hunk.code_window:         code, tag = zope.component.getUtility(interfaces.IDisplay).menu(
               "We were unable to find a vhost with a ServerName "
               "or Address of {0}.{1}Which virtual host would you "
               "like to choose?".format(domain, os.linesep),
               choices, help_label="More Info", ok_label="Select")
       except errors.MissingCommandlineFlag, e:
           msg = ("Failed to run Apache plugin non-interactively{1}{0}{1}"
                  "(The best solution is to add ServerName or ServerAlias "
                  "entries to the VirtualHost directives of your apache "
  
hunk.labels: keep keep keep keep keep replace keep keep keep
hunk.after_edit:     except errors.MissingCommandlineFlag as e:
  
hunk.file_path: letsencrypt-apache/letsencrypt_apache/display_ops.py
hunk.type: replace
file: """Let's Encrypt CLI."""
  from __future__ import print_function
  
  # TODO: Sanity check all input.  Be sure to avoid shell code etc...
  # pylint: disable=too-many-lines
  # (TODO: split this file into main.py and cli.py)
  import argparse
  import atexit
  import functools
  import json
  import logging
  import logging.handlers
  import os
  import sys
  import time
  import traceback
  
  import configargparse
  import OpenSSL
  import zope.component
  import zope.interface.exceptions
  import zope.interface.verify
  
  from acme import jose
  
  import letsencrypt
  
  from letsencrypt import account
  from letsencrypt import colored_logging
  from letsencrypt import configuration
  from letsencrypt import constants
  from letsencrypt import client
  from letsencrypt import crypto_util
  from letsencrypt import errors
  from letsencrypt import interfaces
  from letsencrypt import le_util
  from letsencrypt import log
  from letsencrypt import reporter
  from letsencrypt import storage
  
  from letsencrypt.display import util as display_util
  from letsencrypt.display import ops as display_ops
  from letsencrypt.plugins import disco as plugins_disco
  
  logger = logging.getLogger(__name__)
  
  # For help strings, figure out how the user ran us.
  # When invoked from letsencrypt-auto, sys.argv[0] is something like:
  # "/home/user/.local/share/letsencrypt/bin/letsencrypt"
  # Note that this won't work if the user set VENV_PATH or XDG_DATA_HOME before running
  # letsencrypt-auto (and sudo stops us from seeing if they did), so it should only be used
  # for purposes where inability to detect letsencrypt-auto fails safely
  
  fragment = os.path.join(".local", "share", "letsencrypt")
  cli_command = "letsencrypt-auto" if fragment in sys.argv[0] else "letsencrypt"
  
  # Argparse's help formatting has a lot of unhelpful peculiarities, so we want
  # to replace as much of it as we can...
  
  # This is the stub to include in help generated by argparse
  
  SHORT_USAGE = """
    {0} [SUBCOMMAND] [options] [-d domain] [-d domain] ...
  
  The Let's Encrypt agent can obtain and install HTTPS/TLS/SSL certificates.  By
  default, it will attempt to use a webserver both for obtaining and installing
  the cert. Major SUBCOMMANDS are:
  
    (default) run        Obtain & install a cert in your current webserver
    certonly             Obtain cert, but do not install it (aka "auth")
    install              Install a previously obtained cert in a server
    revoke               Revoke a previously obtained certificate
    rollback             Rollback server configuration changes made during install
    config_changes       Show changes made to server config during installation
    plugins              Display information about installed plugins
  
  """.format(cli_command)
  
  # This is the short help for letsencrypt --help, where we disable argparse
  # altogether
  USAGE = SHORT_USAGE + """Choice of server plugins for obtaining and installing cert:
  
    %s
    --standalone      Run a standalone webserver for authentication
    %s
    --webroot         Place files in a server's webroot folder for authentication
  
  OR use different plugins to obtain (authenticate) the cert and then install it:
  
    --authenticator standalone --installer apache
  
  More detailed help:
  
    -h, --help [topic]    print this message, or detailed help on a topic;
                          the available topics are:
  
     all, automation, paths, security, testing, or any of the subcommands or
     plugins (certonly, install, nginx, apache, standalone, webroot, etc)
  """
  
  
  def usage_strings(plugins):
      """Make usage strings late so that plugins can be initialised late"""
      if "nginx" in plugins:
          nginx_doc = "--nginx           Use the Nginx plugin for authentication & installation"
      else:
          nginx_doc = "(nginx support is experimental, buggy, and not installed by default)"
      if "apache" in plugins:
          apache_doc = "--apache          Use the Apache plugin for authentication & installation"
      else:
          apache_doc = "(the apache plugin is not installed)"
      return USAGE % (apache_doc, nginx_doc), SHORT_USAGE
  
  
  def _find_domains(config, installer):
      if not config.domains:
          domains = display_ops.choose_names(installer)
          # record in config.domains (so that it can be serialised in renewal config files),
          # and set webroot_map entries if applicable
          for d in domains:
              _process_domain(config, d)
      else:
          domains = config.domains
  
      if not domains:
          raise errors.Error("Please specify --domains, or --installer that "
                             "will help in domain names autodiscovery")
  
      return domains
  
  
  def _determine_account(args, config):
      """Determine which account to use.
  
      In order to make the renewer (configuration de/serialization) happy,
      if ``args.account`` is ``None``, it will be updated based on the
      user input. Same for ``args.email``.
  
      :param argparse.Namespace args: CLI arguments
      :param letsencrypt.interface.IConfig config: Configuration object
      :param .AccountStorage account_storage: Account storage.
  
      :returns: Account and optionally ACME client API (biproduct of new
          registration).
      :rtype: `tuple` of `letsencrypt.account.Account` and
          `acme.client.Client`
  
      """
      account_storage = account.AccountFileStorage(config)
      acme = None
  
      if args.account is not None:
          acc = account_storage.load(args.account)
      else:
          accounts = account_storage.find_all()
          if len(accounts) > 1:
              acc = display_ops.choose_account(accounts)
          elif len(accounts) == 1:
              acc = accounts[0]
          else:  # no account registered yet
              if args.email is None and not args.register_unsafely_without_email:
                  args.email = display_ops.get_email()
  
              def _tos_cb(regr):
                  if args.tos:
                      return True
                  msg = ("Please read the Terms of Service at {0}. You "
                         "must agree in order to register with the ACME "
                         "server at {1}".format(
                             regr.terms_of_service, config.server))
                  obj = zope.component.getUtility(interfaces.IDisplay)
                  return obj.yesno(msg, "Agree", "Cancel", cli_flag="--agree-tos")
  
              try:
                  acc, acme = client.register(
                      config, account_storage, tos_cb=_tos_cb)
              except errors.MissingCommandlineFlag:
                  raise
              except errors.Error as error:
                  logger.debug(error, exc_info=True)
                  raise errors.Error(
                      "Unable to register an account with ACME server")
  
      args.account = acc.id
      return acc, acme
  
  
  def _init_le_client(args, config, authenticator, installer):
      if authenticator is not None:
          # if authenticator was given, then we will need account...
          acc, acme = _determine_account(args, config)
          logger.debug("Picked account: %r", acc)
          # XXX
          #crypto_util.validate_key_csr(acc.key)
      else:
          acc, acme = None, None
  
      return client.Client(config, acc, authenticator, installer, acme=acme)
  
  
  def _find_duplicative_certs(config, domains):
      """Find existing certs that duplicate the request."""
  
      identical_names_cert, subset_names_cert = None, None
  
      cli_config = configuration.RenewerConfiguration(config)
      configs_dir = cli_config.renewal_configs_dir
      # Verify the directory is there
      le_util.make_or_verify_dir(configs_dir, mode=0o755, uid=os.geteuid())
  
      for renewal_file in os.listdir(configs_dir):
          if not renewal_file.endswith(".conf"):
              continue
          try:
              full_path = os.path.join(configs_dir, renewal_file)
              candidate_lineage = storage.RenewableCert(full_path, cli_config)
          except (errors.CertStorageError, IOError):
              logger.warning("Renewal configuration file %s is broken. "
                             "Skipping.", full_path)
              continue
          # TODO: Handle these differently depending on whether they are
          #       expired or still valid?
          candidate_names = set(candidate_lineage.names())
          if candidate_names == set(domains):
              identical_names_cert = candidate_lineage
          elif candidate_names.issubset(set(domains)):
              # This logic finds and returns the largest subset-names cert
              # in the case where there are several available.
              if subset_names_cert is None:
                  subset_names_cert = candidate_lineage
              elif len(candidate_names) > len(subset_names_cert.names()):
                  subset_names_cert = candidate_lineage
  
      return identical_names_cert, subset_names_cert
  
  
  def _treat_as_renewal(config, domains):
      """Determine whether there are duplicated names and how to handle them.
  
      :returns: Two-element tuple containing desired new-certificate behavior as
                a string token ("reinstall", "renew", or "newcert"), plus either
                a RenewableCert instance or None if renewal shouldn't occur.
  
      :raises .Error: If the user would like to rerun the client again.
  
      """
      # Considering the possibility that the requested certificate is
      # related to an existing certificate.  (config.duplicate, which
      # is set with --duplicate, skips all of this logic and forces any
      # kind of certificate to be obtained with renewal = False.)
      if config.duplicate:
          return "newcert", None
      # TODO: Also address superset case
      ident_names_cert, subset_names_cert = _find_duplicative_certs(config, domains)
      # XXX ^ schoen is not sure whether that correctly reads the systemwide
      # configuration file.
      if ident_names_cert is None and subset_names_cert is None:
          return "newcert", None
  
      if ident_names_cert is not None:
          return _handle_identical_cert_request(config, ident_names_cert)
      elif subset_names_cert is not None:
          return _handle_subset_cert_request(config, domains, subset_names_cert)
  
  def _handle_identical_cert_request(config, cert):
      """Figure out what to do if a cert has the same names as a perviously obtained one
  
      :param storage.RenewableCert cert:
  
      :returns: Tuple of (string, cert_or_None) as per _treat_as_renewal
      :rtype: tuple
  
      """
      if config.renew_by_default:
          logger.info("Auto-renewal forced with --renew-by-default...")
          return "renew", cert
      if cert.should_autorenew(interactive=True):
          logger.info("Cert is due for renewal, auto-renewing...")
          return "renew", cert
      if config.reinstall:
          # Set with --reinstall, force an identical certificate to be
          # reinstalled without further prompting.
          return "reinstall", cert
  
      question = (
          "You have an existing certificate that contains exactly the same "
          "domains you requested and isn't close to expiry."
          "{br}(ref: {0}){br}{br}What would you like to do?"
      ).format(cert.configfile.filename, br=os.linesep)
  
      if config.verb == "run":
          keep_opt = "Attempt to reinstall this existing certificate"
      elif config.verb == "certonly":
          keep_opt = "Keep the existing certificate for now"
      choices = [keep_opt,
                 "Renew & replace the cert (limit ~5 per 7 days)",
                 "Cancel this operation and do nothing"]
  
      display = zope.component.getUtility(interfaces.IDisplay)
      response = display.menu(question, choices, "OK", "Cancel", default=0)
      if response[0] == "cancel" or response[1] == 2:
          # TODO: Add notification related to command-line options for
          #       skipping the menu for this case.
          raise errors.Error(
              "User chose to cancel the operation and may "
              "reinvoke the client.")
      elif response[1] == 0:
          return "reinstall", cert
      elif response[1] == 1:
          return "renew", cert
      else:
          assert False, "This is impossible"
  
  def _handle_subset_cert_request(config, domains, cert):
      """Figure out what to do if a previous cert had a subset of the names now requested
  
      :param storage.RenewableCert cert:
  
      :returns: Tuple of (string, cert_or_None) as per _treat_as_renewal
      :rtype: tuple
  
      """
      existing = ", ".join(cert.names())
      question = (
          "You have an existing certificate that contains a portion of "
          "the domains you requested (ref: {0}){br}{br}It contains these "
          "names: {1}{br}{br}You requested these names for the new "
          "certificate: {2}.{br}{br}Do you want to expand and replace this existing "
          "certificate with the new certificate?"
      ).format(cert.configfile.filename,
               existing,
               ", ".join(domains),
               br=os.linesep)
      if config.expand or config.renew_by_default or zope.component.getUtility(
              interfaces.IDisplay).yesno(question, "Expand", "Cancel",
                                         cli_flag="--expand (or in some cases, --duplicate)"):
          return "renew", cert
      else:
          reporter_util = zope.component.getUtility(interfaces.IReporter)
          reporter_util.add_message(
              "To obtain a new certificate that contains these names without "
              "replacing your existing certificate for {0}, you must use the "
              "--duplicate option.{br}{br}"
              "For example:{br}{br}{1} --duplicate {2}".format(
                  existing,
                  sys.argv[0], " ".join(sys.argv[1:]),
                  br=os.linesep
              ),
              reporter_util.HIGH_PRIORITY)
          raise errors.Error(
              "User chose to cancel the operation and may "
              "reinvoke the client.")
  
  
  def _report_new_cert(cert_path, fullchain_path):
      """Reports the creation of a new certificate to the user.
  
      :param str cert_path: path to cert
      :param str fullchain_path: path to full chain
  
      """
      expiry = crypto_util.notAfter(cert_path).date()
      reporter_util = zope.component.getUtility(interfaces.IReporter)
      if fullchain_path:
          # Print the path to fullchain.pem because that's what modern webservers
          # (Nginx and Apache2.4) will want.
          and_chain = "and chain have"
          path = fullchain_path
      else:
          # Unless we're in .csr mode and there really isn't one
          and_chain = "has "
          path = cert_path
      # XXX Perhaps one day we could detect the presence of known old webservers
      # and say something more informative here.
      msg = ("Congratulations! Your certificate {0} been saved at {1}."
             " Your cert will expire on {2}. To obtain a new version of the "
             "certificate in the future, simply run Let's Encrypt again."
             .format(and_chain, path, expiry))
      reporter_util.add_message(msg, reporter_util.MEDIUM_PRIORITY)
  
  def _suggest_donate():
      "Suggest a donation to support Let's Encrypt"
      reporter_util = zope.component.getUtility(interfaces.IReporter)
      msg = ("If you like Let's Encrypt, please consider supporting our work by:\n\n"
             "Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate\n"
             "Donating to EFF:                    https://eff.org/donate-le\n\n")
      reporter_util.add_message(msg, reporter_util.LOW_PRIORITY)
  
  
  def _auth_from_domains(le_client, config, domains):
      """Authenticate and enroll certificate."""
      # Note: This can raise errors... caught above us though. This is now
      # a three-way case: reinstall (which results in a no-op here because
      # although there is a relevant lineage, we don't do anything to it
      # inside this function -- we don't obtain a new certificate), renew
      # (which results in treating the request as a renewal), or newcert
      # (which results in treating the request as a new certificate request).
  
      action, lineage = _treat_as_renewal(config, domains)
      if action == "reinstall":
          # The lineage already exists; allow the caller to try installing
          # it without getting a new certificate at all.
          return lineage, "reinstall"
      elif action == "renew":
          original_server = lineage.configuration["renewalparams"]["server"]
          _avoid_invalidating_lineage(config, lineage, original_server)
          # TODO: schoen wishes to reuse key - discussion
          # https://github.com/letsencrypt/letsencrypt/pull/777/files#r40498574
          new_certr, new_chain, new_key, _ = le_client.obtain_certificate(domains)
          # TODO: Check whether it worked! <- or make sure errors are thrown (jdk)
          lineage.save_successor(
              lineage.latest_common_version(), OpenSSL.crypto.dump_certificate(
                  OpenSSL.crypto.FILETYPE_PEM, new_certr.body.wrapped),
              new_key.pem, crypto_util.dump_pyopenssl_chain(new_chain))
  
          lineage.update_all_links_to(lineage.latest_common_version())
          # TODO: Check return value of save_successor
          # TODO: Also update lineage renewal config with any relevant
          #       configuration values from this attempt? <- Absolutely (jdkasten)
      elif action == "newcert":
          # TREAT AS NEW REQUEST
          lineage = le_client.obtain_and_enroll_certificate(domains)
          if not lineage:
              raise errors.Error("Certificate could not be obtained")
  
      _report_new_cert(lineage.cert, lineage.fullchain)
  
      return lineage, action
  
  def _avoid_invalidating_lineage(config, lineage, original_server):
      "Do not renew a valid cert with one from a staging server!"
      def _is_staging(srv):
          return srv == constants.STAGING_URI or "staging" in srv
  
      # Some lineages may have begun with --staging, but then had production certs
      # added to them
      latest_cert = OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM,
                                                    open(lineage.cert).read())
      # all our test certs are from happy hacker fake CA, though maybe one day
      # we should test more methodically
      now_valid = not "fake" in repr(latest_cert.get_issuer()).lower()
  
      if _is_staging(config.server):
          if not _is_staging(original_server) or now_valid:
              if not config.break_my_certs:
                  names = ", ".join(lineage.names())
                  raise errors.Error(
                      "You've asked to renew/replace a seemingly valid certificate with "
                      "a test certificate (domains: {0}). We will not do that "
                      "unless you use the --break-my-certs flag!".format(names))
  
  
  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 .PluginsRegistry 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.\nThe error was: {1!r}"
                     .format(requested, plugins[requested].problem))
      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 "certonly" 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 certonly" to get a cert you can install manually')
      else:
          msg = "{0} could not be determined or is not installed".format(cfg_type)
      raise errors.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 errors.PluginSelectionError(msg.format(repr(previously), repr(now)))
      return now
  
  def cli_plugin_requests(args):
      """
      Figure out which plugins the user requested with CLI and config options
  
      :returns: (requested authenticator string or None, requested installer string or None)
      :rtype: tuple
      """
      req_inst = req_auth = args.configurator
      req_inst = set_configurator(req_inst, args.installer)
      req_auth = set_configurator(req_auth, args.authenticator)
      if args.nginx:
          req_inst = set_configurator(req_inst, "nginx")
          req_auth = set_configurator(req_auth, "nginx")
      if args.apache:
          req_inst = set_configurator(req_inst, "apache")
          req_auth = set_configurator(req_auth, "apache")
      if args.standalone:
          req_auth = set_configurator(req_auth, "standalone")
      if args.webroot:
          req_auth = set_configurator(req_auth, "webroot")
      if args.manual:
          req_auth = set_configurator(req_auth, "manual")
      logger.debug("Requested authenticator %s and installer %s", req_auth, req_inst)
      return req_auth, req_inst
  
  
  noninstaller_plugins = ["webroot", "manual", "standalone"]
  
  def choose_configurator_plugins(args, config, plugins, verb):
      """
      Figure out which configurator we're going to use
      :raises errors.PluginSelectionError if there was a problem
      """
  
      req_auth, req_inst = cli_plugin_requests(args)
  
      # Which plugins do we need?
      if verb == "run":
          need_inst = need_auth = True
          if req_auth in noninstaller_plugins and not req_inst:
              msg = ('With the {0} plugin, you probably want to use the "certonly" command, eg:{1}'
                     '{1}    {2} certonly --{0}{1}{1}'
                     '(Alternatively, add a --installer flag. See https://eff.org/letsencrypt-plugins'
                     '{1} and "--help plugins" for more information.)'.format(
                     req_auth, os.linesep, cli_command))
  
              raise errors.MissingCommandlineFlag, msg
      else:
          need_inst = need_auth = False
      if verb == "certonly":
          need_auth = True
      if verb == "install":
          need_inst = True
          if args.authenticator:
              logger.warn("Specifying an authenticator doesn't make sense in install mode")
  
  
  
      # Try to meet the user's request and/or ask them to pick plugins
      authenticator = installer = None
      if verb == "run" and req_auth == req_inst:
          # Unless the user has explicitly asked for different auth/install,
          # only consider offering a single choice
          authenticator = installer = display_ops.pick_configurator(config, req_inst, plugins)
      else:
          if need_inst or req_inst:
              installer = display_ops.pick_installer(config, req_inst, plugins)
          if need_auth:
              authenticator = display_ops.pick_authenticator(config, req_auth, plugins)
      logger.debug("Selected authenticator %s and installer %s", authenticator, installer)
  
      # Report on any failures
      if need_inst and not installer:
          diagnose_configurator_problem("installer", req_inst, plugins)
      if need_auth and not authenticator:
          diagnose_configurator_problem("authenticator", req_auth, plugins)
  
      record_chosen_plugins(config, plugins, authenticator, installer)
      return installer, authenticator
  
  
  def record_chosen_plugins(config, plugins, auth, inst):
      "Update the config entries to reflect the plugins we actually selected."
      cn = config.namespace
      cn.authenticator = plugins.find_init(auth).name if auth else "none"
      cn.installer = plugins.find_init(inst).name if inst else "none"
  
  
  # TODO: Make run as close to auth + install as possible
  # Possible difficulties: args.csr was hacked into auth
  def run(args, config, plugins):  # pylint: disable=too-many-branches,too-many-locals
      """Obtain a certificate and install."""
      try:
          installer, authenticator = choose_configurator_plugins(args, config, plugins, "run")
      except errors.PluginSelectionError, e:
          return e.message
  
      domains = _find_domains(config, installer)
  
      # TODO: Handle errors from _init_le_client?
      le_client = _init_le_client(args, config, authenticator, installer)
  
      lineage, action = _auth_from_domains(le_client, config, domains)
  
      le_client.deploy_certificate(
          domains, lineage.privkey, lineage.cert,
          lineage.chain, lineage.fullchain)
  
      le_client.enhance_config(domains, config)
  
      if len(lineage.available_versions("cert")) == 1:
          display_ops.success_installation(domains)
      else:
          display_ops.success_renewal(domains, action)
  
      _suggest_donate()
  
  
  def obtain_cert(args, config, plugins):
      """Implements "certonly": authenticate & obtain cert, but do not install it."""
  
      if args.domains and args.csr is not None:
          # TODO: --csr could have a priority, when --domains is
          # supplied, check if CSR matches given domains?
          return "--domains and --csr are mutually exclusive"
  
      try:
          # installers are used in auth mode to determine domain names
          installer, authenticator = choose_configurator_plugins(args, config, plugins, "certonly")
      except errors.PluginSelectionError, e:
          return e.message
  
      # TODO: Handle errors from _init_le_client?
      le_client = _init_le_client(args, config, authenticator, installer)
  
      # This is a special case; cert and chain are simply saved
      if args.csr is not None:
          certr, chain = le_client.obtain_certificate_from_csr(le_util.CSR(
              file=args.csr[0], data=args.csr[1], form="der"))
          cert_path, _, cert_fullchain = le_client.save_certificate(
              certr, chain, args.cert_path, args.chain_path, args.fullchain_path)
          _report_new_cert(cert_path, cert_fullchain)
      else:
          domains = _find_domains(config, installer)
          _auth_from_domains(le_client, config, domains)
  
      _suggest_donate()
  
  
  def install(args, config, plugins):
      """Install a previously obtained cert in a server."""
      # XXX: Update for renewer/RenewableCert
      # FIXME: be consistent about whether errors are raised or returned from
      # this function ...
  
      try:
          installer, _ = choose_configurator_plugins(args, config,
                                                     plugins, "install")
      except errors.PluginSelectionError, e:
          return e.message
  
      domains = _find_domains(config, installer)
      le_client = _init_le_client(
          args, config, authenticator=None, installer=installer)
      assert args.cert_path is not None  # required=True in the subparser
      le_client.deploy_certificate(
          domains, args.key_path, args.cert_path, args.chain_path,
          args.fullchain_path)
      le_client.enhance_config(domains, config)
  
  
  def revoke(args, config, unused_plugins):  # TODO: coop with renewal config
      """Revoke a previously obtained certificate."""
      # For user-agent construction
      config.namespace.installer = config.namespace.authenticator = "none"
      if args.key_path is not None:  # revocation by cert key
          logger.debug("Revoking %s using cert key %s",
                       args.cert_path[0], args.key_path[0])
          key = jose.JWK.load(args.key_path[1])
      else:  # revocation by account key
          logger.debug("Revoking %s using Account Key", args.cert_path[0])
          acc, _ = _determine_account(args, config)
          key = acc.key
      acme = client.acme_from_config_key(config, key)
      cert = crypto_util.pyopenssl_load_certificate(args.cert_path[1])[0]
      acme.revoke(jose.ComparableX509(cert))
  
  
  def rollback(args, config, plugins):
      """Rollback server configuration changes made during install."""
      client.rollback(args.installer, args.checkpoints, config, plugins)
  
  
  def config_changes(unused_args, config, unused_plugins):
      """Show changes made to server config during installation
  
      View checkpoints and associated configuration changes.
  
      """
      client.view_config_changes(config)
  
  
  def plugins_cmd(args, config, plugins):  # TODO: Use IDisplay rather than print
      """List server software plugins."""
      logger.debug("Expected interfaces: %s", args.ifaces)
  
      ifaces = [] if args.ifaces is None else args.ifaces
      filtered = plugins.visible().ifaces(ifaces)
      logger.debug("Filtered plugins: %r", filtered)
  
      if not args.init and not args.prepare:
          print(str(filtered))
          return
  
      filtered.init(config)
      verified = filtered.verify(ifaces)
      logger.debug("Verified plugins: %r", verified)
  
      if not args.prepare:
          print(str(verified))
          return
  
      verified.prepare()
      available = verified.available()
      logger.debug("Prepared plugins: %s", available)
      print(str(available))
  
  
  def read_file(filename, mode="rb"):
      """Returns the given file's contents.
  
      :param str filename: path to file
      :param str mode: open mode (see `open`)
  
      :returns: absolute path of filename and its contents
      :rtype: tuple
  
      :raises argparse.ArgumentTypeError: File does not exist or is not readable.
  
      """
      try:
          filename = os.path.abspath(filename)
          return filename, open(filename, mode).read()
      except IOError as exc:
          raise argparse.ArgumentTypeError(exc.strerror)
  
  
  def flag_default(name):
      """Default value for CLI flag."""
      return constants.CLI_DEFAULTS[name]
  
  
  def config_help(name, hidden=False):
      """Help message for `.IConfig` attribute."""
      if hidden:
          return argparse.SUPPRESS
      else:
          return interfaces.IConfig[name].__doc__
  
  
  class SilentParser(object):  # pylint: disable=too-few-public-methods
      """Silent wrapper around argparse.
  
      A mini parser wrapper that doesn't print help for its
      arguments. This is needed for the use of callbacks to define
      arguments within plugins.
  
      """
      def __init__(self, parser):
          self.parser = parser
  
      def add_argument(self, *args, **kwargs):
          """Wrap, but silence help"""
          kwargs["help"] = argparse.SUPPRESS
          self.parser.add_argument(*args, **kwargs)
  
  
  class HelpfulArgumentParser(object):
      """Argparse Wrapper.
  
      This class wraps argparse, adding the ability to make --help less
      verbose, and request help on specific subcategories at a time, eg
      'letsencrypt --help security' for security options.
  
      """
  
      # Maps verbs/subcommands to the functions that implement them
      VERBS = {"auth": obtain_cert, "certonly": obtain_cert,
               "config_changes": config_changes, "everything": run,
               "install": install, "plugins": plugins_cmd,
               "revoke": revoke, "rollback": rollback, "run": run}
  
      # List of topics for which additional help can be provided
      HELP_TOPICS = ["all", "security",
                     "paths", "automation", "testing"] + VERBS.keys()
  
      def __init__(self, args, plugins):
          plugin_names = [name for name, _p in plugins.iteritems()]
          self.help_topics = self.HELP_TOPICS + plugin_names + [None]
          usage, short_usage = usage_strings(plugins)
          self.parser = configargparse.ArgParser(
              usage=short_usage,
              formatter_class=argparse.ArgumentDefaultsHelpFormatter,
              args_for_setting_config_path=["-c", "--config"],
              default_config_files=flag_default("config_files"))
  
          # This is the only way to turn off overly verbose config flag documentation
          self.parser._add_config_file_help = False  # pylint: disable=protected-access
          self.silent_parser = SilentParser(self.parser)
  
          self.args = args
          self.determine_verb()
          help1 = self.prescan_for_flag("-h", self.help_topics)
          help2 = self.prescan_for_flag("--help", self.help_topics)
          assert max(True, "a") == "a", "Gravity changed direction"
          self.help_arg = max(help1, help2)
          if self.help_arg is True:
              # just --help with no topic; avoid argparse altogether
              print(usage)
              sys.exit(0)
          self.visible_topics = self.determine_help_topics(self.help_arg)
          self.groups = {}  # elements are added by .add_group()
  
      def parse_args(self):
          """Parses command line arguments and returns the result.
  
          :returns: parsed command line arguments
          :rtype: argparse.Namespace
  
          """
          parsed_args = self.parser.parse_args(self.args)
          parsed_args.func = self.VERBS[self.verb]
          parsed_args.verb = self.verb
  
          # Do any post-parsing homework here
  
          # we get domains from -d, but also from the webroot map...
          if parsed_args.webroot_map:
              for domain in parsed_args.webroot_map.keys():
                  if domain not in parsed_args.domains:
                      parsed_args.domains.append(domain)
  
          # argparse seemingly isn't flexible enough to give us this behaviour easily...
          if parsed_args.staging:
              if parsed_args.server not in (flag_default("server"), constants.STAGING_URI):
                  raise errors.Error("--server value conflicts with --staging")
              parsed_args.server = constants.STAGING_URI
  
          return parsed_args
  
  
      def determine_verb(self):
          """Determines the verb/subcommand provided by the user.
  
          This function works around some of the limitations of argparse.
  
          """
          if "-h" in self.args or "--help" in self.args:
              # all verbs double as help arguments; don't get them confused
              self.verb = "help"
              return
  
          for i, token in enumerate(self.args):
              if token in self.VERBS:
                  verb = token
                  if verb == "auth":
                      verb = "certonly"
                  if verb == "everything":
                      verb = "run"
                  self.verb = verb
                  self.args.pop(i)
                  return
  
          self.verb = "run"
  
      def prescan_for_flag(self, flag, possible_arguments):
          """Checks cli input for flags.
  
          Check for a flag, which accepts a fixed set of possible arguments, in
          the command line; we will use this information to configure argparse's
          help correctly.  Return the flag's argument, if it has one that matches
          the sequence @possible_arguments; otherwise return whether the flag is
          present.
  
          """
          if flag not in self.args:
              return False
          pos = self.args.index(flag)
          try:
              nxt = self.args[pos + 1]
              if nxt in possible_arguments:
                  return nxt
          except IndexError:
              pass
          return True
  
      def add(self, topic, *args, **kwargs):
          """Add a new command line argument.
  
          @topic is required, to indicate which part of the help will document
          it, but can be None for `always documented'.
  
          """
          if self.visible_topics[topic]:
              if topic in self.groups:
                  group = self.groups[topic]
                  group.add_argument(*args, **kwargs)
              else:
                  self.parser.add_argument(*args, **kwargs)
          else:
              kwargs["help"] = argparse.SUPPRESS
              self.parser.add_argument(*args, **kwargs)
  
      def add_deprecated_argument(self, argument_name, num_args):
          """Adds a deprecated argument with the name argument_name.
  
          Deprecated arguments are not shown in the help. If they are used
          on the command line, a warning is shown stating that the
          argument is deprecated and no other action is taken.
  
          :param str argument_name: Name of deprecated argument.
          :param int nargs: Number of arguments the option takes.
  
          """
          le_util.add_deprecated_argument(
              self.parser.add_argument, argument_name, num_args)
  
      def add_group(self, topic, **kwargs):
          """
  
          This has to be called once for every topic; but we leave those calls
          next to the argument definitions for clarity. Return something
          arguments can be added to if necessary, either the parser or an argument
          group.
  
          """
          if self.visible_topics[topic]:
              #print("Adding visible group " + topic)
              group = self.parser.add_argument_group(topic, **kwargs)
              self.groups[topic] = group
              return group
          else:
              #print("Invisible group " + topic)
              return self.silent_parser
  
      def add_plugin_args(self, plugins):
          """
  
          Let each of the plugins add its own command line arguments, which
          may or may not be displayed as help topics.
  
          """
          for name, plugin_ep in plugins.iteritems():
              parser_or_group = self.add_group(name, description=plugin_ep.description)
              #print(parser_or_group)
              plugin_ep.plugin_cls.inject_parser_options(parser_or_group, name)
  
      def determine_help_topics(self, chosen_topic):
          """
  
          The user may have requested help on a topic, return a dict of which
          topics to display. @chosen_topic has prescan_for_flag's return type
  
          :returns: dict
  
          """
          # topics maps each topic to whether it should be documented by
          # argparse on the command line
          if chosen_topic == "auth":
              chosen_topic = "certonly"
          if chosen_topic == "everything":
              chosen_topic = "run"
          if chosen_topic == "all":
              return dict([(t, True) for t in self.help_topics])
          elif not chosen_topic:
              return dict([(t, False) for t in self.help_topics])
          else:
              return dict([(t, t == chosen_topic) for t in self.help_topics])
  
  
  def prepare_and_parse_args(plugins, args):
      """Returns parsed command line arguments.
  
      :param .PluginsRegistry plugins: available plugins
      :param list args: command line arguments with the program name removed
  
      :returns: parsed command line arguments
      :rtype: argparse.Namespace
  
      """
      helpful = HelpfulArgumentParser(args, plugins)
  
      # --help is automatically provided by argparse
      helpful.add(
          None, "-v", "--verbose", dest="verbose_count", action="count",
          default=flag_default("verbose_count"), help="This flag can be used "
          "multiple times to incrementally increase the verbosity of output, "
          "e.g. -vvv.")
      helpful.add(
          None, "-t", "--text", dest="text_mode", action="store_true",
          help="Use the text output instead of the curses UI.")
      helpful.add(
          None, "-n", "--non-interactive", "--noninteractive",
          dest="noninteractive_mode", action="store_true",
          help="Run without ever asking for user input. This may require "
                "additional command line flags; the client will try to explain "
                "which ones are required if it finds one missing")
      helpful.add(
          None, "--register-unsafely-without-email", action="store_true",
          help="Specifying this flag enables registering an account with no "
               "email address. This is strongly discouraged, because in the "
               "event of key loss or account compromise you will irrevocably "
               "lose access to your account. You will also be unable to receive "
               "notice about impending expiration or revocation of your "
               "certificates. Updates to the Subscriber Agreement will still "
               "affect you, and will be effective 14 days after posting an "
               "update to the web site.")
      helpful.add(None, "-m", "--email", help=config_help("email"))
      # positional arg shadows --domains, instead of appending, and
      # --domains is useful, because it can be stored in config
      #for subparser in parser_run, parser_auth, parser_install:
      #    subparser.add_argument("domains", nargs="*", metavar="domain")
      helpful.add(None, "-d", "--domains", "--domain", dest="domains",
                  metavar="DOMAIN", action=DomainFlagProcessor, default=[],
                  help="Domain names to apply. For multiple domains you can use "
                  "multiple -d flags or enter a comma separated list of domains "
                  "as a parameter.")
      helpful.add_group(
          "automation",
          description="Arguments for automating execution & other tweaks")
      helpful.add(
          "automation", "--keep-until-expiring", "--keep", "--reinstall",
          dest="reinstall", action="store_true",
          help="If the requested cert matches an existing cert, always keep the "
               "existing one until it is due for renewal (for the "
               "'run' subcommand this means reinstall the existing cert)")
      helpful.add(
          "automation", "--expand", action="store_true",
          help="If an existing cert covers some subset of the requested names, "
               "always expand and replace it with the additional names.")
      helpful.add(
          "automation", "--version", action="version",
          version="%(prog)s {0}".format(letsencrypt.__version__),
          help="show program's version number and exit")
      helpful.add(
          "automation", "--renew-by-default", action="store_true",
          help="Select renewal by default when domains are a superset of a "
               "previously attained cert (often --keep-until-expiring is "
               "more appropriate). Implies --expand.")
      helpful.add(
          "automation", "--agree-tos", dest="tos", action="store_true",
          help="Agree to the Let's Encrypt Subscriber Agreement")
      helpful.add(
          "automation", "--account", metavar="ACCOUNT_ID",
          help="Account ID to use")
      helpful.add(
          "automation", "--duplicate", dest="duplicate", action="store_true",
          help="Allow making a certificate lineage that duplicates an existing one "
               "(both can be renewed in parallel)")
      helpful.add(
          "automation", "--os-packages-only", action="store_true",
          help="(letsencrypt-auto only) install OS package dependencies and then stop")
      helpful.add(
          "automation", "--no-self-upgrade", action="store_true",
          help="(letsencrypt-auto only) prevent the letsencrypt-auto script from"
               " upgrading itself to newer released versions")
  
      helpful.add_group(
          "testing", description="The following flags are meant for "
          "testing purposes only! Do NOT change them, unless you "
          "really know what you're doing!")
      helpful.add(
          "testing", "--debug", action="store_true",
          help="Show tracebacks in case of errors, and allow letsencrypt-auto "
               "execution on experimental platforms")
      helpful.add(
          "testing", "--no-verify-ssl", action="store_true",
          help=config_help("no_verify_ssl"),
          default=flag_default("no_verify_ssl"))
      helpful.add(
          "testing", "--tls-sni-01-port", type=int,
          default=flag_default("tls_sni_01_port"),
          help=config_help("tls_sni_01_port"))
      helpful.add(
          "testing", "--http-01-port", type=int, dest="http01_port",
          default=flag_default("http01_port"), help=config_help("http01_port"))
      helpful.add(
          "testing", "--break-my-certs", action="store_true",
          help="Be willing to replace or renew valid certs with invalid "
               "(testing/staging) certs")
      helpful.add_group(
          "security", description="Security parameters & server settings")
      helpful.add(
          "security", "--rsa-key-size", type=int, metavar="N",
          default=flag_default("rsa_key_size"), help=config_help("rsa_key_size"))
      helpful.add(
          "security", "--redirect", action="store_true",
          help="Automatically redirect all HTTP traffic to HTTPS for the newly "
               "authenticated vhost.", dest="redirect", default=None)
      helpful.add(
          "security", "--no-redirect", action="store_false",
          help="Do not automatically redirect all HTTP traffic to HTTPS for the newly "
               "authenticated vhost.", dest="redirect", default=None)
      helpful.add(
          "security", "--hsts", action="store_true",
          help="Add the Strict-Transport-Security header to every HTTP response."
               " Forcing browser to use always use SSL for the domain."
               " Defends against SSL Stripping.", dest="hsts", default=False)
      helpful.add(
          "security", "--no-hsts", action="store_false",
          help="Do not automatically add the Strict-Transport-Security header"
               " to every HTTP response.", dest="hsts", default=False)
      helpful.add(
          "security", "--uir", action="store_true",
          help="Add the \"Content-Security-Policy: upgrade-insecure-requests\""
               " header to every HTTP response. Forcing the browser to use"
               " https:// for every http:// resource.", dest="uir", default=None)
      helpful.add(
          "security", "--no-uir", action="store_false",
          help=" Do not automatically set the \"Content-Security-Policy:"
          " upgrade-insecure-requests\" header to every HTTP response.",
          dest="uir", default=None)
      helpful.add(
          "security", "--strict-permissions", action="store_true",
          help="Require that all configuration files are owned by the current "
               "user; only needed if your config is somewhere unsafe like /tmp/")
  
      helpful.add_deprecated_argument("--agree-dev-preview", 0)
  
      _create_subparsers(helpful)
      _paths_parser(helpful)
      # _plugins_parsing should be the last thing to act upon the main
      # parser (--help should display plugin-specific options last)
      _plugins_parsing(helpful, plugins)
  
      return helpful.parse_args()
  
  
  def _create_subparsers(helpful):
      helpful.add_group("certonly", description="Options for modifying how a cert is obtained")
      helpful.add_group("install", description="Options for modifying how a cert is deployed")
      helpful.add_group("revoke", description="Options for revocation of certs")
      helpful.add_group("rollback", description="Options for reverting config changes")
      helpful.add_group("plugins", description="Plugin options")
      helpful.add(
          None, "--user-agent", default=None,
          help="Set a custom user agent string for the client. User agent strings allow "
               "the CA to collect high level statistics about success rates by OS and "
               "plugin. If you wish to hide your server OS version from the Let's "
               'Encrypt server, set this to "".')
      helpful.add("certonly",
                  "--csr", type=read_file,
                  help="Path to a Certificate Signing Request (CSR) in DER"
                  " format; note that the .csr file *must* contain a Subject"
                  " Alternative Name field for each domain you want certified."
                  " Currently --csr only works with the 'certonly' subcommand'")
      helpful.add("rollback",
                  "--checkpoints", type=int, metavar="N",
                  default=flag_default("rollback_checkpoints"),
                  help="Revert configuration N number of checkpoints.")
      helpful.add("plugins",
                  "--init", action="store_true", help="Initialize plugins.")
      helpful.add("plugins",
                  "--prepare", action="store_true", help="Initialize and prepare plugins.")
      helpful.add("plugins",
                  "--authenticators", action="append_const", dest="ifaces",
                  const=interfaces.IAuthenticator, help="Limit to authenticator plugins only.")
      helpful.add("plugins",
                  "--installers", action="append_const", dest="ifaces",
                  const=interfaces.IInstaller, help="Limit to installer plugins only.")
  
  
  def _paths_parser(helpful):
      add = helpful.add
      verb = helpful.verb
      if verb == "help":
          verb = helpful.help_arg
      helpful.add_group(
          "paths", description="Arguments changing execution paths & servers")
  
      cph = "Path to where cert is saved (with auth --csr), installed from or revoked."
      section = "paths"
      if verb in ("install", "revoke", "certonly"):
          section = verb
      if verb == "certonly":
          add(section, "--cert-path", type=os.path.abspath,
              default=flag_default("auth_cert_path"), help=cph)
      elif verb == "revoke":
          add(section, "--cert-path", type=read_file, required=True, help=cph)
      else:
          add(section, "--cert-path", type=os.path.abspath,
              help=cph, required=(verb == "install"))
  
      section = "paths"
      if verb in ("install", "revoke"):
          section = verb
      # revoke --key-path reads a file, install --key-path takes a string
      add(section, "--key-path", required=(verb == "install"),
          type=((verb == "revoke" and read_file) or os.path.abspath),
          help="Path to private key for cert installation "
               "or revocation (if account key is missing)")
  
      default_cp = None
      if verb == "certonly":
          default_cp = flag_default("auth_chain_path")
      add("paths", "--fullchain-path", default=default_cp, type=os.path.abspath,
          help="Accompanying path to a full certificate chain (cert plus chain).")
      add("paths", "--chain-path", default=default_cp, type=os.path.abspath,
          help="Accompanying path to a certificate chain.")
      add("paths", "--config-dir", default=flag_default("config_dir"),
          help=config_help("config_dir"))
      add("paths", "--work-dir", default=flag_default("work_dir"),
          help=config_help("work_dir"))
      add("paths", "--logs-dir", default=flag_default("logs_dir"),
          help="Logs directory.")
      add("paths", "--server", default=flag_default("server"),
          help=config_help("server"))
      # overwrites server, handled in HelpfulArgumentParser.parse_args()
      add("testing", "--test-cert", "--staging", action='store_true', dest='staging',
          help='Use the staging server to obtain test (invalid) certs; equivalent'
               ' to --server ' + constants.STAGING_URI)
  
  
  def _plugins_parsing(helpful, plugins):
      helpful.add_group(
          "plugins", description="Let's Encrypt client supports an "
          "extensible plugins architecture. See '%(prog)s plugins' for a "
          "list of all installed plugins and their names. You can force "
          "a particular plugin by setting options provided below. Running "
          "--help <plugin_name> will list flags specific to that plugin.")
      helpful.add(
          "plugins", "-a", "--authenticator", help="Authenticator plugin name.")
      helpful.add(
          "plugins", "-i", "--installer", help="Installer plugin name (also used to find domains).")
      helpful.add(
          "plugins", "--configurator", help="Name of the plugin that is "
          "both an authenticator and an installer. Should not be used "
          "together with --authenticator or --installer.")
      helpful.add("plugins", "--apache", action="store_true",
                  help="Obtain and install certs using Apache")
      helpful.add("plugins", "--nginx", action="store_true",
                  help="Obtain and install certs using Nginx")
      helpful.add("plugins", "--standalone", action="store_true",
                  help='Obtain certs using a "standalone" webserver.')
      helpful.add("plugins", "--manual", action="store_true",
                  help='Provide laborious manual instructions for obtaining a cert')
      helpful.add("plugins", "--webroot", action="store_true",
                  help='Obtain certs by placing files in a webroot directory.')
  
      # things should not be reorder past/pre this comment:
      # plugins_group should be displayed in --help before plugin
      # specific groups (so that plugins_group.description makes sense)
  
      helpful.add_plugin_args(plugins)
  
      # These would normally be a flag within the webroot plugin, but because
      # they are parsed in conjunction with --domains, they live here for
      # legibility. helpful.add_plugin_ags must be called first to add the
      # "webroot" topic
      helpful.add("webroot", "-w", "--webroot-path", action=WebrootPathProcessor,
                  help="public_html / webroot path. This can be specified multiple times to "
                       "handle different domains; each domain will have the webroot path that"
                       " preceded it.  For instance: `-w /var/www/example -d example.com -d "
                       "www.example.com -w /var/www/thing -d thing.net -d m.thing.net`")
      # --webroot-map still has some awkward properties, so it is undocumented
      helpful.add("webroot", "--webroot-map", default={}, action=WebrootMapProcessor,
          help="JSON dictionary mapping domains to webroot paths; this implies -d "
               "for each entry. You may need to escape this from your shell. "
               """Eg: --webroot-map '{"eg1.is,m.eg1.is":"/www/eg1/", "eg2.is":"/www/eg2"}' """
               "This option is merged with, but takes precedence over, -w / -d entries")
  
  class WebrootPathProcessor(argparse.Action): # pylint: disable=missing-docstring
      def __init__(self, *args, **kwargs):
          self.domain_before_webroot = False
          argparse.Action.__init__(self, *args, **kwargs)
  
      def __call__(self, parser, config, webroot, option_string=None):
          """
          Keep a record of --webroot-path / -w flags during processing, so that
          we know which apply to which -d flags
          """
          if config.webroot_path is None:      # first -w flag encountered
              config.webroot_path = []
              # if any --domain flags preceded the first --webroot-path flag,
              # apply that webroot path to those; subsequent entries in
              # config.webroot_map are filled in by cli.DomainFlagProcessor
              if config.domains:
                  self.domain_before_webroot = True
                  for d in config.domains:
                      config.webroot_map.setdefault(d, webroot)
          elif self.domain_before_webroot:
              # FIXME if you set domains in a config file, you should get a different error
              # here, pointing you to --webroot-map
              raise errors.Error("If you specify multiple webroot paths, one of "
                                 "them must precede all domain flags")
          config.webroot_path.append(webroot)
  
  
  _undot = lambda domain: domain[:-1] if domain.endswith('.') else domain
  
  def _process_domain(config, domain_arg, webroot_path=None):
      """
      Process a new -d flag, helping the webroot plugin construct a map of
      {domain : webrootpath} if -w / --webroot-path is in use
      """
      webroot_path = webroot_path if webroot_path else config.webroot_path
  
      for domain in (d.strip() for d in domain_arg.split(",")):
          if domain not in config.domains:
              domain = _undot(domain)
              config.domains.append(domain)
              # Each domain has a webroot_path of the most recent -w flag
              # unless it was explicitly included in webroot_map
              if webroot_path:
                  config.webroot_map.setdefault(domain, webroot_path[-1])
  
  
  class WebrootMapProcessor(argparse.Action): # pylint: disable=missing-docstring
      def __call__(self, parser, config, webroot_map_arg, option_string=None):
          webroot_map = json.loads(webroot_map_arg)
          for domains, webroot_path in webroot_map.iteritems():
              _process_domain(config, domains, [webroot_path])
  
  
  class DomainFlagProcessor(argparse.Action): # pylint: disable=missing-docstring
      def __call__(self, parser, config, domain_arg, option_string=None):
          """Just wrap _process_domain in argparseese."""
          _process_domain(config, domain_arg)
  
  
  def setup_log_file_handler(args, logfile, fmt):
      """Setup file debug logging."""
      log_file_path = os.path.join(args.logs_dir, logfile)
      handler = logging.handlers.RotatingFileHandler(
          log_file_path, maxBytes=2 ** 20, backupCount=10)
      # rotate on each invocation, rollover only possible when maxBytes
      # is nonzero and backupCount is nonzero, so we set maxBytes as big
      # as possible not to overrun in single CLI invocation (1MB).
      handler.doRollover()  # TODO: creates empty letsencrypt.log.1 file
      handler.setLevel(logging.DEBUG)
      handler_formatter = logging.Formatter(fmt=fmt)
      handler_formatter.converter = time.gmtime  # don't use localtime
      handler.setFormatter(handler_formatter)
      return handler, log_file_path
  
  
  def _cli_log_handler(args, level, fmt):
      if args.text_mode:
          handler = colored_logging.StreamHandler()
          handler.setFormatter(logging.Formatter(fmt))
      else:
          handler = log.DialogHandler()
          # dialog box is small, display as less as possible
          handler.setFormatter(logging.Formatter("%(message)s"))
      handler.setLevel(level)
      return handler
  
  
  def setup_logging(args, cli_handler_factory, logfile):
      """Setup logging."""
      fmt = "%(asctime)s:%(levelname)s:%(name)s:%(message)s"
      level = -args.verbose_count * 10
      file_handler, log_file_path = setup_log_file_handler(
          args, logfile=logfile, fmt=fmt)
      cli_handler = cli_handler_factory(args, level, fmt)
  
      # TODO: use fileConfig?
  
      root_logger = logging.getLogger()
      root_logger.setLevel(logging.DEBUG)  # send all records to handlers
      root_logger.addHandler(cli_handler)
      root_logger.addHandler(file_handler)
  
      logger.debug("Root logging level set at %d", level)
      logger.info("Saving debug log to %s", log_file_path)
  
  
  def _handle_exception(exc_type, exc_value, trace, args):
      """Logs exceptions and reports them to the user.
  
      Args is used to determine how to display exceptions to the user. In
      general, if args.debug is True, then the full exception and traceback is
      shown to the user, otherwise it is suppressed. If args itself is None,
      then the traceback and exception is attempted to be written to a logfile.
      If this is successful, the traceback is suppressed, otherwise it is shown
      to the user. sys.exit is always called with a nonzero status.
  
      """
      logger.debug(
          "Exiting abnormally:%s%s",
          os.linesep,
          "".join(traceback.format_exception(exc_type, exc_value, trace)))
  
      if issubclass(exc_type, Exception) and (args is None or not args.debug):
          if args is None:
              logfile = "letsencrypt.log"
              try:
                  with open(logfile, "w") as logfd:
                      traceback.print_exception(
                          exc_type, exc_value, trace, file=logfd)
              except:  # pylint: disable=bare-except
                  sys.exit("".join(
                      traceback.format_exception(exc_type, exc_value, trace)))
  
          if issubclass(exc_type, errors.Error):
              sys.exit(exc_value)
          else:
              # Here we're passing a client or ACME error out to the client at the shell
              # Tell the user a bit about what happened, without overwhelming
              # them with a full traceback
              err = traceback.format_exception_only(exc_type, exc_value)[0]
              # Typical error from the ACME module:
              # acme.messages.Error: urn:acme:error:malformed :: The request message was
              # malformed :: Error creating new registration :: Validation of contact
              # mailto:none@longrandomstring.biz failed: Server failure at resolver
              if ("urn:acme" in err and ":: " in err
                  and args.verbose_count <= flag_default("verbose_count")):
                  # prune ACME error code, we have a human description
                  _code, _sep, err = err.partition(":: ")
              msg = "An unexpected error occurred:\n" + err + "Please see the "
              if args is None:
                  msg += "logfile '{0}' for more details.".format(logfile)
              else:
                  msg += "logfiles in {0} for more details.".format(args.logs_dir)
              sys.exit(msg)
      else:
          sys.exit("".join(
              traceback.format_exception(exc_type, exc_value, trace)))
  
  
  def main(cli_args=sys.argv[1:]):
      """Command line argument parsing and main script execution."""
      sys.excepthook = functools.partial(_handle_exception, args=None)
  
      # note: arg parser internally handles --help (and exits afterwards)
      plugins = plugins_disco.PluginsRegistry.find_all()
      args = prepare_and_parse_args(plugins, cli_args)
      config = configuration.NamespaceConfig(args)
      zope.component.provideUtility(config)
  
      # Setup logging ASAP, otherwise "No handlers could be found for
      # logger ..." TODO: this should be done before plugins discovery
      for directory in config.config_dir, config.work_dir:
          le_util.make_or_verify_dir(
              directory, constants.CONFIG_DIRS_MODE, os.geteuid(),
              "--strict-permissions" in cli_args)
      # TODO: logs might contain sensitive data such as contents of the
      # private key! #525
      le_util.make_or_verify_dir(
          args.logs_dir, 0o700, os.geteuid(), "--strict-permissions" in cli_args)
      setup_logging(args, _cli_log_handler, logfile='letsencrypt.log')
  
      logger.debug("letsencrypt version: %s", letsencrypt.__version__)
      # do not log `args`, as it contains sensitive data (e.g. revoke --key)!
      logger.debug("Arguments: %r", cli_args)
      logger.debug("Discovered plugins: %r", plugins)
  
      sys.excepthook = functools.partial(_handle_exception, args=args)
  
      # Displayer
      if args.noninteractive_mode:
          displayer = display_util.NoninteractiveDisplay(sys.stdout)
      elif args.text_mode:
          displayer = display_util.FileDisplay(sys.stdout)
      else:
          displayer = display_util.NcursesDisplay()
      zope.component.provideUtility(displayer)
  
      # Reporter
      report = reporter.Reporter()
      zope.component.provideUtility(report)
      atexit.register(report.atexit_print_messages)
  
      if not os.geteuid() == 0:
          logger.warning(
              "Root (sudo) is required to run most of letsencrypt functionality.")
          # check must be done after arg parsing as --help should work
          # w/o root; on the other hand, e.g. "letsencrypt run
          # --authenticator dns" or "letsencrypt plugins" does not
          # require root as well
          #return (
          #    "{0}Root is required to run letsencrypt.  Please use sudo.{0}"
          #    .format(os.linesep))
  
      return args.func(args, config, plugins)
  
  if __name__ == "__main__":
      err_string = main()
      if err_string:
          logger.warn("Exiting with message %s", err_string)
      sys.exit(err_string)  # pragma: no cover
  