Python脚本无法在cron中运行的排查求助

目录结构 #

目标目录：path/to/test
执行tree命令输出：

.
├── Pipfile
├── test.py
├── test.sh
└── test.txt

文件内容 #

test.py #

#!/usr/bin/env python3

import datetime

with open("/path/to/test/test.txt", "a") as f:
    f.write(f"{datetime.datetime.now()}\n")

test.sh #

#!/bin/zsh

pipenv run python /Users/ayubkeshtmand/Downloads/test/test.py

Cron配置（crontab -l输出） #

SHELL=/bin/zsh
PATH=/Library/Frameworks/Python.framework/Versions/3.10/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/bin/python3:/Library/Frameworks/Python.framework/Versions/3.10/bin:/opt/homebrew/bin:/opt/homebrew/sbin

* * * * * env > /tmp/env.output                   # 可正常运行
* * * * * touch /path/to/anothertest.txt          # 可正常运行
* * * * * python /path/to/test/test.py            # 无法运行
* * * * * python3 /path/to/test/test.py           # 无法运行
* * * * * pipenv run python /path/to/test/test.py # 无法运行
* * * * * zsh /path/to/test/test.sh               # 无法运行
* * * * * /Library/Frameworks/Python.framework/Versions/3.10/bin/python3 /path/to/test/test.py # 无法运行
* * * * * bash -l -c "python /path/to/test.py"    # 无法运行
* * * * * bash -l -c "pipenv run python /path/to/test.py"    # 无法运行

环境变量对比 #

Cron环境（/tmp/env.output内容） #

SHELL=/bin/zsh
PATH=/Library/Frameworks/Python.framework/Versions/3.10/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/bin/python3:/Library/Frameworks/Python.framework/Versions/3.10/bin:/opt/homebrew/bin:/opt/homebrew/sbin
LOGNAME=myusername
USER=myusername
HOME=/path/to
SHLVL=0
PWD=/path/to
OLDPWD=/path/to
_=/usr/bin/env

常规终端环境（env输出） #

USER=myusername
MallocNanoZone=0
__CFBundleIdentifier=com.microsoft.VSCode
COMMAND_MODE=unix2003
LOGNAME=myusername
PATH=/Library/Frameworks/Python.framework/Versions/3.10/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/bin/python3:/Library/Frameworks/Python.framework/Versions/3.10/bin:/opt/homebrew/bin:/opt/homebrew/sbin
SSH_AUTH_SOCK=/private/tmp/com.apple.launchd.RyAiUT08FA/Listeners
SHELL=/bin/zsh
HOME=/path/to
__CF_USER_TEXT_ENCODING=0x1F6:0:2
TMPDIR=/var/folders/64/wd951s6x3pz3ytpq1wjz5n180000gp/T/
XPC_SERVICE_NAME=0
XPC_FLAGS=0x0
ORIGINAL_XDG_CURRENT_DESKTOP=undefined
SHLVL=1
PWD=/path/to
OLDPWD=/path/to
HOMEBREW_PREFIX=/opt/homebrew
HOMEBREW_CELLAR=/opt/homebrew/Cellar
HOMEBREW_REPOSITORY=/opt/homebrew
MANPATH=/opt/homebrew/share/man:/usr/share/man:/usr/local/share/man:/opt/homebrew/share/man:
INFOPATH=/opt/homebrew/share/info:/opt/homebrew/share/info:
GITHUB_TOKEN=fwlkehjgowih4t089240btonglkwenkjbalfihoi283
TERM_PROGRAM=vscode
TERM_PROGRAM_VERSION=1.74.1
LANG=en_GB.UTF-8
COLORTERM=truecolor
GIT_ASKPASS=/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/git/dist/askpass.sh
VSCODE_GIT_ASKPASS_NODE=/Applications/Visual Studio Code.app/Contents/Frameworks/Code Helper.app/Contents/MacOS/Code Helper
VSCODE_GIT_ASKPASS_EXTRA_ARGS=--ms-enable-electron-run-as-node
VSCODE_GIT_ASKPASS_MAIN=/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/git/dist/askpass-main.js
VSCODE_GIT_IPC_HANDLE=/var/folders/64/gowiehg92834hbgobwkgjegp/T/vscode-git-45fnwiuheg284.sock
VSCODE_INJECTION=1
ZDOTDIR=/path/to
USER_ZDOTDIR=/path/to
TERM=xterm-256color
PS1=%n@%m %1~ %# 
_=/usr/bin/env

补充说明 #

• /var/logs无相关执行日志
• 未收到系统mail的错误提示
• 除env和touch命令外，其余Python/Pipenv相关Cron任务均失败

1. 修复脚本执行权限 #

给Python脚本和Shell脚本添加可执行权限：

chmod +x /path/to/test/test.py
chmod +x /path/to/test/test.sh

2. 解决Pipenv虚拟环境识别问题 #

Pipenv依赖当前目录的Pipfile识别虚拟环境，Cron执行时需先切换到脚本目录，同时指定Pipenv的完整路径：

1. 先在终端查询Pipenv的绝对路径：

which pipenv

2. 修改Cron任务为：

* * * * * cd /path/to/test && /opt/homebrew/bin/pipenv run python test.py >> /tmp/cron_pipenv.log 2>&1

（将/opt/homebrew/bin/pipenv替换为你查询到的实际路径）

3. 直接指定Python解释器完整路径 #

如果不需要Pipenv，直接用系统Python执行，先在终端查Python3的绝对路径：

which python3

然后修改Cron任务：

* * * * * /Library/Frameworks/Python.framework/Versions/3.10/bin/python3 /path/to/test/test.py >> /tmp/cron_python.log 2>&1

4. 给Shell脚本补全环境变量 #

修改test.sh，添加缺失的环境变量并切换到脚本目录：

#!/bin/zsh
# 补全Homebrew相关环境变量
export HOMEBREW_PREFIX=/opt/homebrew
export PATH=$HOMEBREW_PREFIX/bin:$HOMEBREW_PREFIX/sbin:$PATH

# 切换到脚本所在目录
cd /path/to/test
pipenv run python test.py

然后修改Cron任务为：

* * * * * /path/to/test/test.sh >> /tmp/cron_sh.log 2>&1

5. 调试错误日志 #

所有Cron任务添加输出重定向，执行后查看日志文件，就能定位具体错误（比如找不到模块、路径错误、权限不足等）：

# 格式示例
* * * * * [你的命令] >> /tmp/cron_debug.log 2>&1

内容的提问来源于stack exchange，提问作者AK91