Simplify daemon mechanism.

1 files changed, 40 insertions, 126 deletions

diff --git a/bazarr.py b/bazarr.py
index 9466fbd02..30aa26755 100644
--- a/bazarr.py
+++ b/bazarr.py
@@ -2,28 +2,25 @@
 
 import os
 import platform
-import signal
 import subprocess
 import sys
 import time
+import atexit
 
 from bazarr.get_args import args
-from libs.six import PY3
 
 
 def check_python_version():
     python_version = platform.python_version_tuple()
-    minimum_py2_tuple = (2, 7, 13)
     minimum_py3_tuple = (3, 7, 0)
-    minimum_py2_str = ".".join(str(i) for i in minimum_py2_tuple)
     minimum_py3_str = ".".join(str(i) for i in minimum_py3_tuple)
 
-    if int(python_version[0]) < 3:
+    if int(python_version[0]) < minimum_py3_tuple[0]:
         print("Python " + minimum_py3_str + " or greater required. "
               "Current version is " + platform.python_version() + ". Please upgrade Python.")
         sys.exit(1)
     elif (int(python_version[0]) == minimum_py3_tuple[0] and int(python_version[1]) < minimum_py3_tuple[1]) or \
-            (int(python_version[0]) != minimum_py3_tuple[0] and int(python_version[0]) != minimum_py2_tuple[0]):
+            (int(python_version[0]) != minimum_py3_tuple[0]):
         print("Python " + minimum_py3_str + " or greater required. "
               "Current version is " + platform.python_version() + ". Please upgrade Python.")
         sys.exit(1)
@@ -34,138 +31,55 @@ check_python_version()
 dir_name = os.path.dirname(__file__)
 
 
-class ProcessRegistry:
-
-    def register(self, process):
-        pass
-
-    def unregister(self, process):
-        pass
-
-
-class DaemonStatus(ProcessRegistry):
-
-    def __init__(self):
-        self.__should_stop = False
-        self.__processes = set()
-
-    def register(self, process):
-        self.__processes.add(process)
-
-    def unregister(self, process):
-        self.__processes.remove(process)
-
-    @staticmethod
-    def __send_signal(processes, signal_no, live_processes=None):
-        """
-        Sends to every single of the specified processes the given signal and (if live_processes is not None) append to
-        it processes which are still alive.
-        """
-        for ep in processes:
-            if ep.poll() is None:
-                if live_processes is not None:
-                    live_processes.append(ep)
-                try:
-                    ep.send_signal(signal_no)
-                except Exception as e:
-                    print('Failed sending signal %s to process %s because of an unexpected error: %s' % (
-                        signal_no, ep.pid, e))
-        return live_processes
-
-    def stop(self):
-        """
-        Flags this instance as should stop and terminates as smoothly as possible children processes.
-        """
-        self.__should_stop = True
-        DaemonStatus.__send_signal(self.__processes, signal.SIGINT, list())
-
-    def force_stop(self):
-        self.__should_stop = True
-        DaemonStatus.__send_signal(self.__processes, signal.SIGTERM)
-
-    def should_stop(self):
-        return self.__should_stop
-
-
-def start_bazarr(process_registry=ProcessRegistry()):
+def start_bazarr():
     script = [sys.executable, "-u", os.path.normcase(os.path.join(dir_name, 'bazarr', 'main.py'))] + sys.argv[1:]
-
-    print("Bazarr starting...")
-    if PY3:
-        ep = subprocess.Popen(script, stdout=None, stderr=None, stdin=subprocess.DEVNULL)
-    else:
-        ep = subprocess.Popen(script, stdout=None, stderr=None, stdin=None)
-    process_registry.register(ep)
-    try:
-        ep.wait()
-        process_registry.unregister(ep)
-    except KeyboardInterrupt:
-        pass
+    ep = subprocess.Popen(script, stdout=None, stderr=None, stdin=subprocess.DEVNULL)
+    atexit.register(lambda: ep.kill())
+
+
+def check_status():
+    if os.path.exists(stopfile):
+        try:
+            os.remove(stopfile)
+        except Exception:
+            print('Unable to delete stop file.')
+        finally:
+            print('Bazarr exited.')
+            sys.exit(0)
+
+    if os.path.exists(restartfile):
+        try:
+            os.remove(restartfile)
+        except Exception:
+            print('Unable to delete restart file.')
+        else:
+            print("Bazarr is restarting...")
+            start_bazarr()
 
 
 if __name__ == '__main__':
-    restartfile = os.path.normcase(os.path.join(args.config_dir, 'bazarr.restart'))
-    stopfile = os.path.normcase(os.path.join(args.config_dir, 'bazarr.stop'))
+    restartfile = os.path.join(args.config_dir, 'bazarr.restart')
+    stopfile = os.path.join(args.config_dir, 'bazarr.stop')
 
+    # Cleanup leftover files
     try:
         os.remove(restartfile)
-    except Exception:
+    except FileNotFoundError:
         pass
 
     try:
         os.remove(stopfile)
-    except Exception:
+    except FileNotFoundError:
         pass
 
-
-    def daemon(bazarr_runner=lambda: start_bazarr()):
-        if os.path.exists(stopfile):
-            try:
-                os.remove(stopfile)
-            except Exception:
-                print('Unable to delete stop file.')
-            else:
-                print('Bazarr exited.')
-                sys.exit(0)
-
-        if os.path.exists(restartfile):
-            try:
-                os.remove(restartfile)
-            except Exception:
-                print('Unable to delete restart file.')
-            else:
-                bazarr_runner()
-
-
-    bazarr_runner = lambda: start_bazarr()
-
-    should_stop = lambda: False
-
-    if PY3:
-        daemonStatus = DaemonStatus()
-
-        def force_shutdown():
-            # force the killing of children processes
-            daemonStatus.force_stop()
-            # if a new SIGTERM signal is caught the standard behaviour should be followed
-            signal.signal(signal.SIGTERM, signal.SIG_DFL)
-            # emulate a Ctrl C command on itself (bypasses the signal thing but, then, emulates the "Ctrl+C break")
-            os.kill(os.getpid(), signal.SIGINT)
-    
-        def shutdown():
-            # indicates that everything should stop
-            daemonStatus.stop()
-            # if a new sigterm signal is caught it should force the shutdown of children processes
-            signal.signal(signal.SIGTERM, lambda signal_no, frame: force_shutdown())
-
-        signal.signal(signal.SIGTERM, lambda signal_no, frame: shutdown())
-
-        should_stop = lambda: daemonStatus.should_stop()
-        bazarr_runner = lambda: start_bazarr(daemonStatus)
-
-    bazarr_runner()
+    # Initial start of main bazarr process
+    print("Bazarr starting...")
+    start_bazarr()
 
     # Keep the script running forever until stop is requested through term or keyboard interrupt
-    while not should_stop():
-        daemon(bazarr_runner)
-        time.sleep(1)
+    while True:
+        check_status()
+        try:
+            time.sleep(1)
+        except (KeyboardInterrupt, SystemExit):
+            pass