serverless-plugin-simulate

Serverless simulation plugin

This is a proof of concept to see if we can replicate Amazon API Gateway using docker images to run lambda

Features:

• λ runtimes supported by docker-lambda.
• CORS
• Authorizer
  • Custom Authorizer supported
  • Coginito Authorizer not implemented yet
• Lambda Integration
  • Velocity templates support. supported
• Lambda Proxy Integration. supported

Prerequisite

• docker - https://docs.docker.com/engine/installation/

Getting Started

Install the plugin

npm i --save-dev serverless-plugin-simulate

Configure your service to use the plugin

service: my-service
provider:
  name: aws
  runtime: nodejs4.3 # python2.7 is also supported 
 
# this is optional configurations 
# servicesPathDest is use for the case u want to compile all your src and out 
# put to another folder like dist 
# 
# services allows specifying a docker-compose.yml file and (optional) 
# projectName. This will start the docker-compose stack when simulate is run. 
# If projectName is specified, it will be used when running docker-compose, 
# and the default docker-compose network will be passed to lambda docker commands 
# allowing all lambdas to access any hosts defined in docker-compose services 
custom:
  simulate:
    dist: dist
    services:
      file: docker-compose.yml
      # will use: $ docker-compose --project-name myproject ... 
      # and:      $ docker --network myproject_default ... 
      projectName: myproject
 
plugins:
  - serverless-plugin-simulate

If you do not need to chain functions locally you can just run the API Gateway simulation by itself.

sls simulate apigateway -p 5000

Using the Lambda simulator

If you want to chain functions locally, you need to use the Lambda Simulator.

Run the Lambda Simulation

sls simulate lambda -p 4000

Run the API Gateway Simulation

sls simulate apigateway -p 5000 --lambda-port 4000

Use the environment variables to configure the AWS SDK to use the local Lambda simulation. You can use the same technique with any other AWS SDK.

const AWS = require('aws-sdk');
 
const endpoint = process.env.SERVERLESS_SIMULATE ?
  process.env.SERVERLESS_SIMULATE_LAMBDA_ENDPOINT :
  undefined
 
const lambda = new AWS.Lambda({ endpoint })
const handler = (event, context, callback) => {
  const params = {
    FunctionName: 'my-other-function',
    Payload: JSON.stringify({ foo: 'bar' })
  }
  lambda.invoke(params, (err, result) => {
    if (err) {
      return callback(err)
    }
 
    callback(null, {
      statusCode: 200,
      body: result.Payload
    })
  })
}

Examples

See the examples folder for examples.

• npm install - Installs all dependencies
• npm start - Starts API Gateway simulation listening at http://localhost:5000
• npm run start:lambda - Starts Lambda simulation listening at http://localhost:4000
• npm run start:apigateway - Starts API Gateway simulation that uses the Lambda simulation listening at http://localhost:5000
• npm run start:services - Starts mock services defined in docker-compose.yml
• npm test - tests custom authorizer (Authorization:TOKEN 12345)

Authors

• Gert JvR - Initial work - gertjvr
• John McKim - johncmckim

See also the list of contributors who participated in this project.

Contributing

Please create an issue before submitting an Pull Request.

Acknowledgements

This would not be possible without lambci

• docker-lambda - Docker images and test runners that replicate the live AWS Lambda environment

@johncmckim for suggesting the idea