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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/*"
          ]
        }
      }
    }
  ]
}

Setup postgreSQL RDS using Ansible

Setting up PostgreSQL on RDS using ansible is a bit tricky because the main user on RDS is not a SUPERUSER and roles membership is not automatically granted for ex: “ERROR: must be member of role ..” is quite common. Here is a working solution:

Cachita is a golang file and memory cache library

Cachita

Cachita is a golang file and memory cache library

Build Status
GoDoc

  • Simple caching with auto type assertion included.
  • In memory file cache index to avoid unneeded I/O.
  • Msgpack based binary serialization using msgpack library for file caching.

API docs: https://godoc.org/github.com/gadelkareem/cachita.

Examples: https://godoc.org/github.com/gadelkareem/cachita#pkg-examples.

Installation

Install:

go get -u github.com/gadelkareem/cachita

Limit requests per IP on Nginx using HttpLimitZoneModule and HttpLimitReqModule except whitelist

– Make sure to check Nginx, PHP posts for information on Nginx and PHP setup and configuration.

Nginx offers two modules, HttpLimitReqModule and HttpLimitZoneModule, to limit simultaneous connections for the assigned session and the number of requests for a given session from one IP address. Basically these modules are built to protect the web server from possible DDos attacks; For example, this configuration limits remote clients to no more than 20 concurrently “open” connections per remote ip address:

http{
    limit_conn_zone  $binary_remote_addr zone=concurrent:10m;
    limit_conn_log_level warn;
    limit_conn  concurrent  20;