Merge pull request #22464 from Sashwatdas123/develop

Lambda Extension v2.4.0

Author: PallaviWrite

src/content/docs/release-notes/lambda-extension-release-notes/lambda-extension-2.4.0.mdx

@@ -0,0 +1,64 @@
+---
+subject: "Lambda-Extension"
+releaseDate: '2025-12-02'
+version: 2.4.0
+---
+
+##  Major Release: Rust Rewrite
+
+Complete rewrite of the New Relic Lambda Extension from `Go (v2.3.24`) to **Rust** for improved performance, memory safety, and reduced cold start times.
+
+##  New Features
+
+- **APM Mode Support**: Lambda functions can now report directly to New Relic APM platform as application entities
+  - Enable with `NEW_RELIC_APM_LAMBDA_MODE=true`
+  - Full support for metrics, spans, errors, events, and transaction traces
+  - Platform logs converted to APM metrics (`apm.lambda.transaction.*`)
+  - Enhanced error events for timeouts and faults with distributed tracing context
+  - See [APM Mode Documentation](https://docs.newrelic.com/docs/serverless-function-monitoring/aws-lambda-monitoring/instrument-lambda-function/upgrade-to-apm-experience/) for details
+
+- **Request-Scoped Processing**: Improved payload correlation and lifecycle management
+- **Intelligent Buffer Management**: Handles agent payloads that arrive before request context with automatic cleanup
+
+##  Performance Improvements
+
+- **Faster Cold Starts**: Optimized Rust compilation with minimal dependencies and LTO
+- **Lower Memory Usage**: Reduced memory footprint with zero-cost abstractions
+- **Concurrent Processing**: Parallel processing of logs, platform metrics, and agent telemetry
+- **Connection Pooling**: HTTP client connection reuse across invocations
+
+##  Security & Reliability
+
+- **Memory Safety**: Rust's ownership system prevents memory leaks and buffer overflows
+- **Panic Safety**: Global panic handler prevents Lambda crashes from extension failures
+- **Type Safety**: Compile-time guarantees eliminate entire classes of runtime errors
+
+##  Technical Changes
+
+- Migrated from Go `v1.23` to Rust 2021 edition
+- Built on Tokio async runtime
+- AWS SDK v1 for Rust (aws-config 1.8, aws-sdk-secretsmanager 1.88, aws-sdk-ssm 1.93)
+- Modular architecture with clean separation of concerns
+
+##  Configuration
+
+All existing environment variables remain unchanged for backwards compatibility. Key variables:
+- `NEW_RELIC_LICENSE_KEY`: New Relic license key
+- `NEW_RELIC_APM_LAMBDA_MODE`: Enable APM mode (default: false)
+- `NEW_RELIC_EXTENSION_SEND_FUNCTION_LOGS`: Send function logs (default: false)
+- `NEW_RELIC_LAMBDA_LOG_LEVEL`: Extension log level supports more granular control with `info`, `debug`, `warn`, `error`, `trace`, `all`
+
+Full configuration details in the [README](https://github.com/newrelic/newrelic-lambda-extension/blob/2a5c012f5082d2f8f056252e87d2d3eecad5479a/README.md).
+
+##  Migration Notes
+
+- **Drop-in Replacement**: No code changes required for existing users
+- **Environment Variables**: All configuration remains the same
+- **Binary Compatibility**: Maintains compatibility with existing New Relic agents
+- **Performance**: Expect 20-40% faster cold starts and lower memory usage
+
+---
+
+## [2.3.24] - Go Implementation (Legacy)
+
+Last Go-based version before Rust migration. Maintained for reference and legacy support.