common/migration.py
author Adrien Di Mascio <Adrien.DiMascio@logilab.fr>
Tue, 17 Feb 2009 16:33:52 +0100
changeset 676 270eb87a768a
parent 447 0e52d72104a6
child 1802 d628defebc17
permissions -rw-r--r--
provide a new add_cubes() migration function for cases where the new cubes are linked together by new relations In this case, we need to add all new cubes at once.

"""utility to ease migration of application version to newly installed
version

:organization: Logilab
:copyright: 2001-2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
"""
__docformat__ = "restructuredtext en"

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

from logilab.common.decorators import cached
from logilab.common.configuration import REQUIRED, read_old_config


def migration_files(config, toupgrade):
    """return an orderer list of path of scripts to execute to upgrade
    an installed application according to installed cube and cubicweb versions
    """
    merged = []
    for cube, fromversion, toversion in toupgrade:
        if cube == 'cubicweb':
            migrdir = config.migration_scripts_dir()
        else:
            migrdir = config.cube_migration_scripts_dir(cube)
        scripts = filter_scripts(config, migrdir, fromversion, toversion)
        merged += [s[1] for s in scripts]
    if config.accept_mode('Any'):
        migrdir = config.migration_scripts_dir()
        merged.insert(0, join(migrdir, 'bootstrapmigration_repository.py'))
    return merged


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:
        confirm = raw_input('** execute %r (Y/n/s[how]) ?' % scriptpath)
        confirm = confirm.strip().lower()
        if confirm in ('n', 'no'):
            return False
        elif confirm in ('s', '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
        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 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
        scripts = migration_files(self.config, toupgrade)
        if scripts:
            vmap = dict( (pname, (fromver, tover)) for pname, fromver, tover in toupgrade)
            self.__context.update({'applcubicwebversion': vcconf['cubicweb'],
                                   'cubicwebversion': self.config.cubicweb_version(),
                                   'versions_map': vmap})
            self.scripts_session(scripts)
        else:
            print 'no migration script to execute'            

    def shutdown(self):
        pass
    
    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 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):
        """ask for confirmation and return true on positive answer

        if `retry` is true the r[etry] answer may return 2
        """
        print question,
        possibleanswers = 'Y/n'
        if abort:
            possibleanswers += '/a[bort]'
        if shell:
            possibleanswers += '/s[hell]'
        if retry:
            possibleanswers += '/r[etry]'
        try:
            confirm = raw_input('(%s): ' % ( possibleanswers, ))
            answer = confirm.strip().lower()
        except (EOFError, KeyboardInterrupt):
            answer = 'abort'
        if answer in ('n', 'no'):
            return False
        if answer in ('r', 'retry'):
            return 2
        if answer in ('a', 'abort'):
            self.rollback()
            raise SystemExit(1)
        if shell and answer in ('s', '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')
            histfile = os.path.join(os.environ["HOME"], ".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 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
        """
        assert migrscript.endswith('.py'), migrscript
        if self.execscript_confirm(migrscript):
            scriptlocals = self._create_context().copy()
            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)
                    
    def scripts_session(self, migrscripts):
        """execute some scripts in a transaction"""
        try:
            for migrscript in migrscripts:
                self.process_script(migrscript)
            self.commit()
        except:
            self.rollback()
            raise

    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):
        origcubes = self.config._cubes
        basecubes = list(origcubes)
        for pkg in self.config.expand_cubes([cube]):
            try:
                basecubes.remove(pkg)
            except ValueError:
                continue
        self.config._cubes = tuple(self.config.expand_cubes(basecubes))
        removed = [p for p in origcubes if not p in self.config._cubes]
        assert cube in removed, \
               "can't remove cube %s, used as a dependancy" % 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)
        newconfig = mktemp()
        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)
        if exists(newconfig):
            os.unlink(newconfig)


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