Merge pull request #1044 from alephyud/expose-lambda-context

Provide Lambda context in event object

chalice/app.py

@@ -1126,7 +1126,7 @@ def __init__(self, func, event_class):
         self.event_class = event_class
 
     def __call__(self, event, context):
-        event_obj = self.event_class(event)
+        event_obj = self.event_class(event, context)
         return self.func(event_obj)
 
 
@@ -1135,8 +1135,9 @@ def __call__(self, event, context):
 # part of Chalice's public API and must be backwards compatible.
 
 class BaseLambdaEvent(object):
-    def __init__(self, event_dict):
+    def __init__(self, event_dict, context):
         self._event_dict = event_dict
+        self.context = context
         self._extract_attributes(event_dict)
 
     def _extract_attributes(self, event_dict):
@@ -1181,7 +1182,7 @@ def _extract_attributes(self, event_dict):
 
     def __iter__(self):
         for record in self._event_dict['Records']:
-            yield SQSRecord(record)
+            yield SQSRecord(record, self.context)
 
 
 class SQSRecord(BaseLambdaEvent):

docs/source/api.rst

@@ -827,6 +827,12 @@ Event Sources
       For scheduled events, this will include the ARN of the CloudWatch
       rule that triggered this event.
 
+   .. attribute:: context
+
+      A `Lambda context object <https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html>`_
+      that is passed to the handler by AWS Lambda. This is useful if you need
+      the AWS request ID for tracing, or any other data in the context object.
+
    .. method:: to_dict()
 
       Return the original event dictionary provided
@@ -875,6 +881,12 @@ Event Sources
       access to the original URL encoded key name, you can
       access it through the ``to_dict()`` method.
 
+   .. attribute:: context
+
+      A `Lambda context object <https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html>`_
+      that is passed to the handler by AWS Lambda. This is useful if you need
+      the AWS request ID for tracing, or any other data in the context object.
+
    .. method:: to_dict()
 
       Return the original event dictionary provided
@@ -911,6 +923,12 @@ Event Sources
 
       The string value of the SNS message that was published.
 
+   .. attribute:: context
+
+      A `Lambda context object <https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html>`_
+      that is passed to the handler by AWS Lambda. This is useful if you need
+      the AWS request ID for tracing, or any other data in the context object.
+
    .. method:: to_dict()
 
       Return the original event dictionary provided
@@ -942,6 +960,12 @@ Event Sources
       the event.  Each element in the iterable is of type
       :class:`SQSRecord`.
 
+   .. attribute:: context
+
+      A `Lambda context object <https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html>`_
+      that is passed to the handler by AWS Lambda. This is useful if you need
+      the AWS request ID for tracing, or any other data in the context object.
+
    .. method:: to_dict()
 
       Return the original event dictionary provided
@@ -965,6 +989,11 @@ Event Sources
       if you need to manually delete an SQS message to account for
       partial failures.
 
+   .. attribute:: context
+
+      A `Lambda context object <https://docs.aws.amazon.com/lambda/latest/dg/python-context-object.html>`_
+      that is passed to the handler by AWS Lambda.
+
    .. method:: to_dict()
 
       Return the original dictionary associated with the given

tests/unit/test_app.py

@@ -1480,7 +1480,7 @@ def test_s3_event_urldecodes_keys():
             }},
         ]
     }
-    event = app.S3Event(s3_event)
+    event = app.S3Event(s3_event, FakeLambdaContext())
     # We should urldecode the key name.
     assert event.key == 'file with spaces'
     # But the key should remain unchanged in to_dict().
@@ -1504,7 +1504,7 @@ def test_s3_event_urldecodes_unicode_keys():
             }},
         ]
     }
-    event = app.S3Event(s3_event)
+    event = app.S3Event(s3_event, FakeLambdaContext())
     # We should urldecode the key name.
     assert event.key == u'\u2713'
     assert event.bucket == u'mybucket'
@@ -1550,10 +1550,12 @@ def handler(event):
             'TopicArn': 'arn:aws:sns:us-west-2:12345:ConsoleTestTopic',
             'Type': 'Notification',
             'UnsubscribeUrl': 'https://unsubscribe-url/'}}]}
-    actual_event = handler(sns_event, context=None)
+    lambda_context = FakeLambdaContext()
+    actual_event = handler(sns_event, context=lambda_context)
     assert actual_event.message == 'This is a raw message'
     assert actual_event.subject == 'ThisIsTheSubject'
     assert actual_event.to_dict() == sns_event
+    assert actual_event.context == lambda_context
 
 
 def test_can_create_sqs_handler(sample_app):
@@ -1599,14 +1601,16 @@ def handler(event):
         'messageId': 'message-id',
         'receiptHandle': 'receipt-handle'
     }]}
-    actual_event = handler(sqs_event, context=None)
+    lambda_context = FakeLambdaContext()
+    actual_event = handler(sqs_event, context=lambda_context)
     records = list(actual_event)
     assert len(records) == 1
     first_record = records[0]
     assert first_record.body == 'queue message body'
     assert first_record.receipt_handle == 'receipt-handle'
     assert first_record.to_dict() == sqs_event['Records'][0]
     assert actual_event.to_dict() == sqs_event
+    assert actual_event.context == lambda_context
 
 
 def test_bytes_when_binary_type_is_application_json():