• make_download - Code for the application's Lambda function.
• events - Invocation events that you can use to invoke the function.
• tests - Unit tests for the application code.
• template.yaml - A template that defines the application's AWS resources.
• Makefile - Makefile for your convenience to install deps, build, invoke, and deploy your application.

Deploy the sample application

Already know this sample? Run: make hurry - This command will install app deps, build, and deploy your Serverless application using SAM.

Build and deploy your application for the first time by running the following commands in your shell:

mpcontribs-serverless$ make build
mpcontribs-serverless$ make deploy.guided

The first command will build the source of your application within a Docker container. The second command will package and deploy your application to AWS. Guided deploy means SAM CLI will ask you about the name of your deployment/stack, AWS Region, and whether you want to save your choices, so that you can use make deploy next time.

Use the SAM CLI to build and test locally

Whenever you change your application code, you'll have to run build command:

mpcontribs-serverless$ make build

The SAM CLI installs dependencies defined in make_download/requirements.txt, creates a deployment package, and saves it in the .aws-sam/build folder.

Test a single function by invoking it directly with a test event:

mpcontribs-serverless$ make invoke

An event is a JSON document that represents the input that the function receives from the event source. Test events are included in the events folder in this project.

Fetch, tail, and filter Lambda function logs

To simplify troubleshooting, SAM CLI has a command called sam logs. sam logs lets you fetch logs generated by your deployed Lambda function from the command line. In addition to printing the logs on the terminal, this command has several nifty features to help you quickly find the bug.

mpcontribs-serverless$ sam logs -n MPContribsMakeDownloadFunction --stack-name <Name-of-your-deployed-stack> --tail

Unit tests

Tests are defined in the tests folder in this project, and we use Pytest as the test runner for this sample project.

Make sure you install dev dependencies before you run tests with make dev:

mpcontribs-serverless$ make dev
mpcontribs-serverless$ make test

Cleanup

mpcontribs-serverless$ aws cloudformation delete-stack --stack-name mpcontribs-serverless

Appendix

Makefile

We included a Makefile for your convenience - You can find all commands you can use by running make. Under the hood, we're using SAM CLI commands to run these common tasks:

• make build: sam build --use-container
• make deploy.guided: sam deploy --guided
• make invoke: sam local invoke MPContribsMakeDownloadFunction --event events/make_download.json
• make run: sam local start-api

Sync project with function dependencies

Pipenv takes care of isolating dev dependencies and app dependencies. As SAM CLI requires a requirements.txt file, you'd need to generate one if new app dependencies have been added:

mpcontribs-serverless$ pipenv lock -r > make_download/requirements.txt