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Invoking Other Lambdas

Overview

Invoking other Lambdas is a common pattern in serverless architecture. Laconia makes this easy by:

• Automatically stringifying JSON request payload and parsing JSON response payload
• Throwing an error when FunctionError is returned instead of failing silently
• Augmenting stacktrace in the FunctionError thrown based on the stacktrace returned by Lambda invocation
• Set the FunctionError object's name and message thrown based on the error returned by Lambda invocation
• Throwing an error when statusCode returned is not a success code

Guide

Lambda invocation is Laconia is handled by an instance of invoker. Create an invoker and invoke your Lambda through it like so:

/**
 * Lambda Environment variables:
 * - LACONIA_INVOKER_CALL_CAPTURE_CARD_PAYMENT_LAMBDA: capture-card-payment-lambda-name
 */

const invoker = require("@laconia/invoker");
const laconia = require("@laconia/core");

// By convention, the name of the variable `captureCardPaymentLambda` is derived by
// the environment variable name `LACONIA_INVOKER_CALL_CAPTURE_CARD_PAYMENT_LAMBDA`
const app = async (input, { captureCardPaymentLambda }) => {
  const parameter = { transactionId: 1 };
  // Waits for capture-card-payment-lambda-name
  const response = await captureCardPaymentLambda.requestResponse(parameter);
  console.log(response);
};

exports.handler = laconia(app).register(invoker.envVarInstances());

The invoker also supports Event invocation type (asynchronous Lambda execution), which can be called by replacing requestResponse with fireAndForget.