Scaffold a generic module plugin in an existing ansible collection using add subcommand.

docs/installing.md

@@ -330,3 +330,28 @@ $ ansible-creator add resource devfile /home/user/..path/to/your/existing_projec
 ```
 
 This command will scaffold the devfile.yaml file at `/home/user/..path/to/your/existing_project`
+
+### Add support to scaffold plugins in an existing ansible collection
+
+The `add plugin` command enables you to add a plugin to an existing collection project. Use the following command template:
+
+```console
+$ ansible-creator add plugin <plugin-type> <plugin-name> <collection-path>
+```
+
+#### Positional Arguments
+
+| Parameter | Description                                                    |
+| --------- | -------------------------------------------------------------- |
+| action    | Add an action plugin to an existing Ansible Collection.        |
+| filter    | Add a filter plugin to an existing Ansible Collection.         |
+| lookup    | Add a lookup plugin to an existing Ansible Collection.         |
+| module    | Add a generic module plugin to an existing Ansible Collection. |
+
+#### Example
+
+```console
+$ ansible-creator add plugin module test_plugin /home/user/..path/to/your/existing_project
+```
+
+This command will scaffold a generic module plugin at `/home/user/..path/to/your/existing_project`

src/ansible_creator/arg_parser.py

@@ -353,6 +353,7 @@ def _add_plugin(self, subparser: SubParser[ArgumentParser]) -> None:
         self._add_plugin_action(subparser=subparser)
         self._add_plugin_filter(subparser=subparser)
         self._add_plugin_lookup(subparser=subparser)
+        self._add_plugin_module(subparser=subparser)
 
     def _add_plugin_action(self, subparser: SubParser[ArgumentParser]) -> None:
         """Add an action plugin to an existing Ansible collection project.
@@ -399,6 +400,21 @@ def _add_plugin_lookup(self, subparser: SubParser[ArgumentParser]) -> None:
         self._add_overwrite(parser)
         self._add_args_plugin_common(parser)
 
+    def _add_plugin_module(self, subparser: SubParser[ArgumentParser]) -> None:
+        """Add a module plugin to an existing Ansible collection project.
+
+        Args:
+            subparser: The subparser to add module plugin to
+        """
+        parser = subparser.add_parser(
+            "module",
+            help="Add a module plugin to an existing Ansible collection.",
+            formatter_class=CustomHelpFormatter,
+        )
+        self._add_args_common(parser)
+        self._add_overwrite(parser)
+        self._add_args_plugin_common(parser)
+
     def _add_overwrite(self, parser: ArgumentParser) -> None:
         """Add overwrite and no-overwrite arguments to the parser.
 

src/ansible_creator/resources/collection_project/plugins/sample_module/hello_world.py.j2

@@ -0,0 +1,65 @@
+{# module_plugin_template.j2 #}
+{%- set module_name = plugin_name | default("hello_world") -%}
+{%- set author = author |  default("Your Name (@username)") -%}
+{%- set description = description | default("A custom module plugin for Ansible.") -%}
+{%- set license = license | default("GPL-3.0-or-later") -%}
+# {{ module_name }}.py - {{ description }}
+# Author: {{ author }}
+# License: {{ license }}
+
+from __future__ import absolute_import, annotations, division, print_function
+
+
+__metaclass__ = type  # pylint: disable=C0103
+
+from typing import TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from typing import Callable
+
+
+DOCUMENTATION = """
+    name: {{ module_name }}
+    author: {{ author }}
+    version_added: "1.0.0"
+    short_description: {{ description }}
+    description:
+      - This is a demo module plugin designed to return Hello message.
+    options:
+      name:
+        description: Value specified here is appended to the Hello message.
+        type: str
+"""
+
+EXAMPLES = """
+# {{ module_name }} module example
+{% raw %}
+- name: Display a hello message
+  ansible.builtin.debug:
+    msg: "{{ 'ansible-creator' {%- endraw %} | {{ module_name }} }}"
+"""
+
+
+def _hello_world(name: str) -> str:
+    """Returns Hello message.
+
+    Args:
+        name: The name to greet.
+
+    Returns:
+        str: The greeting message.
+    """
+    return "Hello, " + name
+
+
+class SampleModule:
+    """module plugin."""
+
+    def modules(self) -> dict[str, Callable[[str], str]]:
+        """Map module plugin names to their functions.
+
+        Returns:
+            dict: The module plugin functions.
+        """
+        return {"{{ module_name }}": _hello_world}

src/ansible_creator/subcommands/add.py

@@ -209,6 +209,11 @@ def _plugin_scaffold(self, plugin_path: Path) -> None:
             template_data = self._get_plugin_template_data()
             self._perform_lookup_plugin_scaffold(template_data, plugin_path)
 
+        elif self._plugin_type == "module":
+            template_data = self._get_plugin_template_data()
+            plugin_path = self._add_path / "plugins" / "sample_module"
+            plugin_path.mkdir(parents=True, exist_ok=True)
+            self._perform_module_plugin_scaffold(template_data, plugin_path)
         else:
             msg = f"Unsupported plugin type: {self._plugin_type}"
             raise CreatorError(msg)
@@ -243,6 +248,14 @@ def _perform_lookup_plugin_scaffold(
         resources = (f"collection_project.plugins.{self._plugin_type}",)
         self._perform_plugin_scaffold(resources, template_data, plugin_path)
 
+    def _perform_module_plugin_scaffold(
+        self,
+        template_data: TemplateData,
+        plugin_path: Path,
+    ) -> None:
+        resources = ("collection_project.plugins.sample_module",)
+        self._perform_plugin_scaffold(resources, template_data, plugin_path)
+
     def _perform_plugin_scaffold(
         self,
         resources: tuple[str, ...],

tests/fixtures/collection/testorg/testcol/plugins/sample_module/hello_world.py

@@ -0,0 +1,60 @@
+# hello_world.py - A custom module plugin for Ansible.
+# Author: Your Name (@username)
+# License: GPL-3.0-or-later
+
+from __future__ import absolute_import, annotations, division, print_function
+
+
+__metaclass__ = type  # pylint: disable=C0103
+
+from typing import TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from typing import Callable
+
+
+DOCUMENTATION = """
+    name: hello_world
+    author: Your Name (@username)
+    version_added: "1.0.0"
+    short_description: A custom module plugin for Ansible.
+    description:
+      - This is a demo module plugin designed to return Hello message.
+    options:
+      name:
+        description: Value specified here is appended to the Hello message.
+        type: str
+"""
+
+EXAMPLES = """
+# hello_world module example
+
+- name: Display a hello message
+  ansible.builtin.debug:
+    msg: "{{ 'ansible-creator' | hello_world }}"
+"""
+
+
+def _hello_world(name: str) -> str:
+    """Returns Hello message.
+
+    Args:
+        name: The name to greet.
+
+    Returns:
+        str: The greeting message.
+    """
+    return "Hello, " + name
+
+
+class SampleModule:
+    """module plugin."""
+
+    def modules(self) -> dict[str, Callable[[str], str]]:
+        """Map module plugin names to their functions.
+
+        Returns:
+            dict: The module plugin functions.
+        """
+        return {"hello_world": _hello_world}

tests/units/test_add.py

@@ -675,6 +675,83 @@ def mock_update_galaxy_dependency() -> None:
     assert cmp_result1, cmp_result2
 
 
+def test_run_success_add_plugin_module(
+    capsys: pytest.CaptureFixture[str],
+    tmp_path: Path,
+    cli_args: ConfigDict,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Test Add.run().
+
+    Successfully add plugin to path
+
+    Args:
+        capsys: Pytest fixture to capture stdout and stderr.
+        tmp_path: Temporary directory path.
+        cli_args: Dictionary, partial Add class object.
+        monkeypatch: Pytest monkeypatch fixture.
+    """
+    cli_args["plugin_type"] = "module"
+    add = Add(
+        Config(**cli_args),
+    )
+
+    # Mock the "_check_collection_path" method
+    def mock_check_collection_path() -> None:
+        """Mock function to skip checking collection path."""
+
+    monkeypatch.setattr(
+        Add,
+        "_check_collection_path",
+        staticmethod(mock_check_collection_path),
+    )
+    add.run()
+    result = capsys.readouterr().out
+    assert re.search("Note: Module plugin added to", result) is not None
+
+    expected_file = tmp_path / "plugins" / "sample_module" / "hello_world.py"
+    effective_file = (
+        FIXTURES_DIR
+        / "collection"
+        / "testorg"
+        / "testcol"
+        / "plugins"
+        / "sample_module"
+        / "hello_world.py"
+    )
+    cmp_result = cmp(expected_file, effective_file, shallow=False)
+    assert cmp_result
+
+    conflict_file = tmp_path / "plugins" / "sample_module" / "hello_world.py"
+    conflict_file.write_text("Author: Your Name")
+
+    # expect a CreatorError when the response to overwrite is no.
+    monkeypatch.setattr("builtins.input", lambda _: "n")
+    fail_msg = (
+        "The destination directory contains files that will be overwritten."
+        " Please re-run ansible-creator with --overwrite to continue."
+    )
+    with pytest.raises(
+        CreatorError,
+        match=fail_msg,
+    ):
+        add.run()
+
+    # expect a warning followed by module plugin addition msg
+    # when response to overwrite is yes.
+    monkeypatch.setattr("builtins.input", lambda _: "y")
+    add.run()
+    result = capsys.readouterr().out
+    assert (
+        re.search(
+            "already exists",
+            result,
+        )
+        is not None
+    ), result
+    assert re.search("Note: Module plugin added to", result) is not None
+
+
 def test_run_error_plugin_no_overwrite(
     capsys: pytest.CaptureFixture[str],
     tmp_path: Path,