[PYTHON] Ansible self-made module creation-Part 3: Life that wants to judge the necessity of change-

Previous article 1: Creating an Ansible self-made module-Part 1: Life you want to receive arguments- Previous article 2: Creating ansible self-made module-Part 2: Life just wanting to execute commands-

Looking back

--Made a module template (Part 1) --Received multiple arguments (1) --The argument was combined with the command and executed (Part 2)

reference

-Ansible module development (practice) ――Thank you for your help this time as well.

Initial processing

Also for a review. First, create a template (see "Previous Article 1" for reference). The command execution part created as a test (see the reference "Previous article 2") was once removed.

mkfifo.py

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

from ansible.module_utils.basic import AnsibleModule

#Main processing
#-----------------------------------------------------------
def main():
    #AnsibleModule class:Create module
    module = AnsibleModule(

        #Argument reception
        argument_spec=dict(

            #argument: data(str type,def:pong)
            data=dict(type='str', default='pong'),
        ),
        #Argument check enabled
        supports_check_mode=True
    )

    #Result dict:Create result
    result = dict(
        # key:The key given as an argument to ping:Store the value of data
        ping=module.params['data'],
    )

    #The contents of result is key=value,Output in the form of
    module.exit_json(**result)

if __name__ == '__main__':
    main()

Implement the variable receiving part in this.

mkfifo.py

: #(abridgement)
    #AnsibleModule class:Create module
    module = AnsibleModule(

        #Argument reception
        argument_spec=dict(

            #argument: path(Mandatory,str type)
            path=dict(required=True,type='str'),
            #argument: owner(str type,Default=root)
            owner=dict(type='str',default='root'),
            #argument: group(str type,Default=root)
            group=dict(type='str',default='root'),
            #argument: mode(str type,Default=0644)
            mode=dict(type='str',default='0644'),
        ),
        #Argument check enabled
        supports_check_mode=True
    )
: #(abridgement)

At the moment, there is no branching depending on the OS version or distribution. Just set a changed variable ... but where do you define changed? Is it okay outside the `ʻAnsibleModule`` class? Give it a try.

sakrua.py

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

from ansible.module_utils.basic import AnsibleModule

#Main processing
#-----------------------------------------------------------
def main():
    #AnsibleModule class:Create module
    module = AnsibleModule(
        {}
    )

    changed =False ★ Change this value to True

    module.exit_json(changed=changed)

if __name__ == '__main__':
    main()

# changed =If True
$ ansible -i test_grp 192.168.56.104 -m sakura -M library -u root
192.168.56.104 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true
}

# changed =If False
$ ansible -i test_grp 192.168.56.104 -m sakura -M library -u root
192.168.56.104 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false
}

Good. It is defined outside the `ʻAnsibleModule`` class.

Try to judge Changed

The conditions for changed to be True are as follows

1. The named pipe given in path does not exist
2. The named pipe ʻower``: group``: mode`` given in `path`` is not as an argument

Condition 1 can be judged by ReturnCode of test -p xxxxx. Condition 2 can be judged by the standard output of stat -c% U:% G:% a.

However, the result of stat -c% a only shows the last 3 digits, so use stat -c 0% a to deal with it. Also, since stdout is output up to the line feed code, \ n was inserted at the time of comparison.

mkfifo.py

: #(abridgement)
    #Initialize whether or not there is a change(No change)
    changed = False

    #Check if there is a named pipe in path with the test command
    rc, stdout, stderr = module.run_command("test -p " + module.params['path'])
    #Check result
    if ( rc != 0 ):
        #Since it does not exist, it is subject to change
        changed = True
    else:
        #Owner if it exists:group:Get mode
        rc, stdout, stderr = module.run_command("stat -c %U:%G:0%a " + module.params['path'])
        #Comparison. The command result is the line feed code at the end\Note that n is attached
        if ( stdout != module.params['owner'] + ':' + module.params['group'] + ':' + module.params['mode'] + '\n'):
            # owner:group:Since the mode is different, it is subject to change
            changed = True

    #End
    module.exit_json(changed=changed,stdout=stdout,stderr=stderr)
: #(abridgement)

Let's move it up to this point.

$ ansible -i test_grp 192.168.56.104 -m mkfifo -M library -u root -a "path=/tmp/testfifo owner=root group=root mode=0777"
192.168.56.104 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "stderr": "",
    "stderr_lines": [],
    "stdout": "",
    "stdout_lines": []
}

Try to create / tmp / testfifo on the target server.

# /tmp/testfifo root:root:Let's make it with 0644
$ ssh [email protected] "mkfifo /tmp/testfifo; chmod 0644 /tmp/testfifo"
$ ssh [email protected] "ls -l /tmp/testfifo"
prw-r--r--.1 root root 0 June 1 01:30 2020 /tmp/testfifo
$ ansible -i test_grp 192.168.56.104 -m mkfifo -M library -u root -a "path=/tmp/testfifo owner=root group=root mode=0777"
192.168.56.104 | CHANGED => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": true,
    "stderr": "",
    "stderr_lines": [],
    "stdout": "root:root:0644\n",
    "stdout_lines": [
        "root:root:0644"
    ]
}

# /tmp/testfifo root:root:Try to set it to 0777
$ ssh [email protected] "chmod 0777 /tmp/testfifo"
$ ssh [email protected] "ls -l /tmp/testfifo"
prwxrwxrwx.1 root root 0 June 1 01:30 2020 /tmp/testfifo
$ ansible -i test_grp 192.168.56.104 -m mkfifo -M library -u root -a "path=/tmp/testfifo owner=root group=root mode=0777"
192.168.56.104 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    },
    "changed": false,
    "stderr": "",
    "stderr_lines": [],
    "stdout": "root:root:0777\n",
    "stdout_lines": [
        "root:root:0777"
    ]
}

Oke. This section ends here. Next is the command input edition. .. The content seems to be thin.