lambda-sdk-ts

This repository hosts an SDK for developing Lambda functions for the Manetu Platform in the TypeScript programming language.

Prerequisites

• make
• tsc
• rollup
• mjsc

Project setup

The Manetu platform serves Lambda functions within a WebAssembly (WASM) environment. We can leverage the TypeScript language in our Lambda functions using a combination of two tools: rollup to bundle TypeScript to an ECMAScript Module (ESM), followed by mjsc to compile ESM to WASM.

Create a directory for your project

mkdir my-lambda
cd my-lambda

Create the build files

package.json

{
  "name": "hello-ts",
  "type": "module",
  "version": "0.0.1",
  "description": "Hello World as a Manetu Lambda Function",
  "main": "src/main.js",
  "dependencies": {
    "manetu-lambda-sdk": "0.0.1",
    "@rollup/plugin-node-resolve": "^15.0.1"
  }
}

tsconfig.json

{
    "compilerOptions": {
        "module": "ES6",
        "target": "es2020",
        "outDir": "./target",
        "moduleResolution": "bundler"
    },
    "include": [
        "src/**/*"
    ]
}

rollup.config.js

import nodeResolve from "@rollup/plugin-node-resolve";

export default {
    plugins: [
        nodeResolve(), // <-- this allows npm modules to be added to bundle
    ],
};

Makefile

OBJECT=target/lambda.wasm
SRCS = $(shell find src -type f)

all: $(OBJECT)

target:
	mkdir target

node_modules: package*.json
	npm install

target/main.js: target Makefile node_modules $(SRCS)
	tsc

target/lambda.js: target/main.js rollup.config.js
	rollup $< -o $@ -f es -c

$(OBJECT): target/lambda.js
	mjsc compile $^ -o $@

clean:
	-rm -rf target node_modules

Create the Lambda source

Create the source path

mkdir -p src
pushd src

main.ts

import {register} from 'manetu-lambda-sdk';
import {LambdaRequest, LambdaResponse} from 'manetu-lambda-sdk';

function handler(req: LambdaRequest): LambdaResponse {
    // @ts-ignore
    return {status: 200, body: "Hello, " + req.params.name}
}

register(handler);

console.log("Module initialized");

Return to the top-level directory

popd

Compile the program

make

You should now have a file 'target/lambda.wasm' ready for deployment (See general documentation).

Define a specification for your Lambda function

Create a file 'site.yml' with the following contents:

api-version: lambda.manetu.io/v1alpha1
kind: Site
metadata:
  name: hello
spec:
  runtime: wasi.1.alpha2
  image: oci://my-registry.example.com/my-lambda:v0.0.1
  env:
    LOG_LEVEL: trace
  triggers:
    http-queries:
      - route: /greet
        summary: "Returns a greeting to the user"
        description: "This request allows you to test the ability to deploy and invoke a simple lambda function."
        query-parameters:
          - name: "name"
            schema: { type: "string" }
            description: "The caller's name"
        responses:
          200:
            description: "computed greeting"
            content:
              text/plain:
                schema:
                  type: string

Be sure to adjust the image OCI URL.