如何从Dockerfile安装Python 3.7和Pip

Question

我正在尝试基于Ubuntu 18.04构建一个自定义Docker镜像。Ubuntu加载了Python 3.6，但我想1.(安装Python 3.7，2.(使其成为默认的Python版本(因此可以用python而不是python3.7和3.(安装pip。当我运行docker构建时，它无法重新加载~/.bashrc，因此python不是python3.7的别名。如何解决此问题？

FROM ubuntu:18.04
# Set temp work directory
# for package configuration
WORKDIR /usr/src/cache
# Update apt packages
RUN apt update
RUN apt upgrade -y
# Install vim
RUN apt install vim -y
# Install python 3.7
RUN apt install software-properties-common -y
RUN add-apt-repository ppa:deadsnakes/ppa
RUN apt install python3.7 -y
# Make python 3.7 the default
RUN echo "alias python=python3.7" >> ~/.bashrc
RUN export PATH=${PATH}:/usr/bin/python3.7
RUN /bin/bash -c "source ~/.bashrc"
# Install pip
RUN apt install python3-pip -y
RUN python -m pip install --upgrade pip
# Install lsof
RUN apt install lsof
# Install ta-lib
# Source: https://medium.com/@artiya4u/installing-ta-lib-on-ubuntu-944d8ca24eae
RUN apt install build-essential wget -y
RUN wget https://artiya4u.keybase.pub/TA-lib/ta-lib-0.4.0-src.tar.gz
RUN tar -xvf ta-lib-0.4.0-src.tar.gz
RUN /bin/bash -c "cd ta-lib/; ./configure --prefix=/usr; make; make install"
# Install pip packages
COPY requirements.txt ./
RUN pip install -r requirements.txt
# Set working directory for code
WORKDIR /usr/src/app

运行docker build:时的输出

Step 1/20 : FROM ubuntu:18.04
---> c3c304cb4f22
Step 2/20 : WORKDIR /usr/src/cache
---> Using cache
---> 6bab8662b50a
Step 3/20 : RUN apt update
---> Using cache
---> 4d3bc75e5b24
Step 4/20 : RUN apt upgrade -y
---> Using cache
---> 24a93e9b2518
Step 5/20 : RUN apt install software-properties-common -y
---> Using cache
---> 077ead1bcb54
Step 6/20 : RUN add-apt-repository ppa:deadsnakes/ppa
---> Using cache
---> 7771a6ac7068
Step 7/20 : RUN apt install python3.7 -y
---> Using cache
---> 5f57462b0444
Step 8/20 : RUN echo "alias python=python3.7" >> ~/.bashrc
---> Running in c31352b84ecd
Removing intermediate container c31352b84ecd
---> c1060eaa66b8
Step 9/20 : RUN export PATH=${PATH}:/usr/bin/python3.7
---> Running in 5de52797c355
Removing intermediate container 5de52797c355
---> 2a9eb6215da8
Step 10/20 : RUN /bin/bash -c "source ~/.bashrc"
---> Running in cde1dd943e21
Removing intermediate container cde1dd943e21
---> 99eae1743824
Step 11/20 : RUN apt install python3-pip -y
---> Running in 2dece67c9c40
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
Reading package lists...
Building dependency tree...
Reading state information...
........[OMITTING SOME OUTPUT].......
Setting up build-essential (12.4ubuntu1) ...
Processing triggers for libc-bin (2.27-3ubuntu1) ...
Removing intermediate container 2dece67c9c40
---> 34c1ecded3f2
Step 12/20 : RUN python -m pip install --upgrade pip
---> Running in 32ffece96844
/bin/sh: 1: python: not found
The command '/bin/sh -c python -m pip install --upgrade pip' returned a non-zero code: 127

Answer 1

Python3.7可以使用更新选项设置为默认python。在docker文件中安装python3.7的命令之后，添加：

# Add 3.7 to the available alternatives
RUN update-alternatives --install /usr/bin/python python /usr/bin/python3.7 1
# Set python3.7 as the default python
RUN update-alternatives --set python /usr/bin/python3.7

如果您也需要python3指向3.7，那么将上面调用中的/usr/bin/python和python替换为/usr/bin/pyton3和python3。