---
layout: page
title: Express 디버깅
description: Learn how to enable and use debugging logs in Express.js applications by setting the DEBUG environment variable for enhanced troubleshooting.
menu: guide
order: 7
redirect_from: "  "
---

# Express 디버깅

Express에서 사용되는 모든 내부 로그를 확인하려면, 앱을 실행할 때 `DEBUG` 환경 변수를
`express:*`로 설정하십시오.

```bash
$ DEBUG=express:* node index.js
```

Windows에서는 다음과 같은 명령을 사용하십시오.

```bash
> $env:DEBUG = "express:*"; node index.js
```

[Express 생성기](/{{ page.lang }}/starter/generator.html)가 생성한 기본 앱에 대해 이 명령을 실행하면 다음과 같이 인쇄됩니다.

```bash
$ DEBUG=express:* node ./bin/www
  express:router:route new / +0ms
  express:router:layer new / +1ms
  express:router:route get / +1ms
  express:router:layer new / +0ms
  express:router:route new / +1ms
  express:router:layer new / +0ms
  express:router:route get / +0ms
  express:router:layer new / +0ms
  express:application compile etag weak +1ms
  express:application compile query parser extended +0ms
  express:application compile trust proxy false +0ms
  express:application booting in development mode +1ms
  express:router use / query +0ms
  express:router:layer new / +0ms
  express:router use / expressInit +0ms
  express:router:layer new / +0ms
  express:router use / favicon +1ms
  express:router:layer new / +0ms
  express:router use / logger +0ms
  express:router:layer new / +0ms
  express:router use / jsonParser +0ms
  express:router:layer new / +1ms
  express:router use / urlencodedParser +0ms
  express:router:layer new / +0ms
  express:router use / cookieParser +0ms
  express:router:layer new / +0ms
  express:router use / stylus +90ms
  express:router:layer new / +0ms
  express:router use / serveStatic +0ms
  express:router:layer new / +0ms
  express:router use / router +0ms
  express:router:layer new / +1ms
  express:router use /users router +0ms
  express:router:layer new /users +0ms
  express:router use / &amp;lt;anonymous&amp;gt; +0ms
  express:router:layer new / +0ms
  express:router use / &amp;lt;anonymous&amp;gt; +0ms
  express:router:layer new / +0ms
  express:router use / &amp;lt;anonymous&amp;gt; +0ms
  express:router:layer new / +0ms
```

이후 앱에 대한 요청이 이루어지면, Express 코드에 지정된 로그를 확인할 수 있습니다.

```bash
  express:router dispatching GET / +4h
  express:router query  : / +2ms
  express:router expressInit  : / +0ms
  express:router favicon  : / +0ms
  express:router logger  : / +1ms
  express:router jsonParser  : / +0ms
  express:router urlencodedParser  : / +1ms
  express:router cookieParser  : / +0ms
  express:router stylus  : / +0ms
  express:router serveStatic  : / +2ms
  express:router router  : / +2ms
  express:router dispatching GET / +1ms
  express:view lookup "index.pug" +338ms
  express:view stat "/projects/example/views/index.pug" +0ms
  express:view render "/projects/example/views/index.pug" +1ms
```

라우터 구현의 로그만 확인하려면 `DEBUG`의 값을 `express:router`로 설정하십시오. 마찬가지로, 애플리케이션 구현의 로그만 확인하려면 `DEBUG`의 값을 `express:application`으로 설정하십시오. 나머지도 이와 같습니다.

## `express`를 통해 생성된 애플케이션

`express` 명령을 통해 생성된 애플리케이션 또한 `debug` 모듈을 사용하며, 이러한 애플리케이션의 디버그 네임스페이스의 범위는 애플리케이션의 이름으로 한정됩니다.

예를 들어 `$ express sample-app`을 통해 앱을 생성하는 경우에는 다음과 같은 명령을 통해 디버그 명령문을 사용할 수 있습니다.

```bash
$ DEBUG=sample-app:* node ./bin/www
```

다음과 같이 쉼표로 구분된 이름 목록을 지정하면 2개 이상의 디버그 네임스페이스를 지정할 수 있습니다.

```bash
$ DEBUG=http,mail,express:* node index.js
```

## Advanced options

When running through Node.js, you can set a few environment variables that will change the behavior of the debug logging:

| Name                | Purpose                                                           |
| ------------------- | ----------------------------------------------------------------- |
| `DEBUG`             | Enables/disables specific debugging namespaces.   |
| `DEBUG_COLORS`      | Whether or not to use colors in the debug output. |
| `DEBUG_DEPTH`       | Object inspection depth.                          |
| `DEBUG_FD`          | File descriptor to write debug output to.         |
| `DEBUG_SHOW_HIDDEN` | Shows hidden properties on inspected objects.     |

{% capture debug-text %}

The environment variables beginning with `DEBUG_` end up being
converted into an Options object that gets used with `%o`/`%O` formatters.
See the Node.js documentation for
[`util.inspect()`](https://nodejs.org/api/util.html#util_util_inspect_object_options)
for the complete list.

{% endcapture %}

{% include admonitions/note.html content=debug-text %}
