import gzip
import os
import warnings
from django.apps import apps
from django.core import serializers
from django.core.management.base import BaseCommand, CommandError
from django.core.management.utils import parse_apps_and_model_labels
from django.db import DEFAULT_DB_ALIAS, router
try:
import bz2
has_bz2 = True
except ImportError:
has_bz2 = False
try:
import lzma
has_lzma = True
except ImportError:
has_lzma = False
class ProxyModelWarning(Warning):
pass
class Command(BaseCommand):
help = (
"Output the contents of the database as a fixture of the given format "
"(using each model's default manager unless --all is specified)."
)
def add_arguments(self, parser):
parser.add_argument(
'args', metavar='app_label[.ModelName]', nargs='*',
help='Restricts dumped data to the specified app_label or app_label.ModelName.',
)
parser.add_argument(
'--format', default='json',
help='Specifies the output serialization format for fixtures.',
)
parser.add_argument(
'--indent', type=int,
help='Specifies the indent level to use when pretty-printing output.',
)
parser.add_argument(
'--database',
default=DEFAULT_DB_ALIAS,
help='Nominates a specific database to dump fixtures from. '
'Defaults to the "default" database.',
)
parser.add_argument(
'-e', '--exclude', action='append', default=[],
help='An app_label or app_label.ModelName to exclude '
'(use multiple --exclude to exclude multiple apps/models).',
)
parser.add_argument(
'--natural-foreign', action='store_true', dest='use_natural_foreign_keys',
help='Use natural foreign keys if they are available.',
)
parser.add_argument(
'--natural-primary', action='store_true', dest='use_natural_primary_keys',
help='Use natural primary keys if they are available.',
)
parser.add_argument(
'-a', '--all', action='store_true', dest='use_base_manager',
help="Use Django's base manager to dump all models stored in the database, "
"including those that would otherwise be filtered or modified by a custom manager.",
)
parser.add_argument(
'--pks', dest='primary_keys',
help="Only dump objects with given primary keys. Accepts a comma-separated "
"list of keys. This option only works when you specify one model.",
)
parser.add_argument(
'-o', '--output',
help='Specifies file to which the output is written.'
)
def handle(self, *app_labels, **options):
format = options['format']
indent = options['indent']
using = options['database']
excludes = options['exclude']
output = options['output']
show_traceback = options['traceback']
use_natural_foreign_keys = options['use_natural_foreign_keys']
use_natural_primary_keys = options['use_natural_primary_keys']
use_base_manager = options['use_base_manager']
pks = options['primary_keys']
if pks:
primary_keys = [pk.strip() for pk in pks.split(',')]
else:
primary_keys = []
excluded_models, excluded_apps = parse_apps_and_model_labels(excludes)
if not app_labels:
if primary_keys:
raise CommandError("You can only use --pks option with one model")
app_list = dict.fromkeys(
app_config for app_config in apps.get_app_configs()
if app_config.models_module is not None and app_config not in excluded_apps
)
else:
if len(app_labels) > 1 and primary_keys:
raise CommandError("You can only use --pks option with one model")
app_list = {}
for label in app_labels:
try:
app_label, model_label = label.split('.')
try:
app_config = apps.get_app_config(app_label)
except LookupError as e:
raise CommandError(str(e))
if app_config.models_module is None or app_config in excluded_apps:
continue
try:
model = app_config.get_model(model_label)
except LookupError:
raise CommandError("Unknown model: %s.%s" % (app_label, model_label))
app_list_value = app_list.setdefault(app_config, [])
# We may have previously seen an "all-models" request for
# this app (no model qualifier was given). In this case
# there is no need adding specific models to the list.
if app_list_value is not None and model not in app_list_value:
app_list_value.append(model)
except ValueError:
if primary_keys:
raise CommandError("You can only use --pks option with one model")
# This is just an app - no model qualifier
app_label = label
try:
app_config = apps.get_app_config(app_label)
except LookupError as e:
raise CommandError(str(e))
if app_config.models_module is None or app_config in excluded_apps:
continue
app_list[app_config] = None
# Check that the serialization format exists; this is a shortcut to
# avoid collating all the objects and _then_ failing.
if format not in serializers.get_public_serializer_formats():
try:
serializers.get_serializer(format)
except serializers.SerializerDoesNotExist:
pass
raise CommandError("Unknown serialization format: %s" % format)
def get_objects(count_only=False):
"""
Collate the objects to be serialized. If count_only is True, just
count the number of objects to be serialized.
"""
if use_natural_foreign_keys:
models = serializers.sort_dependencies(app_list.items(), allow_cycles=True)
else:
# There is no need to sort dependencies when natural foreign
# keys are not used.
models = []
for (app_config, model_list) in app_list.items():
if model_list is None:
models.extend(app_config.get_models())
else:
models.extend(model_list)
for model in models:
if model in excluded_models:
continue
if model._meta.proxy and model._meta.proxy_for_model not in models:
warnings.warn(
"%s is a proxy model and won't be serialized." % model._meta.label,
category=ProxyModelWarning,
)
if not model._meta.proxy and router.allow_migrate_model(using, model):
if use_base_manager:
objects = model._base_manager
else:
objects = model._default_manager
queryset = objects.using(using).order_by(model._meta.pk.name)
if primary_keys:
queryset = queryset.filter(pk__in=primary_keys)
if count_only:
yield queryset.order_by().count()
else:
yield from queryset.iterator()
try:
self.stdout.ending = None
progress_output = None
object_count = 0
# If dumpdata is outputting to stdout, there is no way to display progress
if output and self.stdout.isatty() and options['verbosity'] > 0:
progress_output = self.stdout
object_count = sum(get_objects(count_only=True))
if output:
file_root, file_ext = os.path.splitext(output)
compression_formats = {
'.bz2': (open, {}, file_root),
'.gz': (gzip.open, {}, output),
'.lzma': (open, {}, file_root),
'.xz': (open, {}, file_root),
'.zip': (open, {}, file_root),
}
if has_bz2:
compression_formats['.bz2'] = (bz2.open, {}, output)
if has_lzma:
compression_formats['.lzma'] = (
lzma.open, {'format': lzma.FORMAT_ALONE}, output
)
compression_formats['.xz'] = (lzma.open, {}, output)
try:
open_method, kwargs, file_path = compression_formats[file_ext]
except KeyError:
open_method, kwargs, file_path = (open, {}, output)
if file_path != output:
file_name = os.path.basename(file_path)
warnings.warn(
f"Unsupported file extension ({file_ext}). "
f"Fixtures saved in '{file_name}'.",
RuntimeWarning,
)
stream = open_method(file_path, 'wt', **kwargs)
else:
stream = None
try:
serializers.serialize(
format, get_objects(), indent=indent,
use_natural_foreign_keys=use_natural_foreign_keys,
use_natural_primary_keys=use_natural_primary_keys,
stream=stream or self.stdout, progress_output=progress_output,
object_count=object_count,
)
finally:
if stream:
stream.close()
except Exception as e:
if show_traceback:
raise
raise CommandError("Unable to serialize database: %s" % e)