Added support for Entity Trigger (#68)

* added durable entities trigger

* fixed style error

* more style issues

* exported entitycontext, generalized tests

* flake8 errors now fixed

Co-authored-by: Varad Meru <vrdmr@users.noreply.github.com>

Author: davidmrdavid

azure/functions/__init__.py

@@ -11,7 +11,7 @@
 from .kafka import KafkaEvent, KafkaConverter, KafkaTriggerConverter  # NoQA
 from ._queue import QueueMessage  # NoQA
 from ._servicebus import ServiceBusMessage  # NoQA
-from ._durable_functions import OrchestrationContext  # NoQA
+from ._durable_functions import OrchestrationContext, EntityContext  # NoQA
 from .meta import get_binding_registry  # NoQA
 
 # Import binding implementations to register them
@@ -47,6 +47,7 @@
     'KafkaConverter',
     'KafkaTriggerConverter',
     'OrchestrationContext',
+    'EntityContext',
     'QueueMessage',
     'ServiceBusMessage',
     'TimerRequest',

azure/functions/_durable_functions.py

@@ -109,3 +109,31 @@ def __repr__(self):
 
     def __str__(self):
         return self.__body
+
+
+class EntityContext(_abc.OrchestrationContext):
+    """A durable function entity context.
+
+    :param str body:
+        The body of orchestration context json.
+    """
+
+    def __init__(self,
+                 body: Union[str, bytes]) -> None:
+        if isinstance(body, str):
+            self.__body = body
+        if isinstance(body, bytes):
+            self.__body = body.decode('utf-8')
+
+    @property
+    def body(self) -> str:
+        return self.__body
+
+    def __repr__(self):
+        return (
+            f'<azure.EntityContext '
+            f'body={self.body}>'
+        )
+
+    def __str__(self):
+        return self.__body

azure/functions/durable_functions.py

@@ -39,6 +39,36 @@ def has_implicit_output(cls) -> bool:
         return True
 
 
+class EnitityTriggerConverter(meta.InConverter,
+                              meta.OutConverter,
+                              binding='entityTrigger',
+                              trigger=True):
+    @classmethod
+    def check_input_type_annotation(cls, pytype):
+        return issubclass(pytype, _durable_functions.EntityContext)
+
+    @classmethod
+    def check_output_type_annotation(cls, pytype):
+        # Implicit output should accept any return type
+        return True
+
+    @classmethod
+    def decode(cls,
+               data: meta.Datum, *,
+               trigger_metadata) -> _durable_functions.EntityContext:
+        return _durable_functions.EntityContext(data.value)
+
+    @classmethod
+    def encode(cls, obj: typing.Any, *,
+               expected_type: typing.Optional[type]) -> meta.Datum:
+        # Durable function context should be a json
+        return meta.Datum(type='json', value=obj)
+
+    @classmethod
+    def has_implicit_output(cls) -> bool:
+        return True
+
+
 # Durable Function Activity Trigger
 class ActivityTriggerConverter(meta.InConverter,
                                meta.OutConverter,

tests/test_durable_functions.py

@@ -6,77 +6,93 @@
 
 from azure.functions.durable_functions import (
     OrchestrationTriggerConverter,
+    EnitityTriggerConverter,
     ActivityTriggerConverter
 )
-from azure.functions._durable_functions import OrchestrationContext
+from azure.functions._durable_functions import (
+    OrchestrationContext,
+    EntityContext
+)
 from azure.functions.meta import Datum
 
+CONTEXT_CLASSES = [OrchestrationContext, EntityContext]
+CONVERTERS = [OrchestrationTriggerConverter, EnitityTriggerConverter]
 
-class TestDurableFunctions(unittest.TestCase):
-    def test_orchestration_context_string_body(self):
-        raw_string = '{ "name": "great function" }'
-        context = OrchestrationContext(raw_string)
-        self.assertIsNotNone(getattr(context, 'body', None))
-
-        content = json.loads(context.body)
-        self.assertEqual(content.get('name'), 'great function')
-
-    def test_orchestration_context_string_cast(self):
-        raw_string = '{ "name": "great function" }'
-        context = OrchestrationContext(raw_string)
-        self.assertEqual(str(context), raw_string)
-
-        content = json.loads(str(context))
-        self.assertEqual(content.get('name'), 'great function')
-
-    def test_orchestration_context_bytes_body(self):
-        raw_bytes = '{ "name": "great function" }'.encode('utf-8')
-        context = OrchestrationContext(raw_bytes)
-        self.assertIsNotNone(getattr(context, 'body', None))
-
-        content = json.loads(context.body)
-        self.assertEqual(content.get('name'), 'great function')
-
-    def test_orchestration_context_bytes_cast(self):
-        raw_bytes = '{ "name": "great function" }'.encode('utf-8')
-        context = OrchestrationContext(raw_bytes)
-        self.assertIsNotNone(getattr(context, 'body', None))
 
-        content = json.loads(context.body)
-        self.assertEqual(content.get('name'), 'great function')
-
-    def test_orchestration_trigger_converter(self):
+class TestDurableFunctions(unittest.TestCase):
+    def test_context_string_body(self):
+        body = '{ "name": "great function" }'
+        for ctx in CONTEXT_CLASSES:
+            context = ctx(body)
+            self.assertIsNotNone(getattr(context, 'body', None))
+
+            content = json.loads(context.body)
+            self.assertEqual(content.get('name'), 'great function')
+
+    def test_context_string_cast(self):
+        body = '{ "name": "great function" }'
+        for ctx in CONTEXT_CLASSES:
+            context = ctx(body)
+            self.assertEqual(str(context), body)
+
+            content = json.loads(str(context))
+            self.assertEqual(content.get('name'), 'great function')
+
+    def test_context_bytes_body(self):
+        body = '{ "name": "great function" }'.encode('utf-8')
+        for ctx in CONTEXT_CLASSES:
+            context = ctx(body)
+            self.assertIsNotNone(getattr(context, 'body', None))
+
+            content = json.loads(context.body)
+            self.assertEqual(content.get('name'), 'great function')
+
+    def test_context_bytes_cast(self):
+        # TODO: this is just like the test above
+        # (test_orchestration_context_bytes_body)
+        body = '{ "name": "great function" }'.encode('utf-8')
+        for ctx in CONTEXT_CLASSES:
+            context = ctx(body)
+            self.assertIsNotNone(getattr(context, 'body', None))
+
+            content = json.loads(context.body)
+            self.assertEqual(content.get('name'), 'great function')
+
+    def test_trigger_converter(self):
         datum = Datum(value='{ "name": "great function" }',
                       type=str)
-        otc = OrchestrationTriggerConverter.decode(datum,
-                                                   trigger_metadata=None)
-        content = json.loads(otc.body)
-        self.assertEqual(content.get('name'), 'great function')
+        for converter in CONVERTERS:
+            otc = converter.decode(datum, trigger_metadata=None)
+            content = json.loads(otc.body)
+            self.assertEqual(content.get('name'), 'great function')
 
-    def test_orchestration_trigger_converter_type(self):
+    def test_trigger_converter_type(self):
         datum = Datum(value='{ "name": "great function" }'.encode('utf-8'),
                       type=bytes)
-        otc = OrchestrationTriggerConverter.decode(datum,
-                                                   trigger_metadata=None)
-        content = json.loads(otc.body)
-        self.assertEqual(content.get('name'), 'great function')
+        for converter in CONVERTERS:
+            otc = converter.decode(datum, trigger_metadata=None)
+            content = json.loads(otc.body)
+            self.assertEqual(content.get('name'), 'great function')
 
-    def test_orchestration_trigger_check_good_annotation(self):
-        for dt in (OrchestrationContext,):
+    def test_trigger_check_good_annotation(self):
+
+        for converter, ctx in zip(CONVERTERS, CONTEXT_CLASSES):
             self.assertTrue(
-                OrchestrationTriggerConverter.check_input_type_annotation(dt)
+                converter.check_input_type_annotation(ctx)
             )
 
-    def test_orchestration_trigger_check_bad_annotation(self):
+    def test_trigger_check_bad_annotation(self):
         for dt in (str, bytes, int):
-            self.assertFalse(
-                OrchestrationTriggerConverter.check_input_type_annotation(dt)
-            )
+            for converter in CONVERTERS:
+                self.assertFalse(
+                    converter.check_input_type_annotation(dt)
+                )
 
-    def test_orchestration_trigger_has_implicit_return(self):
-        self.assertTrue(
-            OrchestrationTriggerConverter.has_implicit_output()
-        )
+    def test_trigger_has_implicit_return(self):
+        for converter in CONVERTERS:
+            self.assertTrue(
+                converter.has_implicit_output()
+            )
 
     def test_activity_trigger_inputs(self):
         # Activity Trigger only accept string type from durable extensions