webmiddle-service-parallel v0.3.0

webmiddle-service-parallel

Its purpose is similar to Pipe, i.e. the execution of services, but they are executed concurrently.

Install

npm install --save webmiddle-service-parallel

Usage

import { PropTypes, rootContext } from 'webmiddle';
import Parallel from 'webmiddle-service-parallel';

const MyService = () => (
  <Parallel name="myResources">
    <SubService1
      name="resource1"
    />

    <SubService2
      name="resource2"
      {/*...*/}
    />

    <SubService3
      name="resource3"
      {/*...*/}
    />
  </Parallel>
);

rootContext.evaluate(<MyService />)
.then(resource => {
  console.log(resource.name); // "myResources" 
  console.log(resource.contentType); // "application/json"
  console.log(resource.content); // { resource1, resource2, resource3 }
});

How it works

If every child is fully synchronous, then its behavior is the same of Pipe. In the other end, if the child returns a promise, then such promise will be added to a pool and the next child will be executed immediately.

The service resolves with a JSON resource whose content is an object <resource name, resource>, where the resource names are extracted directly from the resources returned by the children.

If any of the child fails, then the whole Parallel fails with the error returned by the failed child.

This service also supports a limit property that can be used to limit the maximum number of concurrent tasks that should be running at any given time. If limit is 1, then the children will be executed in order, one after another, similarly to the Pipe service.

Properties