Detect picamera in use error

openflexure_microscope/rescue/check_picamera.py

@@ -13,13 +13,17 @@ picamera_errors = (
     "Camera is not enabled. Try running 'sudo raspi-config' and ensure that the camera has been enabled.",
 )
 
+picamera_mmal_errors = {
+    "Failed to enable connection: Out of resources": "Camera already in use by another application."
+}
+
 
 def main():
     error_sources = []
     logging.info("Attempting to import picamera...")
 
     try:
-        from picamerax import PiCamera
+        import picamerax
     except Exception as e:  # pylint: disable=W0703
         # TODO: Parse exception object for a few different issues, and append
         # different error sources E.g. pi with camera already in use,
@@ -27,12 +31,14 @@ def main():
         logging.error(e)
         error_sources.append(picamera_import_error)
     else:
-        import picamerax.exc.PiCameraError
-
         try:
-            cam = PiCamera()
-        except picamerax.exc.PiCameraError as e:
+            cam = picamerax.PiCamera()
+        except picamerax.PiCameraError as e:
             if e.args[0] in picamera_errors:
                 error_sources.append(ErrorSource(e.args[0]))
+            elif e.args[0] in picamera_mmal_errors:
+                error_sources.append(ErrorSource(picamera_mmal_errors[e.args[0]]))
+            else:
+                error_sources.append(ErrorSource(e.args[0]))
 
     return error_sources