The Simple Web Service

Interactive Reference Architecture

Click on the components or numbered steps below to explore how this architecture works.

This is the most basic of patterns you're likely to see with serverless applications. The Simple Web Service fronts a Lambda function with an API Gateway. I've shown DynamoDB as the database here because it scales nicely with the high concurrency capabilities of Lambda.

Deploy this Pattern

Below are the basic configurations for deploying this pattern using different frameworks and platforms. Additional configuration for your environment will be necessary. The source files and additional examples are available in the GitHub repo.

• SAM

  EMBED DISABLED: https://app.stackery.io/editor/template?owner=serverless-architecture&repo=reference-architectures&file=simple-web-service/sam/template.yaml&standalone=true&sync=stackeryEditorDesign

• Stackery

  EMBED DISABLED: https://app.stackery.io/editor/design?owner=serverless-architecture&repo=reference-architectures&file=simple-web-service/sam/template.yaml&standalone=true&sync=stackeryEditorTemplate

• Serverless Framework

  yamlCopy code
  service: simple-web-service
  provider:
    name: aws
    runtime: nodejs12.x
    stage: ${opt:stage,'dev'}
    region: us-east-1
    stackName: ${self:service}-${self:provider.stage}
    stackTags:
      SERVICE: ${self:service}
    httpApi:
      payload: '2.0'
      cors: true
  
  functions:
    GetUser:
      handler: index.handler
      memorySize: 1024
      timeout: 6
      tracing: Active
      environment:
        TABLE_NAME: !Ref Users
        TABLE_ARN: !GetAtt Users.Arn
      iamRoleStatementsName: ${self:service}-${self:provider.stage}-getuser-role
      iamRoleStatements:
        - Effect: Allow
          Action:
            - dynamodb:getItem
            - dynamodb:putItem
            - dynamodb:updateItem
            - dynamodb:deleteItem
          Resource:
            - !Join [ '/', [ !GetAtt Users.Arn, '*' ] ]
            - !GetAtt Users.Arn
        - Effect: Allow
          Action:
            - xray:PutTraceSegments
            - xray:PutTelemetryRecords
          Resource: "*"
      events:
        - httpApi:
            path: /user/{id}
            method: get
  
  plugins:
    - serverless-iam-roles-per-function
  
  resources:
    Resources:
      Users:
        Type: AWS::DynamoDB::Table
        Properties:
          AttributeDefinitions:
            - AttributeName: id
              AttributeType: S
          BillingMode: PAY_PER_REQUEST
          KeySchema:
            - AttributeName: id
              KeyType: HASH
          StreamSpecification:
            StreamViewType: NEW_AND_OLD_IMAGES
  

• Pulumi

  javascriptCopy code
  // Full example: https://github.com/jeremydaly/reference-architectures/tree/master/simple-web-service/pulumi
  
  import * as aws from "@pulumi/aws";
  import * as awsx from "@pulumi/awsx";
  
  // Provision a DynamoDB Table.
  const users = new aws.dynamodb.Table("users", {
      attributes: [{
          name: "id",
          type: "S",
      }],
      hashKey: "id",
      billingMode: "PAY_PER_REQUEST",
      streamViewType: "NEW_AND_OLD_IMAGES",
  });
  
  // Create an API Gateway with a single /user/{id} route that uses the Table.
  // This uses the default Lambda, IAM, and name settings; for full control over
  // them, see the aws.lambda.CallbackFunction class, which can be allocated
  // separately and passed instead of the inline eventHandler below.
  const api = new awsx.apigateway.API("api", {
      routes: [{
          path: "/user/{id}",
          method: "GET",
          eventHandler: async (event, context) => {
              const tableName = users.name.get();
              const tableArn = users.arn.get();
              return { statusCode: 200, body: JSON.stringify(event) };
          },
      }]
  });
  
  // Export the resulting API Gateway URL:
  export const url = api.url;
  

• CDK

  Are you a CDK Guru? Would you like to contribute patterns to the community? Check out the Github repo!