ion-cortex

Introduction

The "ion-cortex" library is a high-performance communication protocol designed to enable efficient and reliable communication between distributed systems using Redis as the underlying message broker. It simplifies the process of building scalable and resilient microservices.

Installation

To install the "ion-cortex" library, you can use npm:

npm install ion-cortex

Getting Started

To get started with the "ion-cortex" library, require it in your Node.js application:

const Cortex = require("ion-cortex");

Start by creating instance from Cortex

const cortex = new Cortex({
	prefix: "app",
	url: "redis://localhost:6379",
	type: "auth",
});

So as shown above Each instance from Cortex must take 3 necessary arguments

• prefix The namespace of the node , as in redis there could be multiple namespaces with unique nodes for each one.
• url the redis connection url.
• type node type because you might need multiple nodes from the same type up to achieve a cretin goal ex. High Availability.

after creating the instance you could start exposing the function you want by calling cortex.sub like

cortex.sub("validateToken", ({ token }) => {
	// Do Your Processing Here
	return { isValid: true };
});

so now any node in the same namespace could call any exposed function from your service (or as we call it 'node')

cortex.emitToOneOf(
	{
		type: "auth",
		call: "validateToken",
		args: { token: "aW9uLWNvcnRleAo=" },
	},
	async (response) => {
		console.log("Got Response", response); // will log `Got Response { isValid: True }` to the console
	}
);

This call will choose a random node with type auth and make a call to the exposed function validateToken and pass args to it.

you also have async version from it:

const response = await cortex.AsyncEmitToOneOf({
	type: "jat",
	call: "validateToken",
	args: { token: "TOKEN" },
});
console.log("Got Response", response); // will log `Got Response { isValid: True }` to the console

Available Functions

• emitToOneOf: choose random node with given type.
• AsyncEmitToOneOf: the async version of emitToOneOf.
• emitToAllOf: call all nodes with given type.
• AsyncEmitToAllOf: the async version of emitToAllOf.
• emitToOthersOf: call all nodes with given type except the calling node (useful when sharing data with same nodes mostly in high available setup).
• AsyncEmitToOthersOf: the async version of emitToOthersOf.
• emitToOneOfFar: choose random node with given type but not on the physical machine of the callee.
• AsyncEmitToOneOfFar: the async version of emitToOneOfFar.
• emitToAllOfFar call all nodes with given type but not on the physical machine of the callee.
• AsyncEmitToAllOfFar: the async version of emitToAllOfFar.
• waitForNode: Holds until it discover a given node type with timeout (useful if starting of one node depends on another node).

Migrate From Older Version

There some changes in api from the pervious version

• No data param in cortex call:

  cortex.emitToOneOf(
  	{
  		type: "auth",
  		call: "validateToken",
  		data: { token: "aW9uLWNvcnRleAo=" },
  	},
  	async (response) => {
  		console.log("Got Response", response);
  	}
  );

  should become

  cortex.emitToOneOf(
  	{
  		type: "auth",
  		call: "validateToken",
  		args: { token: "aW9uLWNvcnRleAo=" },
  	},
  	async (response) => {
  		console.log("Got Response", response);
  	}
  );

• No Callback

  cortex.sub("validateToken", ({ token }, meta, cb) => {
  	// Do Your Processing Here
  	cb({ isValid: true });
  });

  should become

  cortex.sub("validateToken", ({ token }, meta) => {
  	// Do Your Processing Here
  	return { isValid: true };
  });

Errors

If the function you are calling crashed or thrown error you will get response like this

// Service
cortex.sub("validateToken", ({ token }) => {
	if (!token || token.length < 4) throw new Error("Invalid Token Sent");
	// Do Your Processing Here
	return { isValid: true };
});

// Calling
const response = await cortex.AsyncEmitToOneOf({
	type: "jat",
	call: "validateToken",
	args: { token: "aW9" },
});
console.log("Got Response", response);

you will get this response

 Got response { error: 'Error: Invalid Token Sent' }