以前我一直在用 virtualenv + virtualenvwrapper 插件，其實用的也好好的稽煤，就是依賴不能像 node 的 yarn 一樣區(qū)分開發(fā)和生產(chǎn)核芽，而且沒有 lock 文件，鎖定版本都靠 requirements.txt 文件酵熙，略有不便轧简。今天無聊搜了一下 python 的包管理軟件，發(fā)現(xiàn)了 pipenv匾二。初步看了下介紹 哮独，這不就是我想要的嘛拳芙。遂嘗試將以前的一個爬蟲項目轉(zhuǎn)為使用 pipenv 管理。

安裝 pipenv

安裝 pipenv 非常容易皮璧，只要用 pip install pipenv 命令安裝就好舟扎。

基本使用方法

先進入項目目錄

cd ~/dev/mh

安裝相關(guān)依賴

pipenv install Scrapy

這時候注意了，當(dāng)項目還沒有建立 env 的時候悴务，pipenv 會自動的建立一個對應(yīng)當(dāng)前項目的 env 環(huán)境睹限，并把依賴包安裝進去。在我的機器上是在 ~/.virtualenvs 文件夾里面讯檐。然后會生成 Pipfile 文件邦泄，里面有依賴包的信息，格式是 toml裂垦。我注意到里面還有指定 url 可以使用國內(nèi)的鏡像來加速安裝。

pipenv install ipython --dev

當(dāng)加入 --dev 參數(shù)時肌索，安裝的依賴就會放到 [dev-packages] 下面蕉拢，在生產(chǎn)環(huán)境可以不安裝這個里面的包，減小體積诚亚。

鎖定版本

當(dāng)安裝包所有的依賴包后晕换，執(zhí)行 pipenv lock 會在 Pipfile.lock 里面記錄當(dāng)前所有依賴的版本，當(dāng)部署到新機器上的時候執(zhí)行 pipenv sync 就可以安裝對應(yīng)的依賴了站宗，非常方便闸准。

在新機器上同步環(huán)境

# 安裝環(huán)境，生產(chǎn)環(huán)境用這條
pipenv sync 

# 同時安裝開發(fā)依賴
pipenv sync -d

查看依賴關(guān)系

$ pipenv graph
autopep8==1.3.5
  - pycodestyle [required: >=2.3, installed: 2.3.1]
flake8==3.5.0
  - mccabe [required: >=0.6.0,<0.7.0, installed: 0.6.1]
  - pycodestyle [required: >=2.0.0,<2.4.0, installed: 2.3.1]
  - pyflakes [required: >=1.5.0,<1.7.0, installed: 1.6.0]
ipython==6.4.0
  - appnope [required: Any, installed: 0.1.0]
  - backcall [required: Any, installed: 0.1.0]
  - decorator [required: Any, installed: 4.3.0]
  - jedi [required: >=0.10, installed: 0.12.1]
    - parso [required: >=0.3.0, installed: 0.3.0]
  - pexpect [required: Any, installed: 4.6.0]
    - ptyprocess [required: >=0.5, installed: 0.6.0]
  - pickleshare [required: Any, installed: 0.7.4]
  - prompt-toolkit [required: >=1.0.15,<2.0.0, installed: 1.0.15]
    - six [required: >=1.9.0, installed: 1.11.0]
    - wcwidth [required: Any, installed: 0.1.7]
  - pygments [required: Any, installed: 2.2.0]
  - setuptools [required: >=18.5, installed: 39.2.0]
  - simplegeneric [required: >0.8, installed: 0.8.1]
  - traitlets [required: >=4.2, installed: 4.3.2]
    - decorator [required: Any, installed: 4.3.0]
    - ipython-genutils [required: Any, installed: 0.2.0]
    - six [required: Any, installed: 1.11.0]
Pillow==5.2.0
Scrapy==1.5.0
  - cssselect [required: >=0.9, installed: 1.0.3]
  - lxml [required: Any, installed: 4.2.3]
  - parsel [required: >=1.1, installed: 1.4.0]
    - cssselect [required: >=0.9, installed: 1.0.3]
    - lxml [required: >=2.3, installed: 4.2.3]
    - six [required: >=1.5.2, installed: 1.11.0]
    - w3lib [required: >=1.8.0, installed: 1.19.0]
      - six [required: >=1.4.1, installed: 1.11.0]
  - PyDispatcher [required: >=2.0.5, installed: 2.0.5]
  - pyOpenSSL [required: Any, installed: 18.0.0]
    - cryptography [required: >=2.2.1, installed: 2.2.2]
      - asn1crypto [required: >=0.21.0, installed: 0.24.0]
      - cffi [required: >=1.7, installed: 1.11.5]
        - pycparser [required: Any, installed: 2.18]
      - idna [required: >=2.1, installed: 2.7]
      - six [required: >=1.4.1, installed: 1.11.0]
    - six [required: >=1.5.2, installed: 1.11.0]
  - queuelib [required: Any, installed: 1.5.0]
  - service-identity [required: Any, installed: 17.0.0]
    - attrs [required: Any, installed: 18.1.0]
    - pyasn1 [required: Any, installed: 0.4.3]
    - pyasn1-modules [required: Any, installed: 0.2.2]
      - pyasn1 [required: >=0.4.1,<0.5.0, installed: 0.4.3]
    - pyopenssl [required: >=0.12, installed: 18.0.0]
      - cryptography [required: >=2.2.1, installed: 2.2.2]
        - asn1crypto [required: >=0.21.0, installed: 0.24.0]
        - cffi [required: >=1.7, installed: 1.11.5]
          - pycparser [required: Any, installed: 2.18]
        - idna [required: >=2.1, installed: 2.7]
        - six [required: >=1.4.1, installed: 1.11.0]
      - six [required: >=1.5.2, installed: 1.11.0]
  - six [required: >=1.5.2, installed: 1.11.0]
  - Twisted [required: >=13.1.0, installed: 18.4.0]
    - Automat [required: >=0.3.0, installed: 0.7.0]
      - attrs [required: >=16.1.0, installed: 18.1.0]
      - six [required: Any, installed: 1.11.0]
    - constantly [required: >=15.1, installed: 15.1.0]
    - hyperlink [required: >=17.1.1, installed: 18.0.0]
      - idna [required: >=2.5, installed: 2.7]
    - incremental [required: >=16.10.1, installed: 17.5.0]
    - zope.interface [required: >=4.4.2, installed: 4.5.0]
      - setuptools [required: Any, installed: 39.2.0]
  - w3lib [required: >=1.17.0, installed: 1.19.0]
    - six [required: >=1.4.1, installed: 1.11.0]

執(zhí)行 pipenv graph 命令會像上面那樣顯示出各個包的依賴關(guān)系梢灭。

配合 direnv 使用

direnv 工具可以在進入目錄時自動切換當(dāng)前的環(huán)境夷家，不需要手動執(zhí)行 pipenv shell。我用的是mac敏释，使用 brew install direnv 命令安裝库快，其它的系統(tǒng)參考 https://github.com/direnv/direnv。

在 shell 啟動時載入 direnv

我用的是 fish 钥顽，按照官方的說明 https://github.com/direnv/direnv#fish 义屏，只要在 fish 的啟動配置 (一般是在 ~/.config/fish/config.fish，我用了 oh-my-fish 蜂大，所以在 ~/.config/omf/init.fish) 里面加入 eval (direnv hook fish) 這條命令就可以了闽铐。

在項目目錄里面啟用

現(xiàn)在已經(jīng)安裝好 direnv 了，到項目的目錄里面添加一個 .envrc 文件奶浦，內(nèi)容是 layout_pipenv兄墅，保存后再執(zhí)行 direnv allow。這樣就啟動了當(dāng)前目錄的自動切換環(huán)境功能财喳，只要進入項目目錄就會自動執(zhí)行 pipenv shell察迟。

PS: 我發(fā)現(xiàn)在 vscode 里面斩狱，安裝了 python 插件后也能自動識別 .envrc 文件，打開項目后自動加載對應(yīng)的環(huán)境扎瓶。

vscode