code: def _context_build(self, pending=False):
          
          log = self._params.get('log', self._discard)
          log.debug("called with pending=%s", pending)
          if pending:
              conf = self._config_pending
          else:
              conf = self._config_running
          if not conf:
              log.warning("No config available")
              conf = {}
  
          #  Initially create the context as a copy of the environment.
          #
          context = os.environ.copy()
  
          #  Merge in the built-in items.  It is important that these
          #  will override any values from the environment as they will
          #  have come from a parent instance of "taskforce".
          #
          context.update(
              {
                  context_prefix+'instance': None,
                  context_prefix+'pid': None,
                  context_prefix+'name': self._name,
                  context_prefix+'ppid': os.getpid(),
                  context_prefix+'host': self._legion.host,
                  context_prefix+'fqdn': self._legion.fqdn
              }
          )
  
          #  Add certain config values to the context
          for tag in ['user', 'group', 'pidfile', 'cwd']:
              if tag in conf:
                  context[context_prefix+tag] = self._get(conf[tag], context=context)
  
          if self._legion._config_running:
              self._context_defines(context, self._legion._config_running)
          else:
              log.warning("No legion config available for defines")
          self._context_defines(context, conf)
  
          self._context_defaults(context, conf)
          if self._legion._config_running:
              self._context_defaults(context, self._legion._config_running)
          else:
              log.warning("No legion config available for defaults")
  
          return context
docs: Create a context dict from standard task configuration.
  
          The context is constructed in a standard way and is passed to str.format() on configuration.
          The context consists of the entire os.environ, the config 'defines', and a set
          of pre-defined values which have a common prefix from 'context_prefix'.