AWS Serverless Cloud Native Java RESTful API

Develop an API following the best practices in the set of principles of REST (State Representation Transfer) architecture.

Stack Java SE 8:

  • AWS SAM
  • Amazon API Gateway
  • AWS Lambda
  • Amazon DynamoDB

The travel entity must contain the attributes: Country, City, Date (YYYY / MM / DD) and Reason.

o Create a new trip record:

• HTTP return code 201

o Get trips by period:

• Via query / travel parameter? Start = X and end = Y
• Return 200 containing the results in a list.
• Even when nothing is found, return an empty list and HTTP code 200.
• Returns all fields of the entity in the body.

o get trips by country:

• Via parameter, inform the country / trips /
• Return only one trip from the country.
• HTTP Code 200 case found, body not found empty and HTTP Code 404.

enjoy city trips:

• Via Consulta inform the city and via Path parameter inform the country / trips / /? city ​​=
• The city search for being of type contains (like - LSI Sort Indexing key)
• Return only one trip from the country.
• HTTP Code 200 case found, body not found empty and HTTP Code 404.

• No API source code should contain a README file with instructions for running an API locally and also on AWS.

Requirements

• AWS CLI already configured with at least PowerUser permission
• Java SE Development Kit 8 installed
• Docker installed
• Maven
• SAM CLI
• Python 3

Setup process

Installing dependencies

We use maven to install our dependencies and package our application into a JAR file:

mvn clean install

Local development

Invoking function locally through local API Gateway

1. Update AWS credentials vi .aws/credentials

Go to project local directory where is this repository:

1. Start DynamoDB Local in a Docker container.

docker run -p 8000:8000 -v $(pwd)/local/dynamodb:/data/ amazon/dynamodb-local -jar DynamoDBLocal.jar -sharedDb -dbPath /data

or using docker-compose file to up em down dynamoDB (use it for windows with wsl)

docker-compose up

1. Set permissions for DynamoDB Local in a Docker container. chmod 777 -R $(pwd)/local/dynamodb

2. Create the DynamoDB table.

   Documentation: https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_CreateTable.html

   You can use :

   aws dynamodb create-table --table-name trip --attribute-definitions AttributeName=country,AttributeType=S AttributeName=dateTrip,AttributeType=S AttributeName=city,AttributeType=S AttributeName=reason,AttributeType=S --key-schema AttributeName=country,KeyType=HASH AttributeName=dateTrip,KeyType=RANGE --local-secondary-indexes 'IndexName=cityIndex,KeySchema=[{AttributeName=country,KeyType=HASH},{AttributeName=city,KeyType=RANGE}],Projection={ProjectionType=ALL}' 'IndexName=reasonIndex,KeySchema=[{AttributeName=country,KeyType=HASH},{AttributeName=reason,KeyType=RANGE}],Projection={ProjectionType=ALL}' --billing-mode PAY_PER_REQUEST --endpoint-url http://localhost:8000
   

Or

Use this command inside the project folder:

     aws dynamodb create-table --cli-input-json file://dbDynamo.json --endpoint-url http://localhost:8000
  
- past file dbDynamo.json and run

1. If the table already exist, you can delete: aws dynamodb delete-table --table-name trip --endpoint-url http://localhost:8000

2. Use this command to list all tables: aws dynamodb list-tables --endpoint-url http://localhost:8000

3. Use this command to see the content of table trip: aws dynamodb scan --table-name trip --endpoint-url http://localhost:8000

4. Start the SAM local API.

• On a Mac: sam local start-api --env-vars src/test/resources/test_environment_mac.json
• On Windows: sam local start-api --env-vars src/test/resources/test_environment_windows.json
• On Linux: sam local start-api --env-vars src/test/resources/test_environment_linux.json

OBS: If you already have the container locally (in your case the java8), then you can use --skip-pull-image to remove the download

Packaging and deployment

AWS Lambda Java runtime accepts either a zip file or a standalone JAR file - We use the latter in this example. SAM will use CodeUri property to know where to look up for both application and dependencies:

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:

export BUCKET_NAME=trip-bucket
aws s3 mb s3://$BUCKET_NAME

On Windows

set BUCKET_NAME=trip-bucket
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 $BUCKET_NAME

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

sam deploy --template-file packaged.yaml \
    --stack-name trip-datalake \
    --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 trip-datalake \
    --query 'Stacks[].Outputs'

Appendix

AWS CLI commands

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

Remember to set your credentials (~/.aws/credentials)

• Windows:

set BUCKET_NAME=trip-bucket
set STACK_NAME=trip-datalake

aws s3 mb s3://$BUCKET_NAME

sam package ^
    --template-file template.yaml ^
    --output-template-file packaged.yaml ^
    --s3-bucket %BUCKET_NAME%

sam deploy ^
    --template-file packaged.yaml ^
    --capabilities CAPABILITY_IAM ^
    --stack-name %STACK_NAME%

aws cloudformation describe-stacks ^
    --stack-name %STACK_NAME% --query 'Stacks[].Outputs'

• Linux/Mac:

export BUCKET_NAME=bucket_trip
export STACK_NAME=trip-datalake

aws s3 mb s3://$BUCKET_NAME

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

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

aws cloudformation describe-stacks \
    --stack-name trip-datalake --query 'Stacks[].Outputs'
```