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"""
Data migration creation command
"""
from __future__ import print_function
import sys
import os
import re
from optparse import make_option
try:
set
except NameError:
from sets import Set as set
from django.core.management.base import BaseCommand
from django.core.management.color import no_style
from django.db import models
from django.conf import settings
from south.migration import Migrations
from south.exceptions import NoMigrations
from south.creator import freezer
class Command(BaseCommand):
option_list = BaseCommand.option_list + (
make_option('--freeze', action='append', dest='freeze_list', type='string',
help='Freeze the specified app(s). Provide an app name with each; use the option multiple times for multiple apps'),
make_option('--stdout', action='store_true', dest='stdout', default=False,
help='Print the migration to stdout instead of writing it to a file.'),
)
help = "Creates a new template data migration for the given app"
usage_str = "Usage: ./manage.py datamigration appname migrationname [--stdout] [--freeze appname]"
def handle(self, app=None, name="", freeze_list=None, stdout=False, verbosity=1, **options):
# Any supposed lists that are None become empty lists
freeze_list = freeze_list or []
# --stdout means name = -
if stdout:
name = "-"
# Only allow valid names
if re.search('[^_\w]', name) and name != "-":
self.error("Migration names should contain only alphanumeric characters and underscores.")
# if not name, there's an error
if not name:
self.error("You must provide a name for this migration\n" + self.usage_str)
if not app:
self.error("You must provide an app to create a migration for.\n" + self.usage_str)
# Get the Migrations for this app (creating the migrations dir if needed)
migrations = Migrations(app, force_creation=True, verbose_creation=verbosity > 0)
# See what filename is next in line. We assume they use numbers.
new_filename = migrations.next_filename(name)
# Work out which apps to freeze
apps_to_freeze = self.calc_frozen_apps(migrations, freeze_list)
# So, what's in this file, then?
file_contents = MIGRATION_TEMPLATE % {
"frozen_models": freezer.freeze_apps_to_string(apps_to_freeze),
"complete_apps": apps_to_freeze and "complete_apps = [%s]" % (", ".join(map(repr, apps_to_freeze))) or ""
}
# - is a special name which means 'print to stdout'
if name == "-":
print(file_contents)
# Write the migration file if the name isn't -
else:
fp = open(os.path.join(migrations.migrations_dir(), new_filename), "w")
fp.write(file_contents)
fp.close()
print("Created %s." % new_filename, file=sys.stderr)
def calc_frozen_apps(self, migrations, freeze_list):
"""
Works out, from the current app, settings, and the command line options,
which apps should be frozen.
"""
apps_to_freeze = []
for to_freeze in freeze_list:
if "." in to_freeze:
self.error("You cannot freeze %r; you must provide an app label, like 'auth' or 'books'." % to_freeze)
# Make sure it's a real app
if not models.get_app(to_freeze):
self.error("You cannot freeze %r; it's not an installed app." % to_freeze)
# OK, it's fine
apps_to_freeze.append(to_freeze)
if getattr(settings, 'SOUTH_AUTO_FREEZE_APP', True):
apps_to_freeze.append(migrations.app_label())
return apps_to_freeze
def error(self, message, code=1):
"""
Prints the error, and exits with the given code.
"""
print(message, file=sys.stderr)
sys.exit(code)
MIGRATION_TEMPLATE = """# -*- coding: utf-8 -*-
import datetime
from south.db import db
from south.v2 import DataMigration
from django.db import models
class Migration(DataMigration):
def forwards(self, orm):
"Write your forwards methods here."
# Note: Don't use "from appname.models import ModelName".
# Use orm.ModelName to refer to models in this application,
# and orm['appname.ModelName'] for models in other applications.
def backwards(self, orm):
"Write your backwards methods here."
models = %(frozen_models)s
%(complete_apps)s
symmetrical = True
"""
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