lib/index.js
'use strict';
/**
* @fileOverview base.logger is a basic logger component used throughout zest to log messages onto the
* node console or in log files. It can be used as a zest component or as a standalone module
* @module base-logger
* @requires base-logger/formatter
* @requires base-logger/appenders/console
* @requires {@link external:merge}
* @requires {@link external:util}
*/
var merge = require('merge');
var util = require('util');
// log levels enumeration
var level = {
debug: 1,
info: 2,
warn: 3,
error: 4,
none: 5
};
/**
* @class module:base-logger~Logger
* @augments module:base-logger~LoggerBase
* @description the Logger class provides logging functions and other methods to log messages and profiling
* @param {Array.<module:base-logger~LoggerConfigurations>} options - the log configuration options array
* @param {string} group - the group that should be used for logging
*/
var Logger = function (options, group) {
var logFunctions;
var noOp = function () {
return logFunctions;
};
logFunctions = {
debug: noOp,
info: noOp,
warn: noOp,
error: noOp
};
options.forEach(
function (option) {
var appender;
// populate options with defaults
option = merge(
{
match: '^.*$',
appender: 'console',
level: 'debug',
pattern: {
debug: '\x1B[90m%t[HH.mm.ss.SSS]|\x1B[37m%-1.1l\x1B[90m|%20.20g\x1B[39m| \x1B[36m%m\x1B[39m',
info: '\x1B[90m%t[HH.mm.ss.SSS]|\x1B[37m%-1.1l\x1B[90m|%20.20g\x1B[39m| \x1B[32m%m\x1B[39m',
warn: '\x1B[90m%t[HH.mm.ss.SSS]|\x1B[37m%-1.1l\x1B[90m|%20.20g\x1B[39m| \x1B[33m%m\x1B[39m',
error: '\x1B[90m%t[HH.mm.ss.SSS]|\x1B[37m%-1.1l\x1B[90m|%20.20g\x1B[39m| \x1B[1m\x1B[31m%m' +
'\x1B[39m\x1B[22m'
}
}, option
);
if (!new RegExp(option.match).test(group)) {
// if the group does not match the configuration filter, we dont use it
return;
}
// get the appropriate appender
appender = require('./appenders/' + option.appender)(group, option.pattern, option.appenderOptions);
Object.keys(appender).forEach(
function (logFnName) {
var fn;
if (level[logFnName] < level[option.level]) {
return;
}
fn = logFunctions[logFnName];
logFunctions[logFnName] = function () {
appender[logFnName].apply(appender, arguments);
fn.apply({}, arguments);
return logFunctions;
};
}
);
}
);
// create log functions
(function (logger, levels) {
levels.forEach(
function (level) {
logger[level] = function () {
if (!process.LOGGING_STOP) {
logFunctions[level].apply({}, arguments);
}
return logger;
};
}
);
}(
this,
[
'debug',
'info',
'warn',
'error'
]
));
/**
* @function group
* @description Creates a new group from the existing logger group. The new Group will have a name
* `<<thisGroup>> / <<groupName>>`
* @param {string} groupName - the string to be prepended to the group name to create a new group
* @memberof module:base-logger~Logger.prototype
*/
this.group = function (groupName) {
return new Logger(options, (group + '/' + groupName));
};
};
/**
* Profiles all function in the object and logs the start and end of all calls to the functions, optionally logging
* arguments and return value.
* @param {*} component - the object whose functions have to be profiled
* @param {boolean} [verbose] - if true, the function arguments as well as the return value will be profiled
*/
Logger.prototype.profile = function (component, verbose) {
var log = this;
Object.keys(component).forEach(
function (key) {
var oldFn;
if (!(component[key] instanceof Function)) {
return;
}
oldFn = component[key];
component[key] = function () {
var retVal;
var logProps = [];
var timer;
logProps.push(key);
if (verbose) {
logProps.push('(');
logProps = logProps.concat(Array.prototype.slice.call(arguments));
logProps.push(')');
}
timer = new Date().getTime();
retVal = oldFn.apply(this, arguments);
timer = new Date().getTime() - timer;
if (verbose && retVal) {
logProps.push('->');
logProps.push(retVal);
}
logProps.push('[');
logProps.push(timer);
logProps.push('ms]');
log.debug.apply(log, logProps);
return retVal;
};
}
);
};
/**
* This function returns a Logger object that can be used to log messages.
* @param {string|Array.<module:base-logger~LoggerConfigurations>|module:base-logger~LogOptions} [options] - the
* options used for initializing the logger.
* @returns {module:base-logger~Logger} the logger object
* @example
* // To create a logger with all defaults, we just call the exported module function
* // without any option
* // create the logger
* var logger = require('base.logger')();
* // start logging
* logger.debug('hello world!');
*
* @example
* // If initialized with an array, the logger will assume it to be an array of
* // configuration options.
* // create the logger
* var logger = require('base.logger')([
* // configuration option
* {
* match: '^.*$', // group patterns matcher
* appender: 'console', // where to log
* level: 'debug', // the log level
* pattern: '%t[HH.mm.ss.SSS]|%-1.1l%20.20g| %m' // the logger pattern
* }
* ]);
* // start logging
* logger.debug('hello world!');
*
* @example
* // If a string is used for initialization, it is assumed to be the group name. The
* // logger will initialize with default configuration (which makes it log everything
* // to console) and the returned logger will have its group initialized
* // create the logger
* var logger = require('base.logger')('main');
* // start logging
* logger.debug('hello world!');
*
* @example
* // To initialize the logger with both the group and settings, we use an object form
* // as shown below.
* // create the logger
* var logger = require('base.logger')({
* group: 'main',
* settings: [
* // configuration option
* {
* match: '^.*$', // group patterns matcher
* appender: 'console', // where to log
* level: 'debug', // the log level
* pattern: '%t[HH.mm.ss.SSS]|%-1.1l%20.20g| %m' // the logger pattern
* }
* ]
* });
* // start logging
* logger.debug('hello world!');
*/
module.exports = function (options) {
if (!options) {
options = [
{}
];
}
if (util.isArray(options)) {
return new Logger(options, '');
} else if (typeof options === 'string') {
return new Logger(
[
{}
], options
);
} else {
return new Logger(options.settings, (options.group || ''));
}
};
/**
* @function stop
* @description Stops all loggers from logging
* @memberof module:base-logger
*/
module.exports.stop = function () {
process.LOGGING_STOP = true;
};
/**
* @function start
* @description Resumes logging function after it has been stopped
* @memberof module:base-logger
*/
module.exports.start = function () {
process.LOGGING_STOP = false;
};