AWS Lambda Runtime API Inspector

A lambda layer to print the runtime API requests and responses.

Usage

As a Lambda Layer

1. Download the prebuilt zip from the release page. You can also build it yourself by running cargo build --release, then zip scripts/entry.sh with target/release/aws-lambda-runtime-api-inspector.
2. Upload the zip as a lambda layer. Add the layer to your lambda function.
3. Add an environment variable AWS_LAMBDA_EXEC_WRAPPER to the lambda function with the value /opt/entry.sh to enable the runner.
4. Configure the environment variables below to set the command you want to run.

As a Binary Executable

If you are using a custom lambda runtime (for rust, golang, c++, etc) or container image, you can run this as a parent process of your main handler process.

1. Download the prebuilt zip from the release page to get the aws-lambda-runtime-api-inspector executable. You can also build it yourself by running cargo build --release.
2. Modify the entry command of the lambda function to aws-lambda-runtime-api-inspector <handler-command> <handler-args>
3. Configure the environment variables below to set the command you want to run.

Environment Variables

• AWS_LAMBDA_RUNTIME_API_INSPECTOR_TARGETS
  • Specify which requests and responses to print.
  • Valid values:
    • NextInvocationRequest
    • NextInvocationResponse
    • NextInvocation, equals to NextInvocationRequest,NextInvocationResponse
    • InvocationResponseRequest
    • InvocationResponseResponse
    • InvocationResponse, equals to InvocationResponseRequest,InvocationResponseResponse
    • InitializationErrorRequest
    • InitializationErrorResponse
    • InitializationError, equals to InitializationErrorRequest,InitializationErrorResponse
    • InvocationErrorRequest
    • InvocationErrorResponse
    • InvocationError, equals to InvocationErrorRequest,InvocationErrorResponse
    • Multiple values can be separated by ,.
  • If not set, all Lambda runtime API requests and responses will be printed.
  • For more information about the runtime API, see AWS Lambda Runtime API.

Example Output

Here is an example output of one cold start invocation, with all requests and responses printed:

Runtime API Request: GET /2018-06-01/runtime/invocation/next headers: {"host": "127.0.0.1:3000", "accept": "*/*", "user-agent": "AWS_Lambda_Cpp/0.2.6"} body: b""
Runtime API Response: [200 OK] headers: {"content-type": "application/json", "lambda-runtime-aws-request-id": "04feef66-1b37-4f4f-85e5-c66ff4b5a9c0", "lambda-runtime-deadline-ms": "1713968525978", "lambda-runtime-invoked-function-arn": "arn:aws:lambda:us-east-1:123123123123:function:test", "lambda-runtime-trace-id": "Root=1-6629156f-0a9d5a7f74a36b1059e065fe;Parent=7c4d733f273bdab1;Sampled=0;Lineage=a3f0941e:0", "date": "Wed, 24 Apr 2024 14:21:35 GMT", "content-length": "49"} body: b"{\"key1\":\"value1\",\"key2\":\"value2\",\"key3\":\"value3\"}"
Runtime API Request: POST /2018-06-01/runtime/invocation/04feef66-1b37-4f4f-85e5-c66ff4b5a9c0/response headers: {"host": "127.0.0.1:3000", "accept": "*/*", "content-type": "application/json", "user-agent": "AWS_Lambda_Cpp/0.2.6", "content-length": "33"} body: b"{\"statusCode\":200,\"body\":\"hello\"}"
Runtime API Response: [202 Accepted] headers: {"content-type": "application/json", "date": "Wed, 24 Apr 2024 14:21:35 GMT", "content-length": "16"} body: b"{\"status\":\"OK\"}\n"
Runtime API Request: GET /2018-06-01/runtime/invocation/next headers: {"host": "127.0.0.1:3000", "accept": "*/*", "user-agent": "AWS_Lambda_Cpp/0.2.6"} body: b""

FAQ

• Q: How does this work?
  • By using AWS Lambda Runtime Proxy this tool can intercept the lambda handler process's runtime API requests.

CHANGELOG