• Pin the worker process start method to fork in multi-concurrent (Lambda Managed Instances) mode instead of inheriting the interpreter default, which changed from fork to forkserver in Python 3.14. Workers are now direct children of the runtime process on every supported Python version (#233). No behavior change on Python 3.13 and earlier; no impact on the standard on-demand path.

• Revert pre-fork hooks for multi-concurrent (Lambda Managed Instances) mode introduced in 4.1.0 (#226), as the change was breaking. The awslambdaric.lambda_concurrency_hooks module, the @register_pre_fork decorator and the Runtime.PreForkError error type are removed, restoring the 4.0.4 multi-concurrent startup behavior. No impact on the standard on-demand path.

• Add a w3c() helper to LambdaContext that returns the W3C trace-context fields (traceparent, tracestate, baggage) carried on clientContext.w3c at invoke time (#228)

• Add pre-fork hooks for multi-concurrent (Lambda Managed Instances) mode. A function can register callables with the @register_pre_fork decorator from awslambdaric.lambda_concurrency_hooks; they run once in the parent process, after the handler is imported and before worker processes are started. Workers re-import the handler in their own process, so hooks are for external side effects (starting a subprocess, warming a local service, writing to /tmp) and share no in-memory state with workers. A hook that raises is reported to the Runtime API as an INIT error with the type Runtime.PreForkError and no worker is started. No impact on the standard on-demand path.

• Use the level key (instead of log_level) for the log level field in JSON-formatted uncaught error logs, aligning it with the key used by other structured log events (#221)

• Emit a structured runtime_worker_pool_initializing DEBUG log event once per execution environment during INIT in multi-concurrent (Lambda Managed Instances) mode, reporting workerCount and executionEnvironmentMaxConcurrency for worker pool observability. Only visible when the function log level is DEBUG or lower; no impact on the standard on-demand path.

• Add Lambda-Runtime-Invocation-Id header support for cross-wiring protection. The RIC now echoes the invocation ID received from RAPID on /next back on /response and /error, enabling RAPID to detect and reject stale responses from timed-out invocations.

• Support building on Alpine Linux 3.17+ (musl) without libexecinfo-dev (#204)
• Lazy load multi_concurrent_utils (#211)

What's Changed

• Move unhandled exception warning message to init errors. by @briensea in #189
• Bump version to 3.1.1. by @briensea in #190

Full Changelog: 3.1.0...3.1.1

What's Changed

• feat: add tenant-id to lambda context and structured log message by @ramisa2108 in #187
• Bump to version 3.1.0 by @ramisa2108 in #188

New Contributors

• @ramisa2108 made their first contribution in #187

Full Changelog: 3.0.2...3.1.0