web/lib/django_extensions/management/commands/syncdata.py
changeset 3 526ebd3988b0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django_extensions/management/commands/syncdata.py	Wed Jan 20 12:37:40 2010 +0100
@@ -0,0 +1,221 @@
+""" 
+SyncData
+========
+
+Django command similar to 'loaddata' but also deletes.
+After 'syncdata' has run, the database will have the same data as the fixture - anything
+missing will of been added, anything different will of been updated,
+and anything extra will of been deleted.
+"""
+
+from django.core.management.base import BaseCommand
+from django.core.management.color import no_style
+from optparse import make_option
+import sys
+import os
+
+class Command(BaseCommand):
+    """ syncdata command """
+    
+    help = 'Makes the current database have the same data as the fixture(s), no more, no less.'
+    args = "fixture [fixture ...]"
+    
+    def remove_objects_not_in(self, objects_to_keep, verbosity):
+        """
+        Deletes all the objects in the database that are not in objects_to_keep.
+        - objects_to_keep: A map where the keys are classes, and the values are a
+         set of the objects of that class we should keep.
+        """
+        for class_ in objects_to_keep.keys():
+
+            current = class_.objects.all()
+            current_ids = set( [x.id for x in current] )
+            keep_ids = set( [x.id for x in objects_to_keep[class_]] )
+
+            remove_these_ones = current_ids.difference(keep_ids)
+            if remove_these_ones:
+
+                for obj in current:
+                    if obj.id in remove_these_ones:
+                        obj.delete()
+                        if verbosity >= 2:
+                            print "Deleted object: "+ unicode(obj)
+
+            if verbosity > 0 and remove_these_ones:
+                num_deleted = len(remove_these_ones)
+                if num_deleted > 1:
+                    type_deleted = unicode(class_._meta.verbose_name_plural)
+                else:
+                    type_deleted = unicode(class_._meta.verbose_name)
+
+                print "Deleted "+ str(num_deleted) +" "+ type_deleted
+
+    def handle(self, *fixture_labels, **options):
+        """ Main method of a Django command """
+        from django.db.models import get_apps
+        from django.core import serializers
+        from django.db import connection, transaction
+        from django.conf import settings
+
+        self.style = no_style()
+
+        verbosity = int(options.get('verbosity', 1))
+        show_traceback = options.get('traceback', False)
+        
+        # Keep a count of the installed objects and fixtures
+        fixture_count = 0
+        object_count = 0
+        objects_per_fixture = []
+        models = set()
+
+        humanize = lambda dirname: dirname and "'%s'" % dirname or 'absolute path'
+
+        # Get a cursor (even though we don't need one yet). This has
+        # the side effect of initializing the test database (if
+        # it isn't already initialized).
+        cursor = connection.cursor()
+
+        # Start transaction management. All fixtures are installed in a
+        # single transaction to ensure that all references are resolved.
+        transaction.commit_unless_managed()
+        transaction.enter_transaction_management()
+        transaction.managed(True)
+
+        app_fixtures = [os.path.join(os.path.dirname(app.__file__), 'fixtures') \
+                        for app in get_apps()]
+        for fixture_label in fixture_labels:
+            parts = fixture_label.split('.')
+            if len(parts) == 1:
+                fixture_name = fixture_label
+                formats = serializers.get_public_serializer_formats()
+            else:
+                fixture_name, format = '.'.join(parts[:-1]), parts[-1]
+                if format in serializers.get_public_serializer_formats():
+                    formats = [format]
+                else:
+                    formats = []
+
+            if formats:
+                if verbosity > 1:
+                    print "Loading '%s' fixtures..." % fixture_name
+            else:
+                sys.stderr.write(
+                    self.style.ERROR("Problem installing fixture '%s': %s is not a known "+ \
+                                     "serialization format." % (fixture_name, format))
+                    )
+                transaction.rollback()
+                transaction.leave_transaction_management()
+                return
+
+            if os.path.isabs(fixture_name):
+                fixture_dirs = [fixture_name]
+            else:
+                fixture_dirs = app_fixtures + list(settings.FIXTURE_DIRS) + ['']
+
+            for fixture_dir in fixture_dirs:
+                if verbosity > 1:
+                    print "Checking %s for fixtures..." % humanize(fixture_dir)
+
+                label_found = False
+                for format in formats:
+                    serializer = serializers.get_serializer(format)
+                    if verbosity > 1:
+                        print "Trying %s for %s fixture '%s'..." % \
+                            (humanize(fixture_dir), format, fixture_name)
+                    try:
+                        full_path = os.path.join(fixture_dir, '.'.join([fixture_name, format]))
+                        fixture = open(full_path, 'r')
+                        if label_found:
+                            fixture.close()
+                            print self.style.ERROR("Multiple fixtures named '%s' in %s. Aborting." %
+                                (fixture_name, humanize(fixture_dir)))
+                            transaction.rollback()
+                            transaction.leave_transaction_management()
+                            return
+                        else:
+                            fixture_count += 1
+                            objects_per_fixture.append(0)
+                            if verbosity > 0:
+                                print "Installing %s fixture '%s' from %s." % \
+                                    (format, fixture_name, humanize(fixture_dir))
+                            try:
+                                objects_to_keep = {}
+                                objects = serializers.deserialize(format, fixture)
+                                for obj in objects:
+                                    object_count += 1
+                                    objects_per_fixture[-1] += 1
+
+                                    class_ = obj.object.__class__
+                                    if not class_ in objects_to_keep:
+                                        objects_to_keep[class_] = set()
+                                    objects_to_keep[class_].add(obj.object)
+                                    
+                                    models.add(class_)
+                                    obj.save()
+
+                                self.remove_objects_not_in(objects_to_keep, verbosity)
+
+                                label_found = True
+                            except (SystemExit, KeyboardInterrupt):
+                                raise
+                            except Exception:
+                                import traceback
+                                fixture.close()
+                                transaction.rollback()
+                                transaction.leave_transaction_management()
+                                if show_traceback:
+                                    traceback.print_exc()
+                                else:
+                                    sys.stderr.write(
+                                        self.style.ERROR("Problem installing fixture '%s': %s\n" %
+                                             (full_path, traceback.format_exc())))
+                                return
+                            fixture.close()
+                    except:
+                        if verbosity > 1:
+                            print "No %s fixture '%s' in %s." % \
+                                (format, fixture_name, humanize(fixture_dir))
+
+        # If any of the fixtures we loaded contain 0 objects, assume that an 
+        # error was encountered during fixture loading.
+        if 0 in objects_per_fixture:
+            sys.stderr.write(
+                self.style.ERROR("No fixture data found for '%s'. (File format may be invalid.)" %
+                    (fixture_name)))
+            transaction.rollback()
+            transaction.leave_transaction_management()
+            return
+            
+        # If we found even one object in a fixture, we need to reset the 
+        # database sequences.
+        if object_count > 0:
+            sequence_sql = connection.ops.sequence_reset_sql(self.style, models)
+            if sequence_sql:
+                if verbosity > 1:
+                    print "Resetting sequences"
+                for line in sequence_sql:
+                    cursor.execute(line)
+            
+        transaction.commit()
+        transaction.leave_transaction_management()
+
+        if object_count == 0:
+            if verbosity > 1:
+                print "No fixtures found."
+        else:
+            if verbosity > 0:
+                print "Installed %d object(s) from %d fixture(s)" % (object_count, fixture_count)
+                
+        # Close the DB connection. This is required as a workaround for an
+        # edge case in MySQL: if the same connection is used to
+        # create tables, load data, and query, the query can return
+        # incorrect results. See Django #7572, MySQL #37735.
+        connection.close()
+
+# Backwards compatibility for Django r9110
+if not [opt for opt in Command.option_list if opt.dest=='verbosity']:
+    Command.option_list += (
+        make_option('--verbosity', '-v', action="store", dest="verbosity",
+            default='1', type='choice', choices=['0', '1', '2'],
+            help="Verbosity level; 0=minimal output, 1=normal output, 2=all output"),
+    )