Add has_playbook method to Runtime (#364)

Add functionality for detecting if Ansible can find specific
playbooks, caching the results. This is useful as they can reside
inside collections.

Related: ansible/ansible-lint#4141

src/ansible_compat/runtime.py

@@ -156,6 +156,7 @@ class Runtime:
     # to do it multiple tilmes will cause runtime warnings from within ansible-core
     initialized: bool = False
     plugins: Plugins
+    _has_playbook_cache: dict[tuple[str, Path | None], bool] = {}
 
     def __init__(
         self,
@@ -432,6 +433,28 @@ def version_in_range(
             return False
         return True
 
+    def has_playbook(self, playbook: str, *, basedir: Path | None = None) -> bool:
+        """Return true if ansible can load a given playbook.
+
+        This is also used for checking if playbooks from within collections
+        are present and if they pass syntax check.
+        """
+        if (playbook, basedir) in self._has_playbook_cache:
+            return self._has_playbook_cache[playbook, basedir]
+
+        proc = self.run(["ansible-playbook", "--syntax-check", playbook], cwd=basedir)
+        result = proc.returncode == 0
+        if not result:
+            if not basedir:
+                basedir = Path()
+            msg = f"has_playbook returned false for '{basedir / playbook}' due to syntax check returning {proc.returncode}"
+            logging.debug(msg)
+
+        # cache the result
+        self._has_playbook_cache[playbook, basedir] = result
+
+        return result
+
     def install_collection(
         self,
         collection: str | Path,

test/test_runtime.py

@@ -893,3 +893,16 @@ def test_get_galaxy_role_name_invalid() -> None:
         "role_name": False,  # <-- invalid data, should be string
     }
     assert _get_galaxy_role_name(galaxy_infos) == ""
+
+
+def test_runtime_has_playbook() -> None:
+    """Tests has_playbook method."""
+    runtime = Runtime(require_module=True)
+
+    assert not runtime.has_playbook("this-does-not-exist.yml")
+    # call twice to ensure cache is used:
+    assert not runtime.has_playbook("this-does-not-exist.yml")
+
+    assert not runtime.has_playbook("this-does-not-exist.yml", basedir=Path())
+    # this is part of community.molecule collection
+    assert runtime.has_playbook("community.molecule.validate.yml")

tox.ini

@@ -87,7 +87,7 @@ setenv =
   PIP_DISABLE_PIP_VERSION_CHECK = 1
   PIP_CONSTRAINT = {toxinidir}/.config/constraints.txt
   PRE_COMMIT_COLOR = always
-  PYTEST_REQPASS = 93
+  PYTEST_REQPASS = 94
   FORCE_COLOR = 1
 allowlist_externals =
   ansible