cinovo-logger

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cinovo-logger

cinovo-logger is an async logger for Node.js with multiple endpoints.

Getting started

At first you must install and require the logger.

npm install cinovo-logger

Next you must require the module

var logger = require("cinovo-logger");

Append an endpoint

There are some endpoints available:

• cinovo-logger-console
• cinovo-logger-file
• cinovo-logger-syslog
• cinovo-logger-aws
• cinovo-logger-notificationcenter
• cinovo-logger-loggly

You could also write your own endpoint (see Custom Endpoint).

If you wish to log to console just:

npm install cinovo-logger-console

In your JavaScript code append the endpoint.

logger.append(require("cinovo-logger-console")(true, true, true, true));

If you wish to log to syslog just:

npm install cinovo-logger-syslog

In your JavaScript code append the endpoint.

logger.append(require("cinovo-logger-syslog").local(true, true, true, true, "test", "local0"));

You could also log to file, AWS (S3, SQS, SNS), Mac OS X Notification Center or Loggly

Log something

logger.debug("all values are ok");
logger.info("myscript", "all values are ok");
logger.error("myscript", "some values are not ok", {a: 10, b: 20});
logger.exception("myscript", "some values are not ok", new Error("error"));
logger.critical("myscript", "all values are not ok", {a: 10, b: 20}, function(err) { ... });

Done

Now you can log to multiple endpoints.

Integrate

You are likely to use some other npms so we tried to integrate cinovo-logger with some popular npms by providing wrapprs:

• cinovo-logger-socket.io

API

debug, info, error, critical([origin], message, [metadata], [callback])

Depending on the level you want to log choose one of the four methods.

• origin: String to indicate where the log come from, e. g. the name of the script (optional)
• message: String to tell what happened
• metadata: String, Number, Boolean, Array or Object to tell you more about the situation (optional)
• callback: Function(err) Fired after log was processed by all endpoints (optional)
  • err: Error (optional)

Examples:

logger.debug("all values are ok");
logger.info("myscript", "all values are ok");
logger.error("myscript", "some values are not ok", {a: 10, b: 20});
logger.critical("myscript", "all values are not ok", {a: 10, b: 20}, function(err) { ... });

exception([origin], message, error, [callback])

If you want to log an Error there is a special method exception which logs as an error

• origin: String to indicate where the log come from, e. g. the name of the script (optional)
• message: String to tell what happened
• error: Error
• callback: Function(err) Fired after log was processed by all endpoints (optional)
  • err: Error (optional)

Examples:

logger.exception("some values are not ok", new Error("error"));
logger.exception("myscript", "some values are not ok", new Error("error"));
logger.exception("myscript", "some values are not ok", new Error("error"), function(err) { ... });

Log

The log object contains the following fields:

{
	level: String["debug", "info", "error", "critical"]
	date: Date
	pid: Number
	hostname: String
	origin: String to indicate where the log come from, e. g. the name of the script (optional)
	message: String to tell what happened
	metadata: String, Number, Boolean, Array or Object to tell you more about the situation (optional)
	fullOrigin: {
		file: String of the file name,
		line: Number of the line,
		fn: String of the invoked function name
	} (optional)
}

EventEmitter

The cinovo-logger is also an EventEmitter.

on, addListener(event, listener)

Adds a listener to the end of the listeners array for the specified event.

• event: String
• listener: Function - see Events for signature

once(event, listener)

Adds a one time listener for the event. This listener is invoked only the next time the level is fired, after which it is removed.

• event: String
• listener: Function - see Events for signature

removeListener(event, listener)

Remove a listener from the listener array for the specified event.

• event: String
• listener: Function - see Events for signature

removeAllListeners([event])

Removes all listeners, or those of the specified event.

• event: String (optional)

append(endpoint)

• endpoint: must extend Endpoint see Custom Endpoint

remove(endpoint, callback)

• endpoint: must extend Endpoint see Custom Endpoint
• callback: Function(err)
  • err: Error

stop(callback)

Stop all endpoints to avoid data loss.

• callback: Function(err)
  • err: Error

fullOrigin()

Activates fullOrigin output in log. Locates the caller of an log function debug, info, error, exception, critical by:

{
	file: String of the file name,
	line: Number of the line,
	fn: String of the invoked function name
}

Events

level_debug(log)

On debug log.

• log: Log

level_info(log)

On info log.

• log: Log

level_error(log)

On error log.

• log: Log

level_critical(log)

On critical log.

• log: Log

error(err)

If you use on of the log methods debug, info, error, exception, critical without the optional callback and an Error occurs it is emitted.

• err: Error

endpoint_error(endpoint, err)

If an endpoint.log() returned an error or an error was emitted by an endpoint.

• endpoint: Endpoint
• err: Error

Advanced Stuff

Multiple logger instances

From time to time it makes sense to have more than one logger instance.

var myLogger = require("cinovo-logger").createLogger();

myLogger.append(require("cinovo-logger-console")(true, true, true, true));

myLogger.debug("all values are ok");

Configuration

You can configure the logger during creation or after creation.

during creation:

var cfg = {
	fullOrigin: false,
	filter: {
		"*": true
	}
};
var myLogger = require("cinovo-logger").createLogger(cfg);

after creation:

var logger = require("cinovo-logger");
// do something
logger.cfg.fullOrigin = true;

Options

There are several options available:

fullOrigin

Boolean - Activates fullOrigin output in log. (default: false)

Examples:

var cfg = {
	fullOrigin: true
};

filter

Object - Allow or block log from origin and/or level. (default: {"*": true})

Examples:

`````javascriptvar cfg = { filter: { "*": false, // block everything (required) "*/critical": true, // but allow criticallevel "myorigin/*": true, // and allow everything fromoriginmyorigin "yourorigin/debug": true, // and allow everything fromoriginyourorigin andlevel` debug } };

### Custom Endpoint

Visit [cinovo-logger-lib](https://github.com/cinovo/node-logger-lib).