Node.js npm log4js

忘是亡心i 2022-07-12 06:50 201阅读 0赞

译自 [https://www.npmjs.com/package/log4js][https_www.npmjs.com_package_log4js]

# log4js #

> Port of Log4js to work with node.

工作在 node 下的 Log4js 的接口。

![这里写图片描述][20170215124240469]

> This is a conversion of the [log4js][] framework to work with [node][]. I’ve mainly stripped out the browser-specific code and tidied up some of the javascript.

这里是 log4js 框架运行在 node 环境下的一个转变。我主要剥离出浏览器特定的代码，并且整理了一下 javascript 代码。

> Out of the box it supports the following features:
> 
>  *  coloured console logging to stdout or stderr
>  *  replacement of node’s console.log functions (optional)
>  *  file appender, with configurable log rolling based on file size or date
>  *  SMTP appender
>  *  GELF appender
>  *  Loggly appender
>  *  Logstash UDP appender
>  *  logFaces appender
>  *  multiprocess appender (useful when you’ve got worker processes)
>  *  a logger for connect/express servers
>  *  configurable log message layout/patterns
>  *  different log levels for different log categories (make some parts of your app log as DEBUG, others only ERRORS, etc.)

它非常好地支持如下特性：

*  将带颜色的控制台日志输出到 stdout 或 stderr
 *  替换了 node 的 console.log 函数（可选）
 *  文件追加器，根据文件大小或日期滚动的可配置日志
 *  SMTP 追加器
 *  GELF 追加器
 *  Loggly 追加器
 *  Logstash UDP 追加器
 *  logFaces 追价齐
 *  多进程追加器（当你已经获得多个工作进程时是非常有用的）
 *  connect 或 express 服务的日志记录器
 *  日志消息的布局或模式均是可配置的
 *  不同的日志类型采用不同的日志级别（你的应用程序的某些部分使用 DEBUG 打印日志，其它的只使用 ERRORS，等等）

## Important changes in 1.0（1.0 版本的重大改变） ##

> The default appender has been changed from `console` to `stdout` \- this alleviates a memory problem that happens when logging using console. If you’re using log4js in a browser (via browserify), then you’ll probably need to explicitly configure log4js to use the console appender now (unless browserify handles process.stdout).

默认的追加器已经从 `console` 改为 `stdout` 这样可以缓解使用控制台打印日志时出现的内存问题。如果你在浏览器中使用 log4js（通过browserify），那么现在你可能需要额外配置 log4js 来使用控制台追加器（除非 browserify 处理了 process.stdout）。

> I’m also trying to move away from `vows` for the tests, and use `tape` instead. New tests should be added to `test/tape`, not the `vows` ones.

我也尝试过在测试项目中远离 `vows`，并且使用 `tape` 来取代它。新的测试项目应该被添加到 `test/tape` 中，而不是 `vows`。

> log4js also no longer supports node versions below 0.12.x.

log4js 也不再支持 node 0.12.x 以下的版本。

> 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:

注意：log4js 0.5 之后，你将需要额外启用替换 node 的 console.log 函数。可以通过调用 `log4js.replaceConsole()` 或者使用一个对象进行配置或者使用像这样的 json 文件：

{ appenders: [ { type: "console" }
      ],
      replaceConsole: true
    }

## installation（安装） ##

> npm install log4js

## usage（使用） ##

> Minimalist version:

极简的版本：

var log4js = require('log4js');
    var logger = log4js.getLogger();
    logger.debug("Some debug messages");

> By default, log4js outputs to stdout with the coloured layout (thanks to [masylum][]), so for the above you would see:

默认的情况下，log4js 会使用彩色的布局输出到 stdout（感谢 masylum），因此上面的你将会看到：

[2010-01-17 11:43:37.987] [DEBUG] [default] - Some debug messages

> See example.js for a full example, but here’s a snippet (also in fromreadme.js):

查看 example.js 来获取一个完整的例子，但是这里是一小段（也在 fromreadme.js）：

var log4js = require('log4js');
    //console log is loaded by default, so you won't normally need to do this //log4js.loadAppender('console'); log4js.loadAppender('file'); //log4js.addAppender(log4js.appenders.console()); log4js.addAppender(log4js.appenders.file('logs/cheese.log'), 'cheese'); var logger = log4js.getLogger('cheese'); logger.setLevel('ERROR'); logger.trace('Entering cheese testing'); logger.debug('Got cheese.'); logger.info('Cheese is Gouda.'); logger.warn('Cheese is quite smelly.'); logger.error('Cheese is too ripe!'); logger.fatal('Cheese was breeding ground for listeria.');

> Output:

输出：

[2010-01-17 11:43:37.987] [ERROR] cheese - Cheese is too ripe!
    [2010-01-17 11:43:37.990] [FATAL] cheese - Cheese was breeding ground for listeria.

> The first 5 lines of the code above could also be written as:

上面的前 5 行代码可以被写成这样：

var log4js = require('log4js');
    log4js.configure({
      appenders: [
        { type: 'console' },
        { type: 'file', filename: 'logs/cheese.log', category: 'cheese' }
      ] });

## configuration（配置） ##

> You can configure the appenders and log levels manually (as above), or provide a configuration file (`log4js.configure('path/to/file.json')`), or a configuration object. The configuration file location may also be specified via the environment variable LOG4JS\_CONFIG (`export LOG4JS_CONFIG=path/to/file.json)`. An example file can be found in `test/vows/log4js.json`. An example config file with log rolling is in `test/vows/with-log-rolling.json`. You can configure log4js to check for configuration file changes at regular intervals, and if changed, reload. This allows changes to logging levels to occur without restarting the application.

你手动可以配置追加器和日志级别（像上面一样），或者提供一个配置文件（`log4js.configure('path/to/file.json')`），或者一个配置对象。配置文件的路径也可以通过环境变量 LOG4JS\_CONFIG 来指定（`export LOG4JS_CONFIG=path/to/file.json`）。可以在`test/vows/log4js.json`中找到一个示例文件。带滚动日志的示例配置文件在`test/vows/with-log-rolling.json`中。你可以配置 log4js 来定期检查配置文件是否改变，并且如果改变就重新加载。它允许不重启应用的情况下改变日志级别。

> To turn it on and specify a period:

可以开启它并指定一个时间段：

log4js.configure('file.json', { reloadSecs: 300 });

> For FileAppender you can also pass the path to the log directory as an option where all your log files would be stored.

对于文件追加器，你也可以传递日志文件夹路径作为一个选项，这样你的所有日志文件都将会存储到这里。

log4js.configure('my_log4js_configuration.json', { cwd: '/absolute/path/to/log/dir' });

> 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:

如果你已经在配置文件中为某个 FileAppender 定义了一个绝对路径，你需要添加一个 `"absolute": true` 来给这个特别的 FileAppender 来覆盖传递的 cwd 选项。这里是一个例子：

### my\_log4js\_configuration.json ###

{
      "appenders": [ { "type": "file", "filename": "relative/path/to/log_file.log", "maxLogSize": 20480, "backups": 3, "category": "relative-logger" }, { "type": "file", "absolute": true, "filename": "/absolute/path/to/log_file.log", "maxLogSize": 20480, "backups": 10, "category": "absolute-logger" } ] }

> Documentation for most of the core appenders can be found on the [wiki][], otherwise take a look at the tests and the examples.

大部分核心追加器的文档都可以在 wiki 中找到，其它的可以看看测试项目和示例项目。

## Documentation（文档） ##

> See the [wiki][wiki 1]. Improve the [wiki][wiki 1], please.

参考 wiki，请改进 wiki。

> There’s also [an example application][].

这里也有一个示例应用程序。

## Contributing（贡献） ##

> Contributions welcome, but take a look at the [rules][] first.

欢迎贡献，但是首先请阅读相应规则。

## License（证书） ##

> The original log4js was distributed under the Apache 2.0 License, and so is this. I’ve tried to keep the original copyright and author credits in place, except in sections that I have rewritten extensively.

最开始的 log4js 是在 Apache 2.0 的证书下颁布的，这个也是。除了被我大量重重写的章节，我都尽可能地保持原始的版权信息和作者的身份信息就位。

[https_www.npmjs.com_package_log4js]: https://www.npmjs.com/package/log4js
[20170215124240469]: /images/20220711/c74631f73cb54a9ea0232b437be6c0f1.png
[log4js]: https://github.com/stritti/log4js
[node]: http://nodejs.org/
[masylum]: http://github.com/masylum
[wiki]: https://github.com/nomiddlename/log4js-node/wiki/Appenders
[wiki 1]: https://github.com/nomiddlename/log4js-node/wiki
[an example application]: https://github.com/nomiddlename/log4js-example
[rules]: https://github.com/nomiddlename/log4js-node/wiki/Contributing