fix: use native python function to create non-blocking pipe.

Thanks @azlux for this solution. Close #116.

Also created an option 'redirect_ffmpeg_log' to enable/disable
reading the log of ffmpeg.

configuration.default.ini

@@ -105,6 +105,7 @@ password =
 [debug]
 # Set ffmpeg to True if you want to display DEBUG level log of ffmpeg.
 ffmpeg = False
+redirect_ffmpeg_log = True
 mumbleConnection = False
 
 # This is a list of default radio stations.

mumbleBot.py

@@ -162,6 +162,8 @@ class MumbleBot:
         self._display_rms = False
         self._max_rms = 0
 
+        self.redirect_ffmpeg_log = var.config.getboolean('debug', 'redirect_ffmpeg_log', fallback=True)
+
     # Set the CTRL+C shortcut
     def ctrl_caught(self, signal, frame):
 
@@ -375,9 +377,12 @@ class MumbleBot:
 
         # The ffmpeg process is a thread
         # prepare pipe for catching stderr of ffmpeg
-        pipe_rd, pipe_wd = os.pipe()
+        if self.redirect_ffmpeg_log:
-        util.pipe_no_wait(pipe_rd)  # Let the pipe work in non-blocking mode
+            pipe_rd, pipe_wd = util.pipe_no_wait()  # Let the pipe work in non-blocking mode
-        self.thread_stderr = os.fdopen(pipe_rd)
+            self.thread_stderr = os.fdopen(pipe_rd)
+        else:
+            pipe_rd, pipe_wd = None, None
+
         self.thread = sp.Popen(command, stdout=sp.PIPE, stderr=pipe_wd, bufsize=480)
         self.is_pause = False
         self.read_pcm_size = 0
@@ -449,12 +454,13 @@ class MumbleBot:
                 raw_music = self.thread.stdout.read(480)
                 self.read_pcm_size += 480
 
-                try:
+                if self.redirect_ffmpeg_log:
-                    self.last_ffmpeg_err = self.thread_stderr.readline()
+                    try:
-                    if self.last_ffmpeg_err:
+                        self.last_ffmpeg_err = self.thread_stderr.readline()
-                        self.log.debug("ffmpeg: " + self.last_ffmpeg_err.strip("\n"))
+                        if self.last_ffmpeg_err:
-                except:
+                            self.log.debug("ffmpeg: " + self.last_ffmpeg_err.strip("\n"))
-                    pass
+                    except:
+                        pass
 
                 if raw_music:
                     # Adjust the volume and send it to mumble
@@ -623,9 +629,12 @@ class MumbleBot:
         self.log.info("bot: execute ffmpeg command: " + " ".join(command))
         # The ffmpeg process is a thread
         # prepare pipe for catching stderr of ffmpeg
-        pipe_rd, pipe_wd = os.pipe()
+        if self.redirect_ffmpeg_log:
-        util.pipe_no_wait(pipe_rd)  # Let the pipe work in non-blocking mode
+            pipe_rd, pipe_wd = util.pipe_no_wait()  # Let the pipe work in non-blocking mode
-        self.thread_stderr = os.fdopen(pipe_rd)
+            self.thread_stderr = os.fdopen(pipe_rd)
+        else:
+            pipe_rd, pipe_wd = None, None
+
         self.thread = sp.Popen(command, stdout=sp.PIPE, stderr=pipe_wd, bufsize=480)
         self.last_volume_cycle_time = time.time()
         self.pause_at_id = ""

util.py

@@ -163,19 +163,29 @@ def url_unban(url):
     return res
 
 
-def pipe_no_wait(pipefd):
+def pipe_no_wait():
-    """ Used to fetch the STDERR of ffmpeg. pipefd is the file descriptor returned from os.pipe()"""
+    """ Generate a non-block pipe used to fetch the STDERR of ffmpeg.
+    """
+
     if platform == "linux" or platform == "linux2" or platform == "darwin":
         import fcntl
         import os
-        try:
+
-            fl = fcntl.fcntl(pipefd, fcntl.F_GETFL)
+        pipe_rd = 0
-            fcntl.fcntl(pipefd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
+        pipe_wd = 0
-        except:
+
-            print(sys.exc_info()[1])
+        if hasattr(os, "pipe2"):
-            return False
+            pipe_rd, pipe_wd = os.pipe2(os.O_NONBLOCK)
         else:
-            return True
+            pipe_rd, pipe_wd = os.pipe()
+
+            try:
+                fl = fcntl.fcntl(pipe_rd, fcntl.F_GETFL)
+                fcntl.fcntl(pipe_rd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
+            except:
+                print(sys.exc_info()[1])
+                return None, None
+            return pipe_rd, pipe_wd
 
     elif platform == "win32":
         # https://stackoverflow.com/questions/34504970/non-blocking-read-on-os-pipe-on-windows
@@ -185,6 +195,8 @@ def pipe_no_wait(pipefd):
         from ctypes import windll, byref, wintypes, WinError, POINTER
         from ctypes.wintypes import HANDLE, DWORD, BOOL
 
+        pipe_rd, pipe_wd = os.pipe()
+
         LPDWORD = POINTER(DWORD)
         PIPE_NOWAIT = wintypes.DWORD(0x00000001)
         ERROR_NO_DATA = 232
@@ -193,13 +205,13 @@ def pipe_no_wait(pipefd):
         SetNamedPipeHandleState.argtypes = [HANDLE, LPDWORD, LPDWORD, LPDWORD]
         SetNamedPipeHandleState.restype = BOOL
 
-        h = msvcrt.get_osfhandle(pipefd)
+        h = msvcrt.get_osfhandle(pipe_rd)
 
         res = windll.kernel32.SetNamedPipeHandleState(h, byref(PIPE_NOWAIT), None, None)
         if res == 0:
             print(WinError())
-            return False
+            return None, None
-        return True
+        return pipe_rd, pipe_wd
 
 
 class Dir(object):