change technic to detect running liquidsoap instance

aircox/controllers.py

@@ -141,21 +141,17 @@ class Streamer:
         """
         Check if there is a process that has not been killed
         """
-        # TODO: this method does not work in case the working
-        #       directory has been erased then regenerated
-        if not os.path.exists(self.path + ".pid"):
+        if not os.path.exists(self.socket_path):
             return
 
-        with open(self.path + ".pid") as file:
-            pid = file.read()
-            os.kill(int(pid), signal.SIGKILL)
-
-    def __prevent_zombie(self):
-        """
-        Write process pid
-        """
-        with open(self.path + ".pid", "w") as file:
-            file.write(str(self.process.pid))
+        import psutil
+        conns = [
+            conn for conn in psutil.net_connections(kind='unix')
+            if conn.laddr == self.socket_path
+        ]
+        for conn in conns:
+            if conn.pid is not None:
+                os.kill(conn.pid, signal.SIGKILL)
 
     def process_run(self):
         """
@@ -174,7 +170,6 @@ class Streamer:
 
         self.__check_for_zombie()
         self.process = subprocess.Popen(args, stderr=subprocess.STDOUT)
-        self.__prevent_zombie()
         atexit.register(lambda: self.process_terminate())
 
     def process_terminate(self):
@@ -186,9 +181,6 @@ class Streamer:
             self.process.kill()
             self.process = None
 
-            # the zombie has been killed
-            os.remove(self.path + ".pid")
-
     def process_wait(self):
         """
         Wait for the process to terminate if there is a process

requirements.txt

@@ -3,6 +3,7 @@ Django>=1.10.3
 django-taggit>=0.18.3
 mutagen==1.35.1
 watchdog>=0.8.3
+psutil>=5.0.1
 dateutils>=0.6.6
 bleach>=1.4.3
 django-htmlmin>=0.10.0