Generated: Wed 2013-03-13 10:33 CET
Source file: /media/Envs/Envs/filer-gallery/lib/python2.7/site-packages/south/migration/__init__.py
Stats: 0 executed, 141 missed, 11 excluded, 76 ignored
"""
Main migration logic.
"""
import sys
from django.core.exceptions import ImproperlyConfigured
import south.db
from south import exceptions
from south.models import MigrationHistory
from south.db import db, DEFAULT_DB_ALIAS
from south.migration.migrators import (Backwards, Forwards,
DryRunMigrator, FakeMigrator,
LoadInitialDataMigrator)
from south.migration.base import Migration, Migrations
from south.migration.utils import SortedSet
from south.migration.base import all_migrations
from south.signals import pre_migrate, post_migrate
def to_apply(forwards, done):
return [m for m in forwards if m not in done]
def to_unapply(backwards, done):
return [m for m in backwards if m in done]
def problems(pending, done):
last = None
if not pending:
raise StopIteration()
for migration in pending:
if migration in done:
last = migration
continue
if last and migration not in done:
yield last, migration
def forwards_problems(pending, done, verbosity):
"""
Takes the list of linearised pending migrations, and the set of done ones,
and returns the list of problems, if any.
"""
return inner_problem_check(problems(reversed(pending), done), done, verbosity)
def backwards_problems(pending, done, verbosity):
return inner_problem_check(problems(pending, done), done, verbosity)
def inner_problem_check(problems, done, verbosity):
"Takes a set of possible problems and gets the actual issues out of it."
result = []
for last, migration in problems:
# 'Last' is the last applied migration. Step back from it until we
# either find nothing wrong, or we find something.
to_check = list(last.dependencies)
while to_check:
checking = to_check.pop()
if checking not in done:
# That's bad. Error.
if verbosity:
print (" ! Migration %s should not have been applied "
"before %s but was." % (last, checking))
result.append((last, checking))
else:
to_check.extend(checking.dependencies)
return result
def check_migration_histories(histories, delete_ghosts=False, ignore_ghosts=False):
"Checks that there's no 'ghost' migrations in the database."
exists = SortedSet()
ghosts = []
for h in histories:
try:
m = h.get_migration()
m.migration()
except exceptions.UnknownMigration:
ghosts.append(h)
except ImproperlyConfigured:
pass # Ignore missing applications
else:
exists.add(m)
if ghosts:
# They may want us to delete ghosts.
if delete_ghosts:
for h in ghosts:
h.delete()
elif not ignore_ghosts:
raise exceptions.GhostMigrations(ghosts)
return exists
def get_dependencies(target, migrations):
forwards = list
backwards = list
if target is None:
backwards = migrations[0].backwards_plan
else:
forwards = target.forwards_plan
# When migrating backwards we want to remove up to and
# including the next migration up in this app (not the next
# one, that includes other apps)
migration_before_here = target.next()
if migration_before_here:
backwards = migration_before_here.backwards_plan
return forwards, backwards
def get_direction(target, applied, migrations, verbosity, interactive):
# Get the forwards and reverse dependencies for this target
forwards, backwards = get_dependencies(target, migrations)
# Is the whole forward branch applied?
problems = None
forwards = forwards()
workplan = to_apply(forwards, applied)
if not workplan:
# If they're all applied, we only know it's not backwards
direction = None
else:
# If the remaining migrations are strictly a right segment of
# the forwards trace, we just need to go forwards to our
# target (and check for badness)
problems = forwards_problems(forwards, applied, verbosity)
direction = Forwards(verbosity=verbosity, interactive=interactive)
if not problems:
# What about the whole backward trace then?
backwards = backwards()
missing_backwards = to_apply(backwards, applied)
if missing_backwards != backwards:
# If what's missing is a strict left segment of backwards (i.e.
# all the higher migrations) then we need to go backwards
workplan = to_unapply(backwards, applied)
problems = backwards_problems(backwards, applied, verbosity)
direction = Backwards(verbosity=verbosity, interactive=interactive)
return direction, problems, workplan
def get_migrator(direction, db_dry_run, fake, load_initial_data):
if not direction:
return direction
if db_dry_run:
direction = DryRunMigrator(migrator=direction, ignore_fail=False)
elif fake:
direction = FakeMigrator(migrator=direction)
elif load_initial_data:
direction = LoadInitialDataMigrator(migrator=direction)
return direction
def get_unapplied_migrations(migrations, applied_migrations):
applied_migration_names = ['%s.%s' % (mi.app_name,mi.migration) for mi in applied_migrations]
for migration in migrations:
is_applied = '%s.%s' % (migration.app_label(), migration.name()) in applied_migration_names
if not is_applied:
yield migration
def migrate_app(migrations, target_name=None, merge=False, fake=False, db_dry_run=False, yes=False, verbosity=0, load_initial_data=False, skip=False, database=DEFAULT_DB_ALIAS, delete_ghosts=False, ignore_ghosts=False, interactive=False):
app_label = migrations.app_label()
verbosity = int(verbosity)
# Fire off the pre-migrate signal
pre_migrate.send(None, app=app_label)
# If there aren't any, quit quizically
if not migrations:
print "? You have no migrations for the '%s' app. You might want some." % app_label
return
# Load the entire dependency graph
Migrations.calculate_dependencies()
# Check there's no strange ones in the database
applied_all = MigrationHistory.objects.filter(applied__isnull=False).order_by('applied').using(database)
applied = applied_all.filter(app_name=app_label).using(database)
south.db.db = south.db.dbs[database]
Migrations.invalidate_all_modules()
south.db.db.debug = (verbosity > 1)
if target_name == 'current-1':
if applied.count() > 1:
previous_migration = applied[applied.count() - 2]
if verbosity:
print 'previous_migration: %s (applied: %s)' % (previous_migration.migration, previous_migration.applied)
target_name = previous_migration.migration
else:
if verbosity:
print 'previous_migration: zero'
target_name = 'zero'
elif target_name == 'current+1':
try:
first_unapplied_migration = get_unapplied_migrations(migrations, applied).next()
target_name = first_unapplied_migration.name()
except StopIteration:
target_name = None
applied_all = check_migration_histories(applied_all, delete_ghosts, ignore_ghosts)
# Guess the target_name
target = migrations.guess_migration(target_name)
if verbosity:
if target_name not in ('zero', None) and target.name() != target_name:
print " - Soft matched migration %s to %s." % (target_name,
target.name())
print "Running migrations for %s:" % app_label
# Get the forwards and reverse dependencies for this target
direction, problems, workplan = get_direction(target, applied_all, migrations,
verbosity, interactive)
if problems and not (merge or skip):
raise exceptions.InconsistentMigrationHistory(problems)
# Perform the migration
migrator = get_migrator(direction, db_dry_run, fake, load_initial_data)
if migrator:
migrator.print_title(target)
success = migrator.migrate_many(target, workplan, database)
# Finally, fire off the post-migrate signal
if success:
post_migrate.send(None, app=app_label)
else:
if verbosity:
# Say there's nothing.
print '- Nothing to migrate.'
# If we have initial data enabled, and we're at the most recent
# migration, do initial data.
# Note: We use a fake Forwards() migrator here. It's never used really.
if load_initial_data:
migrator = LoadInitialDataMigrator(migrator=Forwards(verbosity=verbosity))
migrator.load_initial_data(target, db=database)
# Send signal.
post_migrate.send(None, app=app_label)