sandeep-cs-dev

Let's Encrypt

Examples of getting certificates from Let's Encrypt working on Apache, NGINX and Node.js servers.

Obtain certificates

I chose to use the manual method, you have to make a file available to verify you own the domain. Follow the commands from running

git clone https://github.com/letsencrypt/letsencrypt
cd letsencrypt

sandeep-cs-dev

Project Title

One Paragraph of project description goes here

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.

Prerequisites

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INSERT GRAPHIC HERE (include hyperlink in image)

Repository Title Goes Here

Subtitle or Short Description Goes Here

sandeep-cs-dev

Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

sandeep-cs-dev

for (var i = 0; i < 1024 * 1024; i++) {
  process.nextTick(function () { Math.sqrt(i) } )
}

sandeep-cs-dev

@mafintosh asks: "Does anyone have a good code example of when to use setImmediate instead of nextTick?"

https://twitter.com/mafintosh/status/624590818125352960

The answer is "generally anywhere outside of core".

process.nextTick is barely asynchronous. Flow-wise it is asynchronous, but it will trigger before any other asynchronous events can (timers, io, etc.) and thus can starve the event loop.

In this script I show a starved event loop where I just synchronously block, use nextTick and setImmediate

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const { parentPort, workerData, isMainThread } = require("worker_threads");

// CPU consuming function (sorting a big array)
function sortBigArray(bigArray) {
  return bigArray.sort((a, b) => a - b);
}

// check that the sorter was called as a worker thread
if (!isMainThread) {
  // make sure we got an array of data

sandeep-cs-dev

// we determine the key buffer
var stringKey = "example";
var cipherText = ".........";

// we compute the sha256 of the key
var hash = crypto.createHash("sha256");
hash.update(stringKey, "utf8");
var sha256key = hash.digest();
var keyBuffer = new Buffer(sha256key);

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/*
* Self-Explanatory Protocol Buffer Lang Guide
*/


/*
* Why Protocol Buffers?
* Protocol buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler.
* You define how you want your data to be structured once, then you can use special generated source code to easily write and read your structured data to and from a variety of data streams and using a variety of languages.
* Protocol Buffers are Schema Of Messages. They are language agnostic.

sandeep-cs-dev

  --log_gc (Log heap samples on garbage collection for the hp2ps tool.)
        type: bool  default: false
  --expose_gc (expose gc extension)
        type: bool  default: false
  --max_new_space_size (max size of the new generation (in kBytes))
        type: int  default: 0
  --max_old_space_size (max size of the old generation (in Mbytes))
        type: int  default: 0
  --max_executable_size (max size of executable memory (in Mbytes))
        type: int  default: 0