serverless/lib/plugins/aws/package/compile/events/cloud-watch-event.js

import _ from 'lodash'
import ServerlessError from '../../../../../serverless-error.js'
import resolveLambdaTarget from '../../../utils/resolve-lambda-target.js'

class AwsCompileCloudWatchEventEvents {
  constructor(serverless) {
    this.serverless = serverless
    this.provider = this.serverless.getProvider('aws')

    this.hooks = {
      'package:compileEvents': async () => this.compileCloudWatchEventEvents(),
    }

    this.serverless.configSchemaHandler.defineFunctionEvent(
      'aws',
      'cloudwatchEvent',
      {
        type: 'object',
        properties: {
          event: { type: 'object' },
          input: {
            anyOf: [{ type: 'string', maxLength: 8192 }, { type: 'object' }],
          },
          inputPath: { type: 'string', minLength: 1, maxLength: 256 },
          inputTransformer: {
            type: 'object',
            properties: {
              inputPathsMap: {
                type: 'object',
                additionalProperties: { type: 'string', minLength: 1 },
              },
              inputTemplate: { type: 'string', minLength: 1, maxLength: 8192 },
            },
            required: ['inputTemplate'],
            additionalProperties: false,
          },
          description: { type: 'string', maxLength: 512 },
          name: {
            type: 'string',
            pattern: '[a-zA-Z0-9-_.]+',
            minLength: 1,
            maxLength: 64,
          },
          enabled: { type: 'boolean' },
        },
        additionalProperties: false,
      },
    )
  }

  compileCloudWatchEventEvents() {
    this.serverless.service.getAllFunctions().forEach((functionName) => {
      const functionObj = this.serverless.service.getFunction(functionName)
      let cloudWatchEventNumberInFunction = 0

      if (functionObj.events) {
        functionObj.events.forEach((event) => {
          if (event.cloudwatchEvent) {
            cloudWatchEventNumberInFunction++
            let State
            let Input
            let InputTransformer

            const EventPattern = JSON.stringify(event.cloudwatchEvent.event)
            State = 'ENABLED'
            if (event.cloudwatchEvent.enabled === false) {
              State = 'DISABLED'
            }
            const Name = event.cloudwatchEvent.name
            const InputPath = event.cloudwatchEvent.inputPath
            const Description = event.cloudwatchEvent.description
            Input = event.cloudwatchEvent.input
            InputTransformer = event.cloudwatchEvent.inputTransformer

            if (
              [Input, InputPath, InputTransformer].filter(Boolean).length > 1
            ) {
              throw new ServerlessError(
                [
                  'You can only set one of input, inputPath, or inputTransformer ',
                  'properties at the same time for cloudwatch events. ',
                  'Please check the AWS docs for more info',
                ].join(''),
                'CLOUDWATCH_MULTIPLE_INPUT_PROPERTIES',
              )
            }

            if (Input && typeof Input === 'object') {
              Input = JSON.stringify(Input)
            }
            if (Input && typeof Input === 'string') {
              // escape quotes to favor JSON.parse
              Input = Input.replace(/"/g, '\\"')
            }
            if (InputTransformer) {
              InputTransformer = this.formatInputTransformer(InputTransformer)
            }

            const cloudWatchLogicalId =
              this.provider.naming.getCloudWatchEventLogicalId(
                functionName,
                cloudWatchEventNumberInFunction,
              )
            const lambdaPermissionLogicalId =
              this.provider.naming.getLambdaCloudWatchEventPermissionLogicalId(
                functionName,
                cloudWatchEventNumberInFunction,
              )
            const cloudWatchId =
              this.provider.naming.getCloudWatchEventId(functionName)

            const dependsOn = _.get(functionObj.targetAlias, 'logicalId')

            const cloudWatchEventRuleTemplate = `
              {
                "Type": "AWS::Events::Rule",
                ${dependsOn ? `"DependsOn": "${dependsOn}",` : ''}
                "Properties": {
                  "EventPattern": ${EventPattern.replace(/\\n|\\r/g, '')},
                  "State": "${State}",
                  ${Description ? `"Description": "${Description}",` : ''}
                  ${Name ? `"Name": "${Name}",` : ''}
                  "Targets": [{
                    ${
                      Input
                        ? `"Input": "${Input.replace(/\\n|\\r/g, '')}",`
                        : ''
                    }
                    ${
                      InputPath
                        ? `"InputPath": "${InputPath.replace(/\r?\n/g, '')}",`
                        : ''
                    }
                    ${
                      InputTransformer
                        ? `"InputTransformer": ${InputTransformer},`
                        : ''
                    }
                    "Arn": ${JSON.stringify(
                      resolveLambdaTarget(functionName, functionObj),
                    )},
                    "Id": "${cloudWatchId}"
                  }]
                }
              }
            `

            const permissionTemplate = `
              {
                "Type": "AWS::Lambda::Permission",
                ${dependsOn ? `"DependsOn": "${dependsOn}",` : ''}
                "Properties": {
                  "FunctionName": ${JSON.stringify(
                    resolveLambdaTarget(functionName, functionObj),
                  )},
                  "Action": "lambda:InvokeFunction",
                  "Principal": "events.amazonaws.com",
                  "SourceArn": { "Fn::GetAtt": ["${cloudWatchLogicalId}", "Arn"] }
                }
              }
            `

            const newCloudWatchEventRuleObject = {
              [cloudWatchLogicalId]: JSON.parse(cloudWatchEventRuleTemplate),
            }

            const newPermissionObject = {
              [lambdaPermissionLogicalId]: JSON.parse(permissionTemplate),
            }

            _.merge(
              this.serverless.service.provider.compiledCloudFormationTemplate
                .Resources,
              newCloudWatchEventRuleObject,
              newPermissionObject,
            )
          }
        })
      }
    })
  }

  formatInputTransformer(inputTransformer) {
    const cfmOutput = {
      // InputTemplate is required
      InputTemplate: inputTransformer.inputTemplate,
    }
    // InputPathsMap is optional
    if (inputTransformer.inputPathsMap) {
      cfmOutput.InputPathsMap = inputTransformer.inputPathsMap
    }
    return JSON.stringify(cfmOutput)
  }
}

export default AwsCompileCloudWatchEventEvents