Expected Behaviour

POWERTOOLS_LOG_LEVEL (and POWERTOOLS_LOGGER_SAMPLE_RATE`) should decide what log lines Powertools emits.

Lambda’s applicationLogLevelV2 should only act as a platform filter (drop logs below that threshold before forwarding to CloudWatch).

Examples:

• If POWERTOOLS_LOG_LEVEL=INFO and applicationLogLevelV2=DEBUG, then only INFO+ should be emitted, and those should appear in CloudWatch.
• If POWERTOOLS_LOG_LEVEL=DEBUG and applicationLogLevelV2=INFO, then DEBUG logs should be emitted by Powertools but dropped by the platform, so only INFO+ appear in CloudWatch.

Current Behaviour

applicationLogLevelV2=DEBUG causes all logs, including DEBUG, to appear in CloudWatch, even if POWERTOOLS_LOG_LEVEL=INFO.

In effect, the Lambda application log level is overriding Powertools’ log level instead of filtering logs after emission.

POWERTOOLS_LOGGER_SAMPLE_RATE becomes ineffective when combined with applicationLogLevelV2=DEBUG, because all requests in a container emit DEBUG regardless of Powertools’ base level.

Code snippet

from aws_lambda_powertools import Logger

logger = Logger()

@logger.inject_lambda_context
def handler(event, context):
    logger.debug("Debug log line")
    logger.info("Info log line")
    return {"status": "ok"}

Possible Solution

Ensure Powertools filtering (POWERTOOLS_LOG_LEVEL, POWERTOOLS_LOGGER_SAMPLE_RATE) applies before logs are emitted.

The Lambda runtime should then filter logs again according to applicationLogLevelV2.

If this behavior is by design, document clearly that:

• applicationLogLevelV2=DEBUG will force DEBUG logs through, regardless of Powertools config.
• Sampling (POWERTOOLS_LOGGER_SAMPLE_RATE) works per-container and will appear overridden if applicationLogLevelV2=DEBUG is set.

Steps to Reproduce

Case 1

• applicationLogLevelV2 = INFO
• POWERTOOLS_LOG_LEVEL = DEBUG
• Behaviour: Only INFO+ appear.
• ✅ Expected: Only INFO+ appear. (works correctly)

Case 2

• applicationLogLevelV2 = DEBUG
• POWERTOOLS_LOG_LEVEL = INFO
• Behaviour: DEBUG logs also appear.
• ❌ Expected: Only INFO+ logs, since Powertools should suppress DEBUG.

Case 3

• applicationLogLevelV2 = DEBUG
• POWERTOOLS_LOG_LEVEL = INFO
• POWERTOOLS_LOGGER_SAMPLE_RATE = 0.5
• Behaviour: All requests show DEBUG logs.
• ❌ Expected: Only ~50% of requests should show DEBUG logs.

Case 4

• applicationLogLevelV2 = INFO
• POWERTOOLS_LOG_LEVEL = INFO
• POWERTOOLS_LOGGER_SAMPLE_RATE = 0.5
• Behaviour: Only INFO+ appear.
• ❌ Expected: Some requests/containers show DEBUG logs due to sampling.

Powertools for AWS Lambda (Python) version

latest

AWS Lambda function runtime

3.12

Packaging format used

PyPi

Debugging logs