Refactor session db logging and key generation for sessions/otks While I was working on the redis sessiondb stuff, I noticed that log_wanrning, get_logger ... was duplicated. Also there was code to generate a unique key for otks that was duplicated. Changes: creating new sessions_common.py and SessionsCommon class to provide methods: log_warning, log_info, log_debug, get_logger, getUniqueKey getUniqueKey method is closer to the method used to make session keys in client.py. sessions_common.py now report when random_.py chooses a weak random number generator. Removed same from rest.py. get_logger reconciles all logging under roundup.hyperdb.backends.<name of BasicDatabase class> some backends used to log to root logger. have BasicDatabase in other sessions_*.py modules inherit from SessionCommon. change logging to use log_* methods. In addition: remove unused imports reported by flake8 and other formatting changes modify actions.py, rest.py, templating.py to use getUniqueKey method. add tests for new methods test_redis_session.py swap out ModuleNotFoundError for ImportError to prevent crash in python2 when redis is not present. allow injection of username:password or just password into redis connection URL. set pytest_redis_pw envirnment variable to password or user:password when running test.

# Utility for replacing the simple input field for the timezone with
# a select-field that lists the available values.

import cgi

try:
    import pytz
except ImportError:
    pytz = None


def tzfield(prop, name, default):
    if pytz:
        value = prop.plain()        
        if '' == value:
            value = default
        else:
            try:
                value = "Etc/GMT%+d" % int(value)
            except ValueError:
                pass

        l = ['<select name="%s">' % name]
        for zone in pytz.all_timezones:
            s = ' '
            if zone == value:
                s = 'selected=selected '
            z = cgi.escape(zone)
            l.append('<option %svalue="%s">%s</option>' % (s, z, z))
        l.append('</select>')
        return '\n'.join(l)
        
    else:
        return prop.field()

def init(instance):
    instance.registerUtil('tzfield', tzfield)