如何避免在构建Python项目的Docker镜像时重新安装包？

2024-06-04 00:20| 来源: 网络整理| 查看: 265

尝试构建如下所示的Dockerfile：

代码语言：javascript复制FROM my/base WORKDIR /srv ADD ./requirements.txt /srv/requirements.txt RUN pip install -r requirements.txt ADD . /srv RUN python setup.py install ENTRYPOINT ["run_server"]

只要您不对requirements.txt进行任何更改，Docker将在pip安装过程中使用缓存，而不管Docker上的其他代码文件是否已更改。下面是一个例子。

下面是一个简单的Hello, World!程序：

代码语言：javascript复制$ tree . ├── Dockerfile ├── requirements.txt └── run.py 0 directories, 3 file # Dockerfile FROM dockerfile/python WORKDIR /srv ADD ./requirements.txt /srv/requirements.txt RUN pip install -r requirements.txt ADD . /srv CMD python /srv/run.py # requirements.txt pytest==2.3.4 # run.py print("Hello, World")

docker build的输出：

代码语言：javascript复制Step 1 : WORKDIR /srv ---> Running in 22d725d22e10 ---> 55768a00fd94 Removing intermediate container 22d725d22e10 Step 2 : ADD ./requirements.txt /srv/requirements.txt ---> 968a7c3a4483 Removing intermediate container 5f4e01f290fd Step 3 : RUN pip install -r requirements.txt ---> Running in 08188205e92b Downloading/unpacking pytest==2.3.4 (from -r requirements.txt (line 1)) Running setup.py (path:/tmp/pip_build_root/pytest/setup.py) egg_info for package pytest .... Cleaning up... ---> bf5c154b87c9 Removing intermediate container 08188205e92b Step 4 : ADD . /srv ---> 3002a3a67e72 Removing intermediate container 83defd1851d0 Step 5 : CMD python /srv/run.py ---> Running in 11e69b887341 ---> 5c0e7e3726d6 Removing intermediate container 11e69b887341 Successfully built 5c0e7e3726d6

让我们修改一下run.py

代码语言：javascript复制# run.py print("Hello, Python")

尝试再次构建，以下是输出：

正如您在上面看到的，这一次docker在构建过程中使用缓存。现在，让我们更新requirements.txt

代码语言：javascript复制# requirements.txt pytest==2.3.4 ipython

以下是docker build的输出：

代码语言：javascript复制Sending build context to Docker daemon 5.12 kB Sending build context to Docker daemon Step 0 : FROM dockerfile/python ---> f86d6993fc7b Step 1 : WORKDIR /srv ---> Using cache ---> 55768a00fd94 Step 2 : ADD ./requirements.txt /srv/requirements.txt ---> b6c19f0643b5 Removing intermediate container a4d9cb37dff0 Step 3 : RUN pip install -r requirements.txt ---> Running in 4b7a85a64c33 Downloading/unpacking pytest==2.3.4 (from -r requirements.txt (line 1)) Running setup.py (path:/tmp/pip_build_root/pytest/setup.py) egg_info for package pytest Downloading/unpacking ipython (from -r requirements.txt (line 2)) Downloading/unpacking py>=1.4.12 (from pytest==2.3.4->-r requirements.txt (line 1)) Running setup.py (path:/tmp/pip_build_root/py/setup.py) egg_info for package py Installing collected packages: pytest, ipython, py Running setup.py install for pytest Installing py.test script to /usr/local/bin Installing py.test-2.7 script to /usr/local/bin Running setup.py install for py Successfully installed pytest ipython py Cleaning up... ---> 23a1af3df8ed Removing intermediate container 4b7a85a64c33 Step 4 : ADD . /srv ---> d8ae270eca35 Removing intermediate container 7f003ebc3179 Step 5 : CMD python /srv/run.py ---> Running in 510359cf9e12 ---> e42fc9121a77 Removing intermediate container 510359cf9e12 Successfully built e42fc9121a77

注意docker在pip安装过程中没有使用缓存。如果它不工作，请检查您的docker版本。

代码语言：javascript复制Client version: 1.1.2 Client API version: 1.13 Go version (client): go1.2.1 Git commit (client): d84a070 Server version: 1.1.2 Server API version: 1.13 Go version (server): go1.2.1 Git commit (server): d84a070

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