Make ZuulDaemonApp an abstract base class

We use ZuulDaemonApp like an abstract base class with run() as an
abstract method so make that explicit. This creates the groundwork for
later refactorings like centralized signal handling.

Change-Id: I20f14274df27ab181711b2ca2b80251fa5b09938

1 files changed, 9 insertions, 1 deletions

diff --git a/zuul/cmd/__init__.py b/zuul/cmd/__init__.py
index bdb93978f..2aad4eb39 100755
--- a/zuul/cmd/__init__.py
+++ b/zuul/cmd/__init__.py
@@ -14,6 +14,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import abc
 import argparse
 import configparser
 import daemon
@@ -156,7 +157,7 @@ class ZuulApp(object):
         self.connections.configure(self.config, source_only)
 
 
-class ZuulDaemonApp(ZuulApp):
+class ZuulDaemonApp(ZuulApp, metaclass=abc.ABCMeta):
     def createParser(self):
         parser = super(ZuulDaemonApp, self).createParser()
         parser.add_argument('-d', dest='nodaemon', action='store_true',
@@ -169,6 +170,13 @@ class ZuulDaemonApp(ZuulApp):
                              expand_user=True)
         return pid_fn
 
+    @abc.abstractmethod
+    def run(self):
+        """
+        This is the main run method of the application.
+        """
+        pass
+
     def main(self):
         self.parseArguments()
         self.readConfig()