Docker镜像安装Prophet失败，报ujson相关语法错误求助

问题概述 #

基于ubuntu:18.04的Docker镜像中安装Prophet时失败，本地执行pip install prophet可正常完成。报错显示安装cmdstanpy==0.9.68依赖的ujson时，python setup.py egg_info执行失败，触发SyntaxError: future feature annotations is not defined。已安装python3.10、python3-pip及flask、pandas等依赖，尝试先安装ujson再装Prophet仍无法解决。

报错详情 #

19.18 Collecting ujson (from cmdstanpy==0.9.68->prophet)
19.57   Downloading https://files.pythonhosted.org/packages/21/93/ba928551a83251be01f673755819f95a568cda0bfb9e0859be80086dce93/ujson-4.3.0.tar.gz (7.1MB)
23.28     Complete output from command python setup.py egg_info:
23.28     Traceback (most recent call last):
23.28       File "<string>", line 1, in <module>
23.28       File "/tmp/pip-build-hzpc95u_/ujson/setup.py", line 38, in <module>
23.28         "write_to_template": version_template,
23.28       File "/usr/lib/python3/dist-packages/setuptools/__init__.py", line 129, in setup
23.28         return distutils.core.setup(**attrs)
23.28       File "/usr/lib/python3.6/distutils/core.py", line 108, in setup
23.28         _setup_distribution = dist = klass(attrs)
23.28       File "/usr/lib/python3/dist-packages/setuptools/dist.py", line 372, in __init__
23.28         _Distribution.__init__(self, attrs)
23.28       File "/usr/lib/python3.6/distutils/dist.py", line 281, in __init__
23.28         self.finalize_options()
23.28       File "/usr/lib/python3/dist-packages/setuptools/dist.py", line 528, in finalize_options
23.28         ep.load()(self, ep.name, value)
23.28       File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 2324, in load
23.28         return self.resolve()
23.28       File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 2330, in resolve
23.28         module = __import__(self.module_name, fromlist=['__name__'], level=0)
23.28       File "/tmp/pip-build-hzpc95u_/ujson/.eggs/setuptools_scm-7.1.0-py3.6.egg/setuptools_scm/__init__.py", line 5
23.28         from __future__ import annotations
23.28         ^
23.28     SyntaxError: future feature annotations is not defined
23.28     
23.28     ----------------------------------------
23.69 Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-hzpc95u_/ujson/
------
failed to solve: process "/bin/sh -c python3 -m pip install prophet" did not complete successfully: exit code: 1

原Dockerfile内容 #

FROM ubuntu:18.04
RUN apt-get update
# To avoid the questions related to the geographic area
RUN ln -snf /usr/share/zoneinfo/$CONTAINER_TIMEZONE /etc/localtime && echo $CONTAINER_TIMEZONE > /etc/timezone

RUN apt-get install -y python3.10 python3-pip
RUN pip3 install flask pandas numpy cython
RUN python3 -m pip install prophet

COPY app.py app.py
COPY checks.py checks.py
COPY predict.py predict.py

EXPOSE 5000

CMD ["python3", "-u", "app.py"]

解决方法 #

原因分析 #

报错核心是from __future__ import annotations语法不被支持，这是因为安装过程中实际调用了系统默认的Python 3.6（从报错路径/usr/lib/python3.6/distutils/core.py可确认），而setuptools_scm-7.1.0需要Python 3.7+的特性。Ubuntu 18.04默认的python3和pip3绑定Python 3.6，即使安装了Python3.10，若不明确指定，仍会调用旧版本导致兼容性问题。

修复后的Dockerfile #

FROM ubuntu:18.04
RUN apt-get update && apt-get install -y --no-install-recommends tzdata
# 直接设置时区，避免环境变量缺失问题
RUN ln -snf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && echo Asia/Shanghai > /etc/timezone

RUN apt-get install -y python3.10 python3.10-distutils wget
# 安装Python3.10专属的pip
RUN wget https://bootstrap.pypa.io/get-pip.py && python3.10 get-pip.py && rm get-pip.py

# 升级setuptools和pip到兼容版本
RUN python3.10 -m pip install --upgrade setuptools pip
# 用Python3.10的pip安装基础依赖
RUN python3.10 -m pip install flask pandas numpy cython
# 固定ujson为兼容版本，避免自动拉取高版本
RUN python3.10 -m pip install ujson==4.0.2
# 安装Prophet
RUN python3.10 -m pip install prophet

COPY app.py app.py
COPY checks.py checks.py
COPY predict.py predict.py

EXPOSE 5000

# 明确用Python3.10启动应用
CMD ["python3.10", "-u", "app.py"]

关键改动说明 #

1. 安装python3.10-distutils：Ubuntu 18.04默认没有Python3.10的distutils组件，缺失会导致无法安装pip。
2. 明确调用Python3.10：所有pip安装和命令执行都用python3.10，彻底避免和系统默认的Python3.6混淆。
3. 升级setuptools和pip：旧版本无法处理新依赖包的语法特性，升级后可解决兼容性问题。
4. 固定ujson版本：指定兼容Python3.10的ujson版本，避免自动安装高版本触发语法错误。

内容的提问来源于stack exchange，提问作者csymvoul