cli.py 16.2 KB
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#
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#

# Copyright (C) 2006, 2007 Google Inc.
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.


"""Module dealing with command line parsing"""


import sys
import textwrap
import os.path
import copy
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from cStringIO import StringIO
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from ganeti import utils
from ganeti import logger
from ganeti import errors
from ganeti import mcpu
from ganeti import constants
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from ganeti import opcodes
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from optparse import (OptionParser, make_option, TitledHelpFormatter,
                      Option, OptionValueError, SUPPRESS_HELP)

__all__ = ["DEBUG_OPT", "NOHDR_OPT", "SEP_OPT", "GenericMain", "SubmitOpCode",
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           "cli_option", "GenerateTable", "AskUser",
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           "ARGS_NONE", "ARGS_FIXED", "ARGS_ATLEAST", "ARGS_ANY", "ARGS_ONE",
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           "USEUNITS_OPT", "FIELDS_OPT", "FORCE_OPT",
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           "ListTags", "AddTags", "RemoveTags", "TAG_SRC_OPT",
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           "FormatError",
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           ]


def _ExtractTagsObject(opts, args):
  """Extract the tag type object.

  Note that this function will modify its args parameter.

  """
  if not hasattr(opts, "tag_type"):
    raise errors.ProgrammerError("tag_type not passed to _ExtractTagsObject")
  kind = opts.tag_type
  if kind == constants.TAG_CLUSTER:
    retval = kind, kind
  elif kind == constants.TAG_NODE or kind == constants.TAG_INSTANCE:
    if not args:
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      raise errors.OpPrereqError("no arguments passed to the command")
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    name = args.pop(0)
    retval = kind, name
  else:
    raise errors.ProgrammerError("Unhandled tag type '%s'" % kind)
  return retval


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def _ExtendTags(opts, args):
  """Extend the args if a source file has been given.

  This function will extend the tags with the contents of the file
  passed in the 'tags_source' attribute of the opts parameter. A file
  named '-' will be replaced by stdin.

  """
  fname = opts.tags_source
  if fname is None:
    return
  if fname == "-":
    new_fh = sys.stdin
  else:
    new_fh = open(fname, "r")
  new_data = []
  try:
    # we don't use the nice 'new_data = [line.strip() for line in fh]'
    # because of python bug 1633941
    while True:
      line = new_fh.readline()
      if not line:
        break
      new_data.append(line.strip())
  finally:
    new_fh.close()
  args.extend(new_data)


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def ListTags(opts, args):
  """List the tags on a given object.

  This is a generic implementation that knows how to deal with all
  three cases of tag objects (cluster, node, instance). The opts
  argument is expected to contain a tag_type field denoting what
  object type we work on.

  """
  kind, name = _ExtractTagsObject(opts, args)
  op = opcodes.OpGetTags(kind=kind, name=name)
  result = SubmitOpCode(op)
  result = list(result)
  result.sort()
  for tag in result:
    print tag


def AddTags(opts, args):
  """Add tags on a given object.

  This is a generic implementation that knows how to deal with all
  three cases of tag objects (cluster, node, instance). The opts
  argument is expected to contain a tag_type field denoting what
  object type we work on.

  """
  kind, name = _ExtractTagsObject(opts, args)
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  _ExtendTags(opts, args)
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  if not args:
    raise errors.OpPrereqError("No tags to be added")
  op = opcodes.OpAddTags(kind=kind, name=name, tags=args)
  SubmitOpCode(op)


def RemoveTags(opts, args):
  """Remove tags from a given object.

  This is a generic implementation that knows how to deal with all
  three cases of tag objects (cluster, node, instance). The opts
  argument is expected to contain a tag_type field denoting what
  object type we work on.

  """
  kind, name = _ExtractTagsObject(opts, args)
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  _ExtendTags(opts, args)
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  if not args:
    raise errors.OpPrereqError("No tags to be removed")
  op = opcodes.OpDelTags(kind=kind, name=name, tags=args)
  SubmitOpCode(op)

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DEBUG_OPT = make_option("-d", "--debug", default=False,
                        action="store_true",
                        help="Turn debugging on")

NOHDR_OPT = make_option("--no-headers", default=False,
                        action="store_true", dest="no_headers",
                        help="Don't display column headers")

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SEP_OPT = make_option("--separator", default=None,
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                      action="store", dest="separator",
                      help="Separator between output fields"
                      " (defaults to one space)")

USEUNITS_OPT = make_option("--human-readable", default=False,
                           action="store_true", dest="human_readable",
                           help="Print sizes in human readable format")

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FIELDS_OPT = make_option("-o", "--output", dest="output", action="store",
                         type="string", help="Select output fields",
                         metavar="FIELDS")

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FORCE_OPT = make_option("-f", "--force", dest="force", action="store_true",
                        default=False, help="Force the operation")

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_LOCK_OPT = make_option("--lock-retries", default=None,
                        type="int", help=SUPPRESS_HELP)

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TAG_SRC_OPT = make_option("--from", dest="tags_source",
                          default=None, help="File with tag names")

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def ARGS_FIXED(val):
  """Macro-like function denoting a fixed number of arguments"""
  return -val


def ARGS_ATLEAST(val):
  """Macro-like function denoting a minimum number of arguments"""
  return val


ARGS_NONE = None
ARGS_ONE = ARGS_FIXED(1)
ARGS_ANY = ARGS_ATLEAST(0)


def check_unit(option, opt, value):
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  """OptParsers custom converter for units.

  """
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  try:
    return utils.ParseUnit(value)
  except errors.UnitParseError, err:
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    raise OptionValueError("option %s: %s" % (opt, err))
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class CliOption(Option):
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  """Custom option class for optparse.

  """
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  TYPES = Option.TYPES + ("unit",)
  TYPE_CHECKER = copy.copy(Option.TYPE_CHECKER)
  TYPE_CHECKER["unit"] = check_unit


# optparse.py sets make_option, so we do it for our own option class, too
cli_option = CliOption


def _ParseArgs(argv, commands):
  """Parses the command line and return the function which must be
  executed together with its arguments

  Arguments:
    argv: the command line

    commands: dictionary with special contents, see the design doc for
    cmdline handling
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  """
  if len(argv) == 0:
    binary = "<command>"
  else:
    binary = argv[0].split("/")[-1]

  if len(argv) > 1 and argv[1] == "--version":
    print "%s (ganeti) %s" % (binary, constants.RELEASE_VERSION)
    # Quit right away. That way we don't have to care about this special
    # argument. optparse.py does it the same.
    sys.exit(0)

  if len(argv) < 2 or argv[1] not in commands.keys():
    # let's do a nice thing
    sortedcmds = commands.keys()
    sortedcmds.sort()
    print ("Usage: %(bin)s {command} [options...] [argument...]"
           "\n%(bin)s <command> --help to see details, or"
           " man %(bin)s\n" % {"bin": binary})
    # compute the max line length for cmd + usage
    mlen = max([len(" %s %s" % (cmd, commands[cmd][3])) for cmd in commands])
    mlen = min(60, mlen) # should not get here...
    # and format a nice command list
    print "Commands:"
    for cmd in sortedcmds:
      cmdstr = " %s %s" % (cmd, commands[cmd][3])
      help_text = commands[cmd][4]
      help_lines = textwrap.wrap(help_text, 79-3-mlen)
      print "%-*s - %s" % (mlen, cmdstr,
                                          help_lines.pop(0))
      for line in help_lines:
        print "%-*s   %s" % (mlen, "", line)
    print
    return None, None, None
  cmd = argv.pop(1)
  func, nargs, parser_opts, usage, description = commands[cmd]
  parser_opts.append(_LOCK_OPT)
  parser = OptionParser(option_list=parser_opts,
                        description=description,
                        formatter=TitledHelpFormatter(),
                        usage="%%prog %s %s" % (cmd, usage))
  parser.disable_interspersed_args()
  options, args = parser.parse_args()
  if nargs is None:
    if len(args) != 0:
      print >> sys.stderr, ("Error: Command %s expects no arguments" % cmd)
      return None, None, None
  elif nargs < 0 and len(args) != -nargs:
    print >> sys.stderr, ("Error: Command %s expects %d argument(s)" %
                         (cmd, -nargs))
    return None, None, None
  elif nargs >= 0 and len(args) < nargs:
    print >> sys.stderr, ("Error: Command %s expects at least %d argument(s)" %
                         (cmd, nargs))
    return None, None, None

  return func, options, args


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def AskUser(text, choices=None):
  """Ask the user a question.
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  Args:
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    text - the question to ask.
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    choices - list with elements tuples (input_char, return_value,
    description); if not given, it will default to: [('y', True,
    'Perform the operation'), ('n', False, 'Do no do the operation')];
    note that the '?' char is reserved for help

  Returns: one of the return values from the choices list; if input is
  not possible (i.e. not running with a tty, we return the last entry
  from the list
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  """
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  if choices is None:
    choices = [('y', True, 'Perform the operation'),
               ('n', False, 'Do not perform the operation')]
  if not choices or not isinstance(choices, list):
    raise errors.ProgrammerError("Invalid choiches argument to AskUser")
  for entry in choices:
    if not isinstance(entry, tuple) or len(entry) < 3 or entry[0] == '?':
      raise errors.ProgrammerError("Invalid choiches element to AskUser")

  answer = choices[-1][1]
  new_text = []
  for line in text.splitlines():
    new_text.append(textwrap.fill(line, 70, replace_whitespace=False))
  text = "\n".join(new_text)
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  try:
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    f = file("/dev/tty", "a+")
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  except IOError:
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    return answer
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  try:
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    chars = [entry[0] for entry in choices]
    chars[-1] = "[%s]" % chars[-1]
    chars.append('?')
    maps = dict([(entry[0], entry[1]) for entry in choices])
    while True:
      f.write(text)
      f.write('\n')
      f.write("/".join(chars))
      f.write(": ")
      line = f.readline(2).strip().lower()
      if line in maps:
        answer = maps[line]
        break
      elif line == '?':
        for entry in choices:
          f.write(" %s - %s\n" % (entry[0], entry[2]))
        f.write("\n")
        continue
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  finally:
    f.close()
  return answer


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def SubmitOpCode(op, proc=None, feedback_fn=None):
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  """Function to submit an opcode.

  This is just a simple wrapper over the construction of the processor
  instance. It should be extended to better handle feedback and
  interaction functions.

  """
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  if feedback_fn is None:
    feedback_fn = logger.ToStdout
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  if proc is None:
    proc = mcpu.Processor(feedback=feedback_fn)
  return proc.ExecOpCode(op)
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def FormatError(err):
  """Return a formatted error message for a given error.

  This function takes an exception instance and returns a tuple
  consisting of two values: first, the recommended exit code, and
  second, a string describing the error message (not
  newline-terminated).

  """
  retcode = 1
  obuf = StringIO()
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  msg = str(err)
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  if isinstance(err, errors.ConfigurationError):
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    txt = "Corrupt configuration file: %s" % msg
    logger.Error(txt)
    obuf.write(txt + "\n")
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    obuf.write("Aborting.")
    retcode = 2
  elif isinstance(err, errors.HooksAbort):
    obuf.write("Failure: hooks execution failed:\n")
    for node, script, out in err.args[0]:
      if out:
        obuf.write("  node: %s, script: %s, output: %s\n" %
                   (node, script, out))
      else:
        obuf.write("  node: %s, script: %s (no output)\n" %
                   (node, script))
  elif isinstance(err, errors.HooksFailure):
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    obuf.write("Failure: hooks general failure: %s" % msg)
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  elif isinstance(err, errors.ResolverError):
    this_host = utils.HostInfo.SysName()
    if err.args[0] == this_host:
      msg = "Failure: can't resolve my own hostname ('%s')"
    else:
      msg = "Failure: can't resolve hostname '%s'"
    obuf.write(msg % err.args[0])
  elif isinstance(err, errors.OpPrereqError):
    obuf.write("Failure: prerequisites not met for this"
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               " operation:\n%s" % msg)
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  elif isinstance(err, errors.OpExecError):
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    obuf.write("Failure: command execution error:\n%s" % msg)
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  elif isinstance(err, errors.TagError):
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    obuf.write("Failure: invalid tag(s) given:\n%s" % msg)
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  elif isinstance(err, errors.GenericError):
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    obuf.write("Unhandled Ganeti error: %s" % msg)
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  else:
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    obuf.write("Unhandled exception: %s" % msg)
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  return retcode, obuf.getvalue().rstrip('\n')


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def GenericMain(commands, override=None):
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  """Generic main function for all the gnt-* commands.

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  Arguments:
    - commands: a dictionary with a special structure, see the design doc
                for command line handling.
    - override: if not None, we expect a dictionary with keys that will
                override command line options; this can be used to pass
                options from the scripts to generic functions
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  """
  # save the program name and the entire command line for later logging
  if sys.argv:
    binary = os.path.basename(sys.argv[0]) or sys.argv[0]
    if len(sys.argv) >= 2:
      binary += " " + sys.argv[1]
      old_cmdline = " ".join(sys.argv[2:])
    else:
      old_cmdline = ""
  else:
    binary = "<unknown program>"
    old_cmdline = ""

  func, options, args = _ParseArgs(sys.argv, commands)
  if func is None: # parse error
    return 1

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  if override is not None:
    for key, val in override.iteritems():
      setattr(options, key, val)

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  logger.SetupLogging(debug=options.debug, program=binary)

  try:
    utils.Lock('cmd', max_retries=options.lock_retries, debug=options.debug)
  except errors.LockError, err:
    logger.ToStderr(str(err))
    return 1

  if old_cmdline:
    logger.Info("run with arguments '%s'" % old_cmdline)
  else:
    logger.Info("run with no arguments")

  try:
    try:
      result = func(options, args)
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    except errors.GenericError, err:
      result, err_msg = FormatError(err)
      logger.ToStderr(err_msg)
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  finally:
    utils.Unlock('cmd')
    utils.LockCleanup()

  return result
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def GenerateTable(headers, fields, separator, data,
                  numfields=None, unitfields=None):
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  """Prints a table with headers and different fields.

  Args:
    headers: Dict of header titles or None if no headers should be shown
    fields: List of fields to show
    separator: String used to separate fields or None for spaces
    data: Data to be printed
    numfields: List of fields to be aligned to right
    unitfields: List of fields to be formatted as units

  """
  if numfields is None:
    numfields = []
  if unitfields is None:
    unitfields = []

  format_fields = []
  for field in fields:
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    if headers and field not in headers:
      raise errors.ProgrammerError("Missing header description for field '%s'"
                                   % field)
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    if separator is not None:
      format_fields.append("%s")
    elif field in numfields:
      format_fields.append("%*s")
    else:
      format_fields.append("%-*s")

  if separator is None:
    mlens = [0 for name in fields]
    format = ' '.join(format_fields)
  else:
    format = separator.replace("%", "%%").join(format_fields)

  for row in data:
    for idx, val in enumerate(row):
      if fields[idx] in unitfields:
        try:
          val = int(val)
        except ValueError:
          pass
        else:
          val = row[idx] = utils.FormatUnit(val)
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      val = row[idx] = str(val)
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      if separator is None:
        mlens[idx] = max(mlens[idx], len(val))

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  result = []
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  if headers:
    args = []
    for idx, name in enumerate(fields):
      hdr = headers[name]
      if separator is None:
        mlens[idx] = max(mlens[idx], len(hdr))
        args.append(mlens[idx])
      args.append(hdr)
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    result.append(format % tuple(args))
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  for line in data:
    args = []
    for idx in xrange(len(fields)):
      if separator is None:
        args.append(mlens[idx])
      args.append(line[idx])
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    result.append(format % tuple(args))

  return result