deamon: make more robust against serial errors

This should let the script continue to run when the board is
disconnected.

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 48 insertions, 5 deletions

diff --git a/daemon.py b/daemon.py
index 769e6d5..8a61442 100755
--- a/daemon.py
+++ b/daemon.py
@@ -15,11 +15,20 @@ class Config:
     display_width = 16
     display_length = display_lines * display_width
 
+class DaemonException(Exception):
+    pass
+
 class Daemon:
     line = ""
     playing = False
 
     def __init__(self):
+        try:
+            self.connect()
+        except (serial.SerialException):
+            raise DaemonException()
+
+    def connect(self):
         self.ser = serial.Serial(sys.argv[1], 9600, timeout=1)
         logger.debug("connected. waiting for client greeting")
 
@@ -40,7 +49,34 @@ class Daemon:
         logger.debug("connected to mpd")
 
     def readline(self):
-        return self.ser.readline().decode("ascii").strip()
+        logger.debug("Reading from serial")
+
+        try:
+            return self.ser.readline().decode("ascii").strip()
+        except (serial.SerialException):
+            logger.warning("Got exception when reading, trying to close connection")
+            self.ser.close()
+            raise DaemonException()
+
+    def write(self, msg):
+        logger.debug("Writing '%s' to serial", msg)
+
+        try:
+            return self.ser.write(msg)
+        except (serial.SerialException, OSError):
+            logger.warning("Got exception when writing, trying to close connection")
+            self.ser.close()
+            raise DaemonException()
+
+    def inWaiting(self):
+        logger.debug("Checking inWaiting for serial")
+
+        try:
+            return self.ser.inWaiting()
+        except (serial.SerialException, OSError):
+            logger.warning("Got exception when inWaiting, trying to close connection")
+            self.ser.close()
+            raise DaemonException()
 
     def update(self):
         old_line = self.line
@@ -76,7 +112,7 @@ class Daemon:
             now = time.time()
 
             # check for incoming commands from arduino
-            if self.ser.inWaiting() > 0:
+            if self.inWaiting() > 0:
                 incoming = self.readline()
 
                 logger.info("got serial command: '%s'", incoming)
@@ -136,10 +172,17 @@ class Daemon:
                     current_position = 0
 
                 logger.debug("current_position = %s, buf = '%s'", str(current_position).rjust(3), buf)
-                self.ser.write(bytes(buf, "ascii", "replace"))
+                self.write(bytes(buf, "ascii", "replace"))
 
             time.sleep(0.05)
 
 if __name__ == '__main__':
-    d = Daemon()
-    d.run()
+    while 1:
+        try:
+            d = Daemon()
+            d.run()
+        except DaemonException as e:
+            obj = sys.exc_info()[0].__name__
+            logger.warning("ignored {0}: {1}".format(obj, e))
+            time.sleep(1)
+            pass