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First pass on squashmigrations command; files are right, execution not.

This commit is contained in:
Andrew Godwin 2013-10-16 12:00:07 +01:00
parent 42f8666f6a
commit 763ac8b642
4 changed files with 127 additions and 4 deletions
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11
django/core/management/commands/migrate.py
View File

@ -76,7 +76,7 @@ class Command(BaseCommand):
except AmbiguityError:
raise CommandError("More than one migration matches '%s' in app '%s'. Please be more specific." % (app_label, migration_name))
except KeyError:
raise CommandError("Cannot find a migration matching '%s' from app '%s'. Is it in INSTALLED_APPS?" % (app_label, migration_name))
raise CommandError("Cannot find a migration matching '%s' from app '%s'." % (app_label, migration_name))
targets = [(app_label, migration.name)]
target_app_labels_only = False
elif len(args) == 1:
@ -279,10 +279,15 @@ class Command(BaseCommand):
for node in graph.leaf_nodes(app):
for plan_node in graph.forwards_plan(node):
if plan_node not in shown and plan_node[0] == app:
# Give it a nice title if it's a squashed one
title = plan_node[1]
if graph.nodes[plan_node].replaces:
title += " (%s squashed migrations)" % len(graph.nodes[plan_node].replaces)
# Mark it as applied/unapplied
if plan_node in loader.applied_migrations:
self.stdout.write(" [X] %s" % plan_node[1])
self.stdout.write(" [X] %s" % title)
else:
self.stdout.write(" [ ] %s" % plan_node[1])
self.stdout.write(" [ ] %s" % title)
shown.add(plan_node)
# If we didn't print anything, then a small message
if not shown:

108
django/core/management/commands/squashmigrations.py Normal file
View File

@ -0,0 +1,108 @@
import sys
import os
from optparse import make_option
from django.core.management.base import BaseCommand, CommandError
from django.core.exceptions import ImproperlyConfigured
from django.utils import six
from django.db import connections, DEFAULT_DB_ALIAS, migrations
from django.db.migrations.loader import MigrationLoader, AmbiguityError
from django.db.migrations.autodetector import MigrationAutodetector, InteractiveMigrationQuestioner
from django.db.migrations.executor import MigrationExecutor
from django.db.migrations.writer import MigrationWriter
from django.db.models.loading import cache
from django.db.migrations.optimizer import MigrationOptimizer
class Command(BaseCommand):
option_list = BaseCommand.option_list + (
make_option('--no-optimize', action='store_true', dest='no_optimize', default=False,
help='Do not try to optimize the squashed operations.'),
make_option('--noinput', action='store_false', dest='interactive', default=True,
help='Tells Django to NOT prompt the user for input of any kind.'),
)
help = "Squashes an existing set of migrations (from first until specified) into a single new one."
usage_str = "Usage: ./manage.py squashmigrations app migration_name"
def handle(self, app_label=None, migration_name=None, **options):
self.verbosity = int(options.get('verbosity'))
self.interactive = options.get('interactive')
if app_label is None or migration_name is None:
self.stderr.write(self.usage_str)
sys.exit(1)
# Load the current graph state, check the app and migration they asked for exists
executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
if app_label not in executor.loader.migrated_apps:
raise CommandError("App '%s' does not have migrations (so squashmigrations on it makes no sense)" % app_label)
try:
migration = executor.loader.get_migration_by_prefix(app_label, migration_name)
except AmbiguityError:
raise CommandError("More than one migration matches '%s' in app '%s'. Please be more specific." % (app_label, migration_name))
except KeyError:
raise CommandError("Cannot find a migration matching '%s' from app '%s'." % (app_label, migration_name))
# Work out the list of predecessor migrations
migrations_to_squash = [
executor.loader.get_migration(al, mn)
for al, mn in executor.loader.graph.forwards_plan((migration.app_label, migration.name))
if al == migration.app_label
]
# Tell them what we're doing and optionally ask if we should proceed
if self.verbosity > 0 or self.interactive:
self.stdout.write(self.style.MIGRATE_HEADING("Will squash the following migrations:"))
for migration in migrations_to_squash:
self.stdout.write(" - %s" % migration.name)
if self.interactive:
answer = None
while not answer or answer not in "yn":
answer = six.moves.input("Do you wish to proceed? [yN] ")
if not answer:
answer = "n"
break
else:
answer = answer[0].lower()
if answer != "y":
return
# Load the operations from all those migrations and concat together
operations = []
for smigration in migrations_to_squash:
operations.extend(smigration.operations)
if self.verbosity > 0:
self.stdout.write(self.style.MIGRATE_HEADING("Optimizing..."))
optimizer = MigrationOptimizer()
new_operations = optimizer.optimize(operations, migration.app_label)
if self.verbosity > 0:
if len(new_operations) == len(operations):
self.stdout.write(" No optimizations possible.")
else:
self.stdout.write(" Optimized from %s operations to %s operations." % (len(operations), len(new_operations)))
# Make a new migration with those operations
subclass = type("Migration", (migrations.Migration, ), {
"dependencies": [],
"operations": new_operations,
"replaces": [(m.app_label, m.name) for m in migrations_to_squash],
})
new_migration = subclass("0001_squashed_%s" % migration.name, app_label)
# Write out the new migration file
writer = MigrationWriter(new_migration)
with open(writer.path, "wb") as fh:
fh.write(writer.as_string())
if self.verbosity > 0:
self.stdout.write(self.style.MIGRATE_HEADING("Created new squashed migration %s" % writer.path))
self.stdout.write(" You should commit this migration but leave the old ones in place;")
self.stdout.write(" the new migration will be used for new installs. Once you are sure")
self.stdout.write(" all instances of the codebase have applied the migrations you squashed,")
self.stdout.write(" you can delete them.")

6
django/db/migrations/loader.py
View File

@ -101,6 +101,10 @@ class MigrationLoader(object):
if south_style_migrations:
self.unmigrated_apps.add(app_label)
def get_migration(self, app_label, name_prefix):
"Gets the migration exactly named, or raises KeyError"
return self.graph.nodes[app_label, name_prefix]
def get_migration_by_prefix(self, app_label, name_prefix):
"Returns the migration(s) which match the given app label and name _prefix_"
# Make sure we have the disk data
@ -160,6 +164,8 @@ class MigrationLoader(object):
# and remove, repointing dependencies if needs be.
for replaced in migration.replaces:
if replaced in normal:
# We don't care if the replaced migration doesn't exist;
# the usage pattern here is to delete things after a while.
del normal[replaced]
for child_key in reverse_dependencies.get(replaced, set()):
normal[child_key].dependencies.remove(replaced)

6
django/db/migrations/writer.py
View File

@ -26,6 +26,7 @@ class MigrationWriter(object):
"""
items = {
"dependencies": repr(self.migration.dependencies),
"replaces_str": "",
}
imports = set()
# Deconstruct operations
@ -49,6 +50,9 @@ class MigrationWriter(object):
items["imports"] = ""
else:
items["imports"] = "\n".join(imports) + "\n"
# If there's a replaces, make a string for it
if self.migration.replaces:
items['replaces_str'] = "\n replaces = %s\n" % repr(self.migration.replaces)
return (MIGRATION_TEMPLATE % items).encode("utf8")
@property
@ -186,7 +190,7 @@ from django.db import models, migrations
%(imports)s
class Migration(migrations.Migration):
%(replaces_str)s
dependencies = %(dependencies)s
operations = %(operations)s