def diagnose_configurator_problem(cfg_type, requested, plugins):
"""
Raise the most helpful error message about a plugin being unavailable
:param str cfg_type: either "installer" or "authenticator"
:param str requested: the plugin that was requested
:param PluginRegistry plugins: available plugins
:raises error.PluginSelectionError: if there was a problem
"""
if requested:
if requested not in plugins:
msg = "The requested {0} plugin does not appear to be installed".format(
requested)
else:
msg = ("The {0} plugin is not working; there may be problems with "
"your existing configuration").format(requested)
elif cfg_type == "installer":
if os.path.exists("/etc/debian_version"):
# Debian... installers are at least possible
msg = (
'No installers seem to be present and working on your system; '
'fix that or try running letsencrypt with the "auth" command')
else:
# XXX update this logic as we make progress on #788 and nginx support
msg = (
'No installers are available on your OS yet; try running '
'"letsencrypt-auto auth" to get a cert you can install manually'
)
else:
msg = "{0} could not be determined or is not installed".format(
cfg_type)
raise PluginSelectionError(msg)
def set_configurator(previously, now):
"""
Setting configurators multiple ways is okay, as long as they all agree
:param str previously: previously identified request for the installer/authenticator
:param str requested: the request currently being processed
"""
if now is None:
# we're not actually setting anything
return previously
if previously:
if previously != now:
msg = "Too many flags setting configurators/installers/authenticators {0} -> {1}"
raise PluginSelectionError(msg.format(repr(previously), repr(now)))
return now