AWS SAM (serverless application model)

AWS SAM

build package: aws cloudformation package --template-file template.yaml --output-template-file output.yaml --s3-bucket my-bucket-name

deploy package: aws cloudformation deploy --template-file output.yaml --stack-name StackName --capabilities CAPABILITY_IAM

AWS SAM Local

Use aws sam local to test and debug locally.

Setup install

• install docker
• install aws sam local: npm install -g aws-sam-local
• install Go (v1.8+): brew install go
• set GO Env variables (see below)
• run go get github.com/awslabs/aws-sam-local

GO Env variables

export GOROOT=/usr/local/opt/go/libexec

export GOPATH=$HOME/.go

export PATH=$PATH:$GOROOT/bin:$GOPATH/bin

Set local DynamoDB

Follow instructions: http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBLocal.html

To use the AWS CLI with the local dynamoDB, simply add --endpoint-url http://localhost:8000 to each command

Example to create the table reviewTable:

aws dynamodb create-table --table-name reviewTable
--attribute-definitions AttributeName=id,AttributeType=S
--key-schema AttributeName=id,KeyType=HASH
--provisioned-throughput ReadCapacityUnits=1,WriteCapacityUnits=1
--endpoint-url http://localhost:8000

Use

• validate the template yaml: sam validate
• run API Gateway locally: sam local start-api
• invoke a lambda function: sam local invoke "FunctionName" -e event.json

Include environment variables:

• via external file: sam local start-api --env-vars file_with_env_vars.json
• via shell: TABLE_NAME=reviewTable sam local start-api

DynamoDB local

To run: java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

The DB must be running while testing functions that need to access it.

Acces the DynamoDB Javascript Shell on: http://localhost:8000/shell/

Environment variables

Via external JSON file

To correctly use defined environment variables use --env-vars argument on invoke or start-api to provide a JSON file that contains values for environment variables defined in your function.

Example set review table name:

{
  "GetAllFunction": {
    "TABLE_NAME": "reviewTable",
  },
  "GetFunction": {
    "TABLE_NAME": "reviewTable",
  },
  "PutFunction": {
    "TABLE_NAME": "reviewTable",
  },
  "DeleteFunction": {
    "TABLE_NAME": "reviewTable",
  },
}

Via Shell

Simple define the variable while calling sam.

Example: TABLE_NAME=reviewTable sam local start-api

This way is simpler when the variable is used multiple times.