Fixed broken error handling for long-running tasks

openflexure_microscope/api/utilities.py

@@ -1,6 +1,7 @@
 import pprint
+import logging
 import copy
-
+from werkzeug.exceptions import BadRequest
 
 class JsonPayload:
     def __init__(self, request):
@@ -8,7 +9,11 @@ class JsonPayload:
         Object to wrap up simple functionality for parsing a JSON response.
         """
         # Try to load as json
-        self.json = request.get_json()  #: dict: Dictionary representation of request JSON
+        try:
+            self.json = request.get_json()  #: dict: Dictionary representation of request JSON
+        except BadRequest as e:
+            logging.error(e)
+            self.json = {}
 
         if self.json is None:
             self.json = {}

openflexure_microscope/api/v1/blueprints/task.py

@@ -43,6 +43,8 @@ class TaskListAPI(MicroscopeView):
         :>header Content-Type: application/json
         """
 
+        print(self.microscope.task.state)
+
         data = self.microscope.task.state
 
         return jsonify(data)

openflexure_microscope/plugins/example/api.py

@@ -74,3 +74,22 @@ class LongRunningAPI(MicroscopeViewPlugin):
 
         except TaskDeniedException:
             return abort(409)
+
+class SomeExceptionAPI(MicroscopeViewPlugin):
+    """
+    An example API plugin that uses a long-running but broken plugin method.
+    """
+    def post(self):
+        """
+        Method to call when an HTTP POST request is made.
+        """
+        # Get payload JSON
+        payload = JsonPayload(request)
+
+        # Attach the long-running method as a microscope task
+        try:
+            task = self.microscope.task.start(self.plugin.some_exception)
+            return jsonify(task.state), 202
+
+        except TaskDeniedException:
+            return abort(409)

openflexure_microscope/plugins/example/plugin.py

@@ -2,7 +2,7 @@ import random
 import time
 from openflexure_microscope.plugins import MicroscopePlugin
 
-from .api import IdentifyAPI, HelloWorldAPI, LongRunningAPI
+from .api import IdentifyAPI, HelloWorldAPI, LongRunningAPI, SomeExceptionAPI
 
 
 class Plugin(MicroscopePlugin):
@@ -14,6 +14,7 @@ class Plugin(MicroscopePlugin):
         '/identify': IdentifyAPI,
         '/hello': HelloWorldAPI,
         '/long_running': LongRunningAPI,
+        '/some_exception': SomeExceptionAPI,
     }
 
     def identify(self):
@@ -32,6 +33,16 @@ class Plugin(MicroscopePlugin):
 
         return "Hello world!"
 
+    def some_exception(self):
+        """
+        Demonstrate some broken plugin method that would be long running
+        """
+        with self.microscope.lock:
+            time.sleep(3)
+            result = 15./0
+
+        return result
+
     def long_running(self, t_run):
         """
         Demonstrate a long-running method that requires microscope hardware

openflexure_microscope/task.py

@@ -1,6 +1,8 @@
 from threading import Thread
 from functools import wraps
 import datetime
+import logging
+import traceback
 import time
 import uuid
 
@@ -111,7 +113,9 @@ class Task:
                 r = f(*args, **kwargs)
                 s = 'success'
             except Exception as e:
-                r = e
+                logging.error(e)
+                logging.error(traceback.format_exc())
+                r = str(e)
                 s = 'error'
             self.state['return'] = r
             self.state['status'] = s