lightsail-backup

lightsail-backup.js

const AWS = require('aws-sdk');

exports.handler = async (event, context) => {
  console.log(JSON.stringify(event))
  // ================================
  // Define your backups
  // ================================

  const instanceName = event.instanceName || process.env['instanceName'];
  const backupDaysMax = event.days || process.env['days']; // keep at least 7 daily backups 
  const backupWeeksMax = event.weeks || process.env['weeks']; // keep at least 4  weekly  backups
  const backupMonthsMax = event.months || process.env['months']; // keep at least 3  monthly  backups

  // ================================        
  // Unique short tag for snapshots
  // ================================

  const labelTag = process.env['labelTag']+"_"+ instanceName +"_";
  // Set it differently in your Lambdas for different instances. For "ABC" label it would be ABCKW8TAG6 the name of the backups 


  // ================================        
  // Create an AWS lightsail client
  // ================================

  var lightsail = new AWS.Lightsail(
    {
      apiVersion: '2016-11-28',
      region:  process.env['region'] 
    }
  );

  // ================================        
  // Dates calculations for the name
  // ================================

  var now = new Date();
  var start = new Date(now.getFullYear(), 0, 0);
  var diff = now - start;
  var oneDay = 1000 * 60 * 60 * 24;
  var kw = Math.floor(diff / oneDay / 7) + 1;
  var day = Math.floor(diff / oneDay)

  console.log('KW of year: ' + kw);
  console.log('day of year:' + day);
  console.log('day of month:' + now.getDate());
  console.log('day of week:' + now.getDay());
  console.log('month:' + now.getMonth());

  var backupDaysNR = now.getDay() % backupDaysMax;
  var backupWeeksNR = kw % backupWeeksMax;
  var backupMonatsNR = now.getMonth() % backupMonthsMax;

  console.log('backupDaysNR:' + backupDaysNR);
  console.log('backupWeeksNR:' + backupWeeksNR);
  console.log('backupMonatsNR:' + backupMonatsNR);
  
  
  const newDaySnapshot = async (instanceName, backupDaysNR) => {
    var params = {
      instanceName: instanceName,
      instanceSnapshotName: labelTag + backupDaysNR
    };
    try{
      await lightsail.createInstanceSnapshot(params).promise()
      return 'ok'
    }catch(err){
      return err
    }
  }
  
  const deleteOldSnapshot = async (data) =>{
    
    var backupDaysTillNow;
    var saveBackup;
    var backupDate;
    
    for (var i = 0; i < data.instanceSnapshots.length; i++) { // BROWSE THROUGH SNAPSHOTS
      
      var backupFromInstance = data.instanceSnapshots[i].fromInstanceName;
      backupDate = new Date(data.instanceSnapshots[i].createdAt);
      backupDaysTillNow = Math.floor((now - backupDate) / oneDay);
      saveBackup = false;
      
      if (backupFromInstance == instanceName) {
        // DO NOT DELETE LAST backupDaysMax DAYS BACKUPS
        if (backupDaysTillNow <= backupDaysMax) { saveBackup = true; }
        // DO NOT DELETE LAST backupWeeksMax WEEKS BACKUPS
        if (backupDaysTillNow > backupDaysMax && backupDaysTillNow <= backupWeeksMax * 7 && backupDate.getDay() == 0) { saveBackup = true; }
        // DO NOT DELETE LAST backupWeeksMax MONTHS BACKUPS
        if (backupDaysTillNow > backupWeeksMax * 7 && backupDaysTillNow <= backupMonthsMax * 30 && backupDate.getDate() < 8 && backupDate.getDay() == 0) { saveBackup = true; }

        if (saveBackup) {
          // WE KEEP THESE BACKUPS
          console.log(`keep ${backupDate.getDate()} ${data.instanceSnapshots[i].createdAt}  ${data.instanceSnapshots[i].name}`);
        } else {
          if(data.instanceSnapshots[i].name.startsWith(process.env['labelTag']) ) {
            // WE DELETED THESE BACKUPS
            var paramsDelete = {
              "instanceSnapshotName": data.instanceSnapshots[i].name
            }
            
            try{
              await lightsail.deleteInstanceSnapshot(paramsDelete).promise()
              console.log(`Deleted ${paramsDelete.instanceSnapshotName}`);
            }catch(err){
              console.log(err)
            }
          }else{
            console.log(`keep ${backupDate.getDate()} ${data.instanceSnapshots[i].createdAt}  ${data.instanceSnapshots[i].name}`);
          }
          
        }
      } else {
        console.log('Will ignore this backup because it belongs to an instance other than ' + instanceName);
      }
    }

    // IF WE HAVE MORE BACKUPS WE SHOULD NAVIGATE TO THE NEXT PAGE AND USE RECURSION
    console.log('\n\r=============== TOKEN =============== ');
    console.log(data.nextPageToken);
    if (typeof data.nextPageToken != 'undefined') {
      var params = {
        pageToken: data.nextPageToken
      };
      try{
        const data = await lightsail.getInstanceSnapshots(params).promise()
        await deleteOldSnapshot(data)
      }catch(err){
        console.log(err)
      }
      
    }
    
  }
  
  // ================================        
  // CREATE A NEW SNAPSHOT
  // ================================

  var params = {
    "instanceSnapshotName": labelTag + "KW" + kw + "TAG" + backupDaysNR
  }
  
  try{
    const {instanceSnapshot} = await lightsail.getInstanceSnapshot(params).promise()
    console.log('Today Already backup, snapshot name is ' + instanceSnapshot.name);
  }catch(err){
    console.log('no backup, we do it new');
    await newDaySnapshot(instanceName, "KW" + kw + "TAG" + backupDaysNR)
  }

  // ================================        
  //  DELETING OLD SNAPSHOTS
  // ================================

  var params = {};

  try{
    const data = await lightsail.getInstanceSnapshots(params).promise()
    await deleteOldSnapshot(data)
  }catch(err){
    console.log(err, err.stack);
  }

};