LocalStack Logs Analysis
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
# 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 200Filtering Logs
# 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:
# Start with debug mode
DEBUG=1 localstack start -d
# Enable specific debug flags
LS_LOG=trace localstack start -dAnalyzing API Requests
Request/Response Tracking
LocalStack logs include AWS API requests. Look for patterns like:
AWS <service>.<operation> => <status>Example log entries:
AWS s3.CreateBucket => 200
AWS dynamodb.PutItem => 200
AWS lambda.Invoke => 200Common 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
# 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
LAMBDA_DEBUG=1 localstack start -dHealth Check
# 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=1for verbose logging - Lambda issues: Check both LocalStack logs and CloudWatch Logs
- Intermittent errors: Look for resource limits or timing issues