@nazar910/rpc-module v1.2.3
rpc-module
Module that provide you with a possibility to communicate with other modules of your system via rpc
Getting started
What is RPC?
RPC stands for "remote procedure call". Using such tool you can invoke function that is not part of your application. For example, you can make a call to another microservice if you're using such arhictecture.
Usage
First you need to install it into your project:
npm i -S @nazar910/rpc-module
Decide what communication transport you need (at the moment it is only AMQP, but I'm gonna implement other transports):
- AMQP:
npm i -S amqplib
Now you can simply require and use it (see also AMQP example in the tests):
const rpcModule = require('@nazar910/rpc-module');
const { AMQPRPCClient, AMQPRPCServer } = rpcModule.getDriver('amqp');
const RABBITMQ_URI = 'amqp://localhost:5672';
async function main() {
const server = AMQPRPCServer.create(RABBITMQ_URI);
await server.start();
server.addHandler('important', (job) => `"${job}" is very important`);
const client = AMQPRPCClient.create(RABBITMQ_URI);
const result = await client.call('important', 'doing something');
console.log(result);
}
main();
API
- rpcModule.getDriver(driverName: string) Returns apropriate drivers (Server and Client) for specified driverName.
const rpcModule = require('@nazar910/rpc-module');
const { AMQPRPCServer, AMQPRPCClient } = rpcModule.getDriver('amqp');
- Drivers API
!Note: all driver have similar API for easy usage.
create(driverArgs)
AMQPRPCServer and AMQPRPCClient have create
factory method for getting instance of driver (rpcServer
or rpcClient
).
Example:
const rpcModule = require('@nazar910/rpc-module');
const { AMQPRPCServer, AMQPRPCClient } = rpcModule.getDriver('amqp');
const RABBITMQ_URI = 'amqp://localhost:5672';
const rpcServer = AMQPRPCServer.create(RABBITMQ_URI);
const rpcClient = AMQPRPCClient.create(RABBITMQ_URI);
start()
rpcServer
and rpcClient
have start
method for ensuring connection. Required for server to start listening before registering handlers.
Example:
// ...
async function () {
await rpcServer.start();
await rpcClient.start();
}
// ...
rpcServer.addHandler(command: string, job: Function)
rpcServer
has addHandler
method for registering handlers.
Command is the name of rpc procedure
and handler should be a function that returns Promise (or async function) and result will be sent to client.
!!!Note: it is important to call rpcServer.start()
before registering handlers.
Example:
// ...
async function handler(...args) {
console.log('Args are', args);
return args;
}
async function () {
await rpcServer.addHandler('foo', handler);
}
// ...
rpcClient.call
rpcClient
has call(command: string, arg1, arg2, ..., argn)
method for calling rpc.
Command is the name of rpc procedure
and args are arguments to be passed to rpc.
Example:
// ...
async function () {
const result = await rpcClient.call('foo', 'bar');
console.log('Result is', result);
}
// ...
rpcClient.sendRaw
rpcClient
has sendRaw(queueName: string, data: object)
method for just sending msg to a queue.
Example:
// ...
async function () {
await rpcClient.sendRaw('some-queue', {foo: 'bar'});
}
// ...