server: support specifying commit instead of branch

In that case repo is just reset to that commit and updates do not happen.

Signed-off-by: Jakub Sokołowski <jakub@status.im>

README.md

@@ -9,8 +9,10 @@ Required configuration:
 github_webhook_dest_path: '/opt/repo'
 github_webhook_secret: 'super-secret-webhook-secret'
 github_webhook_repo_url: 'https://github.com/example-org/example-repo'
-github_webhook_repo_branch: 'master'
+github_webhook_repo_version: 'master'
 ```
+If `version` is a commit no updates will be performed.
+
 Additionally these options can be useful:
 ```yaml
 github_webhook_ssh_key: '-----BEGIN OPENSSH PRIVATE KEY-----\n...'

defaults/main.yml

@@ -27,4 +27,4 @@ github_webhook_dependencies:
 
 # REQUIRED: details of repo to keep updated
 #github_webhook_repo_url: ~
-#github_webhook_repo_branch: ~
+#github_webhook_repo_version: ~

files/server.py

@@ -20,9 +20,9 @@ def hello_world():
 
 class ManagedRepo:
 
-    def __init__(self, url, branch, dest_path):
+    def __init__(self, url, version, dest_path):
         self.url = url
-        self.branch = branch
+        self.version = version
         self.path = dest_path
         self._init()
         self._checkout()
@@ -30,27 +30,46 @@ class ManagedRepo:
     def _init(self):
         self.repo = Repo.init(self.path)
         self.repo.description = self.name
+
+        log.debug('Set origin: %s', self.url)
+        # Origin can already exist.
         if 'origin' in self.repo.remotes:
             self.origin = self.repo.remotes['origin']
         else:
             self.origin = self.repo.create_remote('origin', self.url)
         log.debug('Fetching from: %s', self.origin.url)
         self.origin.fetch()
-        self.remote_ref = self.origin.refs[self.branch]
+
+        # Version can also be a commit.
+        if self.version_as_commit():
+            log.warning('Version is a commit, no updates will be performed.')
+            self.remote_ref = str(self.version_as_commit())
+        else:
+            self.remote_ref = self.origin.refs[self.version]
 
     def _checkout(self):
-
-        if self.repo.head.ref.name != self.branch:
-            log.debug('Creating HEAD: %s', self.branch)
-            head = self.repo.create_head(self.branch, self.remote_ref)
+        # Branch can not exist yet.
+        if self.repo.head.ref.name != self.version:
+            log.debug('Creating HEAD: %s', self.version)
+            head = self.repo.create_head(self.version, self.remote_ref)
             self.repo.head.set_reference(head)
 
-        if self.repo.head.ref.tracking_branch() != self.remote_ref:
-            log.debug('Setting tracking branch: %s', self.remote_ref)
+        # New branch needs remote trakcing branch set.
+        if self.repo.head.is_detached:
+            log.warning('Unable to set tracking versionf for commit.')
+        elif self.repo.head.ref.tracking_branch() != self.remote_ref:
+            log.debug('Setting tracking version: %s', self.remote_ref)
             self.repo.head.ref.set_tracking_branch(self.remote_ref)
 
-        log.debug('Checking out: %s', self.branch)
-        self.repo.head.ref.checkout()
+        log.debug('Reseting repo to: %s(%s)', self.repo.head.ref, self.repo.head.commit)
+        self.repo.head.reset(index=True, working_tree=True)
+
+    def version_as_commit(self):
+        try:
+            self.repo.branch(self.version)
+        except AttributeError:
+            return self.repo.commit(self.version)
+        return None
 
     @property
     def name(self):
@@ -132,8 +151,8 @@ def parse_args():
     parser.add_argument('-H', '--host', default='localhost', help='Server listen host.')
     parser.add_argument('-p', '--post-command', help='Command to run after repo update.')
     parser.add_argument('-r', '--repo-url', help='Git repository URL.')
-    parser.add_argument('-b', '--repo-branch', default='master',
-                        help='Git repository branch.')
+    parser.add_argument('-v', '--repo-version', default='master',
+                        help='Git repository branch or commit.')
     parser.add_argument('-S', '--secret', default=env.get('WEBHOOK_SECRET'),
                         help='Webhook secret for authentication.')
     return parser.parse_args()
@@ -152,7 +171,7 @@ def main():
         webhook.secret = args.secret
 
     # Initialize repository to manage
-    repo = ManagedRepo(args.repo_url, args.repo_branch, args.path)
+    repo = ManagedRepo(args.repo_url, args.repo_version, args.path)
 
     post_command = None
     if args.post_command:

templates/webhook.service.j2

@@ -10,7 +10,7 @@ User={{ github_webhook_service_user }}
 ExecStart={{ github_webhook_script_dir }}/server.py \
     --port={{ github_webhook_port }} \
     --repo-url={{ github_webhook_repo_url | mandatory }} \
-    --repo-branch={{ github_webhook_repo_branch | mandatory }} \
+    --repo-version={{ github_webhook_repo_version | mandatory }} \
 {% if github_webhook_post_command is defined %}
     --post-command='{{ github_webhook_post_command | mandatory }}' \
 {% endif %}