CDK Entest

Introduction#

GitHub Setup and go through basic concepts of apigw socket

Routes: $connect, $disconnect, $default, $sendMessage
Role for apigw, and role for lambda
SendMessage lambda get the endpointUrl and send messages back to clients
Manage connectionId by a table

Api Socket#

create an api socket, skip deploy options

const api = new aws_apigatewayv2.CfnApi(this, 'ApiGwSocket', {
  name: 'HelloApiGwSocket',
  protocolType: 'WEBSOCKET',
  routeSelectionExpression: '$request.body.action'
})

role for apigw

const role = new aws_iam.Role(this, 'RoleForApiGwInvokeLambda', {
  roleName: 'InvokeLambdaRoleForApiGw',
  assumedBy: new aws_iam.ServicePrincipal('apigateway.amazonaws.com')
})

role.addToPolicy(
  new aws_iam.PolicyStatement({
    effect: Effect.ALLOW,
    resources: [
      connectFunc.functionArn,
      disconnectFunc.functionArn,
      messageFunc.functionArn
    ],
    actions: ['lambda:InvokeFunction']
  })
)

create a table for connection ids

const table = new aws_dynamodb.Table(this, 'ConnectionIdTable', {
  tableName: 'ConnectionIdTable',
  partitionKey: {
    name: 'ConnectionId',
    type: aws_dynamodb.AttributeType.STRING
  },
  readCapacity: 5,
  writeCapacity: 5,
  removalPolicy: RemovalPolicy.DESTROY
})

connect, disconnect handler

const connectFunc = new aws_lambda.Function(this, 'ConnectFunc', {
  functionName: 'ConnectFunc',
  code: aws_lambda.Code.fromAsset(path.join(__dirname, './../lambdas')),
  handler: 'connect.handler',
  runtime: aws_lambda.Runtime.PYTHON_3_8,
  timeout: Duration.seconds(300),
  memorySize: 256,
  environment: {
    TABLE_NAME: table.tableName
  }
})
table.grantReadWriteData(messageFunc)

send message handler which send messages back to clients

const messageFunc = new aws_lambda.Function(this, 'MessageFunc', {
  functionName: 'MessageFunc',
  code: aws_lambda.Code.fromAsset(path.join(__dirname, './../lambdas')),
  handler: 'sendMessage.handler',
  runtime: aws_lambda.Runtime.PYTHON_3_8,
  timeout: Duration.seconds(300),
  memorySize: 256,
  environment: {
    TABLE_NAME: table.tableName,
    ENDPOINT_URL: `https://${api.ref}.execute-api.${this.region}.amazonaws.com/dev`
  },
  initialPolicy: [
    new aws_iam.PolicyStatement({
      effect: Effect.ALLOW,
      actions: ['execute-api:ManageConnections'],
      resources: ['*']
    })
  ]
})

table.grantReadWriteData(messageFunc)

Lambda Integration#

Use proxy integration between lambda and apigw

const connectIntegration = new aws_apigatewayv2.CfnIntegration(
  this,
  'ConnectLambdaIntegration',
  {
    apiId: api.ref,
    integrationType: 'AWS_PROXY',
    integrationUri: `arn:aws:apigateway:${this.region}:lambda:path/2015-03-31/functions/${connectFunc.functionArn}/invocations`,
    credentialsArn: role.roleArn
  }
)

const disconnectIntegration = new aws_apigatewayv2.CfnIntegration(
  this,
  'DisconnectLambdaIntegration',
  {
    apiId: api.ref,
    integrationType: 'AWS_PROXY',
    integrationUri: `arn:aws:apigateway:${this.region}:lambda:path/2015-03-31/functions/${disconnectFunc.functionArn}/invocations`,
    credentialsArn: role.roleArn
  }
)

const messageIntegration = new aws_apigatewayv2.CfnIntegration(
  this,
  'MessageLambdaIntegration',
  {
    apiId: api.ref,
    integrationType: 'AWS_PROXY',
    integrationUri: `arn:aws:apigateway:${this.region}:lambda:path/2015-03-31/functions/${messageFunc.functionArn}/invocations`,
    credentialsArn: role.roleArn
  }
)

then create routes

const connectRoute = new aws_apigatewayv2.CfnRoute(this, 'ConnectRoute', {
  apiId: api.ref,
  routeKey: '$connect',
  authorizationType: 'NONE',
  target: 'integrations/' + connectIntegration.ref
})

const disconnectRoute = new aws_apigatewayv2.CfnRoute(this, 'DisconnectRoute', {
  apiId: api.ref,
  routeKey: '$disconnect',
  authorizationType: 'NONE',
  target: 'integrations/' + disconnectIntegration.ref
})
const messageRoute = new aws_apigatewayv2.CfnRoute(this, 'MessageRoute', {
  apiId: api.ref,
  routeKey: 'sendmessage',
  authorizationType: 'NONE',
  target: 'integrations/' + messageIntegration.ref
})

Deployment and Stage#

const deployment = new aws_apigatewayv2.CfnDeployment(this, 'deployment', {
  apiId: api.ref
})

new aws_apigatewayv2.CfnStage(this, 'DevStage', {
  stageName: 'dev',
  deploymentId: deployment.ref,
  apiId: api.ref,
  autoDeploy: true
})

dependency and export output

deployment.node.addDependency(connectRoute)
deployment.node.addDependency(disconnectRoute)
deployment.node.addDependency(messageRoute)

new CfnOutput(this, 'endpointUrl', {
  exportName: 'apiId',
  value: api.ref
})

Test#

Option 1. Just using online testing tool here message format sent from client

{ "action": "sendmessage", "message": "hello hai tran" }

Option 2. Build a react app

Screen Shot 2022-08-17 at 15 26 08