Would be great to have a test mode that stub out the library #17

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1. tianchu commented on Oct 1, 2019

   

   tianchu

   on Oct 1, 2019

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   Thanks for the feedback @jackyjjc-canva, we will look into this! Meanwhile, do you mind sharing a little bit more details with us, say a code snippet from your tests that you expect to work?
2. jackyjjc-canva commented on Oct 2, 2019

   

   jackyjjc-canva

   on Oct 2, 2019

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   This is my Lamdba function (I took out the parts with business logic)

   @datadog_lambda.wrapper.datadog_lambda_wrapper
   def lambda_handler(event, _):
     try:
       return _lambda_handler(event)
     except AuthenticationError as e:
         metric.lambda_metric("auth.failure", 1, tags=["error:%s" % e.short_message, DATADOG_ENV_TAG])
       return {
         "statusCode": 403
       }
   

   This is my test:

   import unittest
   class TestAuthModule(unittest.TestCase):
     def test_lambda_handler_rejects_user(self) -> None:
         event = {
            "username": "user"
            "password": "invalid-password"
         }
         self.assertEqual(auth.lambda_handler(event, {})["body"], "{}")
   

   The first issue happens when I import the module to be tested because _LambdaDecorator is invoked at that point in time. The exact exception was:

   cannot find the current segment/subsegment, please make sure you have a segment open
   Traceback (most recent call last):
     File "/lambda/.ve/lib/python3.7/site-packages/datadog_lambda/wrapper.py", line 60, in _before
       set_correlation_ids()
     File "/lambda/.ve/lib/python3.7/site-packages/datadog_lambda/tracing.py", line 127, in set_correlation_ids
       context = get_dd_trace_context()
     File "/lambda/.ve/lib/python3.7/site-packages/datadog_lambda/tracing.py", line 98, in get_dd_trace_context
       xray_trace_entity = xray_recorder.get_trace_entity()  # xray (sub)segment
     File "/lambda/.ve/lib/python3.7/site-packages/aws_xray_sdk/core/recorder.py", line 369, in get_trace_entity
       return self.context.get_trace_entity()
     File "/lambda/.ve/lib/python3.7/site-packages/aws_xray_sdk/core/context.py", line 93, in get_trace_entity
       return self.handle_context_missing()
     File "/lambda/.ve/lib/python3.7/site-packages/aws_xray_sdk/core/context.py", line 118, in handle_context_missing
       raise SegmentNotFoundException(MISSING_SEGMENT_MSG)
   aws_xray_sdk.core.exceptions.exceptions.SegmentNotFoundException: cannot find the current segment/subsegment, please make sure you have a segment open
   

   The second issue happens when I run the tests. Of course someone can make the case that I should test the business logic separated and I don't need to test the Lambda code. However I would still like to have an end-to-end test that test the whole Lambda code path besides my business logic tests.
3. tianchu commented on Oct 2, 2019

   

   tianchu

   on Oct 2, 2019

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   @jackyjjc-canva end-to-end tests make perfect sense for Lambda. We will have a fix soon.
4. tianchu commented on Oct 2, 2019

   

   tianchu

   on Oct 2, 2019

   Last edited by tianchu

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   @jackyjjc-canva after a quick look, I believe the issue was introduced in the latest version (v6). While we are fixing the issue, you can probably work around this issue by using version 5 (or 0.5.0 for pip).
5. tianchu commented on Oct 3, 2019

   

   tianchu

   on Oct 3, 2019

   Last edited by tianchu

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   #18 should fix the specific issue caused the exception. Do you mind trying it out and let us know if it works for you?

   You can install it using pip install git+https://github.com/DataDog/datadog-lambda-layer-python@tian.chu/check-for-lambda-context

   I agree, in the long run, there should be a toggle to short-circuit (turn off) all datadog operations for testing purpose. I will queue a ticket in our internal backlog and leave this issue open for tracking.
6. tianchu

   closed this as completedin #18on Oct 3, 2019
7. tianchu

   reopened this on Oct 3, 2019
8. jackyjjc-canva commented on Oct 4, 2019

   

   jackyjjc-canva

   on Oct 4, 2019

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   Thank you @tianchu I will take a look.
9. jackyjjc-canva commented on Oct 8, 2019

   

   jackyjjc-canva

   on Oct 8, 2019

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   Sorry for the delay but I can confirm it has resolved the issue. Thank you! @tianchu
10. jackyjjc-canva

    closed this as completedon Dec 11, 2019
11. tedyu commented on Nov 8, 2023

    

    tedyu

    on Nov 8, 2023

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    @tianchu
    Can you tell me how to stub out datadog handler for unit testing (with node.js) ?
    Thanks