AWS Lambda Local Middleware
Lambda Custom Authorizer Middleware for using with AWS Serverless Express and Serverless Offline plugins
Purpose
Let's say you are using aws-serverless-express. Cool, you can write lambdas responding to API Gateway using favorite express.
Let's say you are using serverless-offline to simulate API Gateway for local development. Cool, now you can invoke your lambdas locally.
Let's say you have custom lambda authorizers defined in your serverless.yml
file like that:
restAP:
handler: lib/handlers/rest-api.handler
events:
- http:
path: v1/{id}/create
method: put
integration: lambda-proxy
authorizer:
arn: arn:aws:lambda:us-east-1:123456789:function:myAuthorizerFunction
resultTtlInSeconds: 0
Pretty soon you find this issue saying you cannot use custom non-local authorizers.
And here it comes. With this package you can provide path on local file system to your custom authorizer function which isn't required to be inside the project.
Install
Note, it's installed not in dev deps.
$ yarn add lambda-custom-authorizer-middleware
Usage
Due to the fact this package is meant to be used with serverless-offline
it relies on its environment variable IS_OFFLINE
to switch on using local Lambda function.
And as for now, it's limited to 1 kind of authorizer function per project.
API
customLocalLambdaAuthorizer
Express middleware function constructor to execute local lambda function
as a custom authorizer and attach request context to req
object
as req.apiGateway.event.requestContext.authorizer
(as for usage with aws-serverless-exporess
npm package)
Parameters
options
Object Configuration object (optional, default{}
)
Examples
import express from 'express';
import awsSlsExpressMiddleware from 'aws-serverless-express/middleware';
import {customLocalLambdaAuthorizer} from 'lambda-custom-authorizer-middleware';
const app = express();
app.use(awsSlsExpressMiddleware.eventContext());
app.use(customLocalLambdaAuthorizer({ // Make sure to add after 'awsSlsExpressMiddleware'
localAuthorizer: {
handlerPath: '../other-project/lambda/auth',
handlerName: 'handler'
}
}));
app.get('/', (req, res) => res.json(req.apiGateway.event.requestContext.authorizer));
- Throws Error Throws when config is not provided
Returns Function Express middleware function. Works only when IS_OFFLINE env var is set.
Development
Debug
This package uses debug library, so set environment variable like that to see the logs.
DEBUG=lambda-custom-authorizer-middleware sls offline start
Lint
$ yarn lint
Build
$ yarn build
Docs
$ yarn docs
Tests
$ yarn test
Coverage
$ yarn coverage