换个源试试

因为 setuptools 最新版本扔了一个 API（见：pypa/setuptools/issues/2017），而 flexget 指定的依赖 MarkupSafe 1.0 还在用那个老的 API，所以就装不上去了。
解决办法是把你的 setuptools 降低版本，输入：pip3 install setuptools==45.3.0
另外 flexget 3 需要 Python 3.6 以上，你 3.5 的话只能装 flexget 2

楼上说的对

吧里大佬贼多

学习了

学习

3楼大佬，牛

Successfully built gevent bs4 rarfile greenlet
Failed to build lxml
Installing collected packages: lxml, chardet, certifi, urllib3, idna, requests, greenlet, gevent, soupsieve, beautifulsoup4, bs4, six, rarfile, subfinder
Running setup.py install for lxml ... error
ERROR: Command errored out with exit status 1:
command: /root/subfinder/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/volume1/@entware-ng/opt/tmp/pip-install-9q7k3cg_/lxml/setup.py'"'"'; __file__='"'"'/volume1/@entware-ng/opt/tmp/pip-install-9q7k3cg_/lxml/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /volume1/@entware-ng/opt/tmp/pip-record-ybp5i42p/install-record.txt --single-version-externally-managed --compile --install-headers /root/subfinder/include/site/python3.6/lxml
cwd: /volume1/@entware-ng/opt/tmp/pip-install-9q7k3cg_/lxml/
Complete output (94 lines):
Building lxml version 4.5.0.
Building without Cython.
ERROR: b'/bin/sh: xslt-config: command not found\n'
** make sure the development packages of libxml2 and libxslt are installed **
Using build configuration of libxslt
running install
running build
running build_py
creating build
creating build/lib.linux-x86_64-3.6
creating build/lib.linux-x86_64-3.6/lxml
copying src/lxml/sax.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/_elementpath.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/builder.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/ElementInclude.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/__init__.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/usedoctest.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/cssselect.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/pyclasslookup.py -> build/lib.linux-x86_64-3.6/lxml
copying src/lxml/doctestcompare.py -> build/lib.linux-x86_64-3.6/lxml
creating build/lib.linux-x86_64-3.6/lxml/includes
copying src/lxml/includes/__init__.py -> build/lib.linux-x86_64-3.6/lxml/includes
creating build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/diff.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/ElementSoup.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/html5parser.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/builder.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/__init__.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/usedoctest.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/_setmixin.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/clean.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/soupparser.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/_html5builder.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/_diffcommand.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/formfill.py -> build/lib.linux-x86_64-3.6/lxml/html
copying src/lxml/html/defs.py -> build/lib.linux-x86_64-3.6/lxml/html
creating build/lib.linux-x86_64-3.6/lxml/isoschematron

(subfinder) root@NAS1_ESXI:~/subfinder# pip3 install subfinder -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com --trusted-host pypi.douban.com
Looking in indexes: http://pypi.douban.com/simple/
Collecting subfinder
Downloading http://pypi.doubanio.com/packages/f3/03/1f28f5c78bd51de9fec1f46cb01847048b55ebf16f6b93db3e5cead0e72c/SubFinder-1.0.9-py2.py3-none-any.whl (234 kB)
|████████████████████████████████| 234 kB 3.8 MB/s
Collecting requests
Downloading http://pypi.doubanio.com/packages/1a/70/1935c770cb3be6e3a8b78ced23d7e0f3b187f5cbfab4749523ed65d7c9b1/requests-2.23.0-py2.py3-none-any.whl (58 kB)
|████████████████████████████████| 58 kB 23.9 MB/s
Collecting six
Downloading http://pypi.doubanio.com/packages/65/eb/1f97cb97bfc2390a276969c6fae16075da282f5058082d4cb10c6c5c1dba/six-1.14.0-py2.py3-none-any.whl (10 kB)
Collecting lxml
Downloading http://pypi.doubanio.com/packages/39/2b/0a66d5436f237aff76b91e68b4d8c041d145ad0a2cdeefe2c42f76ba2857/lxml-4.5.0.tar.gz (4.5 MB)
|████████████████████████████████| 4.5 MB 32.9 MB/s
ERROR: Command errored out with exit status 1:
command: /root/subfinder/bin/python3 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/volume1/@entware-ng/opt/tmp/pip-install-75snp2pd/lxml/setup.py'"'"'; __file__='"'"'/volume1/@entware-ng/opt/tmp/pip-install-75snp2pd/lxml/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /volume1/@entware-ng/opt/tmp/pip-install-75snp2pd/lxml/pip-egg-info
cwd: /volume1/@entware-ng/opt/tmp/pip-install-75snp2pd/lxml/
Complete output (18 lines):
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "<frozen importlib._bootstrap>", line 961, in _find_and_load
File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 646, in _load_unlocked
File "<frozen importlib._bootstrap>", line 616, in _load_backward_compatible
File "/root/subfinder/lib/python3.6/site-packages/setuptools-19.6-py3.6.egg/setuptools/__init__.py", line 14, in <module>
File "<frozen importlib._bootstrap>", line 961, in _find_and_load
File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 646, in _load_unlocked
File "<frozen importlib._bootstrap>", line 616, in _load_backward_compatible
File "/root/subfinder/lib/python3.6/site-packages/setuptools-19.6-py3.6.egg/setuptools/extension.py", line 10, in <module>
File "<frozen importlib._bootstrap>", line 961, in _find_and_load
File "<frozen importlib._bootstrap>", line 946, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 885, in _find_spec
File "/root/subfinder/lib/python3.6/site-packages/_virtualenv.py", line 64, in find_spec
setattr(spec.loader, func_name, partial(func, old))
AttributeError: 'zipimport.zipimporter' object attribute 'load_module' is read-only
----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.