IPC-KeyVal

Inter-Process-Communication (IPC) Key-Value (KeyVal) Storage Abstraction Layer

About

This Node.js module provides an abstraction layer for Inter-Process-Communication through Key-Value Storage. It supports the following modes (in order of increasing process scope and overall complexity):

• Single-Process-Model (SPM): This is for Node applications NOT using the cluster module. The storage is performed with an in-memory hash. No external resource is needed.

• Multi-Process-Model (MPM): This is for Node applications using the cluster module. The storage is performed with an in-memory hash in each process and an IPC message exchange between the processes with the help of the cluster module. No external resource is needed.

• Remote-Process-Model (RPM): This is for Node applications split into distinct process, usually running also on distinct machines. The storage is performed with the help of an external database. Currently SQLite, MySQL/MariaDB, PostgreSQL and Redis are supported.

Installation

$ npm install ipc-keyval --save-dev

For Remote-Process-Model (RPM) with SQLite an additional driver is required. As this is based on native code, you have to install it manually:

$ npm install sqlite3 --save-dev # for SQLite

Usage

(async () => {
    const KeyVal = require("ipc-keyval")

    /*  open connection  */
    let keyval = new KeyVal("spm")
    await keyval.open()

    /*  retrieve all keys  */
    await keyval.keys("*")

    /*  store a value  */
    await keyval.put("foo", "bar")

    /*  retrieve a value  */
    await keyval.get("foo")

    /*  delete a value  */
    await keyval.del("foo")

    /*  acquire exclusive lock  */
    await keyval.acquire()

    /*  release exclusive lock  */
    await keyval.release()

    /*  close connection  */
    await keyval.close()
})

The following URLs are supported on new KeyVal(url):

• spm:<id>
• mpm:<id>
• rpm+sqlite://<filename>[?table=<table>&colKey=<col>&colVal=<col>]
• rpm+mysql://[<username>:<password>@]<host>[:<port>][/<database>][?table=<table>&colKey=<col>&colVal=<col>]
• rpm+pgsql://[<username>:<password>@]<host>[:<port>][/<database>][?table=<table>&colKey=<col>&colVal=<col>]
• rpm+redis://[xxx:<secret>@]<host>[:<port>][/<scope>]

The <id> is an arbitrary unique identifier matching the regular expression ^[a-zA-Z][a-zA-Z0-9-]*$.

Application Programming Interface (API)

declare class KeyVal {
    constructor (url: string);
    open(): Promise<void>;
    keys(pattern?: string): Promise<string[]>;
    put(key: string, value: any): Promise<void>;
    get(key: string): Promise<any>;
    del(key: string): Promise<void>;
    acquire(): Promise<void>;
    release(): Promise<void>;
    close(): Promise<void>;
}

License

Copyright (c) 2017-2019 Dr. Ralf S. Engelschall (http://engelschall.com/)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.