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Here is a simple Ansible playbook:
- name: this command prints FAILED when it fails
command: /usr/bin/example-command -x -y -z
register: command_result
failed_when: "'FAILED' in command_result.stderr"
Now, I know variable command_result has a method called stderr but how can I get a list of all methods?
You can use debug to dump the variable:
- name: this command prints FAILED when it fails
command: /usr/bin/example-command -x -y -z
register: command_result
failed_when: "'FAILED' in command_result.stderr"
- name: dump command_result
debug: var=command_result
This will output something like:
TASK: [dump command_result] **************************************************************
ok: [hostname] => {
"command_result": {
"changed": false,
"cmd": "/usr/bin/example-command -x -y -z",
"delta": "0:00:00.018233",
"end": "2015-05-07 09:33:08.444674",
"invocation": {
"module_args": "/usr/bin/example-command -x -y -z",
"module_name": "command"
},
"rc": 0,
"start": "2015-05-07 09:33:08.426441",
"stderr": "",
"stdout": "whatever",
"stdout_lines": [
"whatever"
],
"warnings": []
}
}
ansible_hostname it does not have any methods, so that mean it is possible this variable only has a subset of all the possible methods, do you agree ? I hope there is a document list all the methods, like an API document.
May 8, 2015 at 7:26
ansible_hostname are facts which are discovered in the first step of running a playbook. You can see what facts exist about a host (and the structure of the information) by running ansible hostname -m setup
cmd method and some variables have others methods. How do I find out them? I would thought there is a document for this but did not find it.
May 13, 2015 at 3:01
Variables in Ansible are basically strings intepreted by Jinja2 template engine. Read the language reference for template variable details. Jinja2's built-in types (string, sequence, mapping, etc.) resembles their counterpart in Python (str, list, dict, etc.) and have many common attributes and methods (callable attributes), but they are not all the same.
Actually, this "variable.stderr" is not a method, but a variable... In Ansible you don't deal with "methods" directly, as it is not a true programming language. The best source to learn, as always is the official docs for ansible, there the modules are pretty well covered.
