Setting up CPython repo is now done in the worker app. (GH-34)

Instead of in the main app.

backport/__main__.py

@@ -11,7 +11,7 @@
 from gidgethub import routing
 from gidgethub import sansio
 
-from . import tasks
+
 from . import backport_pr
 from . import delete_branch
 from . import status_change
@@ -47,10 +47,7 @@ async def main(request):
 
 
 if __name__ == "__main__":  # pragma: no cover
-    id = tasks.setup_cpython_repo.delay()
-    print(f"Setting up CPython Repo Task: {id}")
     app = web.Application()
-    app['cpython_task_id'] = id
     app.router.add_post("/", main)
     port = os.environ.get("PORT")
     if port is not None:

backport/tasks.py

@@ -2,6 +2,8 @@
 import os
 import subprocess
 
+from celery import bootsteps
+
 from cherry_picker import cherry_picker
 
 from . import util
@@ -14,6 +16,7 @@
 
 @app.task(rate_limit="1/m")
 def setup_cpython_repo():
+    print("Setting up CPython repository")
     if "cpython" not in os.listdir('.'):
         subprocess.check_output(
             f"git clone https://{os.environ.get('GH_AUTH')}:[email protected]/miss-islington/cpython.git".split())
@@ -64,3 +67,13 @@ def backport_task(commit_hash, branch, *, issue_number, created_by, merged_by):
                             ```
                             """)
         cp.abort_cherry_pick()
+
+
+class InitRepoStep(bootsteps.StartStopStep):
+
+    def start(self, c):
+        print("Initialize the repository.")
+        setup_cpython_repo()
+
+
+app.steps['worker'].add(InitRepoStep)