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Varnish 5.1 always online

Recently I posted about Varnish with secure AWS S3 bucket as backend and I wanted to have the “always online” enabled, meaning you can take the backend offline while serving from Varnish cache.

Varnish with secure AWS S3 bucket as backend

Serving static contents from S3 is common, but using Varnish in front is a bit tricky. Especially if you want to keep the bucket secure and only serve from Varnish, here is a simple Varnish file to solve this problem.

First secure your bucket via IP policy:

{
  "Version": "2012-10-17",
  "Id": "S3PolicyId1",
  "Statement": [
    {
      "Sid": "IPAllow",
      "Effect": "Allow",
      "Principal": "*",
      "Action": "s3:GetObject",
      "Resource": "arn:aws:s3:::example.bucket/*",
      "Condition": {
        "IpAddress": {
          "aws:SourceIp": [
            "5.6.7.8/32"  //varnish ip
          ]
        }
      }
    },
    {
      "Sid": "Explicit deny to ensure requests are allowed only from specific referer.",
      "Effect": "Deny",
      "Principal": "*",
      "Action": "s3:GetObject",
      "Resource": "arn:aws:s3:::example.bucket/*",
      "Condition": {
        "StringNotLike": {
          "aws:Referer": [
            "https://example.com/*"
          ]
        }
      }
    }
  ]
}

Custom validation messages for sails js

//in api/models/User.js
function validationError(invalidAttributes, status, message) {
  var WLValidationError = require('../../node_modules/sails/node_modules/waterline/lib/waterline/error/WLValidationError.js');
  return new WLValidationError({
      invalidAttributes: invalidAttributes,
      status: status,
      message: message
    }
  );
}
var User = {
  attributes: {
    //...
  },
  ownValidate:: function (values, update, cb) {
    //example of not allowed param on update
    //if it is an update then do not allow email param
    if (update && values.email) {
      return cb(validationError({
        email: [
          {
            message: 'Email is not allowed for updates.'
          }
        ]
      }, 400 /*status*/));
    }
    sails.models['user'].findOne(values.email).exec(function (err, user) {
      if (err) return cb(err);
      if (user) {
        return cb(validationError({
          email: [
            {
              value: values.email,
              rule: 'E_UNIQUE'
              /* unique validation message is left for the default one here */
            }
          ]
        }, 409));
      }
    });
  },
  beforeCreate: function (values, cb) {
    return sails.models['user'].ownValidate(values, false, cb);
  },
  beforeUpdate: function (values, cb) {
    return sails.models['user'].ownValidate(values, true, cb);
  }
}

For blueprint custom messages validation

Compress your HTML, CSS and Javascript using simple PHP Code

Although Compression is a very important method of making your pages lighter and easier for users to download, it’s definitely going to cost you more CPU and on high load servers it’s not recommended unless you already know how to cache your HTML pages.