Update st2-pack-install command so it allows users to install packs from local git repos in a detached head state

CHANGELOG.rst

@@ -15,14 +15,19 @@ Changed
 
 * Speed up pack registration through the ``/v1/packs/register`` API endpoint. (improvement) #4342
 * Triggertypes API now sorts by trigger ref by default. ``st2 trigger list`` will now show a sorted
-  list. (#4348)
+
+Fixed
+~~~~~
+
 * Update ``st2sensorcontainer`` service to throw if user wants to run a sensor from a pack which is
   using Python 3 virtual environment.
 
   We only support running Python runner actions from packs which use mixed Python environments
   (StackStorm components are running under Python 2 and particular a pack virtual environment is
   using Python 3). #4354
-
+* Update ``st2-pack-install`` and ``st2 pack install`` command so it works with local git repos
+  (``file://<path to local git repo>``) which are in a detached head state (e.g. specific revision
+  is checked out). (improvement) #4366
 
 2.9.0 - September 16, 2018
 --------------------------

contrib/packs/tests/test_action_download.py

@@ -89,6 +89,7 @@ def setUp(self):
         self.repo_base = tempfile.mkdtemp()
 
         self.repo_instance = mock.MagicMock()
+        type(self.repo_instance).active_branch = mock.Mock()
 
         def side_effect(url, to_path, **kwargs):
             # Since we have no way to pass pack name here, we would have to derive it from repo url
@@ -113,6 +114,10 @@ def test_run_pack_download(self):
                                                 os.path.join(os.path.expanduser('~'), temp_dir))
         self.assertTrue(os.path.isfile(os.path.join(self.repo_base, 'test/pack.yaml')))
 
+        self.repo_instance.git.checkout.assert_called()
+        self.repo_instance.git.branch.assert_called()
+        self.repo_instance.git.checkout.assert_called()
+
     def test_run_pack_download_existing_pack(self):
         action = self.get_action_instance()
         action.run(packs=['test'], abs_repo_base=self.repo_base)
@@ -295,6 +300,9 @@ def test_resolve_urls(self):
         url = eval_repo_url("file:///home/vagrant/stackstorm-test")
         self.assertEqual(url, "file:///home/vagrant/stackstorm-test")
 
+        url = eval_repo_url("file://localhost/home/vagrant/stackstorm-test")
+        self.assertEqual(url, "file://localhost/home/vagrant/stackstorm-test")
+
         url = eval_repo_url('ssh://<user@host>/AutomationStackStorm')
         self.assertEqual(url, 'ssh://<user@host>/AutomationStackStorm')
 
@@ -363,3 +371,17 @@ def fake_commit(arg_ref):
 
             result = action.run(packs=packs, abs_repo_base=self.repo_base)
             self.assertEqual(result, {'test': 'Success.'})
+
+    def test_run_pack_dowload_local_git_repo_detached_head_state(self):
+        action = self.get_action_instance()
+
+        type(self.repo_instance).active_branch = \
+            mock.PropertyMock(side_effect=TypeError('detached head'))
+
+        result = action.run(packs=['file:///stackstorm-test'], abs_repo_base=self.repo_base)
+        self.assertEqual(result, {'test': 'Success.'})
+
+        # Verify function has bailed out early
+        self.repo_instance.git.checkout.assert_not_called()
+        self.repo_instance.git.branch.assert_not_called()
+        self.repo_instance.git.checkout.assert_not_called()

st2common/st2common/util/pack_management.py

@@ -151,7 +151,22 @@ def clone_repo(temp_dir, repo_url, verify_ssl=True, ref='master'):
     # because we want the user to work with the repo in the
     # future.
     repo = Repo.clone_from(repo_url, temp_dir)
-    active_branch = repo.active_branch
+
+    is_local_repo = repo_url.startswith('file://')
+
+    try:
+        active_branch = repo.active_branch
+    except TypeError as e:
+        if is_local_repo:
+            active_branch = None
+        else:
+            raise e
+
+    # Special case for local git repos - we allow users to install from repos which are checked out
+    # at a specific commit (aka detached HEAD)
+    if is_local_repo and not active_branch and not ref:
+        LOG.debug('Installing pack from git repo on disk, skipping branch checkout')
+        return temp_dir
 
     use_branch = False