参考

https://qiita.com/hayao_k/items/841026f9675d163b58d5

sam-app

This is a sample template for sam-app - Below is a brief explanation of what we have generated for you:

.
├── README.md                   <-- This instructions file
├── hello_world                 <-- Source code for a lambda function
│   ├── app.rb                  <-- Lambda function code
├── Gemfile                     <-- Ruby dependencies
├── template.yaml               <-- SAM template
└── tests                       <-- Unit tests
    └── unit
        └── test_handler.rb

Requirements

AWS CLI already configured with at least PowerUser permission
Ruby 2.5 installed
Docker installed
Ruby Version Manager

Setup process

Match ruby version with docker image

For high fidelity development environment, make sure the local ruby version matches that of the docker image. To do so lets use Ruby Version Manager

Setup Ruby Version Manager from Ruby Version Manager

Run following commands

rvm install ruby-2.5.0
rvm use ruby-2.5.0
rvm --default use 2.5.0

Installing dependencies

sam-app comes with a Gemfile that defines the requirements and manages installing them.

gem install bundler
bundle install
bundle install --deployment --path hello_world/vendor/bundle

Step 1 installs bundlerwhich provides a consistent environment for Ruby projects by tracking and installing the exact gems and versions that are needed.
Step 2 creates a Gemfile.lock that locks down the versions and creates the full dependency closure.
Step 3 installs the gems to hello_world/vendor/bundle.

NOTE: As you change your dependencies during development you'll need to make sure these steps are repeated in order to execute your Lambda and/or API Gateway locally.

Local development

Invoking function locally through local API Gateway

sam local start-api

If the previous command ran successfully you should now be able to hit the following local endpoint to invoke your function http://localhost:3000/hello

SAM CLI is used to emulate both Lambda and API Gateway locally and uses our template.yaml to understand how to bootstrap this environment (runtime, where the source code is, etc.) - The following excerpt is what the CLI will read in order to initialize an API and its routes:

...
Events:
    HelloWorld:
        Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
        Properties:
            Path: /hello
            Method: get

Packaging and deployment

AWS Lambda Ruby runtime requires a flat folder with all dependencies including the application. SAM will use CodeUri property to know where to look up for both application and dependencies:

...
    HelloWorldFunction:
        Type: AWS::Serverless::Function
        Properties:
            CodeUri: hello_world/
            ...

Firstly, we need a S3 bucket where we can upload our Lambda functions packaged as ZIP before we deploy anything - If you don't have a S3 bucket to store code artifacts then this is a good time to create one:

aws s3 mb s3://BUCKET_NAME

Next, run the following command to package our Lambda function to S3:

sam package \
    --template-file template.yaml \
    --output-template-file packaged.yaml \
    --s3-bucket REPLACE_THIS_WITH_YOUR_S3_BUCKET_NAME

Next, the following command will create a Cloudformation Stack and deploy your SAM resources.

sam deploy \
    --template-file packaged.yaml \
    --stack-name sam-app \
    --capabilities CAPABILITY_IAM

See Serverless Application Model (SAM) HOWTO Guide for more details in how to get started.

After deployment is complete you can run the following command to retrieve the API Gateway Endpoint URL:

aws cloudformation describe-stacks \
    --stack-name sam-app \
    --query 'Stacks[].Outputs'

Testing

We use Mocha for testing our code and you can install it using gem: gem install mocha

Next, we run our initial unit tests:

ruby tests/unit/test_hello.rb

NOTE: It is recommended to use a Ruby Version Manager to manage, and work with multiple ruby environments from interpreters to sets of gems

Appendix

AWS CLI commands

AWS CLI commands to package, deploy and describe outputs defined within the cloudformation stack:

sam package \
    --template-file template.yaml \
    --output-template-file packaged.yaml \
    --s3-bucket REPLACE_THIS_WITH_YOUR_S3_BUCKET_NAME

sam deploy \
    --template-file packaged.yaml \
    --stack-name sam-app \
    --capabilities CAPABILITY_IAM \
    --parameter-overrides MyParameterSample=MySampleValue

aws cloudformation describe-stacks \
    --stack-name sam-app --query 'Stacks[].Outputs'

Bringing to the next level

Here are a few ideas that you can use to get more acquainted as to how this overall process works:

Create an additional API resource (e.g. /hello/{proxy+}) and return the name requested through this new path
Update unit test to capture that
Package & Deploy

Next, you can use the following resources to know more about beyond hello world samples and how others structure their Serverless applications:

AWS Serverless Application Repository

corocn / sam-sample