Work out approximate cost per lambda across region over time period using Cloudwatch Log Insights

lambdapricing.js

const aws = require('aws-sdk');
aws.config.region = 'eu-west-1';
const cloudwatchlogs = new aws.CloudWatchLogs();
const moment = require('moment');
const fs = require('fs');

const filename = `results-${new Date().getTime()}.csv`;
fs.appendFileSync(filename, ['logGroup','dollars','rcnt','numberdollars','total'].join(",") + "\n");

const endTime = moment().toDate().getTime();
const startTime = moment().subtract(1, 'day').toDate().getTime();

const queryString = `
filter @type = "REPORT"
|  fields 1 as req, @timestamp as Timestamp, @requestId as RequestID, @logStream as LogStream, @billedDuration as BilledDurationInMS, @memorySize/1000000 as MemorySetInMB, @billedDuration/1000*MemorySetInMB/1024 as BilledDurationInGBSeconds
| stats sum(BilledDurationInGBSeconds) * 0.0000166667 as dollars,
  sum(req)* 1  as rcnt,
  sum(req) / 1000000 * 0.2 as numberdollars,
  dollars + numberdollars as total
`

async function getPricing(logGroup) {
  const data = await getQueryResults(logGroup);
  if (!data.length) {
    return [0,0,0,0]
  }
  return data[0].map( (lol) => {
    return lol.value;
  });
}

async function getQueryResults(logGroup) {
  var params = {
    endTime,
    startTime,
    queryString,
    limit: 1000,
    logGroupName: logGroup
  };
  const query = await cloudwatchlogs.startQuery(params).promise();


  let ret = false;
  let data;
  while (!ret) {
    console.log(logGroup, 'sleeping');
    await sleepPromise(5000);

    data = await cloudwatchlogs.getQueryResults({
      queryId: query.queryId
    }).promise();

    if (data.status === 'Complete') {
      ret = true;
      data = data.results
    }

  }
  return data;
}

async function priceLogGroups(logGroups) {
  await Promise.all(logGroups.map( async (logGroup) => {
    const data = await getPricing(logGroup);
    fs.appendFileSync(filename, [logGroup].concat(data).join(",") + "\n");
  }))
}

async function priceLambda() {
  let done = false;
  const params = {
    limit: 9,
    logGroupNamePrefix: '/aws/lambda/'
  }

  while (!done) {
    const data = await cloudwatchlogs.describeLogGroups(params).promise();

    const logGroupNames = data.logGroups.map( ({logGroupName}) => {
      return logGroupName;
    });

    await priceLogGroups(logGroupNames);

    const nextToken = data.nextToken;
    if (!nextToken || !logGroupNames.length) {
      done = true;
    } else {
      params.nextToken = nextToken;
    }
  }
}

function sleepPromise(t) {
  return new Promise((resolve) => {
    setTimeout(resolve, t);
  });
}

priceLambda()
.then( () => {
  console.log('done');
});