pip-services4-logic-node

Business Logic Components for Node.js / ES2017

This module is a part of the Pip.Services polyglot microservices toolkit.

The Logic module contains standard component definitions to handle complex business transactions.

The module contains the following packages:

• Cache - distributed cache
• Lock - distributed lock components
• State - distributed state management components

Quick links:

• Logging
• Configuration
• API Reference
• Change Log
• Get Help
• Contribute

Use

Install the NPM package as

npm install pip-services4-logic-node --save

Example how to use caching and locking. Here we assume that references are passed externally.

import { Descriptor } from 'pip-services4-commons-node'; 
import { References } from 'pip-services4-commons-node'; 
import { IReferences } from 'pip-services4-commons-node'; 
import { IReferenceable } from 'pip-services4-commons-node'; 
import { ILock } from 'pip-services4-logic-node'; 
import { MemoryLock } from 'pip-services4-logic-node'; 
import { ICache } from 'pip-services4-logic-node'; 
import { MemoryCache } from 'pip-services4-logic-node'; 

export class MyComponent implements IReferenceable {
  private _cache: ICache;
  private _lock: ILock;
  
  public setReferences(refs: IReferences): void {
    this._cache = refs.getOneRequired<ICache>(new Descriptor("*", "cache", "*", "*", "1.0"));
    this._lock = refs.getOneRequired<ILock>(new Descriptor("*", "lock", "*", "*", "1.0"));
  }
  
  public async myMethod(context: IContext, param1: any): Promise<any> {
    // First check cache for result
    result := await this._cache.retrieve(context, "mykey");
    if (result != null) {
      return result;
    }
      
    // Lock..
    await this._lock.acquireLock(context, "mykey", 1000, 1000);
    
    // Do processing
    ...
    
    // Store result to cache async
    this._cache.store(context, "mykey", result, 3600000);

    // Release lock async
    this._lock.releaseLock(context, "mykey");

    return result;
  }
}

// Use the component
let myComponent = new MyComponent();

myComponent.setReferences(References.fromTuples(
  new Descriptor("pip-services", "cache", "memory", "default", "1.0"), new MemoryCache(),
  new Descriptor("pip-services", "lock", "memory", "default", "1.0"), new MemoryLock(),
);

result := await myComponent.myMethod(null);

Develop

For development you shall install the following prerequisites:

• Node.js 14+
• Visual Studio Code or another IDE of your choice
• Docker
• Typescript

Install dependencies:

npm install

Compile the code:

tsc

Run automated tests:

npm test

Generate API documentation:

./docgen.ps1

Before committing changes run dockerized build and test as:

./build.ps1
./test.ps1
./clear.ps1

Contacts

The library is created and maintained by Sergey Seroukhov and Danil Prisyazhniy.

The documentation is written by Mark Makarychev and Eugenio Andrieu.