When using synctl with workers, don't start the main synapse automatically

CHANGES.rst

+Unreleased
+==========
+
+synctl no longer starts the main synapse when using ``-a`` option with workers.
+A new worker file should be added with ``worker_app: synapse.app.homeserver``
+
+
 Changes in synapse v0.26.0 (2018-01-05)
 =======================================
 

synapse/app/synctl.py

@@ -184,6 +184,9 @@ def main():
         worker_configfiles.append(worker_configfile)
 
     if options.all_processes:
+        # To start the main synapse with -a you need to add a worker file
+        # with worker_app == "synapse.app.homeserver"
+        start_stop_synapse = False
         worker_configdir = options.all_processes
         if not os.path.isdir(worker_configdir):
             write(
@@ -200,14 +203,29 @@ def main():
         with open(worker_configfile) as stream:
             worker_config = yaml.load(stream)
         worker_app = worker_config["worker_app"]
-        worker_pidfile = worker_config["worker_pid_file"]
-        worker_daemonize = worker_config["worker_daemonize"]
-        assert worker_daemonize, "In config %r: expected '%s' to be True" % (
-            worker_configfile, "worker_daemonize")
-        worker_cache_factor = worker_config.get("synctl_cache_factor")
-        workers.append(Worker(
-            worker_app, worker_configfile, worker_pidfile, worker_cache_factor,
-        ))
+        if worker_app == "synapse.app.homeserver":
+            # We need to special case all of this to pick up options that may
+            # be set in the main config file or in this worker config file.
+            worker_pidfile = (
+                worker_config.get("worker_pid_file")
+                or worker_config("pid_file")
+                or pidfile
+            )
+            workers.append(Worker(
+                "synapse.app.homeserver",
+                worker_configfile,
+                worker_pidfile,
+                worker_config.get("synctl_cache_factor") or cache_factor,
+            ))
+        else:
+            worker_pidfile = worker_config["worker_pid_file"]
+            worker_daemonize = worker_config["worker_daemonize"]
+            assert worker_daemonize, "In config %r: expected '%s' to be True" % (
+                worker_configfile, "worker_daemonize")
+            worker_cache_factor = worker_config.get("synctl_cache_factor")
+            workers.append(Worker(
+                worker_app, worker_configfile, worker_pidfile, worker_cache_factor,
+            ))
 
     action = options.action