144 lines
5.0 KiB
Markdown
144 lines
5.0 KiB
Markdown
# log4js-node [](http://travis-ci.org/nomiddlename/log4js-node)
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This is a conversion of the [log4js](http://log4js.berlios.de/index.html)
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framework to work with [node](http://nodejs.org). I've mainly stripped out the browser-specific code and tidied up some of the javascript.
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Out of the box it supports the following features:
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* coloured console logging
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* replacement of node's console.log functions (optional)
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* file appender, with log rolling based on file size
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* SMTP appender
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* GELF appender
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* hook.io appender
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* multiprocess appender (useful when you've got worker processes)
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* a logger for connect/express servers
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* configurable log message layout/patterns
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* different log levels for different log categories (make some parts of your app log as DEBUG, others only ERRORS, etc.)
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NOTE: from log4js 0.5 onwards you'll need to explicitly enable replacement of node's console.log functions. Do this either by calling `log4js.replaceConsole()` or configuring with an object or json file like this:
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```javascript
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{
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appenders: [
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{ type: "console" }
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],
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replaceConsole: true
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}
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```
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## installation
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npm install log4js
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## usage
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Minimalist version:
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```javascript
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var log4js = require('log4js');
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var logger = log4js.getLogger();
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logger.debug("Some debug messages");
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```
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By default, log4js outputs to stdout with the coloured layout (thanks to [masylum](http://github.com/masylum)), so for the above you would see:
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```bash
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[2010-01-17 11:43:37.987] [DEBUG] [default] - Some debug messages
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```
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See example.js for a full example, but here's a snippet (also in fromreadme.js):
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```javascript
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var log4js = require('log4js');
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//console log is loaded by default, so you won't normally need to do this
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//log4js.loadAppender('console');
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log4js.loadAppender('file');
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//log4js.addAppender(log4js.appenders.console());
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log4js.addAppender(log4js.appenders.file('logs/cheese.log'), 'cheese');
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var logger = log4js.getLogger('cheese');
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logger.setLevel('ERROR');
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logger.trace('Entering cheese testing');
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logger.debug('Got cheese.');
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logger.info('Cheese is Gouda.');
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logger.warn('Cheese is quite smelly.');
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logger.error('Cheese is too ripe!');
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logger.fatal('Cheese was breeding ground for listeria.');
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```
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Output:
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```bash
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[2010-01-17 11:43:37.987] [ERROR] cheese - Cheese is too ripe!
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[2010-01-17 11:43:37.990] [FATAL] cheese - Cheese was breeding ground for listeria.
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```
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The first 5 lines of the code above could also be written as:
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```javascript
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var log4js = require('log4js');
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log4js.configure({
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appenders: [
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{ type: 'console' },
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{ type: 'file', filename: 'logs/cheese.log', category: 'cheese' }
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]
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});
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```
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## configuration
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You can configure the appenders and log levels manually (as above), or provide a
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configuration file (`log4js.configure('path/to/file.json')`), or a configuration object. The
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configuration file location may also be specified via the environment variable
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LOG4JS_CONFIG (`export LOG4JS_CONFIG=path/to/file.json`).
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An example file can be found in `test/log4js.json`. An example config file with log rolling is in `test/with-log-rolling.json`.
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By default, the configuration file is checked for changes every 60 seconds, and if changed, reloaded. This allows changes to logging levels to occur without restarting the application.
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To turn off configuration file change checking, configure with:
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```javascript
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var log4js = require('log4js');
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log4js.configure('my_log4js_configuration.json', {});
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```
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To specify a different period:
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```javascript
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log4js.configure('file.json', { reloadSecs: 300 });
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```
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For FileAppender you can also pass the path to the log directory as an option where all your log files would be stored.
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```javascript
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log4js.configure('my_log4js_configuration.json', { cwd: '/absolute/path/to/log/dir' });
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```
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If you have already defined an absolute path for one of the FileAppenders in the configuration file, you could add a "absolute": true to the particular FileAppender to override the cwd option passed. Here is an example configuration file:
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```json
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#### my_log4js_configuration.json ####
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{
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"appenders": [
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{
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"type": "file",
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"filename": "relative/path/to/log_file.log",
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"maxLogSize": 20480,
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"backups": 3,
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"category": "relative-logger"
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},
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{
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"type": "file",
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"absolute": true,
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"filename": "/absolute/path/to/log_file.log",
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"maxLogSize": 20480,
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"backups": 10,
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"category": "absolute-logger"
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}
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]
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}
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```
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Documentation for most of the core appenders can be found on the [wiki](log4js-node/wiki/Appenders), otherwise take a look at the tests and the examples.
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## Documentation
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See the [wiki](log4js-node/wiki). Improve the [wiki](log4js-node/wiki), please.
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## Contributing
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Contributions welcome, but take a look at the [rules](log4js-node/wiki/Contributing) first.
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## License
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The original log4js was distributed under the Apache 2.0 License, and so is this. I've tried to
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keep the original copyright and author credits in place, except in sections that I have rewritten
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extensively.
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