migration.py
author Alexandre Fayolle <alexandre.fayolle@logilab.fr>
Sat, 29 May 2010 09:52:31 +0000
branchstable
changeset 5600 a826996875e7
parent 5488 ded032692cb9
child 5508 6718ba5db0eb
child 5580 3e9e6dd54ebb
permissions -rw-r--r--
[win32 service] activate logging to the configured file as soon as possible since we don't always have access to the system events of the computer running CW it is important to get as much information as possible in the log file, especially startup failure messages.

# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
"""utilities for instances migration

"""
__docformat__ = "restructuredtext en"

import sys
import os
import logging
import tempfile
from os.path import exists, join, basename, splitext

from logilab.common.decorators import cached
from logilab.common.configuration import REQUIRED, read_old_config
from logilab.common.shellutils import ASK
from logilab.common.changelog import Version

from cubicweb import ConfigurationError


def filter_scripts(config, directory, fromversion, toversion, quiet=True):
    """return a list of paths of migration files to consider to upgrade
    from a version to a greater one
    """
    from logilab.common.changelog import Version # doesn't work with appengine
    assert fromversion
    assert toversion
    assert isinstance(fromversion, tuple), fromversion.__class__
    assert isinstance(toversion, tuple), toversion.__class__
    assert fromversion <= toversion, (fromversion, toversion)
    if not exists(directory):
        if not quiet:
            print directory, "doesn't exists, no migration path"
        return []
    if fromversion == toversion:
        return []
    result = []
    for fname in os.listdir(directory):
        if fname.endswith('.pyc') or fname.endswith('.pyo') \
               or fname.endswith('~'):
            continue
        fpath = join(directory, fname)
        try:
            tver, mode = fname.split('_', 1)
        except ValueError:
            continue
        mode = mode.split('.', 1)[0]
        if not config.accept_mode(mode):
            continue
        try:
            tver = Version(tver)
        except ValueError:
            continue
        if tver <= fromversion:
            continue
        if tver > toversion:
            continue
        result.append((tver, fpath))
    # be sure scripts are executed in order
    return sorted(result)


IGNORED_EXTENSIONS = ('.swp', '~')


def execscript_confirm(scriptpath):
    """asks for confirmation before executing a script and provides the
    ability to show the script's content
    """
    while True:
        answer = ASK.ask('Execute %r ?' % scriptpath,
                         ('Y','n','show','abort'), 'Y')
        if answer == 'abort':
            raise SystemExit(1)
        elif answer == 'n':
            return False
        elif answer == 'show':
            stream = open(scriptpath)
            scriptcontent = stream.read()
            stream.close()
            print
            print scriptcontent
            print
        else:
            return True

def yes(*args, **kwargs):
    return True


class MigrationHelper(object):
    """class holding CubicWeb Migration Actions used by migration scripts"""

    def __init__(self, config, interactive=True, verbosity=1):
        self.config = config
        if config:
            # no config on shell to a remote instance
            self.config.init_log(logthreshold=logging.ERROR, debug=True)
        # 0: no confirmation, 1: only main commands confirmed, 2 ask for everything
        self.verbosity = verbosity
        self.need_wrap = True
        if not interactive or not verbosity:
            self.confirm = yes
            self.execscript_confirm = yes
        else:
            self.execscript_confirm = execscript_confirm
        self._option_changes = []
        self.__context = {'confirm': self.confirm,
                          'config': self.config,
                          'interactive_mode': interactive,
                          }

    def __getattribute__(self, name):
        try:
            return object.__getattribute__(self, name)
        except AttributeError:
            cmd = 'cmd_%s' % name
            if hasattr(self, cmd):
                meth = getattr(self, cmd)
                return lambda *args, **kwargs: self.interact(args, kwargs,
                                                             meth=meth)
            raise
        raise AttributeError(name)

    def repo_connect(self):
        return self.config.repository()

    def migrate(self, vcconf, toupgrade, options):
        """upgrade the given set of cubes

        `cubes` is an ordered list of 3-uple:
        (cube, fromversion, toversion)
        """
        if options.fs_only:
            # monkey path configuration.accept_mode so database mode (e.g. Any)
            # won't be accepted
            orig_accept_mode = self.config.accept_mode
            def accept_mode(mode):
                if mode == 'Any':
                    return False
                return orig_accept_mode(mode)
            self.config.accept_mode = accept_mode
        # may be an iterator
        toupgrade = tuple(toupgrade)
        vmap = dict( (cube, (fromver, tover)) for cube, fromver, tover in toupgrade)
        ctx = self.__context
        ctx['versions_map'] = vmap
        if self.config.accept_mode('Any') and 'cubicweb' in vmap:
            migrdir = self.config.migration_scripts_dir()
            self.cmd_process_script(join(migrdir, 'bootstrapmigration_repository.py'))
        for cube, fromversion, toversion in toupgrade:
            if cube == 'cubicweb':
                migrdir = self.config.migration_scripts_dir()
            else:
                migrdir = self.config.cube_migration_scripts_dir(cube)
            scripts = filter_scripts(self.config, migrdir, fromversion, toversion)
            if scripts:
                prevversion = None
                for version, script in scripts:
                    # take care to X.Y.Z_Any.py / X.Y.Z_common.py: we've to call
                    # cube_upgraded once all script of X.Y.Z have been executed
                    if prevversion is not None and version != prevversion:
                        self.cube_upgraded(cube, prevversion)
                    prevversion = version
                    self.cmd_process_script(script)
                self.cube_upgraded(cube, toversion)
            else:
                self.cube_upgraded(cube, toversion)

    def cube_upgraded(self, cube, version):
        pass

    def shutdown(self):
        pass

    def interact(self, args, kwargs, meth):
        """execute the given method according to user's confirmation"""
        msg = 'Execute command: %s(%s) ?' % (
            meth.__name__[4:],
            ', '.join([repr(arg) for arg in args] +
                      ['%s=%r' % (n,v) for n,v in kwargs.items()]))
        if 'ask_confirm' in kwargs:
            ask_confirm = kwargs.pop('ask_confirm')
        else:
            ask_confirm = True
        if not ask_confirm or self.confirm(msg):
            return meth(*args, **kwargs)

    def confirm(self, question, shell=True, abort=True, retry=False, default='y'):
        """ask for confirmation and return true on positive answer

        if `retry` is true the r[etry] answer may return 2
        """
        possibleanswers = ['y', 'n']
        if abort:
            possibleanswers.append('abort')
        if shell:
            possibleanswers.append('shell')
        if retry:
            possibleanswers.append('retry')
        try:
            answer = ASK.ask(question, possibleanswers, default)
        except (EOFError, KeyboardInterrupt):
            answer = 'abort'
        if answer == 'n':
            return False
        if answer == 'retry':
            return 2
        if answer == 'abort':
            raise SystemExit(1)
        if shell and answer == 'shell':
            self.interactive_shell()
            return self.confirm(question)
        return True

    def interactive_shell(self):
        self.confirm = yes
        self.need_wrap = False
        # avoid '_' to be added to builtins by sys.display_hook
        def do_not_add___to_builtins(obj):
            if obj is not None:
                print repr(obj)
        sys.displayhook = do_not_add___to_builtins
        local_ctx = self._create_context()
        try:
            import readline
            from rlcompleter import Completer
        except ImportError:
            # readline not available
            pass
        else:
            readline.set_completer(Completer(local_ctx).complete)
            readline.parse_and_bind('tab: complete')
            home_key = 'HOME'
            if sys.platform == 'win32':
                home_key = 'USERPROFILE'
            histfile = os.path.join(os.environ[home_key], ".eshellhist")
            try:
                readline.read_history_file(histfile)
            except IOError:
                pass
        from code import interact
        banner = """entering the migration python shell
just type migration commands or arbitrary python code and type ENTER to execute it
type "exit" or Ctrl-D to quit the shell and resume operation"""
        # give custom readfunc to avoid http://bugs.python.org/issue1288615
        def unicode_raw_input(prompt):
            return unicode(raw_input(prompt), sys.stdin.encoding)
        interact(banner, readfunc=unicode_raw_input, local=local_ctx)
        readline.write_history_file(histfile)
        # delete instance's confirm attribute to avoid questions
        del self.confirm
        self.need_wrap = True

    @cached
    def _create_context(self):
        """return a dictionary to use as migration script execution context"""
        context = self.__context
        for attr in dir(self):
            if attr.startswith('cmd_'):
                if self.need_wrap:
                    context[attr[4:]] = getattr(self, attr[4:])
                else:
                    context[attr[4:]] = getattr(self, attr)
        return context

    def cmd_process_script(self, migrscript, funcname=None, *args, **kwargs):
        """execute a migration script
        in interactive mode,  display the migration script path, ask for
        confirmation and execute it if confirmed
        """
        migrscript = os.path.normpath(migrscript)
        if migrscript.endswith('.py'):
            script_mode = 'python'
        elif migrscript.endswith('.txt') or migrscript.endswith('.rst'):
            script_mode = 'doctest'
        else:
            raise Exception('This is not a valid cubicweb shell input')
        if not self.execscript_confirm(migrscript):
            return
        scriptlocals = self._create_context().copy()
        if script_mode == 'python':
            if funcname is None:
                pyname = '__main__'
            else:
                pyname = splitext(basename(migrscript))[0]
            scriptlocals.update({'__file__': migrscript, '__name__': pyname})
            execfile(migrscript, scriptlocals)
            if funcname is not None:
                try:
                    func = scriptlocals[funcname]
                    self.info('found %s in locals', funcname)
                    assert callable(func), '%s (%s) is not callable' % (func, funcname)
                except KeyError:
                    self.critical('no %s in script %s', funcname, migrscript)
                    return None
                return func(*args, **kwargs)
        else: # script_mode == 'doctest'
            import doctest
            doctest.testfile(migrscript, module_relative=False,
                             optionflags=doctest.ELLIPSIS, globs=scriptlocals)

    def cmd_option_renamed(self, oldname, newname):
        """a configuration option has been renamed"""
        self._option_changes.append(('renamed', oldname, newname))

    def cmd_option_group_change(self, option, oldgroup, newgroup):
        """a configuration option has been moved in another group"""
        self._option_changes.append(('moved', option, oldgroup, newgroup))

    def cmd_option_added(self, optname):
        """a configuration option has been added"""
        self._option_changes.append(('added', optname))

    def cmd_option_removed(self, optname):
        """a configuration option has been removed"""
        # can safely be ignored
        #self._option_changes.append(('removed', optname))

    def cmd_option_type_changed(self, optname, oldtype, newvalue):
        """a configuration option's type has changed"""
        self._option_changes.append(('typechanged', optname, oldtype, newvalue))

    def cmd_add_cubes(self, cubes):
        """modify the list of used cubes in the in-memory config
        returns newly inserted cubes, including dependencies
        """
        if isinstance(cubes, basestring):
            cubes = (cubes,)
        origcubes = self.config.cubes()
        newcubes = [p for p in self.config.expand_cubes(cubes)
                       if not p in origcubes]
        if newcubes:
            for cube in cubes:
                assert cube in newcubes
            self.config.add_cubes(newcubes)
        return newcubes

    def cmd_remove_cube(self, cube, removedeps=False):
        if removedeps:
            toremove = self.config.expand_cubes([cube])
        else:
            toremove = (cube,)
        origcubes = self.config._cubes
        basecubes = [c for c in origcubes if not c in toremove]
        self.config._cubes = tuple(self.config.expand_cubes(basecubes))
        removed = [p for p in origcubes if not p in self.config._cubes]
        if not cube in removed:
            raise ConfigurationError("can't remove cube %s, "
                                     "used as a dependency" % cube)
        return removed

    def rewrite_configuration(self):
        # import locally, show_diffs unavailable in gae environment
        from cubicweb.toolsutils import show_diffs
        configfile = self.config.main_config_file()
        if self._option_changes:
            read_old_config(self.config, self._option_changes, configfile)
        fd, newconfig = tempfile.mkstemp()
        for optdescr in self._option_changes:
            if optdescr[0] == 'added':
                optdict = self.config.get_option_def(optdescr[1])
                if optdict.get('default') is REQUIRED:
                    self.config.input_option(optdescr[1], optdict)
        self.config.generate_config(open(newconfig, 'w'))
        show_diffs(configfile, newconfig, askconfirm=self.confirm is not yes)
        os.close(fd)
        if exists(newconfig):
            os.unlink(newconfig)


from logging import getLogger
from cubicweb import set_log_methods
set_log_methods(MigrationHelper, getLogger('cubicweb.migration'))


def version_strictly_lower(a, b):
    if a:
        a = Version(a)
    if b:
        b = Version(b)
    return a < b

def max_version(a, b):
    return str(max(Version(a), Version(b)))

class ConfigurationProblem(object):
    """Each cube has its own list of dependencies on other cubes/versions.

    The ConfigurationProblem is used to record the loaded cubes, then to detect
    inconsistencies in their dependencies.

    See configuration management on wikipedia for litterature.
    """

    def __init__(self, config):
        self.cubes = {}
        self.config = config

    def add_cube(self, name, version):
        self.cubes[name] = version

    def solve(self):
        self.warnings = []
        self.errors = []
        self.read_constraints()
        for cube, versions in sorted(self.constraints.items()):
            oper, version = None, None
            # simplify constraints
            if versions:
                for constraint in versions:
                    op, ver = constraint
                    if oper is None:
                        oper = op
                        version = ver
                    elif op == '>=' and oper == '>=':
                        version = max_version(ver, version)
                    else:
                        print 'unable to handle this case', oper, version, op, ver
            # "solve" constraint satisfaction problem
            if cube not in self.cubes:
                self.errors.append( ('add', cube, version) )
            elif versions:
                lower_strict = version_strictly_lower(self.cubes[cube], version)
                if oper in ('>=','='):
                    if lower_strict:
                        self.errors.append( ('update', cube, version) )
                else:
                    print 'unknown operator', oper

    def read_constraints(self):
        self.constraints = {}
        self.reverse_constraints = {}
        for cube in self.cubes:
            use = self.config.cube_dependencies(cube)
            for name, constraint in use.iteritems():
                self.constraints.setdefault(name,set())
                if constraint:
                    try:
                        oper, version = constraint.split()
                        self.constraints[name].add( (oper, version) )
                    except:
                        self.warnings.append(
                            'cube %s depends on %s but constraint badly '
                            'formatted: %s' % (cube, name, constraint))
                self.reverse_constraints.setdefault(name, set()).add(cube)