# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
# (c) 2016, Toshio Kuratomi <tkuratomi@ansible.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

# Make coding more python3-ish
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import operator
import optparse
import os
import sys
import time
import yaml
import re
import getpass
import signal
import subprocess
from abc import ABCMeta, abstractmethod

from ansible.release import __version__
from ansible import constants as C
from ansible.compat.six import with_metaclass
from ansible.errors import AnsibleError, AnsibleOptionsError
from ansible.module_utils._text import to_bytes, to_text

try:
    from __main__ import display
except ImportError:
    from ansible.utils.display import Display
    display = Display()


class SortedOptParser(optparse.OptionParser):
    '''Optparser which sorts the options by opt before outputting --help'''

    #FIXME: epilog parsing: OptionParser.format_epilog = lambda self, formatter: self.epilog

    def format_help(self, formatter=None, epilog=None):
        self.option_list.sort(key=operator.methodcaller('get_opt_string'))
        return optparse.OptionParser.format_help(self, formatter=None)


# Note: Inherit from SortedOptParser so that we get our format_help method
class InvalidOptsParser(SortedOptParser):
    '''Ignore invalid options.

    Meant for the special case where we need to take care of help and version
    but may not know the full range of options yet.  (See it in use in set_action)
    '''
    def __init__(self, parser):
        # Since this is special purposed to just handle help and version, we
        # take a pre-existing option parser here and set our options from
        # that.  This allows us to give accurate help based on the given
        # option parser.
        SortedOptParser.__init__(self, usage=parser.usage,
                                 option_list=parser.option_list,
                                 option_class=parser.option_class,
                                 conflict_handler=parser.conflict_handler,
                                 description=parser.description,
                                 formatter=parser.formatter,
                                 add_help_option=False,
                                 prog=parser.prog,
                                 epilog=parser.epilog)
        self.version=parser.version

    def _process_long_opt(self, rargs, values):
        try:
            optparse.OptionParser._process_long_opt(self, rargs, values)
        except optparse.BadOptionError:
            pass

    def _process_short_opts(self, rargs, values):
        try:
            optparse.OptionParser._process_short_opts(self, rargs, values)
        except optparse.BadOptionError:
            pass


class CLI(with_metaclass(ABCMeta, object)):
    ''' code behind bin/ansible* programs '''

    VALID_ACTIONS = ['No Actions']

    _ITALIC = re.compile(r"I\(([^)]+)\)")
    _BOLD   = re.compile(r"B\(([^)]+)\)")
    _MODULE = re.compile(r"M\(([^)]+)\)")
    _URL    = re.compile(r"U\(([^)]+)\)")
    _CONST  = re.compile(r"C\(([^)]+)\)")

    PAGER   = 'less'
    LESS_OPTS = 'FRSX'  # -F (quit-if-one-screen) -R (allow raw ansi control chars)
                        # -S (chop long lines) -X (disable termcap init and de-init)

    def __init__(self, args, callback=None):
        """
        Base init method for all command line programs
        """

        self.args = args
        self.options = None
        self.parser = None
        self.action = None
        self.callback = callback

    def set_action(self):
        """
        Get the action the user wants to execute from the sys argv list.
        """
        for i in range(0, len(self.args)):
            arg = self.args[i]
            if arg in self.VALID_ACTIONS:
                self.action = arg
                del self.args[i]
                break

        if not self.action:
            # if we're asked for help or version, we don't need an action.
            # have to use a special purpose Option Parser to figure that out as
            # the standard OptionParser throws an error for unknown options and
            # without knowing action, we only know of a subset of the options
            # that could be legal for this command
            tmp_parser = InvalidOptsParser(self.parser)
            tmp_options, tmp_args = tmp_parser.parse_args(self.args)
            if not(hasattr(tmp_options, 'help') and tmp_options.help) or (hasattr(tmp_options, 'version') and tmp_options.version):
                raise AnsibleOptionsError("Missing required action")

    def execute(self):
        """
        Actually runs a child defined method using the execute_<action> pattern
        """
        fn = getattr(self, "execute_%s" % self.action)
        fn()

    @abstractmethod
    def run(self):
        """Run the ansible command

        Subclasses must implement this method.  It does the actual work of
        running an Ansible command.
        """

        if self.options.verbosity > 0:
            if C.CONFIG_FILE:
                display.display(u"Using %s as config file" % to_text(C.CONFIG_FILE))
            else:
                display.display(u"No config file found; using defaults")

    @staticmethod
    def ask_vault_passwords():
        ''' prompt for vault password and/or password change '''

        vault_pass = None
        try:
            vault_pass = getpass.getpass(prompt="Vault password: ")

        except EOFError:
            pass

        # enforce no newline chars at the end of passwords
        if vault_pass:
            vault_pass = to_bytes(vault_pass, errors='strict', nonstring='simplerepr').strip()

        return vault_pass

    @staticmethod
    def ask_new_vault_passwords():
        new_vault_pass = None
        try:
            new_vault_pass = getpass.getpass(prompt="New Vault password: ")
            new_vault_pass2 = getpass.getpass(prompt="Confirm New Vault password: ")
            if new_vault_pass != new_vault_pass2:
                raise AnsibleError("Passwords do not match")
        except EOFError:
            pass

        if new_vault_pass:
            new_vault_pass = to_bytes(new_vault_pass, errors='strict', nonstring='simplerepr').strip()

        return new_vault_pass

    def ask_passwords(self):
        ''' prompt for connection and become passwords if needed '''

        op = self.options
        sshpass = None
        becomepass = None
        become_prompt = ''

        try:
            if op.ask_pass:
                sshpass = getpass.getpass(prompt="SSH password: ")
                become_prompt = "%s password[defaults to SSH password]: " % op.become_method.upper()
                if sshpass:
                    sshpass = to_bytes(sshpass, errors='strict', nonstring='simplerepr')
            else:
                become_prompt = "%s password: " % op.become_method.upper()

            if op.become_ask_pass:
                becomepass = getpass.getpass(prompt=become_prompt)
                if op.ask_pass and becomepass == '':
                    becomepass = sshpass
                if becomepass:
                    becomepass = to_bytes(becomepass)
        except EOFError:
            pass

        return (sshpass, becomepass)

    def normalize_become_options(self):
        ''' this keeps backwards compatibility with sudo/su self.options '''
        self.options.become_ask_pass = self.options.become_ask_pass or self.options.ask_sudo_pass or self.options.ask_su_pass or C.DEFAULT_BECOME_ASK_PASS
        self.options.become_user     = self.options.become_user or self.options.sudo_user or self.options.su_user or C.DEFAULT_BECOME_USER

        if self.options.become:
            pass
        elif self.options.sudo:
            self.options.become = True
            self.options.become_method = 'sudo'
        elif self.options.su:
            self.options.become = True
            self.options.become_method = 'su'

    def validate_conflicts(self, vault_opts=False, runas_opts=False, fork_opts=False):
        ''' check for conflicting options '''

        op = self.options

        if vault_opts:
            # Check for vault related conflicts
            if (op.ask_vault_pass and op.vault_password_file):
                self.parser.error("--ask-vault-pass and --vault-password-file are mutually exclusive")

        if runas_opts:
            # Check for privilege escalation conflicts
            if (op.su or op.su_user) and (op.sudo or op.sudo_user) or \
                (op.su or op.su_user) and (op.become or op.become_user) or \
                (op.sudo or op.sudo_user) and (op.become or op.become_user):

                self.parser.error("Sudo arguments ('--sudo', '--sudo-user', and '--ask-sudo-pass') "
                                  "and su arguments ('-su', '--su-user', and '--ask-su-pass') "
                                  "and become arguments ('--become', '--become-user', and '--ask-become-pass')"
                                  " are exclusive of each other")

        if fork_opts:
            if op.forks < 1:
                self.parser.error("The number of processes (--forks) must be >= 1")

    @staticmethod
    def expand_tilde(option, opt, value, parser):
        setattr(parser.values, option.dest, os.path.expanduser(value))

    @staticmethod
    def expand_paths(option, opt, value, parser):
        """optparse action callback to convert a PATH style string arg to a list of path strings.

        For ex, cli arg of '-p /blip/foo:/foo/bar' would be split on the
        default os.pathsep and the option value would be set to
        the list ['/blip/foo', '/foo/bar']. Each path string in the list
        will also have '~/' values expand via os.path.expanduser()."""
        path_entries = value.split(os.pathsep)
        expanded_path_entries = [os.path.expanduser(path_entry) for path_entry in path_entries]
        setattr(parser.values, option.dest, expanded_path_entries)

    @staticmethod
    def base_parser(usage="", output_opts=False, runas_opts=False, meta_opts=False, runtask_opts=False, vault_opts=False, module_opts=False,
            async_opts=False, connect_opts=False, subset_opts=False, check_opts=False, inventory_opts=False, epilog=None, fork_opts=False, runas_prompt_opts=False):
        ''' create an options parser for most ansible scripts '''

        # TODO: implement epilog parsing
        #       OptionParser.format_epilog = lambda self, formatter: self.epilog

        # base opts
        parser = SortedOptParser(usage, version=CLI.version("%prog"))
        parser.add_option('-v','--verbose', dest='verbosity', default=0, action="count",
            help="verbose mode (-vvv for more, -vvvv to enable connection debugging)")

        if inventory_opts:
            parser.add_option('-i', '--inventory-file', dest='inventory',
                help="specify inventory host path (default=%s) or comma separated host list." % C.DEFAULT_HOST_LIST,
                default=C.DEFAULT_HOST_LIST, action="callback", callback=CLI.expand_tilde, type=str)
            parser.add_option('--list-hosts', dest='listhosts', action='store_true',
                help='outputs a list of matching hosts; does not execute anything else')
            parser.add_option('-l', '--limit', default=C.DEFAULT_SUBSET, dest='subset',
                help='further limit selected hosts to an additional pattern')

        if module_opts:
            parser.add_option('-M', '--module-path', dest='module_path', default=None,
                help="specify path(s) to module library (default=%s)" % C.DEFAULT_MODULE_PATH,
                action="callback", callback=CLI.expand_tilde, type=str)
        if runtask_opts:
            parser.add_option('-e', '--extra-vars', dest="extra_vars", action="append",
                help="set additional variables as key=value or YAML/JSON", default=[])

        if fork_opts:
            parser.add_option('-f','--forks', dest='forks', default=C.DEFAULT_FORKS, type='int',
                help="specify number of parallel processes to use (default=%s)" % C.DEFAULT_FORKS)

        if vault_opts:
            parser.add_option('--ask-vault-pass', default=C.DEFAULT_ASK_VAULT_PASS, dest='ask_vault_pass', action='store_true',
                help='ask for vault password')
            parser.add_option('--vault-password-file', default=C.DEFAULT_VAULT_PASSWORD_FILE, dest='vault_password_file',
                help="vault password file", action="callback", callback=CLI.expand_tilde, type=str)
            parser.add_option('--new-vault-password-file', dest='new_vault_password_file',
                help="new vault password file for rekey", action="callback", callback=CLI.expand_tilde, type=str)
            parser.add_option('--output', default=None, dest='output_file',
                help='output file name for encrypt or decrypt; use - for stdout',
                action="callback", callback=CLI.expand_tilde, type=str)

        if subset_opts:
            parser.add_option('-t', '--tags', dest='tags', default=[], action='append',
                help="only run plays and tasks tagged with these values")
            parser.add_option('--skip-tags', dest='skip_tags', default=[], action='append',
                help="only run plays and tasks whose tags do not match these values")

        if output_opts:
            parser.add_option('-o', '--one-line', dest='one_line', action='store_true',
                help='condense output')
            parser.add_option('-t', '--tree', dest='tree', default=None,
                help='log output to this directory')

        if connect_opts:
            connect_group = optparse.OptionGroup(parser, "Connection Options", "control as whom and how to connect to hosts")
            connect_group.add_option('-k', '--ask-pass', default=C.DEFAULT_ASK_PASS, dest='ask_pass', action='store_true',
                help='ask for connection password')
            connect_group.add_option('--private-key','--key-file', default=C.DEFAULT_PRIVATE_KEY_FILE, dest='private_key_file',
                help='use this file to authenticate the connection')
            connect_group.add_option('-u', '--user', default=C.DEFAULT_REMOTE_USER, dest='remote_user',
                help='connect as this user (default=%s)' % C.DEFAULT_REMOTE_USER)
            connect_group.add_option('-c', '--connection', dest='connection', default=C.DEFAULT_TRANSPORT,
                help="connection type to use (default=%s)" % C.DEFAULT_TRANSPORT)
            connect_group.add_option('-T', '--timeout', default=C.DEFAULT_TIMEOUT, type='int', dest='timeout',
                help="override the connection timeout in seconds (default=%s)" % C.DEFAULT_TIMEOUT)
            connect_group.add_option('--ssh-common-args', default='', dest='ssh_common_args',
                help="specify common arguments to pass to sftp/scp/ssh (e.g. ProxyCommand)")
            connect_group.add_option('--sftp-extra-args', default='', dest='sftp_extra_args',
                help="specify extra arguments to pass to sftp only (e.g. -f, -l)")
            connect_group.add_option('--scp-extra-args', default='', dest='scp_extra_args',
                help="specify extra arguments to pass to scp only (e.g. -l)")
            connect_group.add_option('--ssh-extra-args', default='', dest='ssh_extra_args',
                help="specify extra arguments to pass to ssh only (e.g. -R)")

            parser.add_option_group(connect_group)

        runas_group = None
        rg = optparse.OptionGroup(parser, "Privilege Escalation Options", "control how and which user you become as on target hosts")
        if runas_opts:
            runas_group = rg
            # priv user defaults to root later on to enable detecting when this option was given here
            runas_group.add_option("-s", "--sudo", default=C.DEFAULT_SUDO, action="store_true", dest='sudo',
                help="run operations with sudo (nopasswd) (deprecated, use become)")
            runas_group.add_option('-U', '--sudo-user', dest='sudo_user', default=None,
                              help='desired sudo user (default=root) (deprecated, use become)')
            runas_group.add_option('-S', '--su', default=C.DEFAULT_SU, action='store_true',
                help='run operations with su (deprecated, use become)')
            runas_group.add_option('-R', '--su-user', default=None,
                help='run operations with su as this user (default=%s) (deprecated, use become)' % C.DEFAULT_SU_USER)

            # consolidated privilege escalation (become)
            runas_group.add_option("-b", "--become", default=C.DEFAULT_BECOME, action="store_true", dest='become',
                help="run operations with become (does not imply password prompting)")
            runas_group.add_option('--become-method', dest='become_method', default=C.DEFAULT_BECOME_METHOD, type='choice', choices=C.BECOME_METHODS,
                help="privilege escalation method to use (default=%s), valid choices: [ %s ]" % (C.DEFAULT_BECOME_METHOD, ' | '.join(C.BECOME_METHODS)))
            runas_group.add_option('--become-user', default=None, dest='become_user', type='string',
                help='run operations as this user (default=%s)' % C.DEFAULT_BECOME_USER)

        if runas_opts or runas_prompt_opts:
            if not runas_group:
                runas_group = rg
            runas_group.add_option('--ask-sudo-pass', default=C.DEFAULT_ASK_SUDO_PASS, dest='ask_sudo_pass', action='store_true',
                help='ask for sudo password (deprecated, use become)')
            runas_group.add_option('--ask-su-pass', default=C.DEFAULT_ASK_SU_PASS, dest='ask_su_pass', action='store_true',
                help='ask for su password (deprecated, use become)')
            runas_group.add_option('-K', '--ask-become-pass', default=False, dest='become_ask_pass', action='store_true',
                help='ask for privilege escalation password')

        if runas_group:
            parser.add_option_group(runas_group)

        if async_opts:
            parser.add_option('-P', '--poll', default=C.DEFAULT_POLL_INTERVAL, type='int', dest='poll_interval',
                help="set the poll interval if using -B (default=%s)" % C.DEFAULT_POLL_INTERVAL)
            parser.add_option('-B', '--background', dest='seconds', type='int', default=0,
                help='run asynchronously, failing after X seconds (default=N/A)')

        if check_opts:
            parser.add_option("-C", "--check", default=False, dest='check', action='store_true',
                help="don't make any changes; instead, try to predict some of the changes that may occur")
            parser.add_option('--syntax-check', dest='syntax', action='store_true',
                help="perform a syntax check on the playbook, but do not execute it")
            parser.add_option("-D", "--diff", default=False, dest='diff', action='store_true',
                help="when changing (small) files and templates, show the differences in those files; works great with --check")

        if meta_opts:
            parser.add_option('--force-handlers', default=C.DEFAULT_FORCE_HANDLERS, dest='force_handlers', action='store_true',
                help="run handlers even if a task fails")
            parser.add_option('--flush-cache', dest='flush_cache', action='store_true',
                help="clear the fact cache")

        return parser

    @abstractmethod
    def parse(self):
        """Parse the command line args

        This method parses the command line arguments.  It uses the parser
        stored in the self.parser attribute and saves the args and options in
        self.args and self.options respectively.

        Subclasses need to implement this method.  They will usually create
        a base_parser, add their own options to the base_parser, and then call
        this method to do the actual parsing.  An implementation will look
        something like this::

            def parse(self):
                parser = super(MyCLI, self).base_parser(usage="My Ansible CLI", inventory_opts=True)
                parser.add_option('--my-option', dest='my_option', action='store')
                self.parser = parser
                super(MyCLI, self).parse()
                # If some additional transformations are needed for the
                # arguments and options, do it here.
        """
        self.options, self.args = self.parser.parse_args(self.args[1:])
        if hasattr(self.options, 'tags') and not self.options.tags:
            # optparse defaults does not do what's expected
            self.options.tags = ['all']
        if hasattr(self.options, 'tags') and self.options.tags:
            if not C.MERGE_MULTIPLE_CLI_TAGS:
                if len(self.options.tags) > 1:
                    display.deprecated('Specifying --tags multiple times on the command line currently uses the last specified value. In 2.4, values will be merged instead.  Set merge_multiple_cli_tags=True in ansible.cfg to get this behavior now.', version=2.5, removed=False)
                    self.options.tags = [self.options.tags[-1]]

            tags = set()
            for tag_set in self.options.tags:
                for tag in tag_set.split(u','):
                    tags.add(tag.strip())
            self.options.tags = list(tags)

        if hasattr(self.options, 'skip_tags') and self.options.skip_tags:
            if not C.MERGE_MULTIPLE_CLI_TAGS:
                if len(self.options.skip_tags) > 1:
                    display.deprecated('Specifying --skip-tags multiple times on the command line currently uses the last specified value. In 2.4, values will be merged instead.  Set merge_multiple_cli_tags=True in ansible.cfg to get this behavior now.', version=2.5, removed=False)
                    self.options.skip_tags = [self.options.skip_tags[-1]]

            skip_tags = set()
            for tag_set in self.options.skip_tags:
                for tag in tag_set.split(u','):
                    skip_tags.add(tag.strip())
            self.options.skip_tags = list(skip_tags)

    @staticmethod
    def version(prog):
        ''' return ansible version '''
        result = "{0} {1}".format(prog, __version__)
        gitinfo = CLI._gitinfo()
        if gitinfo:
            result = result + " {0}".format(gitinfo)
        result += "\n  config file = %s" % C.CONFIG_FILE
        if C.DEFAULT_MODULE_PATH is None:
            cpath = "Default w/o overrides"
        else:
            cpath = C.DEFAULT_MODULE_PATH
        result = result + "\n  configured module search path = %s" % cpath
        return result

    @staticmethod
    def version_info(gitinfo=False):
        ''' return full ansible version info '''
        if gitinfo:
            # expensive call, user with care
            ansible_version_string = CLI.version('')
        else:
            ansible_version_string = __version__
        ansible_version = ansible_version_string.split()[0]
        ansible_versions = ansible_version.split('.')
        for counter in range(len(ansible_versions)):
            if ansible_versions[counter] == "":
                ansible_versions[counter] = 0
            try:
                ansible_versions[counter] = int(ansible_versions[counter])
            except:
                pass
        if len(ansible_versions) < 3:
            for counter in range(len(ansible_versions), 3):
                ansible_versions.append(0)
        return {'string':      ansible_version_string.strip(),
                'full':        ansible_version,
                'major':       ansible_versions[0],
                'minor':       ansible_versions[1],
                'revision':    ansible_versions[2]}

    @staticmethod
    def _git_repo_info(repo_path):
        ''' returns a string containing git branch, commit id and commit date '''
        result = None
        if os.path.exists(repo_path):
            # Check if the .git is a file. If it is a file, it means that we are in a submodule structure.
            if os.path.isfile(repo_path):
                try:
                    gitdir = yaml.safe_load(open(repo_path)).get('gitdir')
                    # There is a possibility the .git file to have an absolute path.
                    if os.path.isabs(gitdir):
                        repo_path = gitdir
                    else:
                        repo_path = os.path.join(repo_path[:-4], gitdir)
                except (IOError, AttributeError):
                    return ''
            f = open(os.path.join(repo_path, "HEAD"))
            line = f.readline().rstrip("\n")
            if line.startswith("ref:"):
                branch_path = os.path.join(repo_path, line[5:])
            else:
                branch_path = None
            f.close()
            if branch_path and os.path.exists(branch_path):
                branch = '/'.join(line.split('/')[2:])
                f = open(branch_path)
                commit = f.readline()[:10]
                f.close()
            else:
                # detached HEAD
                commit = line[:10]
                branch = 'detached HEAD'
                branch_path = os.path.join(repo_path, "HEAD")

            date = time.localtime(os.stat(branch_path).st_mtime)
            if time.daylight == 0:
                offset = time.timezone
            else:
                offset = time.altzone
            result = "({0} {1}) last updated {2} (GMT {3:+04d})".format(branch, commit,
                time.strftime("%Y/%m/%d %H:%M:%S", date), int(offset / -36))
        else:
            result = ''
        return result

    @staticmethod
    def _gitinfo():
        basedir = os.path.join(os.path.dirname(__file__), '..', '..', '..')
        repo_path = os.path.join(basedir, '.git')
        result = CLI._git_repo_info(repo_path)
        submodules = os.path.join(basedir, '.gitmodules')
        if not os.path.exists(submodules):
            return result
        f = open(submodules)
        for line in f:
            tokens = line.strip().split(' ')
            if tokens[0] == 'path':
                submodule_path = tokens[2]
                submodule_info = CLI._git_repo_info(os.path.join(basedir, submodule_path, '.git'))
                if not submodule_info:
                    submodule_info = ' not found - use git submodule update --init ' + submodule_path
                result += "\n  {0}: {1}".format(submodule_path, submodule_info)
        f.close()
        return result

    def pager(self, text):
        ''' find reasonable way to display text '''
        # this is a much simpler form of what is in pydoc.py
        if not sys.stdout.isatty():
            display.display(text)
        elif 'PAGER' in os.environ:
            if sys.platform == 'win32':
                display.display(text)
            else:
                self.pager_pipe(text, os.environ['PAGER'])
        else:
            p = subprocess.Popen('less --version', shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
            p.communicate()
            if p.returncode == 0:
                self.pager_pipe(text, 'less')
            else:
                display.display(text)

    @staticmethod
    def pager_pipe(text, cmd):
        ''' pipe text through a pager '''
        if 'LESS' not in os.environ:
            os.environ['LESS'] = CLI.LESS_OPTS
        try:
            cmd = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE, stdout=sys.stdout)
            cmd.communicate(input=to_bytes(text))
        except IOError:
            pass
        except KeyboardInterrupt:
            pass

    @classmethod
    def tty_ify(cls, text):

        t = cls._ITALIC.sub("`" + r"\1" + "'", text)    # I(word) => `word'
        t = cls._BOLD.sub("*" + r"\1" + "*", t)         # B(word) => *word*
        t = cls._MODULE.sub("[" + r"\1" + "]", t)       # M(word) => [word]
        t = cls._URL.sub(r"\1", t)                      # U(word) => word
        t = cls._CONST.sub("`" + r"\1" + "'", t)        # C(word) => `word'

        return t

    @staticmethod
    def read_vault_password_file(vault_password_file, loader):
        """
        Read a vault password from a file or if executable, execute the script and
        retrieve password from STDOUT
        """

        this_path = os.path.realpath(os.path.expanduser(vault_password_file))
        if not os.path.exists(this_path):
            raise AnsibleError("The vault password file %s was not found" % this_path)

        if loader.is_executable(this_path):
            try:
                # STDERR not captured to make it easier for users to prompt for input in their scripts
                p = subprocess.Popen(this_path, stdout=subprocess.PIPE)
            except OSError as e:
                raise AnsibleError("Problem running vault password script %s (%s). If this is not a script, remove the executable bit from the file." % (' '.join(this_path), e))
            stdout, stderr = p.communicate()
            if p.returncode != 0:
                raise AnsibleError("Vault password script %s returned non-zero (%s): %s" % (this_path, p.returncode, p.stderr))
            vault_pass = stdout.strip('\r\n')
        else:
            try:
                f = open(this_path, "rb")
                vault_pass=f.read().strip()
                f.close()
            except (OSError, IOError) as e:
                raise AnsibleError("Could not read vault password file %s: %s" % (this_path, e))

        return vault_pass

    def get_opt(self, k, defval=""):
        """
        Returns an option from an Optparse values instance.
        """
        try:
            data = getattr(self.options, k)
        except:
            return defval
        # FIXME: Can this be removed if cli and/or constants ensures it's a
        # list?
        if k == "roles_path":
            if os.pathsep in data:
                data = data.split(os.pathsep)[0]
        return data
