# egg-logger

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[npm-image]: https://img.shields.io/npm/v/egg-logger.svg?style=flat-square
[npm-url]: https://npmjs.org/package/egg-logger
[github-action-image]: https://github.com/eggjs/egg-logger/workflows/Node.js%20CI/badge.svg
[github-action-url]: https://github.com/eggjs/egg-logger/actions
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[snyk-image]: https://snyk.io/test/npm/egg-logger/badge.svg?style=flat-square
[snyk-url]: https://snyk.io/test/npm/egg-logger
[download-image]: https://img.shields.io/npm/dm/egg-logger.svg?style=flat-square
[download-url]: https://npmjs.org/package/egg-logger

Egg 的日志工具。

![](diagram.png)

主要由 Logger 和 Transport 两个基类组成。

Transport 是一种写入日志的渠道，可以是终端、文件等等。

Logger 是所有日志的基类，可以进行扩展。一个 Logger 可以添加多个 Transport，只要调用一次就可以将日志写入多个地方。

---

## Install

```bash
$ npm i egg-logger
```

## Usage

创建一个 Logger，添加一个文件的 Transport

```js
const Logger = require('egg-logger').Logger;
const FileTransport = require('egg-logger').FileTransport;
const ConsoleTransport = require('egg-logger').ConsoleTransport;

const logger = new Logger();
logger.set('file', new FileTransport({
  file: '/path/to/file',
  level: 'INFO',
}));
logger.set('console', new ConsoleTransport({
  level: 'DEBUG',
}));
logger.debug('debug foo'); // 不会输出到文件，只输出到终端
logger.info('info foo');
logger.warn('warn foo');
logger.error(new Error('error foo'));
```

### 开启/关闭 Transport

```js
logger.disable('file');
logger.info('info'); // 不会输出
logger.enable('file');
logger.info('info'); // 开启后会输出
```

### 汇集日志

可以把日志复制一份到指定的日志对象，支持可选的 `options.excludes` 来排除对应的 tranport

```js
logger.duplicate('error', errorLogger, { excludes: [ 'console' ] });
logger.error(new Error('print to errorLogger')); // 会多调用一次 `errorLogger.error`
```

### 重定向日志

可以将日志重定向到指定的日志对象

```js
oneLogger.redirect('debug', debugLogger); // oneLogger 的调试日志将被 debugLogger 接管，输出过去。
```

### 重新加载文件

```js
logger.reload(); // will end the exists write stream and create a new one.
```

### 自定义 Transport

可以自定义一个 Transport 用于输出日志，比如发送到服务器。

```js
const urllib = require('urllib');
const Transport = require('egg-logger').Transport;

class UrllibTransport extends Transport {

  log(level, args, meta) {
    const msg = super.log(level, args, meta);
    return urllib.request('url?msg=' + msg);
  }
}

const logger = new Logger();
logger.set('remote', new UrllibTransport({
  level: 'DEBUG',
}));
logger.info('info');
```

## console 默认打印级别设置

设置环境变量 NODE_CONSOLE_LOGGRE_LEVEL = 'INFO' | 'WARN' | 'ERROR'



## License

[MIT](LICENSE)
<!-- GITCONTRIBUTOR_START -->

## Contributors

|[<img src="https://avatars.githubusercontent.com/u/156269?v=4" width="100px;"/><br/><sub><b>fengmk2</b></sub>](https://github.com/fengmk2)<br/>|[<img src="https://avatars.githubusercontent.com/u/985607?v=4" width="100px;"/><br/><sub><b>dead-horse</b></sub>](https://github.com/dead-horse)<br/>|[<img src="https://avatars.githubusercontent.com/u/360661?v=4" width="100px;"/><br/><sub><b>popomore</b></sub>](https://github.com/popomore)<br/>|[<img src="https://avatars.githubusercontent.com/u/227713?v=4" width="100px;"/><br/><sub><b>atian25</b></sub>](https://github.com/atian25)<br/>|[<img src="https://avatars.githubusercontent.com/u/5856440?v=4" width="100px;"/><br/><sub><b>whxaxes</b></sub>](https://github.com/whxaxes)<br/>|[<img src="https://avatars.githubusercontent.com/u/3367820?v=4" width="100px;"/><br/><sub><b>Jeff-Tian</b></sub>](https://github.com/Jeff-Tian)<br/>|
| :---: | :---: | :---: | :---: | :---: | :---: |
|[<img src="https://avatars.githubusercontent.com/u/2160731?v=4" width="100px;"/><br/><sub><b>mansonchor</b></sub>](https://github.com/mansonchor)<br/>|[<img src="https://avatars.githubusercontent.com/u/19274678?v=4" width="100px;"/><br/><sub><b>andy-ms</b></sub>](https://github.com/andy-ms)<br/>|[<img src="https://avatars.githubusercontent.com/u/5886475?v=4" width="100px;"/><br/><sub><b>DavidCai1993</b></sub>](https://github.com/DavidCai1993)<br/>|[<img src="https://avatars.githubusercontent.com/u/1474688?v=4" width="100px;"/><br/><sub><b>luckydrq</b></sub>](https://github.com/luckydrq)<br/>|[<img src="https://avatars.githubusercontent.com/u/2842176?v=4" width="100px;"/><br/><sub><b>XadillaX</b></sub>](https://github.com/XadillaX)<br/>|[<img src="https://avatars.githubusercontent.com/u/8201516?v=4" width="100px;"/><br/><sub><b>linrf</b></sub>](https://github.com/linrf)<br/>|
[<img src="https://avatars.githubusercontent.com/u/30541930?v=4" width="100px;"/><br/><sub><b>duqingyu</b></sub>](https://github.com/duqingyu)<br/>|[<img src="https://avatars.githubusercontent.com/u/7779883?v=4" width="100px;"/><br/><sub><b>lix059</b></sub>](https://github.com/lix059)<br/>|[<img src="https://avatars.githubusercontent.com/u/2675419?v=4" width="100px;"/><br/><sub><b>congyuandong</b></sub>](https://github.com/congyuandong)<br/>|[<img src="https://avatars.githubusercontent.com/u/1763067?v=4" width="100px;"/><br/><sub><b>waitingsong</b></sub>](https://github.com/waitingsong)<br/>

This project follows the git-contributor [spec](https://github.com/xudafeng/git-contributor), auto updated at `Tue Mar 22 2022 23:31:56 GMT+0800`.

<!-- GITCONTRIBUTOR_END -->