How to use @aws-cdk/core

constructor(parent, id, props) {
  super(parent, id, props);

  // Create a lambda that recrawls changelogs discovered in the past
  const recrawlLambda = new lambda.Function(this, 'recrawl', {
   runtime: lambda.Runtime.NODEJS_12_X,
   handler: 'recrawl.handle',
   code: lambda.Code.asset('./app/recrawl'),
   timeout: cdk.Duration.minutes(5),
   environment: {
    CHANGELOGS_TABLE_NAME: props.changelogsTable.tableName,
    DISCOVERED_TOPIC_NAME: props.toCrawlTopic.topicArn
   }
  });

  // Grant the lambda permission to modify the tables
  props.changelogsTable.grantReadWriteData(recrawlLambda.role);
  props.toCrawlTopic.grantPublish(recrawlLambda.role);

  // Schedule the recrawler to run once every minute
  this.eventRule = new events.Rule(this, 'recrawl-check-schedule', {
   schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
   targets: [new eventTargets.LambdaFunction(recrawlLambda)]
  });
 }

 schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
 targets: [new eventTargets.LambdaFunction(regenerateHomepage)]
});

constructor(parent, id, props) {
  super(parent, id, props);

  // Create a lambda that returns autocomplete results
  const recentlyCrawled = new lambda.Function(this, 'recently-crawled', {
   runtime: lambda.Runtime.NODEJS_12_X,
   handler: 'recently-crawled.handle',
   code: lambda.Code.asset('./app/recently-crawled'),
   environment: {
    FEEDS_TABLE_NAME: props.feedsTable.tableName,
    API_BUCKET_NAME: props.apiBucket.bucketName
   }
  });

  // Grant the lambda permission to modify the tables and S3 bucket
  props.feedsTable.grantReadWriteData(recentlyCrawled.role);
  props.apiBucket.grantReadWrite(recentlyCrawled.role);

  // Schedule the recrawler to run once every minute
  this.eventRule = new events.Rule(this, 'recrawl-check-schedule', {
   schedule: events.Schedule.rate(cdk.Duration.minutes(1)),
   targets: [new eventTargets.LambdaFunction(recentlyCrawled)]
  });
 }

code: lambda.Code.asset('src'),
handler: 'handler.main',
timeout: cdk.Duration.seconds(300),
runtime: lambda.Runtime.NODEJS_10_X,
environment: {

handler: 'crawl.handle',
code: lambda.Code.asset('./app/crawl'),
timeout: cdk.Duration.seconds(30),
vpc: props.vpc,
environment: {

constructor(parent, id, props) {
  super(parent, id, props);

  // Create the lambda
  const pypiFollower = new lambda.Function(this, 'pypi-follower', {
   runtime: lambda.Runtime.NODEJS_12_X,
   handler: 'pypi-recent.handle',
   code: lambda.Code.asset('./app/pypi-recent'),
   timeout: cdk.Duration.minutes(1),
   environment: {
    CHANGELOGS_TABLE_NAME: props.changelogsTable.tableName,
    DISCOVERED_TOPIC_NAME: props.toCrawlTopic.topicArn
   }
  });

  // Grant this application access to the DynamoDB table and SNS topic
  props.changelogsTable.grantReadWriteData(pypiFollower.role);
  props.toCrawlTopic.grantPublish(pypiFollower.role);

  // Schedule the follower to run once every 5 mins
  this.eventRule = new events.Rule(this, 'check-recent-pypi', {
   schedule: events.Schedule.rate(cdk.Duration.minutes(5)),
   targets: [new eventTargets.LambdaFunction(pypiFollower)]
  });
 }

constructor(parent, id, props) {
  super(parent, id, props);

  // Create the lambda
  const rubygemFollower = new lambda.Function(this, 'rubygem-follower', {
   runtime: lambda.Runtime.NODEJS_12_X,
   handler: 'rubygem-recent.handle',
   code: lambda.Code.asset('./app/rubygem-recent'),
   timeout: cdk.Duration.minutes(1),
   environment: {
    CHANGELOGS_TABLE_NAME: props.changelogsTable.tableName,
    DISCOVERED_TOPIC_NAME: props.toCrawlTopic.topicArn
   }
  });

  // Grant this application access to the DynamoDB table and SNS topic
  props.changelogsTable.grantReadWriteData(rubygemFollower.role);
  props.toCrawlTopic.grantPublish(rubygemFollower.role);

  // Schedule the follower to run once every 5 mins
  this.eventRule = new events.Rule(this, 'check-recent-rubygems', {
   schedule: events.Schedule.rate(cdk.Duration.minutes(5)),
   targets: [new eventTargets.LambdaFunction(rubygemFollower)]
  });
 }