TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

[jongio]

When running sudo pip install -U azure-iot-edge-runtime-ctl on Raspbian Stretch Lite, I got the following error, but only got it once. It went away after I tried a second time.

pi@jongpi6-lite:~ $ sudo pip install -U azure-iot-edge-runtime-ctl

Collecting cffi>=1.7 (from cryptography>=1.3.4; extra == "tls"->docker[tls]==2.6->azure-iot-edge-runtime-ctl)
Exception:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 353, in run
    wb.build(autobuilding=True)
  File "/usr/lib/python2.7/dist-packages/pip/wheel.py", line 749, in build
    self.requirement_set.prepare_files(self.finder)
  File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 380, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 554, in _prepare_file
    require_hashes
  File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 278, in populate_link
    self.link = finder.find_requirement(self, upgrade)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 465, in find_requirement
    all_candidates = self.find_all_candidates(req.name)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 423, in find_all_candidates
    for page in self._get_pages(url_locations, project_name):
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 568, in _get_pages
    page = self._get_page(location)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 683, in _get_page
    return HTMLPage.get_page(link, session=self.session)
  File "/usr/lib/python2.7/dist-packages/pip/index.py", line 792, in get_page
    "Cache-Control": "max-age=600",
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 501, in get
    return self.request('GET', url, **kwargs)
  File "/usr/lib/python2.7/dist-packages/pip/download.py", line 386, in request
    return super(PipSession, self).request(method, url, *args, **kwargs)
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 488, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 609, in send
    r = adapter.send(request, **kwargs)
  File "/usr/share/python-wheels/CacheControl-0.11.7-py2.py3-none-any.whl/cachecontrol/adapter.py", line 47, in send
    resp = super(CacheControlAdapter, self).send(request, **kw)
  File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/adapters.py", line 423, in send
    timeout=timeout
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 643, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 315, in increment
    total -= 1
TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

[rogerdawson]

I got this also.

[darobs]

I created a new Raspbian Stretch Lite image last night, and was able to run the command first time without any trouble:

$ pip --version
pip 9.0.1 from /usr/lib/python2.7/dist-packages (python 2.7)
$ python --version
Python 2.7.13
$ uname -a
Linux angular-pi4 4.9.41-v7+ #1023 SMP Tue Aug 8 16:00:15 BST 2017 armv7l GNU/Linux
$ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 9.1 (stretch)
Release:        9.1
Codename:       stretch

I even tried uninstalling it and reinstalling it, with and without the cache.

Is there something I'm missing?

[jongio]

It is intermittent.

[jongio]

Saw this again today on pi

[jongio]

Upgrading pip might solve this, but not confirmed

pip install --upgrade pip

[duncanhoggan]

I had the same issue, looks like there is a system cryptography dependency missing.
I installed build essentials using the following...

sudo apt-get install build-essential libssl-dev libffi-dev python-dev

and everything is good, @jonbgallant please confirm.

[jongio]

I haven't seen this in a while. Let's close with that resolution and reopen if we see it again.