# `site` — 사이트별 구성 훅

소스 코드: Lib/site.py

이 모듈은 초기화 중에 자동으로 임포트 됩니다. 인터프리터의 `-S` 옵션을 사용하여 자동 임포트를 억제할 수 있습니다.

Importing this module normally appends site-specific paths to the module search path and adds callables, including `help()` to the built-in namespace. However, Python startup option `-S` blocks this, and this module can be safely imported with no automatic modifications to the module search path or additions to the builtins. To explicitly trigger the usual site-specific additions, call the `main()` function.

버전 3.3에서 변경: `-S`를 사용하는 경우에도 모듈을 임포트 하면 경로 조작을 트리거 했습니다.

It starts by constructing up to four directories from a head and a tail part. For the head part, it uses `sys.prefix` and `sys.exec_prefix`; empty heads are skipped. For the tail part, it uses the empty string and then `lib/site-packages` (on Windows) or `lib/pythonX.Y[t]/site-packages` (on Unix and macOS). (The optional suffix “t” indicates the free-threaded build, and is appended if `"t"` is present in the `sys.abiflags` constant.) For each of the distinct head-tail combinations, it sees if it refers to an existing directory, and if so, adds it to `sys.path` and also inspects the newly added path for configuration files.

버전 3.5에서 변경: “site-python” 디렉터리에 대한 지원이 제거되었습니다.

버전 3.13에서 변경: On Unix, Free threading Python installations are identified by the “t” suffix in the version-specific directory name, such as `lib/python3.13t/`.

버전 3.14에서 변경: `site` is no longer responsible for updating `sys.prefix` and `sys.exec_prefix` on Virtual Environments. This is now done during the path initialization. As a result, under Virtual Environments, `sys.prefix` and `sys.exec_prefix` no longer depend on the `site` initialization, and are therefore unaffected by `-S`.

When running under a virtual environment, the `pyvenv.cfg` file in `sys.prefix` is checked for site-specific configurations. If the `include-system-site-packages` key exists and is set to `true` (case-insensitive), the system-level prefixes will be searched for site-packages, otherwise they won’t. If the system-level prefixes are not searched then the user site prefixes are also implicitly not searched for site-packages.

The `site` module recognizes two startup configuration files of the form `name.pth` for path configurations, and `name.start` for pre-first-line code execution. Both files can exist in one of the four directories mentioned above. Within each directory, these files are sorted alphabetically by filename, then parsed in sorted order.

## Path extensions (`.pth` files)

`name.pth` contains additional items (one per line) to be appended to `sys.path`. Items that name non-existing directories are never added to `sys.path`, and no check is made that the item refers to a directory rather than a file. No item is added to `sys.path` more than once. Blank lines and lines beginning with `#` are skipped.

For backward compatibility, lines starting with `import` (followed by space or tab) are executed with `exec()`.

버전 3.13에서 변경: The `.pth` files are now decoded by UTF-8 at first and then by the locale encoding if it fails.

버전 3.15에서 변경: `.pth` file lines starting with `import` are deprecated. During the deprecation period, such lines are still executed (except in the case below), but a diagnostic message is emitted only when the `-v` flag is given.

`import` lines in `name.pth` are silently ignored when a matching `name.start` file exists.

Errors on individual lines no longer abort processing of the rest of the file. Each error is reported and the remaining lines continue to be processed.

Deprecated since version 3.15, will be removed in version 3.20: Decoding `name.pth` files in any encoding other than `utf-8-sig` is deprecated in Python 3.15, and support for decoding from the locale encoding will be removed in Python 3.20.

`import` lines in `name.pth` files are deprecated and will be silently ignored in Python 3.18 and 3.19. In Python 3.20 a warning will be produced for `import` lines in `name.pth` files.

## Startup entry points (`.start` files)

Added in version 3.15.

A startup entry point file is a file whose name has the form `name.start` and exists in one of the site-packages directories described above. Each file specifies entry points to be called during interpreter startup, using the `pkg.mod:callable` syntax understood by `pkgutil.resolve_name()`.

Each non-blank line that does not begin with `#` must contain an entry point reference in the form `pkg.mod:callable`. The colon and callable portion are mandatory. Each callable is invoked with no arguments, and any return value is discarded.

`.start` files are processed after all `.pth` path extensions have been applied to `sys.path`, ensuring that paths are available before any startup code runs.

Unlike `sys.path` extensions from `.pth` files, duplicate entry points are not de-duplicated — if an entry point appears more than once, it will be called more than once.

If an exception occurs during resolution or invocation of an entry point, a traceback is printed to `sys.stderr` and processing continues with the remaining entry points.

`.start` files must be encoded in UTF-8.

PEP 829 defined the original specification for these features.

참고

If a `name.start` file exists alongside a `name.pth` file with the same base name, any `import` lines in the `.pth` file are ignored in favor of the entry points in the `.start` file.

참고

Executable lines (`import` lines in `name.pth` files and `name.start` file entry points) are always run at Python startup (unless `-S` is given to disable the `site.py` module entirely), regardless of whether a particular module is actually going to be used.

참고

`name.start` files invoke `pkgutil.resolve_name()` with `strict=True`, which requires the full `pkg.mod:callable` form.

## Startup file examples

For example, suppose `sys.prefix` and `sys.exec_prefix` are set to `/usr/local`. The Python X.Y library is then installed in `/usr/local/lib/pythonX.Y`. Suppose this has a subdirectory `/usr/local/lib/pythonX.Y/site-packages` with three sub-subdirectories, `foo`, `bar` and `spam`, and two path configuration files, `foo.pth` and `bar.pth`. Assume `foo.pth` contains the following:

    # foo package configuration

    foo
    bar
    bletch

`bar.pth`는 다음을 포함한다고 가정하십시오:

    # bar package configuration

    bar

그러면 다음과 같은 버전 별 디렉터리가 이 순서대로 `sys.path`에 추가됩니다:

    /usr/local/lib/pythonX.Y/site-packages/bar
    /usr/local/lib/pythonX.Y/site-packages/foo

`bletch`가 존재하지 않기 때문에 생략되었음에 유의하십시오; `bar.pth`가 알파벳순으로 `foo.pth` 앞에 오기 때문에 `bar` 디렉터리가 `foo` 디렉터리보다 앞에 옵니다; `spam`은 경로 구성 파일에 언급되어 있지 않기 때문에 생략되었습니다.

Let’s say that there is also a `foo.start` file containing the following:

    # foo package startup code

    foo.submod:initialize

Now, after `sys.path` has been extended as above, and before Python turns control over to user code, the `foo.submod` module is imported and the `initialize()` function from that module is called.

## Migrating from `import` lines in `.pth` files to `.start` files

If your package currently ships a `name.pth` file, you can keep all `sys.path` extension lines unchanged. Only `import` lines need to be migrated.

To migrate, create a callable (taking zero arguments) within an importable module in your package. Reference it as a `pkg.mod:callable` entry point in a matching `name.start` file. Move everything on your `import` line after the first semi-colon into the `callable()` function.

If your package must straddle older Pythons that do not support PEP 829 and newer Pythons that do, change the `import` lines in your `name.pth` to use the following form:

    import pkg.mod; pkg.mod.callable()

Older Pythons will execute these `import` lines, while newer Pythons will ignore them in favor of the `name.start` file. After the straddling period, remove all `import` lines from your `.pth` files.

## `sitecustomize`

After these path manipulations, an attempt is made to import a module named `sitecustomize`, which can perform arbitrary site-specific customizations. It is typically created by a system administrator in the site-packages directory. If this import fails with an `ImportError` or its subclass exception, and the exception’s `name` attribute equals `'sitecustomize'`, it is silently ignored. If Python is started without output streams available, as with `pythonw.exe` on Windows (which is used by default to start IDLE), attempted output from `sitecustomize` is ignored. Any other exception causes a silent and perhaps mysterious failure of the process.

## `usercustomize`

After this, an attempt is made to import a module named `usercustomize`, which can perform arbitrary user-specific customizations, if `ENABLE_USER_SITE` is true. This file is intended to be created in the user site-packages directory (see below), which is part of `sys.path` unless disabled by `-s`. If this import fails with an `ImportError` or its subclass exception, and the exception’s `name` attribute equals `'usercustomize'`, it is silently ignored.

Note that for some non-Unix systems, `sys.prefix` and `sys.exec_prefix` are empty, and the path manipulations are skipped; however the import of `sitecustomize` and `usercustomize` is still attempted.

## Readline 구성

On systems that support `readline`, this module will also import and configure the `rlcompleter` module, if Python is started in interactive mode and without the `-S` option. The default behavior is to enable tab completion and to use `~/.python_history` as the history save file. To disable it, delete (or override) the `sys.__interactivehook__` attribute in your `sitecustomize` or `usercustomize` module or your `PYTHONSTARTUP` file.

버전 3.4에서 변경: rlcompleter와 히스토리 활성화가 자동으로 이루어졌습니다.

## 모듈 내용

site.PREFIXES

  site-packages 디렉터리의 접두사 리스트.

site.ENABLE_USER_SITE

  사용자 site-packages 디렉터리의 상태를 나타내는 플래그. `True`는 활성화되어 `sys.path`에 추가되었음을 의미합니다. `False`는 사용자 요청(`-s`나 `PYTHONNOUSERSITE`로)에 의해 비활성화되었음을 의미합니다. `None`은 보안상의 이유(사용자나 그룹 id와 유효(effective) id가 일치하지 않음)로 또는 관리자에 의해 비활성화되었음을 의미합니다.

site.USER_SITE

  실행 중인 파이썬의 사용자 site-packages 경로. `getusersitepackages()`가 아직 호출되지 않았으면 `None`일 수 있습니다. 기본값은 유닉스와 비 프레임워크 맥 OS 빌드의 경우 `~/.local/lib/pythonX.Y[t]/site-packages`, 맥 OS 프레임워크 빌드의 경우 `~/Library/Python/X.Y/lib/python/site-packages`, 윈도우의 경우 `%APPDATA%\Python\PythonXY\site-packages`입니다. 선택적 “t” 는 자유 스레딩 빌드를 나타냅니다. 이 디렉터리는 사이트 디렉터리이며, 이는 그 안에 있는 `.pth` 파일이 처리됨을 의미합니다.

site.USER_BASE

  사용자 site-packages의 베이스 디렉터리에 대한 경로. `getuserbase()`가 아직 호출되지 않았으면 `None`일 수 있습니다. 기본값은 유닉스와 맥 OS 비 프레임워크 빌드의 경우 `~/.local`, 맥 OS 프레임워크 빌드의 경우 `~/Library/Python/X.Y`, 윈도우의 경우 `%APPDATA%\Python`입니다. 이 값은 사용자 설치 스킴의 스크립트, 데이터 파일, 파이썬 모듈 등의 설치 디렉터리를 계산하는 데 사용됩니다. `PYTHONUSERBASE` 도 참조하십시오.

site.main()

  모든 표준 사이트별 디렉터리를 모듈 검색 경로에 추가합니다. 파이썬 인터프리터가 `-S` 플래그로 시작되지 않았으면, 이 모듈이 임포트 될 때 이 함수가 자동으로 호출됩니다.

  버전 3.3에서 변경: 이 함수는 무조건 호출되었습니다.

site.addsitedir(sitedir, known_paths=None, *, defer_processing_start_files=False)

  Add a directory to sys.path and parse the `.pth` and `.start` files found in that directory. Typically used in `sitecustomize` or `usercustomize` (see above).

  The known_paths argument is an optional set of case-normalized paths used to prevent duplicate `sys.path` entries. When `None` (the default), the set is built from the current `sys.path`.

  While `.pth` and `.start` files are always parsed, set defer_processing_start_files to `True` to prevent processing the startup data found in those files, so that you can process them explicitly (this is typically used by the `main()` function).

  버전 3.15에서 변경: Also processes `.start` files. See Startup entry points (.start files). All `.pth` and `.start` files are now read and accumulated before any path extensions, `import` line execution, or entry point invocations take place.

site.getsitepackages()

  모든 전역 site-packages 디렉터리를 포함하는 리스트를 반환합니다.

  Added in version 3.2.

site.getuserbase()

  사용자 베이스 디렉터리 `USER_BASE`의 경로를 반환합니다. 아직 초기화되지 않았으면, 이 함수는 `PYTHONUSERBASE`를 따라 설정합니다.

  Added in version 3.2.

site.getusersitepackages()

  사용자별 site-packages 디렉터리 `USER_SITE`의 경로를 반환합니다. 아직 초기화되지 않았으면, 이 함수는 `USER_BASE`를 따라 설정합니다. 사용자별 site-packages가 `sys.path`에 추가되었는지 확인하려면 `ENABLE_USER_SITE`를 사용해야 합니다.

  Added in version 3.2.

## Command-line interface

The `site` module also provides a way to get the user directories from the command line:

    $ python -m site --user-site
    /home/user/.local/lib/python3.11/site-packages

인자 없이 호출되면, 표준 출력에 `sys.path`의 내용을 인쇄한 다음, `USER_BASE`의 값과 디렉터리가 존재하는지를 인쇄하고, `USER_SITE`에 대해 같은 것을 인쇄하고, 마지막으로 `ENABLE_USER_SITE`의 값을 인쇄합니다.

--user-base

  사용자 베이스 디렉터리의 경로를 인쇄합니다.

--user-site

  사용자 site-packages 디렉터리의 경로를 인쇄합니다.

두 옵션이 모두 제공되면, `os.pathsep`으로 구분하여, 사용자 베이스와 사용자 사이트를 (항상 이 순서대로) 인쇄합니다.

어떤 옵션이건 제공되면, 스크립트는 다음 값 중 하나로 종료됩니다: 사용자 site-packages 디렉터리가 활성화되었으면 `0`, 사용자에 의해 비활성화되었으면 `1`, 보안상의 이유나 관리자에 의해 비활성화되었으면 `2`, 그리고 에러가 있으면 2보다 큰 값.

더 보기

- PEP 370 – 사용자별 site-packages 디렉터리

- PEP 829 – Startup entry points and the deprecation of import lines in `.pth` files

- The initialization of the sys.path module search path – The initialization of `sys.path`.