From 293c3b077d37f4ca9f9690a771e916fdd9b531fc Mon Sep 17 00:00:00 2001
From: Griatch <griatch@gmail.com>
Date: Thu, 8 Dec 2016 23:24:14 +0100
Subject: [PATCH] Add external-runner option to the launcher to allow for
 replacing the native evennia runner with an external process manager (like
 Linux' start-stop-daemon). Note that without a replacement, this option will
 make evennia un-reloadable.

---
 evennia/server/evennia_launcher.py | 14 ++++++++++++--
 evennia/server/evennia_runner.py   | 22 +++++++++++++++++-----
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/evennia/server/evennia_launcher.py b/evennia/server/evennia_launcher.py
index 65d1db73d3..36aa64f16d 100644
--- a/evennia/server/evennia_launcher.py
+++ b/evennia/server/evennia_launcher.py
@@ -1084,7 +1084,7 @@ def run_menu():
         return
 
 
-def server_operation(mode, service, interactive, profiler, logserver=False):
+def server_operation(mode, service, interactive, profiler, logserver=False, doexit=False):
     """
     Handle argument options given on the command line.
 
@@ -1095,6 +1095,10 @@ def server_operation(mode, service, interactive, profiler, logserver=False):
         profiler (bool): Run the service under the profiler.
         logserver (bool, optional): Log Server data to logfile
             specified by settings.SERVER_LOG_FILE.
+        doexit (bool, optional): If True, immediately exit the runner after
+            starting the relevant processes. If the runner exits, Evennia
+            cannot be reloaded. This is meant to be used with an external
+            process manager like Linux' start-stop-daemon.
 
     """
 
@@ -1136,6 +1140,8 @@ def server_operation(mode, service, interactive, profiler, logserver=False):
                 cmdstr.append('--logserver')
             django.core.management.call_command(
                 'collectstatic', verbosity=1, interactive=False)
+        if doexit:
+            cmdstr.append('--doexit')
         cmdstr.extend([
             GAMEDIR, TWISTED_BINARY, SERVER_LOGFILE,
             PORTAL_LOGFILE, HTTP_LOGFILE])
@@ -1242,6 +1248,10 @@ def main():
         '--initsettings', action='store_true', dest="initsettings",
         default=False,
         help="Create a new, empty settings file as gamedir/server/conf/settings.py.")
+    parser.add_argument(
+        '--external-runner', action='store_true', dest="doexit",
+        default=False,
+        help="Handle server restart with an external process manager.")
     parser.add_argument(
         "operation", nargs='?', default="noop",
         help="Operation to perform: 'start', 'stop', 'reload' or 'menu'.")
@@ -1315,7 +1325,7 @@ def main():
     elif option in ('start', 'reload', 'stop'):
         # operate the server directly
         init_game_directory(CURRENT_DIR, check_db=True)
-        server_operation(option, service, args.interactive, args.profiler, args.logserver)
+        server_operation(option, service, args.interactive, args.profiler, args.logserver, doexit=args.doexit)
     elif option != "noop":
         # pass-through to django manager
         check_db = False
diff --git a/evennia/server/evennia_runner.py b/evennia/server/evennia_runner.py
index ce9299f4f5..d963f8dd21 100644
--- a/evennia/server/evennia_runner.py
+++ b/evennia/server/evennia_runner.py
@@ -75,6 +75,7 @@ PROCESS_IOERROR = \
 
 PROCESS_RESTART = "{component} restarting ..."
 
+PROCESS_DOEXIT = "Deferring to external runner."
 
 # Functions
 
@@ -134,7 +135,7 @@ def cycle_logfile(logfile):
 # Start program management
 
 
-def start_services(server_argv, portal_argv):
+def start_services(server_argv, portal_argv, doexit=False):
     """
     This calls a threaded loop that launces the Portal and Server
     and then restarts them when they finish.
@@ -162,7 +163,7 @@ def start_services(server_argv, portal_argv):
 
     if portal_argv:
         try:
-            if get_restart_mode(PORTAL_RESTART) == "True":
+            if not doexit and get_restart_mode(PORTAL_RESTART) == "True":
                 # start portal as interactive, reloadable thread
                 PORTAL = thread.start_new_thread(portal_waiter, (processes, ))
             else:
@@ -175,12 +176,19 @@ def start_services(server_argv, portal_argv):
 
     try:
         if server_argv:
-            # start server as a reloadable thread
-            SERVER = thread.start_new_thread(server_waiter, (processes, ))
+            if doexit:
+                SERVER = Popen(server_argv, env=getenv())
+            else:
+                # start server as a reloadable thread
+                SERVER = thread.start_new_thread(server_waiter, (processes, ))
     except IOError as e:
         print(PROCESS_IOERROR.format(component="Server", traceback=e))
         return
 
+    if doexit:
+        # Exit immediately
+        return
+
     # Reload loop
     while True:
 
@@ -234,6 +242,8 @@ def main():
                         default=False, help='Profile Portal')
     parser.add_argument('--nologcycle', action='store_false', dest='nologcycle',
                         default=True, help='Do not cycle log files')
+    parser.add_argument('--doexit', action='store_true', dest='doexit',
+                        default=False, help='Immediately exit after processes have started.')
     parser.add_argument('gamedir', help="path to game dir")
     parser.add_argument('twistdbinary', help="path to twistd binary")
     parser.add_argument('slogfile', help="path to server log file")
@@ -327,6 +337,8 @@ def main():
         if args.pportal:
             portal_argv.extend(pportal_argv)
             print("\nRunning Evennia Portal under cProfile.")
+    if args.doexit:
+        print(PROCESS_DOEXIT)
 
     # Windows fixes (Windows don't support pidfiles natively)
     if os.name == 'nt':
@@ -336,7 +348,7 @@ def main():
             del portal_argv[-2]
 
     # Start processes
-    start_services(server_argv, portal_argv)
+    start_services(server_argv, portal_argv, doexit=args.doexit)
 
 if __name__ == '__main__':
     main()