AWS Lambda Router for NodeJS
A collection of tools to handle ApiGateway requests and direct function invocation calls on AWS Lambda. Use it as a stand-alone lib in a Lambda function or plugged-in to Apex or any other serverless framework on NodeJS. I'd recommend deploying and managing your Lambda functions with Apex and LambdaReq since they play nicely together.
Installation
npm install lambda-req --save
Deploy it with Apex
import LambdaReq from 'lambda-req'
const lambda = new LambdaReq()
// set APIGateway handlers
lambda.get('/lreqex_hello', (req, router)=> {
const { params } = req
return { message: 'hello world!', params }
})
lambda.post('/lreqex_hello', (req, router)=> {
const { params } = req
return { message: 'hello world!', params }
})
// set direct invocation handlers
lambda.proxy('hello', (req, router)=> {
const { params } = req
return { message: 'hello world!', params }
})
export default lambda.invoke
Use it stand-alone on Lambda
import LambdaReq from 'lambda-req'
// initialize Lambda with no params, pass them later from handler
const lambda = new LambdaReq()
// set handlers
lambda.get('/v1/test', (req, router)=> {})
lambda.proxy('migrate', (req, router)=> Promise.resolve({}))
// export the handler
// pass the event params on invocation time
export { handler: lambda.invoke }
Invoke other Lambdas
import LambdaReq, { LambdaProxy, LambdaReqError } from 'lambda-req'
const lambda = new LambdaReq()
// set APIGateway handlers
lambda.get('/lreqex_proxy', (req, router)=> {
const { params } = req
const proxy = new LambdaProxy()
// Invoke another Lambda in the same AWS VPC
return proxy.invoke('lreqex_hello', 'hello', params)
.then((response)=> {
return { message: 'Proxy response from lreqex_hello', response }
})
.catch((err)=> {
console.error(err)
throw new LambdaReqError({
message: {
error: {
code: 'lambdaInvocationError',
message: 'lreqex_hello Lambda is unresponsive.'
}
}
})
})
})
export default lambda.invoke
See more examples.
API
LambdaReq
This is the Lambda router object. It binds routes and proxies events for a Lambda handler.
.constructor([event = Object], [context = Object], [callback = function])
Pass in the lambda handler event, context and callback on object initialization. However, this is optional since they can be sent diectly on hanlder invocation.
Node 4.3:
const LambdaReq = require('lambda-req').default
function handler (event, context, callback) {
const lambda = new LambdaReq(event, context, callback)
lambda.invoke()
}
module.exports = { handler }
With Babel:
import LambdaReq from 'lambda-req'
function handler (event, context, callback) {
const lambda = new LambdaReq(event, context, callback)
lambda.invoke()
}
export { handler }
.get|.post|.put|.delete|.options(path = String, handler = function)
Shorthand methods for binding APIGateway route handlers. ALL APIGateway params (path, query, body) are passed through the params key on the req argument. A router instance is passed as the second handler arg. router._event and router._context are mapped to the original handler params.
const lambda = new LambdaReq(event, context, callback)
lambda.get('/test', handler)
lambda.post('/test', handler)
lambda.put('/test', handler)
lambda.delete('/test', handler)
lambda.invoke()
async function handler (req, router) {
const { params, headers } = req
return {}
}
A request to https://api-gateway-id.execute-api.eu-west-1.amazonaws.com/prod/test will fire up the GET handler on the /test route.
.proxy(name = String, handler = function)
Shorthand method for binding Lambda direct invocation handlers. Used for maintenance tasks (i.e. db migrations, cronjobs) and internal Lambda calls. Each proxy handler has a unique name, passed as a command key on the Lambda event. A direct call, proxies all the event data to the handler.
const lambda = new LambdaReq(event, context, callback)
lambda.proxy('db_migrate', handler)
lambda.invoke()
async function handler (req, router) {
const { params } = req
return {}
}
Invoke this functions from command line with aws-cli:
#!/usr/bin/env bash
PAYLOAD='{"command":"db_migrate","params":{"name":"users"}}'
aws lambda invoke \
--function-name myFunction \
--payload $PAYLOAD \
out.log
or through aws-sdk:
import AWS from 'aws-sdk'
const config = {
FunctionName: 'myFunction',
Payload: JSON.stringify({ command: 'db_migrate', params: { name: 'users' } })
}
const lambda = new AWS.Lambda()
lambda.invoke(config).promise().then(response => JSON.parse(response.Payload))
.invoke([event = Object], [context = Object], [callback = function])
Invokes the handlers that match the current Lambda route from APIGateway or by a direct invocation call. Optionally, Lambda handler params will be passed along. It's recommended to export this method as a Lambda handler.
import LambdaReq from 'lambda-req'
const lambda = new LambdaReq()
lambda.get('/test', ()=> {})
lambda.proxy('db_migrate', ()=> {})
export { handler: lambda.invoke }
or with Apex and WebPack
import LambdaReq from 'lambda-req'
const lambda = new LambdaReq()
lambda.get('/test', ()=> {})
lambda.proxy('db_migrate', ()=> {})
export default lambda.invoke
.isApiGateway Bool
It returns true if the request was an APIGateway invocation. Internally, checks if an HTTP method is set on the Lambda event.
const lambda = new LambdaReq(event, context, callback)
if (lambda.isApiGateway) {
// it's a HTTP call
}
.isProxy Bool
It return true if the request was a direct Lambda invocation. Internally, checks if a property command is set on the Lambda event.
const lambda = new LambdaReq(event, context, callback)
if (lambda.isProxy) {
// it's a direct invocation
}
.params Object
Has all the params coming from event.queryStringParameters, event.pathParameters and event.body for an APIGateway call. Stores all the params coming from event.params for a direct invocation. Referenced through req.params on a handler.
const lambda = new LambdaReq(event, context, callback)
lambda.get('/test', (req)=> {
const { params } = req
// process APIGateway data
})
lambda.proxy('db_migrate', (req)=> {
const { params } = req
// process direct invocation data
})
if (lambda.params) {
// process data
}
.headers Object
Stores the HTTP headers from an APIGateway call.
const lambda = new LambdaReq(event, context, callback)
lambda.get('/test', (req)=> {
const { headers } = req
if (headers['x-auth']) {
// process user authentication
}
})
.currentRoute String
Returns the current invocation route.
LambdaProxy
A wrapper for direct Lambda invocation calls. Sets the command and parameters on internal calls.
.constructor([client = Object = AWS.Lambda])
.invoke(functionName = String, command = String, [params = Object])
Call a Lambda internally, pass in the command and params.
import { LambdaProxy } from 'lambda-req'
const proxy = new LambdaProxy()
proxy.invoke('myFunction', 'db_migrate', { name: 'users' })
.then((response)=> {
return { message: 'Proxy response from myFunction', response }
})
.catch((err)=> {
console.error('myFunction Lambda is unresponsive', err)
})
LambdaReqError
A tiny wrapper for Lambda request errors.
.constructor({ message, status })
The error has a message and a status that will be passed along to the APIGateway.
lambda.get('/users', (req, router)=> {
const { params } = req
if (!params.id) {
throw new LambdaReqError({
message: {
error: {
code: 'userNotFound',
message: 'User not found.'
}
},
status: 404
})
} else {
const user = await dbConnection.findUser(params.id)
return { user }
}
})
See more examples.
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