Workaround broken Twisted conch

[oberstet]

2019-04-12T22:34:11+0000 [Controller   6124] Booting node from local configuration [parallel_worker_start=False] .. <crossbar.node.node.Node.boot_from_config>
2019-04-12T22:34:11+0000 [Controller   6124] NodeController.onUserError(): "ModuleNotFoundError: No module named 'bcrypt'"
Traceback (most recent call last):
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/txaio/tx.py", line 429, in as_future
    return maybeDeferred(fun, *args, **kwargs)
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/twisted/internet/defer.py", line 151, in maybeDeferred
    result = f(*args, **kw)
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/twisted/internet/defer.py", line 1613, in unwindGenerator
    return _cancellableInlineCallbacks(gen)
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/twisted/internet/defer.py", line 1529, in _cancellableInlineCallbacks
    _inlineCallbacks(None, g, status)
--- <exception caught here> ---
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/twisted/internet/defer.py", line 1418, in _inlineCallbacks
    result = g.send(result)
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/crossbar/common/process.py", line 543, in start_manhole
    from twisted.conch.ssh import keys
  File "/home/travis/build/crossbario/crossbar/.tox/py37-cli/lib/python3.7/site-packages/twisted/conch/ssh/keys.py", line 18, in <module>
    import bcrypt
builtins.ModuleNotFoundError: No module named 'bcrypt'
CROSSBAR:NODE_STARTUP_FAILED                

see: https://travis-ci.org/crossbario/crossbar/jobs/519472449

I haven't analyzed why exactly, but Twisted 19.9.2 now requires

• bcrypt
• cryptography
• pyasn1

to be installed explicitly. Doing that makes the import

from twisted.conch.ssh import keys

work again:

oberstet@intel-nuci7:~$ ~/cpy372/bin/python3 -m venv ~/cpy372_5
oberstet@intel-nuci7:~$ source ~/cpy372_5/bin/activate
(cpy372_5) oberstet@intel-nuci7:~$ pip install twisted
Collecting twisted
  Downloading https://files.pythonhosted.org/packages/f8/2b/a80a70f71eb2b86992ffa5aaae41457791ae67faa70927fd16b76127c2b7/Twisted-19.2.0.tar.bz2 (3.1MB)
    100% |████████████████████████████████| 3.1MB 5.8MB/s 
Collecting zope.interface>=4.4.2 (from twisted)
  Using cached https://files.pythonhosted.org/packages/3a/b5/5cbafbe09bbfc242503b0cd9bcf9dee32458b3ca166f6a63cb7b4f465b60/zope.interface-4.6.0-cp37-cp37m-manylinux1_x86_64.whl
Collecting constantly>=15.1 (from twisted)
  Using cached https://files.pythonhosted.org/packages/b9/65/48c1909d0c0aeae6c10213340ce682db01b48ea900a7d9fce7a7910ff318/constantly-15.1.0-py2.py3-none-any.whl
Collecting incremental>=16.10.1 (from twisted)
  Using cached https://files.pythonhosted.org/packages/f5/1d/c98a587dc06e107115cf4a58b49de20b19222c83d75335a192052af4c4b7/incremental-17.5.0-py2.py3-none-any.whl
Collecting Automat>=0.3.0 (from twisted)
  Using cached https://files.pythonhosted.org/packages/a3/86/14c16bb98a5a3542ed8fed5d74fb064a902de3bdd98d6584b34553353c45/Automat-0.7.0-py2.py3-none-any.whl
Collecting hyperlink>=17.1.1 (from twisted)
  Downloading https://files.pythonhosted.org/packages/7f/91/e916ca10a2de1cb7101a9b24da546fb90ee14629e23160086cf3361c4fb8/hyperlink-19.0.0-py2.py3-none-any.whl
Collecting PyHamcrest>=1.9.0 (from twisted)
  Using cached https://files.pythonhosted.org/packages/9a/d5/d37fd731b7d0e91afcc84577edeccf4638b4f9b82f5ffe2f8b62e2ddc609/PyHamcrest-1.9.0-py2.py3-none-any.whl
Collecting attrs>=17.4.0 (from twisted)
  Using cached https://files.pythonhosted.org/packages/23/96/d828354fa2dbdf216eaa7b7de0db692f12c234f7ef888cc14980ef40d1d2/attrs-19.1.0-py2.py3-none-any.whl
Requirement already satisfied: setuptools in ./cpy372_5/lib/python3.7/site-packages (from zope.interface>=4.4.2->twisted) (40.6.2)
Collecting six (from Automat>=0.3.0->twisted)
  Using cached https://files.pythonhosted.org/packages/73/fb/00a976f728d0d1fecfe898238ce23f502a721c0ac0ecfedb80e0d88c64e9/six-1.12.0-py2.py3-none-any.whl
Collecting idna>=2.5 (from hyperlink>=17.1.1->twisted)
  Using cached https://files.pythonhosted.org/packages/14/2c/cd551d81dbe15200be1cf41cd03869a46fe7226e7450af7a6545bfc474c9/idna-2.8-py2.py3-none-any.whl
Installing collected packages: zope.interface, constantly, incremental, attrs, six, Automat, idna, hyperlink, PyHamcrest, twisted
  Running setup.py install for twisted ... done
Successfully installed Automat-0.7.0 PyHamcrest-1.9.0 attrs-19.1.0 constantly-15.1.0 hyperlink-19.0.0 idna-2.8 incremental-17.5.0 six-1.12.0 twisted-19.2.0 zope.interface-4.6.0
You are using pip version 18.1, however version 19.0.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
(cpy372_5) oberstet@intel-nuci7:~$ which python
/home/oberstet/cpy372_5/bin/python
(cpy372_5) oberstet@intel-nuci7:~$ python
Python 3.7.2 (default, Feb 25 2019, 08:26:41) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from twisted.conch.ssh import keys
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/oberstet/cpy372_5/lib/python3.7/site-packages/twisted/conch/ssh/keys.py", line 18, in <module>
    import bcrypt
ModuleNotFoundError: No module named 'bcrypt'
>>> 
KeyboardInterrupt
>>> 
(cpy372_5) oberstet@intel-nuci7:~$ pip install bcrypt
Collecting bcrypt
  Using cached https://files.pythonhosted.org/packages/d0/79/79a4d167a31cc206117d9b396926615fa9c1fdbd52017bcced80937ac501/bcrypt-3.1.6-cp34-abi3-manylinux1_x86_64.whl
Requirement already satisfied: six>=1.4.1 in ./cpy372_5/lib/python3.7/site-packages (from bcrypt) (1.12.0)
Collecting cffi>=1.1 (from bcrypt)
  Using cached https://files.pythonhosted.org/packages/a7/3f/2667a1516d935938245bd256b56a2f96d739ac3683e6778380f06c6e4c79/cffi-1.12.2-cp37-cp37m-manylinux1_x86_64.whl
Collecting pycparser (from cffi>=1.1->bcrypt)
Installing collected packages: pycparser, cffi, bcrypt
Successfully installed bcrypt-3.1.6 cffi-1.12.2 pycparser-2.19
You are using pip version 18.1, however version 19.0.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
(cpy372_5) oberstet@intel-nuci7:~$ python
Python 3.7.2 (default, Feb 25 2019, 08:26:41) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from twisted.conch.ssh import keys
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/oberstet/cpy372_5/lib/python3.7/site-packages/twisted/conch/ssh/keys.py", line 19, in <module>
    from cryptography.exceptions import InvalidSignature
ModuleNotFoundError: No module named 'cryptography'
>>> 
(cpy372_5) oberstet@intel-nuci7:~$ pip install cryptography
Collecting cryptography
  Using cached https://files.pythonhosted.org/packages/5b/12/b0409a94dad366d98a8eee2a77678c7a73aafd8c0e4b835abea634ea3896/cryptography-2.6.1-cp34-abi3-manylinux1_x86_64.whl
Collecting asn1crypto>=0.21.0 (from cryptography)
  Using cached https://files.pythonhosted.org/packages/ea/cd/35485615f45f30a510576f1a56d1e0a7ad7bd8ab5ed7cdc600ef7cd06222/asn1crypto-0.24.0-py2.py3-none-any.whl
Requirement already satisfied: six>=1.4.1 in ./cpy372_5/lib/python3.7/site-packages (from cryptography) (1.12.0)
Requirement already satisfied: cffi!=1.11.3,>=1.8 in ./cpy372_5/lib/python3.7/site-packages (from cryptography) (1.12.2)
Requirement already satisfied: pycparser in ./cpy372_5/lib/python3.7/site-packages (from cffi!=1.11.3,>=1.8->cryptography) (2.19)
Installing collected packages: asn1crypto, cryptography
Successfully installed asn1crypto-0.24.0 cryptography-2.6.1
You are using pip version 18.1, however version 19.0.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
(cpy372_5) oberstet@intel-nuci7:~$ python
Python 3.7.2 (default, Feb 25 2019, 08:26:41) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from twisted.conch.ssh import keys
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/oberstet/cpy372_5/lib/python3.7/site-packages/twisted/conch/ssh/keys.py", line 37, in <module>
    from pyasn1.error import PyAsn1Error
ModuleNotFoundError: No module named 'pyasn1'
>>> 
(cpy372_5) oberstet@intel-nuci7:~$ pip install pyasn1
Collecting pyasn1
  Using cached https://files.pythonhosted.org/packages/7b/7c/c9386b82a25115cccf1903441bba3cbadcfae7b678a20167347fa8ded34c/pyasn1-0.4.5-py2.py3-none-any.whl
Installing collected packages: pyasn1
Successfully installed pyasn1-0.4.5
You are using pip version 18.1, however version 19.0.3 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
(cpy372_5) oberstet@intel-nuci7:~$ python
Python 3.7.2 (default, Feb 25 2019, 08:26:41) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from twisted.conch.ssh import keys
>>> 
KeyboardInterrupt
>>> 
(cpy372_5) oberstet@intel-nuci7:~$ 

[oberstet]

fixed via #1556 by adding bcrypt>=3.1.6 to requirements-min.txt