synctl.py: wait for synapse to stop before restarting (#2020)

synapse/app/synctl.py

@@ -23,14 +23,27 @@ import signal
 import subprocess
 import sys
 import yaml
+import errno
+import time
 
 SYNAPSE = [sys.executable, "-B", "-m", "synapse.app.homeserver"]
 
 GREEN = "\x1b[1;32m"
+YELLOW = "\x1b[1;33m"
 RED = "\x1b[1;31m"
 NORMAL = "\x1b[m"
 
 
+def pid_running(pid):
+    try:
+        os.kill(pid, 0)
+        return True
+    except OSError, err:
+        if err.errno == errno.EPERM:
+            return True
+        return False
+
+
 def write(message, colour=NORMAL, stream=sys.stdout):
     if colour == NORMAL:
         stream.write(message + "\n")
@@ -38,6 +51,11 @@ def write(message, colour=NORMAL, stream=sys.stdout):
         stream.write(colour + message + NORMAL + "\n")
 
 
+def abort(message, colour=RED, stream=sys.stderr):
+    write(message, colour, stream)
+    sys.exit(1)
+
+
 def start(configfile):
     write("Starting ...")
     args = SYNAPSE
@@ -45,7 +63,8 @@ def start(configfile):
 
     try:
         subprocess.check_call(args)
-        write("started synapse.app.homeserver(%r)" % (configfile,), colour=GREEN)
+        write("started synapse.app.homeserver(%r)" %
+              (configfile,), colour=GREEN)
     except subprocess.CalledProcessError as e:
         write(
             "error starting (exit code: %d); see above for logs" % e.returncode,
@@ -76,8 +95,16 @@ def start_worker(app, configfile, worker_configfile):
 def stop(pidfile, app):
     if os.path.exists(pidfile):
         pid = int(open(pidfile).read())
+        try:
             os.kill(pid, signal.SIGTERM)
             write("stopped %s" % (app,), colour=GREEN)
+        except OSError, err:
+            if err.errno == errno.ESRCH:
+                write("%s not running" % (app,), colour=YELLOW)
+            elif err.errno == errno.EPERM:
+                abort("Cannot stop %s: Operation not permitted" % (app,))
+            else:
+                abort("Cannot stop %s: Unknown error" % (app,))
 
 
 Worker = collections.namedtuple("Worker", [
@@ -190,7 +217,19 @@ def main():
         if start_stop_synapse:
             stop(pidfile, "synapse.app.homeserver")
 
-        # TODO: Wait for synapse to actually shutdown before starting it again
+    # Wait for synapse to actually shutdown before starting it again
+    if action == "restart":
+        running_pids = []
+        if start_stop_synapse and os.path.exists(pidfile):
+            running_pids.append(int(open(pidfile).read()))
+        for worker in workers:
+            if os.path.exists(worker.pidfile):
+                running_pids.append(int(open(worker.pidfile).read()))
+        if len(running_pids) > 0:
+            write("Waiting for process to exit before restarting...")
+            for running_pid in running_pids:
+                while pid_running(running_pid):
+                    time.sleep(0.2)
 
     if action == "start" or action == "restart":
         if start_stop_synapse: