SnapStart + Node.js 24 base image: all restored invocations fail with Runtime.PlatformError (Missing AWS_LAMBDA_LOG_GROUP_NAME / AWS_LAMBDA_LOG_STREAM_NAME) #205

Summary

With a Node.js 24 Lambda base image (public.ecr.aws/lambda/nodejs:24) and SnapStart enabled
(LABEL com.amazonaws.lambda.feature.snapstart="Allow"), every invocation after a SnapStart
restore fails with Runtime.PlatformError. The same setup works on the Node.js 22 base image.

Environment

• Region: ap-northeast-1, architecture: arm64
• Base image: public.ecr.aws/lambda/nodejs:24 (runtime v24.21.0 as of 2026-10-17)
• Deployment: container image, SnapStart via Dockerfile LABEL (no runtime hooks)
• Date observed: 2026-10-17

Steps to reproduce

1. Build a container image from the Node.js 24 base image with
   LABEL com.amazonaws.lambda.feature.snapstart="Allow".
2. Publish a new version (SnapStart creates a snapshot).
3. Invoke the published version.

Observed behavior

All 60 invocations against newly-restored execution environments failed with:

Runtime.PlatformError: Missing required environment variables: AWS_LAMBDA_LOG_GROUP_NAME, AWS_LAMBDA_LOG_STREAM_NAME
at ContextBuilder.validateEnvironment (file:///var/runtime/index.mjs:303:13)

Expected behavior

The invocation should succeed, as it does on the Node.js 22 base image under the same
SnapStart setup.

Analysis

Per the AWS documentation (https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html),
AWS_LAMBDA_LOG_GROUP_NAME and AWS_LAMBDA_LOG_STREAM_NAME are not set for functions with
SnapStart enabled. ContextBuilder.validateEnvironment() in this repo
(https://github.com/aws/aws-lambda-nodejs-runtime-interface-client/blob/main/src/context/context-builder.ts)
treats both as required on every invocation and does not special-case SnapStart, which appears
to be the cause.

Workaround (not officially supported)

Setting dummy values for both variables during the SnapStart beforeSnapshot hook (or at
module load, gated on AWS_LAMBDA_INITIALIZATION_TYPE === "snap-start") avoids the error, but
context.logStreamName etc. then hold dummy values.