }}'
(debug) p task.args
{u'data': '{{ var1 }}'}
(debug) redo
ok: [192.0.2.10]
PLAY RECAP ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** ***** *** *
192.0.2.10 : ok=1 changed=0 unreachable=0 failed=0
This time, the task runs successfully!
.. _available_commands:
Available Commands
++++++++++++++++++
.. _p_command:
p *task/vars/host/result*
`` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ``
Print values used to execute a module::
(debug) p task
TASK: install package
(debug) p task.args
{u'name': u'{{ pkg_name }}'}
(debug) p vars
{u'ansible_all_ipv4_addresses': [u'192.0.2.10'],
u'ansible_architecture': u'x86_64',
...
}
(debug) p vars['pkg_name']
u'bash'
(debug) p host
192.0.2.10
(debug) p result
{'_ansible_no_log': False,
'changed': False,
u'failed': True,
...
u'msg': u"No package matching 'not_exist' is available"}
.. _update_args_command:
task.args[*key* ] = *value*
`` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ``
Update module's argument.
If you run a playbook like this::
- hosts: test
strategy: debug
gather_facts: yes
vars:
pkg_name: not_exist
tasks:
- name: install package
apt: name={{ pkg_name }}
Debugger is invoked due to wrong package name, so let's fix the module's args::
(debug) p task.args
{u'name': u'{{ pkg_name }}'}
(debug) task.args['name'] = 'bash'
(debug) p task.args
{u'name': 'bash'}
(debug) redo
Then the task runs again with new args.
.. _update_vars_command:
vars[*key* ] = *value*
`` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ``
Update vars.
Let's use the same playbook above, but fix vars instead of args::
(debug) p vars['pkg_name']
u'not_exist'
(debug) vars['pkg_name'] = 'bash'
(debug) p vars['pkg_name']
'bash'
(debug) redo
Then the task runs again with new vars.
.. _redo_command:
r(edo)
`` ` ` ``
Run the task again.
.. _continue_command:
c(ontinue)
`` ` ` ` ` ` ` ``
Just continue.
.. _quit_command:
q(uit)
`` ` ` ``
Quit from the debugger. The playbook execution is aborted.
.. seealso ::
:doc: `playbooks`
An introduction to playbooks
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