django/core/management/commands/migrate.py
import sys
import time
from importlib import import_module
from django.apps import apps
from django.core.management.base import BaseCommand, CommandError, no_translations
from django.core.management.sql import emit_post_migrate_signal, emit_pre_migrate_signal
from django.db import DEFAULT_DB_ALIAS, connections, router
from django.db.migrations.autodetector import MigrationAutodetector
from django.db.migrations.executor import MigrationExecutor
from django.db.migrations.loader import AmbiguityError
from django.db.migrations.state import ModelState, ProjectState
from django.utils.module_loading import module_has_submodule
from django.utils.text import Truncator
class Command(BaseCommand):
help = (
"Updates database schema. Manages both apps with migrations and those without."
)
requires_system_checks = []
def add_arguments(self, parser):
parser.add_argument(
"--skip-checks",
action="store_true",
help="Skip system checks.",
)
parser.add_argument(
"app_label",
nargs="?",
help="App label of an application to synchronize the state.",
)
parser.add_argument(
"migration_name",
nargs="?",
help="Database state will be brought to the state after that "
'migration. Use the name "zero" to unapply all migrations.',
)
parser.add_argument(
"--noinput",
"--no-input",
action="store_false",
dest="interactive",
help="Tells Django to NOT prompt the user for input of any kind.",
)
parser.add_argument(
"--database",
default=DEFAULT_DB_ALIAS,
help=(
'Nominates a database to synchronize. Defaults to the "default" '
"database."
),
)
parser.add_argument(
"--fake",
action="store_true",
help="Mark migrations as run without actually running them.",
)
parser.add_argument(
"--fake-initial",
action="store_true",
help=(
"Detect if tables already exist and fake-apply initial migrations if "
"so. Make sure that the current database schema matches your initial "
"migration before using this flag. Django will only check for an "
"existing table name."
),
)
parser.add_argument(
"--plan",
action="store_true",
help="Shows a list of the migration actions that will be performed.",
)
parser.add_argument(
"--run-syncdb",
action="store_true",
help="Creates tables for apps without migrations.",
)
parser.add_argument(
"--check",
action="store_true",
dest="check_unapplied",
help=(
"Exits with a non-zero status if unapplied migrations exist and does "
"not actually apply migrations."
),
)
parser.add_argument(
"--prune",
action="store_true",
dest="prune",
help="Delete nonexistent migrations from the django_migrations table.",
)
@no_translations
def handle(self, *args, **options):
database = options["database"]
if not options["skip_checks"]:
self.check(databases=[database])
self.verbosity = options["verbosity"]
self.interactive = options["interactive"]
# Import the 'management' module within each installed app, to register
# dispatcher events.
for app_config in apps.get_app_configs():
if module_has_submodule(app_config.module, "management"):
import_module(".management", app_config.name)
# Get the database we're operating from
connection = connections[database]
# Hook for backends needing any database preparation
connection.prepare_database()
# Work out which apps have migrations and which do not
executor = MigrationExecutor(connection, self.migration_progress_callback)
# Raise an error if any migrations are applied before their dependencies.
executor.loader.check_consistent_history(connection)
# Before anything else, see if there's conflicting apps and drop out
# hard if there are any
conflicts = executor.loader.detect_conflicts()
if conflicts:
name_str = "; ".join(
"%s in %s" % (", ".join(names), app) for app, names in conflicts.items()
)
raise CommandError(
"Conflicting migrations detected; multiple leaf nodes in the "
"migration graph: (%s).\nTo fix them run "
"'python manage.py makemigrations --merge'" % name_str
)
# If they supplied command line arguments, work out what they mean.
run_syncdb = options["run_syncdb"]
target_app_labels_only = True
if options["app_label"]:
# Validate app_label.
app_label = options["app_label"]
try:
apps.get_app_config(app_label)
except LookupError as err:
raise CommandError(str(err))
if run_syncdb:
if app_label in executor.loader.migrated_apps:
raise CommandError(
"Can't use run_syncdb with app '%s' as it has migrations."
% app_label
)
elif app_label not in executor.loader.migrated_apps:
raise CommandError("App '%s' does not have migrations." % app_label)
if options["app_label"] and options["migration_name"]:
migration_name = options["migration_name"]
if migration_name == "zero":
targets = [(app_label, None)]
else:
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." % (migration_name, app_label)
)
except KeyError:
raise CommandError(
"Cannot find a migration matching '%s' from app '%s'."
% (migration_name, app_label)
)
target = (app_label, migration.name)
# Partially applied squashed migrations are not included in the
# graph, use the last replacement instead.
if (
target not in executor.loader.graph.nodes
and target in executor.loader.replacements
):
incomplete_migration = executor.loader.replacements[target]
target = incomplete_migration.replaces[-1]
targets = [target]
target_app_labels_only = False
elif options["app_label"]:
targets = [
key for key in executor.loader.graph.leaf_nodes() if key[0] == app_label
]
else:
targets = executor.loader.graph.leaf_nodes()
if options["prune"]:
if not options["app_label"]:
raise CommandError(
"Migrations can be pruned only when an app is specified."
)
if self.verbosity > 0:
self.stdout.write("Pruning migrations:", self.style.MIGRATE_HEADING)
to_prune = sorted(
migration
for migration in set(executor.loader.applied_migrations)
- set(executor.loader.disk_migrations)
if migration[0] == app_label
)
squashed_migrations_with_deleted_replaced_migrations = [
migration_key
for migration_key, migration_obj in executor.loader.replacements.items()
if any(replaced in to_prune for replaced in migration_obj.replaces)
]
if squashed_migrations_with_deleted_replaced_migrations:
self.stdout.write(
self.style.NOTICE(
" Cannot use --prune because the following squashed "
"migrations have their 'replaces' attributes and may not "
"be recorded as applied:"
)
)
for migration in squashed_migrations_with_deleted_replaced_migrations:
app, name = migration
self.stdout.write(f" {app}.{name}")
self.stdout.write(
self.style.NOTICE(
" Re-run 'manage.py migrate' if they are not marked as "
"applied, and remove 'replaces' attributes in their "
"Migration classes."
)
)
else:
if to_prune:
for migration in to_prune:
app, name = migration
if self.verbosity > 0:
self.stdout.write(
self.style.MIGRATE_LABEL(f" Pruning {app}.{name}"),
ending="",
)
executor.recorder.record_unapplied(app, name)
if self.verbosity > 0:
self.stdout.write(self.style.SUCCESS(" OK"))
elif self.verbosity > 0:
self.stdout.write(" No migrations to prune.")
plan = executor.migration_plan(targets)
if options["plan"]:
self.stdout.write("Planned operations:", self.style.MIGRATE_LABEL)
if not plan:
self.stdout.write(" No planned migration operations.")
else:
for migration, backwards in plan:
self.stdout.write(str(migration), self.style.MIGRATE_HEADING)
for operation in migration.operations:
message, is_error = self.describe_operation(
operation, backwards
)
style = self.style.WARNING if is_error else None
self.stdout.write(" " + message, style)
if options["check_unapplied"]:
sys.exit(1)
return
if options["check_unapplied"]:
if plan:
sys.exit(1)
return
if options["prune"]:
return
# At this point, ignore run_syncdb if there aren't any apps to sync.
run_syncdb = options["run_syncdb"] and executor.loader.unmigrated_apps
# Print some useful info
if self.verbosity >= 1:
self.stdout.write(self.style.MIGRATE_HEADING("Operations to perform:"))
if run_syncdb:
if options["app_label"]:
self.stdout.write(
self.style.MIGRATE_LABEL(
" Synchronize unmigrated app: %s" % app_label
)
)
else:
self.stdout.write(
self.style.MIGRATE_LABEL(" Synchronize unmigrated apps: ")
+ (", ".join(sorted(executor.loader.unmigrated_apps)))
)
if target_app_labels_only:
self.stdout.write(
self.style.MIGRATE_LABEL(" Apply all migrations: ")
+ (", ".join(sorted({a for a, n in targets})) or "(none)")
)
else:
if targets[0][1] is None:
self.stdout.write(
self.style.MIGRATE_LABEL(" Unapply all migrations: ")
+ str(targets[0][0])
)
else:
self.stdout.write(
self.style.MIGRATE_LABEL(" Target specific migration: ")
+ "%s, from %s" % (targets[0][1], targets[0][0])
)
pre_migrate_state = executor._create_project_state(with_applied_migrations=True)
pre_migrate_apps = pre_migrate_state.apps
emit_pre_migrate_signal(
self.verbosity,
self.interactive,
connection.alias,
stdout=self.stdout,
apps=pre_migrate_apps,
plan=plan,
)
# Run the syncdb phase.
if run_syncdb:
if self.verbosity >= 1:
self.stdout.write(
self.style.MIGRATE_HEADING("Synchronizing apps without migrations:")
)
if options["app_label"]:
self.sync_apps(connection, [app_label])
else:
self.sync_apps(connection, executor.loader.unmigrated_apps)
# Migrate!
if self.verbosity >= 1:
self.stdout.write(self.style.MIGRATE_HEADING("Running migrations:"))
if not plan:
if self.verbosity >= 1:
self.stdout.write(" No migrations to apply.")
# If there's changes that aren't in migrations yet, tell them
# how to fix it.
autodetector = MigrationAutodetector(
executor.loader.project_state(),
ProjectState.from_apps(apps),
)
changes = autodetector.changes(graph=executor.loader.graph)
if changes:
self.stdout.write(
self.style.NOTICE(
" Your models in app(s): %s have changes that are not "
"yet reflected in a migration, and so won't be "
"applied." % ", ".join(repr(app) for app in sorted(changes))
)
)
self.stdout.write(
self.style.NOTICE(
" Run 'manage.py makemigrations' to make new "
"migrations, and then re-run 'manage.py migrate' to "
"apply them."
)
)
fake = False
fake_initial = False
else:
fake = options["fake"]
fake_initial = options["fake_initial"]
post_migrate_state = executor.migrate(
targets,
plan=plan,
state=pre_migrate_state.clone(),
fake=fake,
fake_initial=fake_initial,
)
# post_migrate signals have access to all models. Ensure that all models
# are reloaded in case any are delayed.
post_migrate_state.clear_delayed_apps_cache()
post_migrate_apps = post_migrate_state.apps
# Re-render models of real apps to include relationships now that
# we've got a final state. This wouldn't be necessary if real apps
# models were rendered with relationships in the first place.
with post_migrate_apps.bulk_update():
model_keys = []
for model_state in post_migrate_apps.real_models:
model_key = model_state.app_label, model_state.name_lower
model_keys.append(model_key)
post_migrate_apps.unregister_model(*model_key)
post_migrate_apps.render_multiple(
[ModelState.from_model(apps.get_model(*model)) for model in model_keys]
)
# Send the post_migrate signal, so individual apps can do whatever they need
# to do at this point.
emit_post_migrate_signal(
self.verbosity,
self.interactive,
connection.alias,
stdout=self.stdout,
apps=post_migrate_apps,
plan=plan,
)
def migration_progress_callback(self, action, migration=None, fake=False):
if self.verbosity >= 1:
compute_time = self.verbosity > 1
if action == "apply_start":
if compute_time:
self.start = time.monotonic()
self.stdout.write(" Applying %s..." % migration, ending="")
self.stdout.flush()
elif action == "apply_success":
elapsed = (
" (%.3fs)" % (time.monotonic() - self.start) if compute_time else ""
)
if fake:
self.stdout.write(self.style.SUCCESS(" FAKED" + elapsed))
else:
self.stdout.write(self.style.SUCCESS(" OK" + elapsed))
elif action == "unapply_start":
if compute_time:
self.start = time.monotonic()
self.stdout.write(" Unapplying %s..." % migration, ending="")
self.stdout.flush()
elif action == "unapply_success":
elapsed = (
" (%.3fs)" % (time.monotonic() - self.start) if compute_time else ""
)
if fake:
self.stdout.write(self.style.SUCCESS(" FAKED" + elapsed))
else:
self.stdout.write(self.style.SUCCESS(" OK" + elapsed))
elif action == "render_start":
if compute_time:
self.start = time.monotonic()
self.stdout.write(" Rendering model states...", ending="")
self.stdout.flush()
elif action == "render_success":
elapsed = (
" (%.3fs)" % (time.monotonic() - self.start) if compute_time else ""
)
self.stdout.write(self.style.SUCCESS(" DONE" + elapsed))
def sync_apps(self, connection, app_labels):
"""Run the old syncdb-style operation on a list of app_labels."""
with connection.cursor() as cursor:
tables = connection.introspection.table_names(cursor)
# Build the manifest of apps and models that are to be synchronized.
all_models = [
(
app_config.label,
router.get_migratable_models(
app_config, connection.alias, include_auto_created=False
),
)
for app_config in apps.get_app_configs()
if app_config.models_module is not None and app_config.label in app_labels
]
def model_installed(model):
opts = model._meta
converter = connection.introspection.identifier_converter
return not (
(converter(opts.db_table) in tables)
or (
opts.auto_created
and converter(opts.auto_created._meta.db_table) in tables
)
)
manifest = {
app_name: list(filter(model_installed, model_list))
for app_name, model_list in all_models
}
# Create the tables for each model
if self.verbosity >= 1:
self.stdout.write(" Creating tables...")
with connection.schema_editor() as editor:
for app_name, model_list in manifest.items():
for model in model_list:
# Never install unmanaged models, etc.
if not model._meta.can_migrate(connection):
continue
if self.verbosity >= 3:
self.stdout.write(
" Processing %s.%s model"
% (app_name, model._meta.object_name)
)
if self.verbosity >= 1:
self.stdout.write(
" Creating table %s" % model._meta.db_table
)
editor.create_model(model)
# Deferred SQL is executed when exiting the editor's context.
if self.verbosity >= 1:
self.stdout.write(" Running deferred SQL...")
@staticmethod
def describe_operation(operation, backwards):
"""Return a string that describes a migration operation for --plan."""
prefix = ""
is_error = False
if hasattr(operation, "code"):
code = operation.reverse_code if backwards else operation.code
action = (code.__doc__ or "") if code else None
elif hasattr(operation, "sql"):
action = operation.reverse_sql if backwards else operation.sql
else:
action = ""
if backwards:
prefix = "Undo "
if action is not None:
action = str(action).replace("\n", "")
elif backwards:
action = "IRREVERSIBLE"
is_error = True
if action:
action = " -> " + action
truncated = Truncator(action)
return prefix + operation.describe() + truncated.chars(40), is_error