problems with curses version / No module named '_curses'

[dcsan]

having problems with an install and not sure how to resolve...

(venv) root@gb3-docker:/opt/rikai/webnlp/app# python webrun.py 
Traceback (most recent call last):
  File "webrun.py", line 5, in <module>
    from webapp import routes
  File "/opt/rikai/webnlp/app/webapp/routes.py", line 11, in <module>
    import utils.log
  File "/opt/rikai/webnlp/app/utils/log.py", line 4, in <module>
    import blessed
ModuleNotFoundError: No module named 'blessed'
(venv) root@gb3-docker:/opt/rikai/webnlp/app# pip install blessed
Collecting blessed
  Downloading blessed-1.14.2-py2.py3-none-any.whl (64kB)
    100% |████████████████████████████████| 71kB 7.4MB/s 
Collecting wcwidth>=0.1.4 (from blessed)
  Downloading wcwidth-0.1.7-py2.py3-none-any.whl
Collecting six>=1.9.0 (from blessed)
  Downloading six-1.10.0-py2.py3-none-any.whl
Installing collected packages: wcwidth, six, blessed
Successfully installed blessed-1.14.2 six-1.10.0 wcwidth-0.1.7
(venv) root@gb3-docker:/opt/rikai/webnlp/app# python webrun.py 
Traceback (most recent call last):
  File "webrun.py", line 5, in <module>
    from webapp import routes
  File "/opt/rikai/webnlp/app/webapp/routes.py", line 11, in <module>
    import utils.log
  File "/opt/rikai/webnlp/app/utils/log.py", line 4, in <module>
    import blessed
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/blessed/__init__.py", line 10, in <module>
    from blessed.terminal import Terminal
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/blessed/terminal.py", line 8, in <module>
    import curses
  File "/usr/local/lib/python3.6/curses/__init__.py", line 13, in <module>
    from _curses import *
ModuleNotFoundError: No module named '_curses'

(venv) root@gb3-docker:/opt/rikai/webnlp/app# pip install curses
Collecting curses
  Could not find a version that satisfies the requirement curses (from versions: )
No matching distribution found for curses
(venv) root@gb3-docker:/opt/rikai/webnlp/app# pip install _curses
Invalid requirement: '_curses'
Traceback (most recent call last):
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/packaging/requirements.py", line 92, in __init__
    req = REQUIREMENT.parseString(requirement_string)
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1617, in parseString
    raise exc
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1607, in parseString
    loc, tokens = self._parse( instring, 0 )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1379, in _parseNoCache
    loc,tokens = self.parseImpl( instring, preloc, doActions )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 3376, in parseImpl
    loc, exprtokens = e._parse( instring, loc, doActions )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1379, in _parseNoCache
    loc,tokens = self.parseImpl( instring, preloc, doActions )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 3698, in parseImpl
    return self.expr._parse( instring, loc, doActions, callPreParse=False )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1379, in _parseNoCache
    loc,tokens = self.parseImpl( instring, preloc, doActions )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 3359, in parseImpl
    loc, resultlist = self.exprs[0]._parse( instring, loc, doActions, callPreParse=False )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 1383, in _parseNoCache
    loc,tokens = self.parseImpl( instring, preloc, doActions )
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/pyparsing.py", line 2670, in parseImpl
    raise ParseException(instring, loc, self.errmsg, self)
pip._vendor.pyparsing.ParseException: Expected W:(abcd...) (at char 0), (line:1, col:1)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/req/req_install.py", line 82, in __init__
    req = Requirement(req)
  File "/opt/rikai/webnlp/venv/lib/python3.6/site-packages/pip/_vendor/packaging/requirements.py", line 96, in __init__
    requirement_string[e.loc:e.loc + 8]))
pip._vendor.packaging.requirements.InvalidRequirement: Invalid requirement, parse error at "'_curses'"

(venv) root@gb3-docker:/opt/rikai/webnlp/app# pip -vvv install blessed
Requirement already satisfied: blessed in /opt/rikai/webnlp/venv/lib/python3.6/site-packages
Requirement already satisfied: wcwidth>=0.1.4 in /opt/rikai/webnlp/venv/lib/python3.6/site-packages (from blessed)
Requirement already satisfied: six>=1.9.0 in /opt/rikai/webnlp/venv/lib/python3.6/site-packages (from blessed)
Cleaning up...
(venv) root@gb3-docker:/opt/rikai/webnlp/app# 

FWIW

(venv) root@gb3-docker:/opt/rikai/webnlp/app# python -V
Python 3.6.0
(venv) root@gb3-docker:/opt/rikai/webnlp/app# pip -V
pip 9.0.1 from /opt/rikai/webnlp/venv/lib/python3.6/site-packages (python 3.6)
(venv) root@gb3-docker:/opt/rikai/webnlp/app# 

[dcsan]

(venv) root@gb3-docker:/opt/rikai/webnlp/app# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.2 LTS
Release:	16.04
Codename:	xenial
(venv) root@gb3-docker:/opt/rikai/webnlp/app# 

[beastsenior]

I have solved this problem using
apt-get install libncurses5 libncurses5-dev libncursesw5
and rebuilding the python3

[jquast]

If you're building python yourselves, which appears to be the case, yes, you need libncurses, etc.

at the end of ./configure python reports modules that cannot be built because their dependent libraries are not found, pay closer attention to that next time!