calculate.js

'use strict';

const AWS = require('aws-sdk')

const main = async () => {
  const env = process.argv[2]
  const regions = {
    'eu-west-1': {
      data_processing_cost: 0.008,
      lcu_cost: 0.008
    },
    'us-east-1':{
      data_processing_cost: 0.008,
      lcu_cost: 0.008
    },
    'us-west-2': {
      data_processing_cost: 0.008,
      lcu_cost: 0.008
    }
  }
  const start = '2018-07', end = '2018-08'

  console.log("Environment\tRegion\tLoad Balancer Name\tEstimated Data Processed\tEstimated ELB Cost\tEstimated LCUs Consumed\tEstimated ALB Cost")

  for (const region of Object.keys(regions)) {
    const CloudWatch = new AWS.CloudWatch({region: region})
    const ELB = new AWS.ELB({region: region})

    const lb_names = (await ELB.describeLoadBalancers({}).promise())
      .LoadBalancerDescriptions.map((lb) => { return lb.LoadBalancerName })

    for (const lb of lb_names) {
      const results = await CloudWatch.getMetricData(cloudwatch_query(lb, start, end)).promise()
      const data_processed = results.MetricDataResults[0].Values.reduce((accumlator, bytes) => {
        return accumlator + (bytes / 1000000000)
      }, 0)
      const data_processed_cost = data_processed * regions[region].data_processing_cost
      const lcus_consumed = results.MetricDataResults[1].Values.reduce((accumlator, lcus) => {
        return accumlator + lcus
      }, 0)
      const lcus_cost = lcus_consumed * regions[region].lcu_cost

      console.log(`${env}\t${region}\t${lb}\t${data_processed}\t${data_processed_cost}\t${lcus_consumed}\t${lcus_cost}`)
    }
  }
}

main();

const cloudwatch_query = (elb, start_date, end_date) => {
  const start = new Date(start_date)
  const end = new Date(end_date)

  return {
    MetricDataQueries: [{
      Id: 'processed_bytes_query',
      MetricStat: {
        Metric: {
          Dimensions: [{
            Name: 'LoadBalancerName',
            Value: elb
          }],
          MetricName: 'EstimatedProcessedBytes',
          Namespace: 'AWS/ELB'
        },
        Period: 86400,
        Stat: 'Sum',
        Unit: 'Bytes'
      }
    }, {
      Id: 'alb_consumed_lcus',
      MetricStat: {
        Metric: {
          Dimensions: [{
            Name: 'LoadBalancerName',
            Value: elb
          }],
          MetricName: 'EstimatedALBConsumedLCUs',
          Namespace: 'AWS/ELB'
        },
        Period: 86400,
        Stat: 'Sum'
      }
    }],
    StartTime: start,
    EndTime: end
  }
}