Babashka AWS Lambda custom runtime

This builds a custom runtime for creating AWS Lambda functions as babashka scripts.

Building

To build the image you can run: bb build

Using

See serverless-example folder for an example.

Create a new Dockerfile that starts from the bb-lambda image and copy Clojure source files to ${LAMBDA_TASK_ROOT}. The handler function is given as fully qualified clojure symbol (eg. some.namespace/handler-fn-name). The bootstrap script will require the namespace and resolve the function name.

The handler function will receive two arguments: event and context. The event is the JSON passed into the Lambda parsed as Clojure data (with keywordized keys) and context contains the headers from API runtime invocation.

The handler must return a value that can be encoded as JSON. If the handler throws an exception, an invocation error is signaled with the exception message as the errorMessage in the response.

Local testing

You can run the lambda locally in docker and test it with curl.

For example you can run the Clojure merge function as lambda like:

% docker run -p 9000:8080 -t bb-lambda clojure.core/merge

And test it with curl:

% curl -XPOST "http://localhost:9000/2015-03-31/functions/function/invocations" -d '{"hello": "world"}'