Bug: Logs populating into cloudwatch as multiple lines instead of a single object

[thault]

Expected Behaviour

I'm expecting the logs to populate as a single json object in cloudwatch.

Current Behaviour

Logger logs are shown as single lines within cloudwatch creating a lot of lines within the log stream. I have tried the log format as text and JSON and get the issue both ways.

Code snippet

from aws_lambda_powertools import Logger
from aws_lambda_powertools.utilities.typing import LambdaContext
logger = Logger(log_uncaught_exceptions=True)

@logger.inject_lambda_context(log_event=True)
def lambda_handler(event, context)
    logger.info("Token retrieval started")

Possible Solution

No response

Steps to Reproduce

Lambda using the powertools layer arn:aws:lambda:us-east-1:017000801446:layer:AWSLambdaPowertoolsPythonV2:60, followed the guide for basic logging with context included. All logs created via logger.info() or logger.debug() have the issue.

Powertools for AWS Lambda (Python) version

latest

AWS Lambda function runtime

3.12

Packaging format used

Lambda Layers

Debugging logs

No response

[boring-cyborg]

Thanks for opening your first issue here! We'll come back to you as soon as we can.
In the meantime, check out the #python channel on our Powertools for AWS Lambda Discord: Invite link

[heitorlessa]

trying to reproduce it now... from my recollection that only happens when you have \n since CloudWatch Logs creates a new line like that. Logger prints as a string. The only behavior change is when you have POWERTOOLS_DEV env var where we increase indentation .

[heitorlessa]

Couldn't reproduce, will try more scenarios

• Same code snippet on Python 3.11
• Same code snippet older Powertools for AWS Lambda version (2.31.0)
• Same code snippet on Python 3.12
• Use POWERTOOLS_DEV env
• Use POWERTOOLS_DEBUG env
• Copy existing Logger config to other std/libraries (noticed in your screenshot X-Ray/boto appears)

[heitorlessa]

As expected, reproduced with POWERTOOLS_DEV where indentation is increased for local debugging. Checking the last scenario to triple check.

Local effect (intended use case)

Local effect with SAM CLI logs pulling from CloudWatch Logs

CloudWatch Logs effect (extra indentation is transformed

[heitorlessa]

All scenarios tested, this only seems to occur due to POWERTOOLS_DEV as expected -- could you please check whether you have that turned on?

---

Logger config copied to boto3+X-Ray SDK loggers + DEBUG log level

[thault]

Looks like you are correct that it's from the POWERTOOLS_DEV; when I set that to false the logs started populating as single lines.

So this is expected behavior when POWERTOOLS_DEV is true; is there a way to work around that? It makes sense when running locally with SAM, but it makes the logs a pain when testing in AWS.

[heitorlessa]

I'm sure we can figure something out -- what made you enable POWERTOOLS_DEV? That will help understand alternative solutions or trade-offs we might be able to make.

Customers also use this feature with pytest live debugging feature.

[heitorlessa]

Summarizing our discussion on Discord.

What you were after was POWERTOOLS_DEBUG to get extra details about every operation (Logger) while using CloudWatch Logs view.

POWERTOOLS_DEV on the other hand is focused on local development, where you want to run your code locally with tools like SAM CLI, or pytest live log feature.

I'm closing this issue and created a PR to make this more explicit in our docs to prevent future confusion.

Thank you so much for taking the time to report this and help improve the docs!

[github-actions]

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[github-actions]

This is now released under 2.34.0 version!