Returning Values in Modules

Ansible Modules 

Ansible modules often return a data structure that can be stored in a variable or immediately observed when the ansible application outputs it. It is optional for each module to document its distinct return values.

Now let’s have a look at the return values of the modules.

Common

backup_file

When altering files, a path to the backup file is created for modules that use backup=no|yes.

"backup_file": "./foo.txt.32729.2020-07-30@06:24:19~"

Changed

Whether the task needed to make changes to the target or delegated host is indicated by this boolean.

"changed": true

Diff

information on the variations between the former condition and the present one. A dictionary with before and after entries is frequently used, and the callback plugin will format it for a diff display.

"diff": [
        {
            "after": "",
            "after_header": "foo.txt (content)",
            "before": "",
            "before_header": "foo.txt (content)"
        },
        {
            "after_header": "foo.txt (file attributes)",
            "before_header": "foo.txt (file attributes)"
        }

Failed

A boolean that tells if the task failed or not.

"failed": false

Invocation

Information about the module's callback mechanism.

"invocation": {
        "module_args": {
            "_original_basename": "foo.txt",
            "attributes": null,
            "backup": true,
            "checksum": "da39a3ee5e6b4b0d3255bfef95601890afd8070",
            "content": null,
            "delimiter": null,
            "dest": "/foo.txt",
            "directory_mode": null,
            "follow": false,
            "force": true,
            "group": null,
            "local_follow": null,
            "mode": "6666",
            "owner": null,
            "regexp": null,
            "remote_src": null,
            "selevel": null,
            "serole": null,
            "setype": null,
            "seuser": null,
            "src": "/Users/foo/.ansible/tmp/ansible-tmp-1596115458.110205-10571746450515/source",
            "unsafe_writes": null,
            "validate": null
        }

Msg

A string that conveys to the user a general message.

"msg": "line added"

Rc

This field includes the "return code" of the command line utilities used by some modules to execute commands directly (raw, shell, command, and so on).

"rc": 257

Results

If this key is present, it means that a task-specific loop was used and that it provides a list of the typical module "result" for each item.
 

"results": [
    {
        "ansible_loop_var": "item",
        "backup": "foo.txt.83170.2020-07-30@07:03:05~",
        "changed": true,
        "diff": [
            {
                "after": "",
                "after_header": "foo.txt (content)",
                "before": "",
                "before_header": "foo.txt (content)"
            },
            {
                "after_header": "foo.txt (file attributes)",
                "before_header": "foo.txt (file attributes)"
            }
        ],
        "failed": false,
        "invocation": {
            "module_args": {
                "attributes": null,
                "backrefs": false,
                "backup": true
            }
        },
        "item": "foo",
        "msg": "line added"
    },
    {
        "ansible_loop_var": "item",
        "backup": "foo.txt.83187.2020-07-30@07:03:05~",
        "changed": true,
        "diff": [
            {
                "after": "",
                "after_header": "foo.txt (content)",
                "before": "",
                "before_header": "foo.txt (content)"
            },
            {
                "after_header": "foo.txt (file attributes)",
                "before_header": "foo.txt (file attributes)"
            }
        ],
        "failed": false,
        "invocation": {
            "module_args": {
                "attributes": null,
                "backrefs": false,
                "backup": true
            }
        },
        "item": "bar",
        "msg": "line added"
    }
    ]

Skipped

 Boolean value that represents whether or not the task was skipped

"skipped": true

Stderr

This field includes the error output from command line tools that some modules use to run commands directly (raw, shell, command, and etc).

"stderr": "ls: foo: No such file or directory"

Stderr_lines

This field, a list of strings with one item per line from the original, is always included when stderr is returned.

"stderr_lines": [
        "ls: doesntexist: No such file or directory"
        ]

Stdout

Some modules are designed to run commands directly or to run command line utilities (raw, shell, command, and so on). The typical output of these utilities is contained in this field.

"stdout": "foo!"

Stdout_lines

Ansible always gives a list of strings containing one item per line from the initial output when stdout is returned.

"stdout_lines": [
"foo!"
]

Internal use

These keys are "consumed" by ansible itself; modules may add them, but they will be removed from registered variables.

Ansible_facts

A dictionary that will be added to the host's facts should be included in this key. These won't require utilizing a registered variable and will be readily accessible.

Exception

This key may provide traceback data brought on by a module exception. It will only be visible on pages with many words (-vvv).

Warnings

A list of strings that will be shown to the user is contained in this key.

Deprecations

A list of dictionaries that will be shown to the user is contained in this key. Dictionary values include strings, with the version key's value being an empty string. The dictionaries' keys are msg and version.

Frequently Asked Questions

What do you mean by returning a value?

It simply means to return the method's value to the caller.

How do you use the returned value of a method?

A method's return type is specified in the method declaration. The return statement is used in the method's body to return the value.

Why do we return value?

A return value is typically used when the function represents a step in the middle of a calculation.

What are the ansible modules?

Ansible modules are standalone, reusable scripts that can be used by the ansible or ansible-playbook programs and the ansible API.

Is Ansible a CI tool?

Ansible is a potent IT automation tool used in a CI/CD process to provision the target environment before deploying the application.

Conclusion

This blog has extensively discussed Returning Values in Modules in this article.

If you want to learn more, check out the excellent content on the Coding Ninjas Website:

Ansible Interview Questions Part 1, Ansible Interview Questions Part 2, 12 Best DevOps Tools To Get Acquainted With, and DevOps Interview Questions.

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