text: # -*- coding: utf-8 -*-
  # -----------------------------------------------------------------------------
  # Project   : Cuisine - Functions to write Fabric recipies
  # -----------------------------------------------------------------------------
  # Author    : Sebastien Pierre                            <sebastien@ffctn.com>
  # Author    : Thierry Stiegler   (gentoo port)     <thierry.stiegler@gmail.com>
  # Author    : Jim McCoy (distro checks and rpm port)      <jim.mccoy@gmail.com>
  # License   : Revised BSD License
  # -----------------------------------------------------------------------------
  # Creation  : 26-Apr-2010
  # Last mod  : 31-Oct-2011
  # -----------------------------------------------------------------------------
  
  """
  `cuisine` makes it easy to write automatic server installation
  and configuration recipies by wrapping common administrative tasks
  (installing packages, creating users and groups) in Python
  functions.
  
  `cuisine` is designed to work with Fabric and provide all you
  need for getting your new server up and running in minutes.
  
  Note, that right now, Cuisine only supports Debian-based Linux
  systems.
  
  See also:
  
  - Deploying Django with Fabric
    <http://lethain.com/entry/2008/nov/04/deploying-django-with-fabric>
  
  - Notes on Python Fabric 0.9b1
    <http://www.saltycrane.com/blog/2009/10/notes-python-fabric-09b1>`_
  
  - EC2, fabric, and "err: stdin: is not a tty"
    <http://blog.markfeeney.com/2009/12/ec2-fabric-and-err-stdin-is-not-tty.html>`_
  
  :copyright: (c) 2011 by Sébastien Pierre, see AUTHORS for more details.
  :license:   BSD, see LICENSE for more details.
  """
  
  import base64, bz2, crypt, hashlib, os, random, re, string, tempfile, subprocess
  import fabric, fabric.api, fabric.operations, fabric.context_managers
  
  VERSION     = "0.1.1"
  
  RE_SPACES   = re.compile("[\s\t]+")
  MAC_EOL     = "\n"
  UNIX_EOL    = "\n"
  WINDOWS_EOL = "\r\n"
  # FIXME: MODE should be in the fabric env, as this is definitely not thread-safe
  MODE_USER   = "user"
  MODE_SUDO   = "sudo"
  MODE        = MODE_USER
  
  
  # context managers and wrappers around fabric's run/sudo; used to
  # either execute cuisine functions with sudo or as current user:
  #
  # with mode_sudo():
  #     pass
  
  class mode_user(object):
      """Cuisine functions will be executed as the current user."""
  
      def __init__(self):
          global MODE
          self._old_mode = MODE
          MODE = MODE_USER
  
      def __enter__(self):
          pass
  
      def __exit__(self, *args, **kws):
          global MODE
          MODE = self._old_mode
  
  
  class mode_sudo(object):
      """Cuisine functions will be executed with sudo."""
  
      def __init__(self):
          global MODE
          self._old_mode = MODE
          MODE = MODE_SUDO
  
      def __enter__(self):
          pass
  
      def __exit__(self, *args, **kws):
          global MODE
          MODE = self._old_mode
  
  
  def run(*args, **kwargs):
      """A wrapper to Fabric's run/sudo commands, using the
      'cuisine.MODE' global to tell wether the command should be run as
      regular user or sudo."""
      if MODE == MODE_SUDO:
          return fabric.api.sudo(*args, **kwargs)
      else:
          return fabric.api.run(*args, **kwargs)
  
  def run_local(command):
      """A wrapper around subprocess"""
      pipe = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE).stdout
      res = pipe.read()
      # FIXME: Should stream the pipe, and only print it if fabric's properties allow it
      print res
      return pipe
  
  
  def sudo(*args, **kwargs):
      """A wrapper to Fabric's run/sudo commands, using the
      'cuisine.MODE' global to tell wether the command should be run as
      regular user or sudo."""
      return fabric.api.sudo(*args, **kwargs)
  
  
  ### decorators
  
  def multiargs(function):
      """Decorated functions will be 'map'ed to every element of the
      first argument if it is a list or a tuple, otherwise the function
      will execute normally."""
      def wrapper(*args, **kwargs):
          if len(args) == 0:
              return function()
          arg = args[0]
          args = args[1:]
          if type(arg) in (tuple, list):
              return map(lambda _: function(_, *args, **kwargs), arg)
          else:
              return function(arg, *args, **kwargs)
      return wrapper
  
  
  ### text_<operation> functions
  
  def text_detect_eol(text):
      # FIXME: Should look at the first line
      if text.find("\r\n") != -1:
          return WINDOWS_EOL
      elif text.find("\n") != -1:
          return UNIX_EOL
      elif text.find("\r") != -1:
          return MAC_EOL
      else:
          return "\n"
  
  
  def text_get_line(text, predicate):
      """Returns the first line that matches the given predicate."""
      for line in text.split("\n"):
          if predicate(line):
              return line
      return ""
  
  
  def text_normalize(text):
      """Converts tabs and spaces to single space and strips the text."""
      return RE_SPACES.sub(" ", text).strip()
  
  
  def text_nospace(text):
      """Converts tabs and spaces to single space and strips the text."""
      return RE_SPACES.sub("", text).strip()
  
  
  def text_replace_line(text, old, new, find=lambda old, new: old == new,
                        process=lambda _: _):
      """Replaces lines equal to 'old' with 'new', returning the new
      text and the count of replacements."""
      res = []
      replaced = 0
      eol = text_detect_eol(text)
      for line in text.split(eol):
          if find(process(line), process(old)):
              res.append(new)
              replaced += 1
          else:
              res.append(line)
      return eol.join(res), replaced
  
  
  def text_ensure_line(text, *lines):
      """Ensures that the given lines are present in the given text,
      otherwise appends the lines that are not already in the text at
      the end of it."""
      eol = text_detect_eol(text)
      res = list(text.split(eol))
      for line in lines:
          assert line.find(eol) == -1, \
                 "No EOL allowed in lines parameter: " + repr(line)
          found = False
          for l in res:
              if l == line:
                  found = True
                  break
          if not found:
              res.append(line)
      return eol.join(res)
  
  
  def text_strip_margin(text, margin="|"):
      res = []
      eol = text_detect_eol(text)
      for line in text.split(eol):
          l = line.split(margin, 1)
          if len(l) == 2:
              _, line = l
              res.append(line)
      return eol.join(res)
  
  
  def text_template(text, variables):
      """Substitutes '${PLACEHOLDER}'s within the text with the
      corresponding values from variables."""
      template = string.Template(text)
      return template.safe_substitute(variables)
  
  
  ### file_<operation> functions
  
  def file_local_read(location):
      """Reads a *local* file from the given location, expanding '~' and
      shell variables."""
      p = os.path.expandvars(os.path.expanduser(location))
      f = file(p, 'rb')
      t = f.read()
      f.close()
      return t
  
  
  def file_read(location):
      """Reads the *remote* file at the given location."""
      # NOTE: We use base64 here to be sure to preserve the encoding (UNIX/DOC/MAC) of EOLs
      return base64.b64decode(run('cat "%s" | base64' % (location)))
  
  
  def file_exists(location):
      """Tests if there is a *remote* file at the given location."""
      return run('test -f "%s" && echo OK ; true' % (location)) == "OK"
  
  
  def file_attribs(location, mode=None, owner=None, group=None,
                   recursive=False):
      """Updates the mode/owner/group for the remote file at the given
      location."""
      recursive = recursive and "-R " or ""
      if mode:
          run('chmod %s %s "%s"' % (recursive, mode,  location))
      if owner:
          run('chown %s %s "%s"' % (recursive, owner, location))
      if group:
          run('chgrp %s %s "%s"' % (recursive, group, location))
  
  
  def file_attribs_get(location):
      """Return mode, owner, and group for remote path.
      Return mode, owner, and group if remote path exists, 'None'
      otherwise.
      """
      if file_exists(location):
          fs_check = run('stat %s %s' % (location, '--format="%a %U %G"'))
          (mode, owner, group) = fs_check.split(' ')
          return {'mode': mode, 'owner': owner, 'group': group}
      else:
          return None
  
  def file_write(location, content, mode=None, owner=None, group=None):
      """Writes the given content to the file at the given remote
      location, optionally setting mode/owner/group."""
      # FIXME: Big files are never transferred properly!
      # Gets the content signature and write it to a secure tempfile
      sig            = hashlib.sha256(content).hexdigest()
      fd, local_path = tempfile.mkstemp()
      os.write(fd, content)
      # Upload the content if necessary
      if not file_exists(location) or sig != file_sha256(location):
          fabric.operations.put(local_path, location, use_sudo=(MODE == MODE_SUDO))
      # Remove the local temp file
      os.close(fd)
      os.unlink(local_path)
      # Ensure that the signature matches
      assert sig == file_sha256(location)
  
  def file_ensure(location, mode=None, owner=None, group=None,
                   recursive=False):
      """Updates the mode/owner/group for the remote file at the given
      location."""
      if file_exists(location):
          file_attribs(mode=mode,owner=owner,group=group)
      else:
          file_write(location,"",mode=mode,owner=owner,group=group)
  
  def file_upload(remote, local):
      """Uploads the local file to the remote location only if the remote location does not
      exists or the content are different."""
      # FIXME: Big files are never transferred properly!
      f       = file(local, 'rb')
      content = f.read()
      f.close()
      sig     = hashlib.sha256(content).hexdigest()
      if not file_exists(remote) or sig != file_sha256(remote):
          fabric.operations.put(local, remote, use_sudo=(MODE == MODE_SUDO))
  
  def file_update(location, updater=lambda x: x):
      """Updates the content of the given by passing the existing
      content of the remote file at the given location to the 'updater'
      function.
  
      For instance, if you'd like to convert an existing file to all
      uppercase, simply do:
  
      >   file_update("/etc/myfile", lambda _:_.upper())
      """
      assert file_exists(location), "File does not exists: " + location
      new_content = updater(file_read(location))
  
      assert type(new_content) in (str, unicode, fabric.operations._AttributeString), \
             "Updater must be like (string)->string, got: %s() = %s" % \
             (updater, type(new_content))
      run('echo "%s" | base64 -d > "%s"' %
          (base64.b64encode(new_content), location))
  
  
  def file_append(location, content, mode=None, owner=None, group=None):
      """Appends the given content to the remote file at the given
      location, optionally updating its mode/owner/group."""
      run('echo "%s" | base64 -d >> "%s"' %
          (base64.b64encode(content), location))
      file_attribs(location, mode, owner, group)
  
  def file_link(source, destination, symbolic=True, mode=None, owner=None, group=None):
      """Creates a (symbolic) link between source and destination on the remote host,
      optionally setting its mode/owner/group."""
      if symbolic:
          run('ln -sf "%s" "%s"' % (source, destination))
      else:
          run('ln -f "%s" "%s"' % (source, destination))
      file_attribs(destination, mode, owner, group)
  
  def file_sha256(location):
      """Returns the SHA-256 sum (as a hex string) for the remote file at the given location"""
      return run('sha256sum "%s" | cut -d" " -f1' % (location))
  
  # TODO: From McCoy's version, consider merging
  # def file_append( location, content, use_sudo=False, partial=False, escape=True):
  #       """Wrapper for fabric.contrib.files.append."""
  #       fabric.contrib.files.append(location, content, use_sudo, partial, escape)
  
  
  ### dir_<operation> functions
  
  def dir_attribs(location, mode=None, owner=None, group=None, recursive=False):
      """Updates the mode/owner/group for the given remote directory."""
      file_attribs(location, mode, owner, group, recursive)
  
  
  def dir_exists(location):
      """Tells if there is a remote directory at the given location."""
      return run('test -d "%s" && echo OK ; true' % (location)).endswith("OK")
  
  
  def dir_ensure(location, recursive=False, mode=None, owner=None, group=None):
      """Ensures that there is a remote directory at the given location,
      optionnaly updating its mode/owner/group.
  
      If we are not updating the owner/group then this can be done as a single
      ssh call, so use that method, otherwise set owner/group after creation."""
      if mode:
          mode_arg = "-m %s" % (mode)
      else:
          mode_arg = ""
      run('test -d "%s" || mkdir %s %s "%s" && echo OK ; true' %
          (location, recursive and "-p" or "", mode_arg, location))
      if owner or group:
          dir_attribs(location, owner=owner, group=group)
  
  
  ### package_<operation> functions
  
  def package_update(package=None):
      """Updates the package database (when no argument) or update the package
      or list of packages given as argument."""
      if package == None:
          sudo("apt-get --yes update")
      else:
          if type(package) in (list, tuple):
              package = " ".join(package)
          sudo("apt-get --yes upgrade " + package)
  
  
  def package_install(package, update=False):
      """Installs the given package/list of package, optionnaly updating
      the package database."""
      if update:
          sudo("apt-get --yes update")
      if type(package) in (list, tuple):
          package = " ".join(package)
      sudo("apt-get --yes install %s" % (package))
  
  
  @multiargs
  def package_ensure(package):
      """Tests if the given package is installed, and installes it in
      case it's not already there."""
      status = run("dpkg-query -W -f='${Status}' %s ; true" % package)
      if status.find("not-installed") != -1 or status.find("installed") == -1:
          package_install(package)
          return False
      else:
          return True
  
  
  ### command_<operation> functions
  
  def command_check(command):
      """Tests if the given command is available on the system."""
      return run("which '%s' >& /dev/null && echo OK ; true" % command).endswith("OK")
  
  
  def command_ensure(command, package=None):
      """Ensures that the given command is present, if not installs the
      package with the given name, which is the same as the command by
      default."""
      if package is None:
          package = command
      if not command_check(command):
          package_install(package)
      assert command_check(command), \
             "Command was not installed, check for errors: %s" % (command)
  
  
  ### user_<operation> functions
  
  def user_create(name, passwd=None, home=None, uid=None, gid=None, shell=None,
                  uid_min=None, uid_max=None):
      """Creates the user with the given name, optionally giving a
      specific password/home/uid/gid/shell."""
      options = ["-m"]
      if passwd:
          method = 6
          saltchars = string.ascii_letters + string.digits + './'
          salt = ''.join([random.choice(saltchars) for x in range(8)])
          passwd_crypted = crypt.crypt(passwd, '$%s$%s' % (method, salt))
          options.append("-p '%s'" % (passwd_crypted))
      if home:
          options.append("-d '%s'" % (home))
      if uid:
          options.append("-u '%s'" % (uid))
      if gid:
          options.append("-g '%s'" % (gid))
      if shell:
          options.append("-s '%s'" % (shell))
      if uid_min:
          options.append("-K UID_MIN='%s'" % (uid_min))
      if uid_max:
          options.append("-K UID_MAX='%s'" % (uid_max))
      sudo("useradd %s '%s'" % (" ".join(options), name))
  
  
  def user_check(name):
      """Checks if there is a user defined with the given name,
      returning its information as a
      '{"name":<str>,"uid":<str>,"gid":<str>,"home":<str>,"shell":<str>}'
      or 'None' if the user does not exists."""
      d = sudo("cat /etc/passwd | egrep '^%s:' ; true" % (name))
      s = sudo("cat /etc/shadow | egrep '^%s:' | awk -F':' '{print $2}'" % (name))
      results = {}
      if d:
          d = d.split(":")
          results = dict(name=d[0], uid=d[2], gid=d[3], home=d[5], shell=d[6])
      if s:
          results['passwd'] = s
      if results:
          return results
      else:
          return None
  
  
  def user_ensure(name, passwd=None, home=None, uid=None, gid=None, shell=None):
      """Ensures that the given users exists, optionally updating their
      passwd/home/uid/gid/shell."""
      d = user_check(name)
      if not d:
          user_create(name, passwd, home, uid, gid, shell)
      else:
          options = []
          if passwd != None and d.get('passwd') != None:
              method, salt = d.get('passwd').split('$')[1:3]
              passwd_crypted = crypt.crypt(passwd, '$%s$%s' % (method, salt))
              if passwd_crypted != d.get('passwd'):
                  options.append("-p '%s'" % (passwd_crypted))
          if passwd != None and d.get('passwd') is None:
              # user doesn't have passwd
              method = 6
              saltchars = string.ascii_letters + string.digits + './'
              salt = ''.join([random.choice(saltchars) for x in range(8)])
              passwd_crypted = crypt.crypt(passwd, '$%s$%s' % (method, salt))
              options.append("-p '%s'" % (passwd_crypted))
          if home != None and d.get("home") != home:
              options.append("-d '%s'" % (home))
          if uid != None and d.get("uid") != uid:
              options.append("-u '%s'" % (uid))
          if gid != None and d.get("gid") != gid:
              options.append("-g '%s'" % (gid))
          if shell != None and d.get("shell") != shell:
              options.append("-s '%s'" % (shell))
          if options:
              sudo("usermod %s '%s'" % (" ".join(options), name))
  
  
  ### group_<operation> functions
  
  def group_create(name, gid=None):
      """Creates a group with the given name, and optionally given gid."""
      options = []
      if gid:
          options.append("-g '%s'" % (gid))
      sudo("groupadd %s '%s'" % (" ".join(options), name))
  
  
  def group_check(name):
      """Checks if there is a group defined with the given name,
      returning its information as a
      '{"name":<str>,"gid":<str>,"members":<list[str]>}' or 'None' if
      the group does not exists."""
      group_data = run("cat /etc/group | egrep '^%s:' ; true" % (name))
      if group_data:
          name, _, gid, members = group_data.split(":", 4)
          return dict(name=name, gid=gid,
                      members=tuple(m.strip() for m in members.split(",")))
      else:
          return None
  
  
  def group_ensure(name, gid=None):
      """Ensures that the group with the given name (and optional gid)
      exists."""
      d = group_check(name)
      if not d:
          group_create(name, gid)
      else:
          if gid != None and d.get("gid") != gid:
              sudo("groupmod -g %s '%s'" % (gid, name))
  
  
  def group_user_check(group, user):
      """Checks if the given user is a member of the given group. It
      will return 'False' if the group does not exist."""
      d = group_check(group)
      if d is None:
          return False
      else:
          return user in d["members"]
  
  
  def group_user_add(group, user):
      """Adds the given user/list of users to the given group/groups."""
      assert group_check(group), "Group does not exist: %s" % (group)
      if not group_user_check(group, user):
          sudo("usermod -a -G '%s' '%s'" % (group, user))
  
  
  def group_user_ensure(group, user):
      """Ensure that a given user is a member of a given group."""
      d = group_check(group)
      if user not in d["members"]:
          group_user_add(group, user)
  
  
  ### ssh_<operation> functions
  
  def ssh_keygen(user, keytype="dsa"):
      """Generates a pair of ssh keys in the user's home .ssh directory."""
      d = user_check(user)
      assert d, "User does not exist: %s" % (user)
      home = d["home"]
      key_file = home + "/.ssh/id_%s.pub" % keytype
      if not file_exists(key_file):
          dir_ensure(home + "/.ssh", mode="0700", owner=user, group=user)
          run("ssh-keygen -q -t %s -f '%s/.ssh/id_%s' -N ''" %
              (keytype, home, keytype))
          file_attribs(home + "/.ssh/id_%s" % keytype, owner=user, group=user)
          file_attribs(home + "/.ssh/id_%s.pub" % keytype, owner=user, group=user)
          return False
      else:
          return True
  
  
  def ssh_authorize(user, key):
      """Adds the given key to the '.ssh/authorized_keys' for the given
      user."""
      d = user_check(user)
      keyf = d["home"] + "/.ssh/authorized_keys"
      if key[-1] != "\n":
          key += "\n"
      if file_exists(keyf):
          d = file_read(keyf)
          if file_read(keyf).find(key[:-1]) == -1:
              file_append(keyf, key)
              return False
          else:
              return True
      else:
          file_write(keyf, key)
          return False
  
  
  ### miscellaneous (utility/helper) functions
  
  def upstart_ensure(name):
      """Ensures that the given upstart service is running, restarting
      it if necessary"""
      if sudo("status " + name).find("/running") >= 0:
          sudo("restart " + name)
      else:
          sudo("start " + name)
  
  
  def system_uuid_alias_add():
      """Adds system UUID alias to /etc/hosts.
  
      Some tools/processes rely/want the hostname as an alias in
      /etc/hosts e.g. `127.0.0.1 localhost <hostname>`.
  
      """
      with mode_sudo(), cd('/etc'):
          old = "127.0.0.1 localhost"
          new = old + " " + system_uuid()
          file_update('hosts', lambda x: text_replace_line(x, old, new)[0])
  
  
  def system_uuid():
      """Gets a machines UUID (Universally Unique Identifier)."""
      return sudo('dmidecode -s system-uuid | tr "[A-Z]" "[a-z]"')
  
  # EOF - vim: ts=4 sw=4 et
  