Xray: TypeError: string indices must be integers

[michaelbrewer]

Xray PR to fix this: aws/aws-xray-sdk-python#284

Proof of concept code:

import json
from aws_lambda_powertools import Tracer
import boto3

tracer = Tracer()

@tracer.capture_method
def my_method():
    sts = boto3.client("sts")
    sts.get_caller_identity()
    raise RuntimeError("Error happens!")

@tracer.capture_lambda_handler
def lambda_handler(event, context):
    my_method()
    return {"statusCode": 200, "body": json.dumps({"hello": "world"})}

Logs

[ERROR]	2021-04-05T05:33:00.732Z	8a4d5027-4faa-4f4f-8d08-df63b7ea72ed	Failed to serialize ## lambda_handler
Traceback (most recent call last):
  File "/var/task/aws_lambda_powertools/tracing/tracer.py", line 313, in decorate
    response = lambda_handler(event, context, **kwargs)
  File "/var/task/app.py", line 17, in lambda_handler
    my_method()
  File "/var/task/aws_lambda_powertools/tracing/tracer.py", line 612, in decorate
    response = method(*args, **kwargs)
  File "/var/task/app.py", line 12, in my_method
    raise RuntimeError("Error happens!")
RuntimeError: Error happens!

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/var/task/aws_xray_sdk/core/models/entity.py", line 263, in serialize
    return json.dumps(self.to_dict(), default=str)
  File "/var/task/aws_xray_sdk/core/models/subsegment.py", line 157, in to_dict
    subsegment_dict = super(Subsegment, self).to_dict()
  File "/var/task/aws_xray_sdk/core/models/entity.py", line 284, in to_dict
    entity_dict[key]['working_directory'] = self.cause['working_directory']
TypeError: string indices must be integers

Xray screenshot:

Xray screenshot without @tracer.capture_method :

[heitorlessa]

hey @michaelbrewer - I can't reproduce this using the latest version, however I remember X-Ray SDK team changed the serialization from jsonpickle to their own, and this line tells there's an issue with the new implementation

 File "/var/task/aws_xray_sdk/core/models/subsegment.py", line 157, in to_dict

Could you open up an issue upstream with them?

It's a regression only available in the develop branch. Lambda Powertools 1.13.0 doesn't have this issue as it uses X-Ray SDK 2.6.0

I'll lock to 2.6.0 in the meantime as we near 1.14.0 release this week.

[heitorlessa]

I've subscribed to the upstream issue pending PR merge so I can revert the dependency pinning to the working version of X-Ray SDK. For now, I am closing this issue as 1.14.0 uses a previous working version.