cache-micro

cache-micro

cache-micro is an utility for data caching focused on micro framework. The problem this package solves is to save the already requested data in-memory to have it available for a configurated time without processing it again.

Usage

cd my-micro-project/
npm install --save cache-micro

and add use the package like this:

// index.js
const cache = require('cache-micro')

const microFn = (req, res) => {
  return new Date()
}

module.exports = cache(60 * 60 * 1000, microFn)

then just run your microservice normally and it will return the same result for an hour (first param as miliseconds) unless that you change the request url.

A more useful example:

Let's say that we need a microservice that receives a name (string) and search data of a person on 3 or 4 APIs:

const { parse } = require('url')
const fetch = require('node-fetch')

module.exports = async (req, res) => {
  const { searchName } = parse(req.url, true).query
  const facebookData = await fetch('https://someapi1.com')
  const githubData = await fetch('https://someapi2.com')
  const financialData = await fetch('https://someapi3.com')
  return { facebookData, githubData, financialData }
}

This microservice would fetch 3 APIs every time it receives a request. Probably, in some cases, if the microservice receive the same name it will return the same data, at least for the same day, so you can just add cache-micro like this:

const { parse } = require('url')
const fetch = require('node-fetch')
const cache = require('cache-micro')

const microFn = async (req, res) => {
  const { searchName } = parse(req.url, true).query
  const facebookData = await fetch('https://someapi1.com')
  const githubData = await fetch('https://someapi2.com')
  const financialData = await fetch('https://someapi3.com')
  return { facebookData, githubData, financialData }
}

module.exports = cache(24 * 60 * 60 * 1000, microFn) // One day data caching

Mongo Support

cache-micro supports Mongo (and hopefully Redis in the future) because in-memory data cache can't scale horizontally and if you work with microservices you will loose that advantage. So you can avoid that problem setting the MONGO_URL and MONGO_DB enviroment variables so all your microservice's instances use the same cache.

Why?

I worked on a project with micro using it for making web-scrapping workers that take too long the first time to get the data, and users requested often the same data so with this I can save a lot of requests, processing and time making requests of +5000ms only take 50ms.

Contributing

• Fork this repository to your own GitHub account and then clone it to your local device
• Link the package to the global module directory: npm link
• Within the module you want to test your local development instance of cache-micro, just link it to the dependencies: npm link cache-micro. Instead of the default one from npm, node will now use your clone of cache-micro!

Credits

Thanks to ZEIT Team for giving us micro to make our life easier!