The new AWS Lambda middleware introduces external service dependencies that could impact gateway performance. Each request to a Lambda endpoint creates a new AWS SDK client, makes network calls to AWS Lambda, and performs JSON marshaling/unmarshaling operations. These operations add latency and resource overhead to the request processing path.

The middleware is positioned before VirtualEndpoint in the chain, so it will be executed for all requests matching Lambda paths, potentially adding overhead even when Lambda functions aren't invoked.

1. AWS SDK Client Creation: A new AWS SDK client is created for each request in invokeLambda(), which is inefficient and could lead to resource exhaustion under high load.

2. Timeout Calculation: Line ~60-70 contains a type conversion issue: timeout = time.Duration(sec * float64(time.Second)) won't compile as time.Duration expects integer types. This affects default timeout when TimeoutMs <= 0.

3. Memory Usage: The entire request body is read into memory before processing, which could cause memory pressure with large payloads.

4. Request/Response Transformation: JSON marshaling/unmarshaling operations for proxy integration mode add CPU overhead.

1. Client Pooling: Implement AWS SDK client pooling or caching per API definition to avoid creating new clients for each request.

2. Fix Timeout Calculation: Change timeout = time.Duration(sec * float64(time.Second)) to timeout = time.Duration(sec) * time.Second.

3. Streaming Support: Consider supporting streaming for large request/response bodies instead of loading everything into memory.

4. Connection Reuse: Ensure AWS SDK HTTP client is configured to reuse connections to reduce connection establishment overhead.

5. Metrics & Monitoring: Add metrics for Lambda invocation latency to identify performance bottlenecks.

• The AWS Lambda middleware adds significant external dependencies to the request path that could impact performance.
• Per-request AWS SDK client creation is inefficient and should be optimized with client pooling.
• The timeout calculation has a type conversion issue that needs to be fixed.
• Memory usage could be optimized for large payloads with streaming support.
• Additional metrics would help monitor the performance impact in production.

This PR adds AWS Lambda integration to the Tyk Gateway, introducing new API definition fields and middleware. The changes primarily impact tyk-operator which needs to understand the new API definition schema, and portal which would need UI components to configure Lambda integrations. The changes are additive and shouldn't break existing functionality, but downstream repositories need updates to fully support this feature.

tyk-operator:

• CRD definitions need updating to include AWS Lambda configuration
• Validation logic for AWS Lambda fields
• Controller logic to handle Lambda path specs

portal:

• UI components for AWS Lambda configuration
• Form validation for Lambda settings
• Documentation on Lambda integration options

tyk-charts:

• No critical updates required, but documentation should mention Lambda support
• May need to add AWS SDK dependencies to Docker images

tyk-sink:

• API definition handling code may need updates if it processes ExtendedPathsSet
• RPC protocol should handle the new AWSLambda fields in API definitions

• The API definition schema changes are additive and shouldn't break backward compatibility
• Older versions of tyk-operator will ignore the new fields but won't be able to manage Lambda integrations
• Portal will need updates to display and configure Lambda settings, otherwise these will be inaccessible via UI
• AWS credentials in API definitions need proper handling to avoid security issues (redaction in logs, etc.)
• The implementation has potential security issues with credential handling - it loads AWS config via default chain but doesn't honor explicit credentials in AWSCredentialsConfig

• Coordinate releases with tyk-operator to ensure CRDs are updated to support AWS Lambda configuration
• Update portal with UI components for Lambda configuration
• Add documentation for AWS Lambda integration in all affected repositories
• Ensure AWS credentials are properly handled and not exposed in logs or analytics
• Fix the credential handling in the middleware to properly use the provided credentials rather than just the default chain
• Consider adding tests for the Lambda integration to ensure it works correctly with different credential sources

• Redis Connections: The AWS Lambda middleware doesn't interact with Redis directly. It operates independently of the Redis connection pool and doesn't add any new Redis operations.
• RPC Connections: No RPC connectivity is used by the Lambda middleware. It doesn't affect MDCB mode operations or RPC-based storage.
• Synchronization Mechanisms: The middleware doesn't participate in cluster synchronization via Redis pub/sub channels. It's a stateless middleware that processes requests in isolation.

• Redis Tests: Not applicable as the middleware doesn't interact with Redis.
• RPC Tests: Not applicable as the middleware doesn't use RPC connections.
• Failure Scenario Tests: ⚠️ The implementation handles AWS Lambda connection failures and timeouts, but there are no explicit tests for these scenarios. Consider adding tests for Lambda connection failures, timeouts, and error responses.

• Authentication Changes: The middleware introduces AWS credentials handling, but these are passed directly to the AWS SDK without affecting Tyk's authentication systems.
• Performance Considerations: 🟡 Each Lambda invocation creates a new external HTTP connection which could impact latency. The middleware properly implements timeout handling, but high-volume APIs might experience increased latency.
• Error Handling: The middleware has comprehensive error handling for AWS Lambda invocations, including timeouts, connection failures, and function errors. Errors are properly mapped to HTTP responses.

• The AWS Lambda middleware is well-isolated from Tyk's core connectivity systems (Redis/RPC) and doesn't introduce risks to existing connection management.
• Consider adding explicit tests for Lambda connection failures and timeout scenarios.
• No suggestions to provide – change LGTM.