问题描述
服务器镜像有宝塔面板 + Python2，用yum和pip3安装Python3 + Flask + Gunicorn后，宝塔面板打不开了。报错如下：
Starting Bt-Panel..........failed
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[Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/gunicorn/util.py", line 135, in load_class
mod = import_module('.'.join(components))
File "/usr/local/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 941, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'geventwebsocket'
]
------------------------------------------------------
Error: BT-Panel service startup failed.
done
报错早就刷上去了，找不回来，这段照搬别人的[^引用1]，因为看着差不了多少。
其实我的情况跟引用1差不多，但是就是最后一步依然报错。
修复
修复目标是让宝塔面板和Python3都能正常使用。
01 | 卸载python3+修复软链接
听说宝塔面板使用Python2编写，直接安装Python3的话会出现问题。[^引用4]
卸载Python3之后依然报如上的错，路径居然依然是python3.6，猜测可能是软链接接错了。
[root@server bin]# ll | grep python
lrwxrwxrwx 1 root root 7 Jul 11 2019 python -> python2
lrwxrwxrwx 1 root root 9 Jul 11 2019 python2 -> python2.7
-rwxr-xr-x 1 root root 7216 Jun 21 2019 python2.7
-rwxr-xr-x 1 root root 1835 Jun 21 2019 python2.7-config
lrwxrwxrwx 1 root root 16 Jul 11 2019 python2-config -> python2.7-config
lrwxrwxrwx 1 root root 14 Jul 11 2019 python-config -> python2-config
虽然看着好像没错，但还是按照官方论坛里的方法[^引用2]操作一遍。
[root@server bin]# ll | grep python
lrwxrwxrwx 1 root root 18 Mar 2 17:01 python -> /usr/bin/python2.7
-rwxr-xr-x 1 root root 7216 Jun 21 2019 python2.7
-rwxr-xr-x 1 root root 1835 Jun 21 2019 python2.7-config
lrwxrwxrwx 1 root root 16 Jul 11 2019 python2-config -> python2.7-config
lrwxrwxrwx 1 root root 14 Jul 11 2019 python-config -> python2-config
02 | 再次启动，路径正常了但仍报错
Error: Not a string: ['0.0.0.0:8888
']
.........failed
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from BTPanel import app,sys,public
File "/usr/lib64/python2.7/site-packages/gevent/builtins.py", line 96, in __import__
result = _import(*args, **kwargs)
File "/www/server/panel/BTPanel/__init__.py", line 28, in <module>
from flask_sockets import Sockets
File "/usr/lib64/python2.7/site-packages/gevent/builtins.py", line 96, in __import__
result = _import(*args, **kwargs)
File "class/flask_sockets.py", line 11, in <module>
from geventwebsocket.gunicorn.workers import GeventWebSocketWorker as Worker
File "/usr/lib64/python2.7/site-packages/gevent/builtins.py", line 96, in __import__
result = _import(*args, **kwargs)
File "/usr/lib/python2.7/site-packages/geventwebsocket/gunicorn/workers.py", line 2, in <module>
from gunicorn.workers.ggevent import GeventPyWSGIWorker
File "/usr/lib64/python2.7/site-packages/gevent/builtins.py", line 96, in __import__
result = _import(*args, **kwargs)
File "/usr/lib/python2.7/site-packages/gunicorn/workers/ggevent.py", line 39, in <module>
class GeventWorker(AsyncWorker):
File "/usr/lib/python2.7/site-packages/gunicorn/workers/ggevent.py", line 90, in GeventWorker
if hasattr(gevent.core, 'dns_shutdown'):
AttributeError: 'module' object has no attribute 'core'
------------------------------------------------------
Error: BT-Panel service startup failed.
03 | 根据引用1重装gunicorn
报错
ERROR: Package 'gunicorn' requires a different Python: 2.7.5 not in '>=3.4'
不明白为什么使用python2的pip安装会出现这个错误，但还是找到了解决方法[^引用3]：
[root@server bin]# pip install gunicorn==999
[root@server bin]# pip install gunicorn==0.14.1
先指定安装一个不存在的版本999，回车后会提示可以安装的版本，然后随便挑一个安装就好了，我挑了偏中间的0.14.1安装。
04 | 重装gunicorn后报错依旧
到这步就没辙了，甚至更新过宝塔面板也依然没用。耗了很久，心态爆炸。
看了很多资料，看见有人去分析过宝塔面板的源码去纠错，于是我也找到了宝塔面板的开源地址，无意间看到源代码根目录下有一份requirements.txt（pip freeze导出的需要的库的名单和版本，见引用5），发现里面根本就没有gunicorn，人家用的是gevent！
嗯，心态爆炸了。
卸载掉gunicorn，下一刻就启动起来了……
简单测试过后，一点猫饼都没有。