LocalStack Logs Analysis

Name: localstack-logs
Rating: 78
Author: localstack

Analyze LocalStack logs to debug issues, identify errors, and understand AWS API interactions.

Capabilities

•View and filter LocalStack logs
•Identify error patterns and failures
•Analyze AWS API request/response cycles
•Track service-specific operations
•Debug Lambda function executions

Viewing Logs

Basic Log Commands

bash

# Follow logs in real-time
localstack logs -f

# View last N lines
localstack logs --tail 100

# Via Docker
docker logs localstack-main -f
docker logs localstack-main --tail 200

Filtering Logs

bash

# Filter by service
localstack logs | grep -i s3
localstack logs | grep -i lambda
localstack logs | grep -i dynamodb

# Filter errors only
localstack logs | grep -i error
localstack logs | grep -i exception

# Filter by request ID
localstack logs | grep "request-id-here"

Debug Mode

Enable detailed logging:

bash

# Start with debug mode
DEBUG=1 localstack start -d

# Enable specific debug flags
LS_LOG=trace localstack start -d

Analyzing API Requests

Request/Response Tracking

LocalStack logs include AWS API requests. Look for patterns like:

code

AWS <service>.<operation> => <status>

Example log entries:

code

AWS s3.CreateBucket => 200
AWS dynamodb.PutItem => 200
AWS lambda.Invoke => 200

Common Error Patterns

Error	Possible Cause	Solution
`ResourceNotFoundException`	Resource doesn't exist	Create the resource first
`AccessDeniedException`	IAM policy issue	Check IAM enforcement mode
`ValidationException`	Invalid parameters	Verify request parameters
`ServiceException`	Internal error	Check LocalStack logs for details

Lambda Debugging

View Lambda Logs

bash

# Lambda function logs appear in LocalStack logs
localstack logs | grep -A 10 "Lambda"

# Or use CloudWatch Logs locally
awslocal logs describe-log-groups
awslocal logs get-log-events \
  --log-group-name /aws/lambda/my-function \
  --log-stream-name <stream-name>

Enable Lambda Debug Mode

bash

LAMBDA_DEBUG=1 localstack start -d

Health Check

bash

# Check overall health
curl http://localhost:4566/_localstack/health | jq

# Check specific service
curl http://localhost:4566/_localstack/health | jq '.services.s3'

Troubleshooting Tips

•No logs appearing: Ensure LocalStack is running (localstack status)
•Missing debug info: Enable DEBUG=1 for verbose logging
•Lambda issues: Check both LocalStack logs and CloudWatch Logs
•Intermittent errors: Look for resource limits or timing issues