ajaysinghj8/osham

A Configurable Proxy + Cache Server.

ओषम् (Osham)

A Configurable Proxy Cache Server.

npx osham

 npm i -g osham

 npm i osham

What is ओषम् (Osham) ?

Osham is a cache service for APIs.

The idea behind Osham is to support higher concurrent requests with fewer resources and fast response time.

In a public facing API/frontend, most of the request remains the same and so the response is also the same. To avoid rendering the same request from the backend and to speed up the response time we should use CACHE.

The cache can solve many problems and it uses fewer backend resources to provide a good response time.

But that's not it.

In a real-world scenario, what happens when your backend is requested with hundreds of concurrent requests for the first time. In all those concurrent requests, there will be cache miss and will cause a thundering herd problem.

All of these problems and many more can be resolved by using Osham in your architecture.

Setup and Configure

• Create a folder.

  mkdir cache

• Move in this newly created folder

  cd cache

• Install osham using

  npm install osham

  OR

  npm install osham -g

• Create a .env file.

  touch .env

• Configure and place following in the .env file.

  # Port number on the cache server will listen to incoming requests
  PORT=26192
  # Redis host name
  REDIS_HOST=localhost
  # Redis port number
  REDIS_PORT=6379
  # HTTPS Options
  SECURE=false
  SSL_KEY=
  SSL_CERT=
  # Timeout for cache service. Default is 5000 ms
  TIMEOUT=7000
  

• Now, just need to create a cache-config.yml file. To get started copy file from here.

• Run osham as If you have installed it using -g flag, you will be able to run it directly from cmd.

  osham

  Or

  ./node_module/.bin/osham

  Or using package.json add into scripts of package.json as "start": "osham"

  npm start
  

• Open http://localhost:26192/api/v1/employees in the browser. Cache Server will hit the http://dummy.restapiexample.com/api/v1/employees . It will cache the result for the next 5 minutes as per over about cache configuration.

Cache Options

• expose The proxy path which will expose from osham.

• target The actual server HOST name (with path).

• changeOrigin: The actual request's HOST name will be passed to backend.

• followRedirects The HTTP/HTTPS agent will be changes to follow redirects if server has internal redirection enabled.

• timeout Default 5000 miliseconds.

Use Cases

You are a frontend developer and you don't want to set up backend on your machine, but want a faster development experience.

To reduce TTFB on google page insights in the production environment.

To support a large number of requests with fewer resources.

Centralized many servers end-points to one.

Limitations

1. It only supports anonymous requests.
2. It will only cache GET requests.
3. In Node Cluster, Requests will be pooled and served from the single response of backend per cache thread.

Architecture

More Optimized Osham

osham's Issues

Replace Koa with Native Http

Metrics

Is there a possibility to get metrics

• Cache hit ratio
• Cache miss ratio

Single cmd to get started.

osham -e /api/v1/* -t http://drupal/api/v1 -p 3000

Validate YAML Cache Config

By Pass HTTP verbs other than GET

Create cache configuration from react application

Koa Server Setup

Not responding if unable to connect to redis

Error when proxy respond 404 or other error

events.js:170
throw er; // Unhandled 'error' event
^
ReplyError: ERR wrong number of arguments for 'publish' command

Replace Axios with Request or native http client

Basic Setup

NPM module name ??

Response time Middleware

Request Handler based on YAML Config

In logs cache Key is not helpful to track api call. Replace cache key with path

Request Timeout

Add additional header info

X-Powered by: Osham server
X-osham-cache: hit/miss

Faker for HTTP Options verb

Create GitHub Documentation page in React

Does not works for https

proxy:https://api.github.com

HASH key from URL token

Not using global cache config when rules not available

Allow/Disallow urls patterns

env variable support in cache-config.yml file or use .js file as config

It would be better to fetch the config from the environment variable and it will be easy to manage as per environments.

ByPass cache using some query string or header value

Change TSLint to ESLint

Purge cache request

Feature request to purge cache based on

• cache id
• wild card cache id [APC:hotels/*]

Configure npm -> clean -> build -> publish -> versioning

Way to define redis re-connection strategy

Replace redis pub sub with event Emitter

YAML Config reader

Request Pool

Benchmarks

Health Check and ping

Request timeout because of a failed request added in Pool