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serverless_example

https://www.serverless.com/blog/cicd-for-serverless-part-1/ https://www.serverless.com/blog/cicd-for-serverless-part-2/

Getting started with Lambda isn't hard at all. But if you are shooting for a super simple API you are still left with a lot of boilerplate things and missing pieces to make it really useful. Each which have their own small gotchas. Testing, deployments, API Gateway, cors, staged deployments, database setup, roles, permissions, javascript modules, dependency install, etc. It can still be a decent amount of work to get to something straightforward: A datasource accessible through lambda driven by a restful API written with Javascript with no hoops for pulling in additional js dependencies. Serverless helps you get there without worrying about all that boilerplate.

Do this first (prerequisites):

Getting Started

  1. Fork the project.
  2. Look through the project:
    • Understand what is being created in AWS
      • Look at serverless.yml for the definitions of things going into AWS.
      • Make sure to check service, region, and stage on the provider entry in serverless.yml to your desired otherwise you'll deploy to us-west-2 and the stage will be named dev The first time you create all this in AWS you probably should go look through everything that got created. It is all happening with CloudFormation and it is doing a lot of nice things for you and all the names and such are coming from the serverless.yml file and are under your control.
    • Understand the Lambda
      • Look at exampleFile.js for the lambda code - this just prints out the path variable that was passed in from the URI.
    • Understand which names are what
      • The file name of the file with the lambda code in it (exampleFile.js)
      • the defined functionName in the serverless.yml file (exampleFunction) - this will be the name you see in AWS for the lambda.
      • the name of the exported method on the lambda. (exampleFile.exampleWithPathParameters) This just allows the serverless.yml fill to understand where to start executing code for the lambda.
    • Understand the API and the API mocking:
      • We use local data file to mock the data we would be getting from an http call...things like the path, the path parameters, query parameters, thing like that. Look at test/shaefer/get-local.json This file simulates the call https://xxxxxxxxxx.execute-api.{region}.amazonaws.com/{stage}/shaefer/{id} for example https://xxxxxxxxxx.execute-api.us-east-1.amazonaws.com/dev/shaefer/15 if you don't change any of the default project settings.
  3. Run it locally serverless invoke local --function exampleFunction --path test/shaefer/get-local.json This is like hitting your lambda live with the earlier mentioned URI.
  4. Run serverless deploy to create the lambda and dynamodb table in AWS. The output for the deploy will show success and give you the url for the deployed API gateway endpoint that you can hit to test it live.
  5. OPTIONAL BUT IMPORTANT: If you forgot something and want to rollback...BEFORE you change anything in the serverless.yml just run a serverless remove and it will delete all the resources it just created...or try to. Since serverless created everything with Cloudformation it can remove it too. Find more details in the serverless docs.