certbot/letsencrypt/cli.py

"""Let's Encrypt CLI."""
# TODO: Sanity check all input.  Be sure to avoid shell code etc...
import argparse
import atexit
import logging
import os
import sys

import configargparse
import zope.component
import zope.interface.exceptions
import zope.interface.verify

import letsencrypt

from letsencrypt import account
from letsencrypt import configuration
from letsencrypt import constants
from letsencrypt import client
from letsencrypt import errors
from letsencrypt import interfaces
from letsencrypt import le_util
from letsencrypt import log
from letsencrypt import reporter

from letsencrypt.display import util as display_util
from letsencrypt.display import ops as display_ops
from letsencrypt.plugins import disco as plugins_disco

# 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 = """
  letsencrypt [SUBCOMMAND] [options] [domains]

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.  """

# This is the short help for letsencrypt --help, where we disable argparse
# altogether
USAGE = SHORT_USAGE + """Major SUBCOMMANDS are:

  (default) everything Obtain & install a cert in your current webserver
  auth                 Authenticate & obtain cert, but do not install it
  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

Choice of server for authentication/installation:

  --apache          Use the Apache plugin for authentication & installation
  --nginx           Use the Nginx plugin for authentication & installation
  --standalone      Run a standalone HTTPS server (for authentication only)
  OR:
  --authenticator standalone --installer nginx

More detailed help:

  -h, --help [topic]    print this message, or detailed help on a topic; 
                        the available topics are:

   all, apache, automation, nginx, paths, security, testing, or any of the
   sucommands
"""



def _account_init(args, config):
    le_util.make_or_verify_dir(
        config.config_dir, constants.CONFIG_DIRS_MODE, os.geteuid())

    # Prepare for init of Client
    if args.email is None:
        return client.determine_account(config)
    else:
        try:
            # The way to get the default would be args.email = ""
            # First try existing account
            return account.Account.from_existing_account(config, args.email)
        except errors.LetsEncryptClientError:
            try:
                # Try to make an account based on the email address
                return account.Account.from_email(config, args.email)
            except errors.LetsEncryptClientError:
                return None


def _find_domains(args, installer):
    if args.domains is None:
        domains = display_ops.choose_names(installer)
    else:
        domains = args.domains

    if not domains:
        sys.exit("Please specify --domains, or --installer that will "
                 "help in domain names autodiscovery")

    return domains


def _init_acme(config, acc, authenticator, installer):
    acme = client.Client(config, acc, authenticator, installer)

    # Validate the key and csr
    client.validate_key_csr(acc.key)

    if authenticator is not None:
        if acc.regr is None:
            try:
                acme.register()
            except errors.LetsEncryptClientError:
                sys.exit("Unable to register an account with ACME server")

    return acme


def run(args, config, plugins):
    """Obtain a certificate and install."""
    acc = _account_init(args, config)
    if acc is None:
        return None

    if args.configurator is not None and (args.installer is not None or
                                          args.authenticator is not None):
        return ("Either --configurator or --authenticator/--installer"
                "pair, but not both, is allowed")

    if args.authenticator is not None or args.installer is not None:
        installer = display_ops.pick_installer(
            config, args.installer, plugins)
        authenticator = display_ops.pick_authenticator(
            config, args.authenticator, plugins)
    else:
        # TODO: this assume that user doesn't want to pick authenticator
        #       and installer separately...
        authenticator = installer = display_ops.pick_configurator(
            config, args.configurator, plugins)

    if installer is None or authenticator is None:
        return "Configurator could not be determined"

    domains = _find_domains(args, installer)
    # TODO: Handle errors from _init_acme?
    acme = _init_acme(config, acc, authenticator, installer)
    lineage = acme.obtain_and_enroll_certificate(
        domains, authenticator, installer, plugins)
    if not lineage:
        return "Certificate could not be obtained"
    acme.deploy_certificate(domains, lineage.privkey, lineage.cert, lineage.chain)
    acme.enhance_config(domains, args.redirect)


def auth(args, config, plugins):
    """Authenticate & obtain cert, but do not install it."""
    # XXX: Update for renewer / RenewableCert

    if args.domains is not None 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"

    acc = _account_init(args, config)
    if acc is None:
        return None

    authenticator = display_ops.pick_authenticator(
        config, args.authenticator, plugins)
    if authenticator is None:
        return "Authenticator could not be determined"

    if args.installer is not None:
        installer = display_ops.pick_installer(config, args.installer, plugins)
    else:
        installer = None

    # TODO: Handle errors from _init_acme?
    acme = _init_acme(config, acc, authenticator, installer)

    if args.csr is not None:
        certr, chain = acme.obtain_certificate_from_csr(le_util.CSR(
            file=args.csr[0], data=args.csr[1], form="der"))
        acme.save_certificate(certr, chain, args.cert_path, args.chain_path)
    else:
        domains = _find_domains(args, installer)
        if not acme.obtain_and_enroll_certificate(
                domains, authenticator, installer, plugins):
            return "Certificate could not be obtained"

def install(args, config, plugins):
    """Install a previously obtained cert in a server."""
    # XXX: Update for renewer/RenewableCert
    acc = _account_init(args, config)
    if acc is None:
        return None

    installer = display_ops.pick_installer(config, args.installer, plugins)
    if installer is None:
        return "Installer could not be determined"
    domains = _find_domains(args, installer)
    acme = _init_acme(config, acc, authenticator=None, installer=installer)
    assert args.cert_path is not None
    acme.deploy_certificate(domains, acc.key.file, args.cert_path, args.chain_path)
    acme.enhance_config(domains, args.redirect)


def revoke(args, unused_config, unused_plugins):
    """Revoke a previously obtained certificate."""
    if args.rev_cert is None and args.rev_key is None:
        return "At least one of --certificate or --key is required"

    # This depends on the renewal config and cannot be completed yet.
    zope.component.getUtility(interfaces.IDisplay).notification(
        "Revocation is not available with the new Boulder server yet.")
    #client.revoke(args.installer, config, plugins, args.no_confirm,
    #              args.rev_cert, args.rev_key)


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 IDiplay rathern than print
    """List server software plugins."""
    logging.debug("Expected interfaces: %s", args.ifaces)

    ifaces = [] if args.ifaces is None else args.ifaces
    filtered = plugins.ifaces(ifaces)
    logging.debug("Filtered plugins: %r", filtered)

    if not args.init and not args.prepare:
        print str(filtered)
        return

    filtered.init(config)
    verified = filtered.verify(ifaces)
    logging.debug("Verified plugins: %r", verified)

    if not args.prepare:
        print str(verified)
        return

    verified.prepare()
    available = verified.available()
    logging.debug("Prepared plugins: %s", available)
    print str(available)


def read_file(filename, mode="rb"):
    """Returns the given file's contents.

    :param str filename: Filename
    :param str mode: open mode (see `open`)

    :returns: A tuple of filename and its contents
    :rtype: tuple

    :raises argparse.ArgumentTypeError: File does not exist or is not readable.

    """
    try:
        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)


HELP_TOPICS = ["all", "security", "paths", "automation", "testing"]


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.

    """
    def __init__(self, args, plugins):
        self.args = args
        plugin_names = [name for name, _p in plugins.iteritems()]
        self.help_topics = HELP_TOPICS + plugin_names
        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)

        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"
        help_arg = max(help1, help2)
        if help_arg == True:
            # just --help with no topic; avoid argparse altogether
            print USAGE
            sys.exit(0)
        self.visible_topics = self.determine_help_topics(help_arg)
        #print self.visible_topics
        self.groups = {}  # elements are added by .add_group()
        self.add_plugin_args(plugins)

    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 topic and self.visible_topics[topic]:
            group = self.groups[topic]
            group.add_argument(*args, **kwargs)
        else:
            kwargs["help"] = argparse.SUPPRESS
            self.parser.add_argument(*args, **kwargs)

    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.

        """
        # TODO: plugin_parser should be called for every detected plugin
        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 == "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 create_parser(plugins, args):
    """Create parser."""
    helpful = HelpfulArgumentParser(args, plugins)

    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.")
    # --help is automatically provided by argparse

    helpful.add_group(
        "automation",
        description="Arguments for automating execution & other tweaks")
    helpful.add(
        "automation", "--version", action="version",
        version="%(prog)s {0}".format(letsencrypt.__version__),
        help="show program's version number and exit")
    helpful.add(
        "automation", "--no-confirm", dest="no_confirm", action="store_true",
        help="Turn off confirmation screens, currently used for --revoke")
    helpful.add(
        "automation", "--agree-eula", "-e", dest="tos", action="store_true",
        help="Agree to the Let's Encrypt Subscriber Agreement")
    helpful.add(
        None, "-t", "--text", dest="text_mode", action="store_true",
        help="Use the text output instead of the curses UI.")


    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", "--no-verify-ssl", action="store_true",
        help=config_help("no_verify_ssl"),
        default=flag_default("no_verify_ssl"))
    # TODO: apache and nginx plugins do NOT respect it
    helpful.add(
        "testing", "--dvsni-port", type=int, default=flag_default("dvsni_port"),
        help=config_help("dvsni_port"))

    helpful.add("testing", "--no-simple-http-tls", action="store_true",
                help=config_help("no_simple_http_tls"))

    subparsers = helpful.parser.add_subparsers(metavar="SUBCOMMAND")

    def add_subparser(name, func):  # pylint: disable=missing-docstring
        subparser = subparsers.add_parser(
            name, help=func.__doc__.splitlines()[0], description=func.__doc__)
        subparser.set_defaults(func=func)
        return subparser

    add_subparser("run", run)
    parser_auth = add_subparser("auth", auth)
    add_subparser("install", install)
    parser_revoke = add_subparser("revoke", revoke)
    parser_rollback = add_subparser("rollback", rollback)
    add_subparser("config_changes", config_changes)

    parser_auth.add_argument(
        "--csr", type=read_file, help="Path to a Certificate Signing "
        "Request (CSR) in DER format.")
    parser_auth.add_argument(
        "--cert-path", default=flag_default("cert_path"),
        help="When using --csr this is where certificate is saved.")
    parser_auth.add_argument(
        "--chain-path", default=flag_default("chain_path"),
        help="When using --csr this is where certificate chain is saved.")

    parser_plugins = add_subparser("plugins", plugins_cmd)
    parser_plugins.add_argument("--init", action="store_true")
    parser_plugins.add_argument("--prepare", action="store_true")
    parser_plugins.add_argument(
        "--authenticators", action="append_const", dest="ifaces",
        const=interfaces.IAuthenticator)
    parser_plugins.add_argument(
        "--installers", action="append_const", dest="ifaces",
        const=interfaces.IInstaller)

    helpful.add(None, "--configurator")
    helpful.add(None, "-a", "--authenticator")
    helpful.add(None, "-i", "--installer")

    # 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", metavar="DOMAIN", action="append")
    helpful.add(None, "-k", "--accountkey", type=read_file,
                help="Path to the account key file")
    helpful.add(None, "-m", "--email", help=config_help("email"))

    helpful.add_group(
        "security", description="Security parameters & server settings")
    helpful.add(
        "security", "-B", "--rsa-key-size", type=int, metavar="N",
        default=flag_default("rsa_key_size"), help=config_help("rsa_key_size"))
    # TODO: resolve - assumes binary logic while client.py assumes ternary.
    helpful.add(
        "security", "-r", "--redirect", action="store_true",
        help="Automatically redirect all HTTP traffic to HTTPS for the newly "
             "authenticated vhost.")

    parser_revoke.add_argument(
        "--certificate", dest="rev_cert", type=read_file, metavar="CERT_PATH",
        help="Revoke a specific certificate.")
    parser_revoke.add_argument(
        "--key", dest="rev_key", type=read_file, metavar="KEY_PATH",
        help="Revoke all certs generated by the provided authorized key.")

    parser_rollback.add_argument(
        "--checkpoints", type=int, metavar="N",
        default=flag_default("rollback_checkpoints"),
        help="Revert configuration N number of checkpoints.")

    _paths_parser(helpful)

    return helpful.parser


def _paths_parser(helpful):
    add = helpful.add
    helpful.add_group("paths", description="Arguments changing execution paths & servers")
    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", "--backup-dir", default=flag_default("backup_dir"),
        help=config_help("backup_dir"))
    add("paths", "--key-dir", default=flag_default("key_dir"),
        help=config_help("key_dir"))
    add("paths", "--cert-dir", default=flag_default("certs_dir"),
        help=config_help("cert_dir"))
    add("paths", "--le-vhost-ext", default="-le-ssl.conf",
        help=config_help("le_vhost_ext"))
    add("paths", "--renewer-config-file", default=flag_default("renewer_config_file"),
        help=config_help("renewer_config_file"))
    add("paths", "-s", "--server", default=flag_default("server"),
        help=config_help("server"))


def main(args=sys.argv[1:]):
    """Command line argument parsing and main script execution."""
    # note: arg parser internally handles --help (and exits afterwards)
    plugins = plugins_disco.PluginsRegistry.find_all()
    args = create_parser(plugins, args).parse_args(args)
    config = configuration.NamespaceConfig(args)

    # Displayer
    if 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)

    # Logging
    level = -args.verbose_count * 10
    logger = logging.getLogger()
    logger.setLevel(level)
    logging.debug("Logging level set at %d", level)
    if not args.text_mode:
        logger.addHandler(log.DialogHandler())

    logging.debug("Discovered plugins: %r", plugins)

    if not os.geteuid() == 0:
        logging.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__":
    sys.exit(main())  # pragma: no cover