Add an additional 'restarting' message to the bus to enable better fe…

…edback to be reported

ui/driver/driver.py

@@ -46,6 +46,11 @@ def get_data(self, expected_cmd):
     def send_data(self, cmd, data=[]):
         return
 
+    def restarting(self, restart):
+        # indicates we're starting a restart to reset the display / re-read
+        # data / reconnect after timeout
+        return
+
     @abc.abstractmethod
     async def async_get_data(self, cmd, data=[]):
         return

ui/driver/driver_pi.py

@@ -1,3 +1,4 @@
+import sys
 import time
 from .driver import Driver
 import asyncio
@@ -83,7 +84,8 @@ def setup_serial(self, port):
             return serial_port
         except IOError as e:
             log.error('check usb connection to arduino %s', e)
-            exit(1)
+            self.restarting('no-connection')
+            sys.exit(1)
 
     def is_ok(self):
         """checks the serial connection. There doesn't seem to be a specific
@@ -176,6 +178,10 @@ def _publish_line(self, row, content):
         self.socket.send_pyobj(
             {'line_number': row, 'visual': brf, 'braille': brl})
 
+    def restarting(self, reason):
+        if hasattr(self, 'context'):
+            self.socket.send_pyobj({'restarting': reason})
+
     async def async_get_data(self, expected_cmd):
         """gets 2 bytes of data from the hardware
 
@@ -213,6 +219,9 @@ def get_data(self, expected_cmd):
             # where it lands, since this interface makes no allowance
             # for failure.
             raise e
+        except OSError as e:
+            # Input/output error
+            raise e
         except RuntimeError as e:
             # No complete frame within timeout.  Same again.
             raise e

ui/main.py

@@ -84,7 +84,18 @@ def main():
         try:
             debounce = config.get('hardware', {}).get('button_debounce', 1)
             with Pi(port=args.tty, timeout=timeout, button_threshold=debounce) as driver:
-                run(driver, config)
+                try:
+                    run(driver, config)
+                except ValueError as err:
+                    if err.args[0] == 'Invalid Frame (CRC FAIL)':
+                        log.info('USB B I/O error, canute probably switched off')
+                        driver.restarting('disconnected')
+                        sys.exit(0)
+                except OSError as err:
+                    if err.errno == 5:
+                        log.info('USB B I/O error, canute probably switched off')
+                        driver.restarting('disconnected')
+                        sys.exit(0)
         except RuntimeError as err:
             if err.args[0] == 'readFrame timeout':
                 log.info(
@@ -113,7 +124,7 @@ async def run_async_timeout(driver, config, duration, loop):
 
 # This is a task in its own right that listens to an external process for media
 # change notifications, and handles them.
-async def handle_media_changes(media_helper):
+async def handle_media_changes(media_helper, driver):
     proc = await asyncio.create_subprocess_exec(
         media_helper, stdout=asyncio.subprocess.PIPE)
 
@@ -136,6 +147,7 @@ def stop_helper(*args):
             # For now we do nothing more sophisticated than die and allow
             # supervision to restart us, at which point we'll rescan the
             # library.
+            driver.restarting('media')
             sys.exit(0)
 
 
@@ -159,9 +171,14 @@ async def run_async(driver, config, loop):
 
     media_helper = config.get('filese', {}).get('media_helper')
     if media_helper is not None:
-        media_handler = asyncio.ensure_future(handle_media_changes(media_helper))
+        media_handler = asyncio.ensure_future(handle_media_changes(media_helper, driver))
     else:
         media_handler = None
+        def sighup_helper(*args):
+            log.debug('shutting down for library rescan')
+            driver.restarting('media')
+            sys.exit(0)
+        signal.signal(signal.SIGHUP, sighup_helper)
 
     if config.get('hardware', {}).get('log_duty', False):
         duty_logger = asyncio.ensure_future(driver.track_duty())
@@ -309,6 +326,7 @@ async def handle_hardware(driver, state, media_dir):
         return True
     elif state.hardware.resetting_display == 'start':
         log.warning('long-press of square: exiting to cause reset')
+        driver.restarting('reset')
         sys.exit(0)
     elif state.hardware.warming_up == 'start':
         state.hardware.warm_up('in progress')