simple-log-manager

simple Node.js log manager with different outputs

Install

$ npm install simple-log-manager

Info

You can use 3 different output types:

1. File logger
2. Console logger
3. Dummy logger

Each logger has 4 methods for output - log, warn, info, error.

File logger

File loggers will write all output to file with logger name.

To create file logger you should specify logger name and 2 options: fileName and dir.

you can specify fileNamePattern instead of fileName:

    {
        fileNamePattern: "instance-<DATE>.log",
        dir: "../logs"
    }

Example:

    var manager = require('simple-log-manager');
 
    var options = {
       fileNamePattern: "testName-<DATE>.log",
       dir: require('path').join(__dirname, "logs")
    }
 
    var logger = manager.createFileLogger("testName", options);
 
    // now you can use log methods:
    logger.log("Hello", "World", "!");
    logger.warn("Hello", "World", "!");
    logger.error("Hello", "World", "!");
 
 
    //output testName-05_07.log:
 
    14:19:38.038 LOG Hello World !
    14:19:38.040 WARN Hello World !
    14:19:38.041 ERROR Hello World !

---

Console logger

Console logger is simple js console instance. So all methods will output to console.

Example:

    var manager = require('simple-log-manager');
    var logger = manager.createConsoleLogger("testName");
 
    logger.log("Hello", "World", "!");   // => "Hello World !"
    logger.warn("Hello", "World", "!");  // => "Hello World !"
    logger.error("Hello", "World", "!"); // => "Hello World !"

---

Dummy logger

Name speaks for itself. It's dummy logger with all log method which will do nothing.

Example:

    var manager = require('simple-log-manager');
    var logger = manager.createDummyLogger("testName");
 
    logger.log("Hello", "World", "!");   // => nothing
    logger.warn("Hello", "World", "!");  // => nothing
    logger.error("Hello", "World", "!"); // => nothing

---

Usage

You can create loggers in your entry file and get it deeper in your app

Example

    //main.js
    var manager = require('simple-log-manager');
 
    manager.createConsoleLogger("console");
    manager.createFileLogger("file", {
        fileName: "test",
        dir: "logs"
    });
 
 
    //app.js
    var logger = require('simple-log-manager').get("console");
 
    //controller.js
    var logger = require('simple-log-manager').get("file");

you can remove already created logger: manager.remove(console)

Also you can switch between different output types with any condition, e.g. with environment variable.

Example:

const logger = (() => {
    const manager = require('simple-log-manager');
 
    if (process.env.LOG && Boolean(process.env.LOG) === false) {
        return manager.createDummyLogger("instance");
 
    }
 
    if (Boolean(process.env.DEBUG)) {
        return manager.createConsoleLogger("instance");
    }
 
    return manager.createFileLogger("instance", {
        fileNamePattern: "instance-<DATE>.log",
        dir: require('path').join(__dirname, "..", "logs")
    })
})();
 
 
logger.log("app was started");
...
logger.error("something went wrong!")

In the example above all application logs will prints to file in logs dir. But if you need to debug you can pass DEBUG=true to environment and vualá - all output is in your console. Also you can pass LOG=false and all logs will be disabled without any changes in source code.