Serverless Framework Docs

#capture_exception

Your lambda function may throw an exception, but your function handles it in order to respond to the requester without throwing the error. One very common example is functions tied to HTTP endpoints. Those usually should still return JSON, even if there is an error since the API Gateway integration will fail rather than returning a meaningful error.

For this case, we provide a captureError function available on either the context or on the module imported from 'serverless_sdk'. This will cause the invocation to still display as an error in the serverless dashboard while allowing you to return an error to the user.

Here is an example of how to use it from the context object:

def hello(event, context):
    try:
        # do some real stuff but it throws an error, oh no!
        raise Exception('aa')
    except Exception as exc:
        context.capture_exception(exc)
    return {
        'statusCode': 500,
        'body': '{"name": "bob"}',
    }

And to import it instead, import with from serverless_sdk import capture_exception then call capture_exception instead of context.capture_exception.

from serverless_sdk import capture_exception

def hello(event, context):
    try:
        # do some real stuff but it throws an error, oh no!
        raise Exception('aa')
    except Exception as exc:
        capture_exception(exc)
    return {
        'statusCode': 500,
        'body': '{"name": "bob"}',
    }

#span

While the serverless_sdk automatically instruments AWS SDK and HTTP spans, you may be interested in capturing span data for functions that do numerical computation or functions making database queries. For this use-case, you can use the span context manager provided by serverless_sdk. It accepts one argument of a label. The code within the with statement using the context manager will be captured as a span in the Dashboard.

def handler(event, context):
    with context.span('some-label'):
        pass # the execution of this `with` statement will be captured as a span

You can also import the function from serverless_sdk

from serverless_sdk import span
def handler(event, context):
    with span('some-label'):
        pass # the execution of this `with` statement will be captured as a span

It also works as an async context manager for use with async with.

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