From e41623b4ade8236971c93e5f5bd4489df49d64b1 Mon Sep 17 00:00:00 2001
From: Corey Oordt <coreyoordt@gmail.com>
Date: Tue, 28 Aug 2012 06:56:55 -0500
Subject: [PATCH] Refactored the migration script to use the syncdb signal. The
 post_migrate signal only fires for south-managed apps, so it isn't as useful.

---
 categories/migration.py | 42 +++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/categories/migration.py b/categories/migration.py
index 470abd5..cb02f10 100644
--- a/categories/migration.py
+++ b/categories/migration.py
@@ -1,24 +1,27 @@
 from django.db import models, DatabaseError
 from django.core.exceptions import ImproperlyConfigured
-from .fields import CategoryM2MField, CategoryFKField
-from .models import Category
-from .settings import FIELD_REGISTRY
 
 
-def migrate_app(app, *args, **kwargs):
+def migrate_app(sender, app, created_models, verbosity, *args, **kwargs):
     """
     Migrate all models of this app registered
     """
+    from .fields import CategoryM2MField, CategoryFKField
+    from .models import Category
+    from .settings import FIELD_REGISTRY
+    import sys
+    import StringIO
+
+    org_stderror = sys.stderr
+    sys.stderr = StringIO.StringIO()  # south will print out errors to stderr
     try:
         from south.db import db
     except ImportError:
         raise ImproperlyConfigured("South must be installed for this command to work")
-
     # pull the information from the registry
-    if not isinstance(app, basestring):
-        return
-    fields = [fld for fld in FIELD_REGISTRY.keys() if fld.startswith(app)]
+    app_name = app.__name__.split('.')[-2]
 
+    fields = [fld for fld in FIELD_REGISTRY.keys() if fld.startswith(app_name)]
     # call the south commands to add the fields/tables
     for fld in fields:
         app_name, model_name, field_name = fld.split('.')
@@ -28,21 +31,23 @@ def migrate_app(app, *args, **kwargs):
         mdl = models.get_model(app_name, model_name)
 
         if isinstance(FIELD_REGISTRY[fld], CategoryFKField):
-            print "Adding ForeignKey %s to %s" % (field_name, model_name)
             try:
                 db.start_transaction()
                 table_name = mdl._meta.db_table
                 FIELD_REGISTRY[fld].default = -1
                 db.add_column(table_name, field_name, FIELD_REGISTRY[fld], keep_default=False)
                 db.commit_transaction()
+                if verbosity:
+                    print "Added ForeignKey %s to %s" % (field_name, model_name)
             except DatabaseError, e:
                 db.rollback_transaction()
                 if "already exists" in str(e):
-                    print "Already exists"
+                    if verbosity > 1:
+                        print "ForeignKey %s to %s already exists" % (field_name, model_name)
                 else:
+                    sys.stderr = org_stderror
                     raise e
         elif isinstance(FIELD_REGISTRY[fld], CategoryM2MField):
-            print "Adding Many2Many table between %s and %s" % (model_name, 'category')
             table_name = "%s_%s" % (mdl._meta.db_table, 'categories')
             try:
                 db.start_transaction()
@@ -53,12 +58,17 @@ def migrate_app(app, *args, **kwargs):
                 ))
                 db.create_unique(table_name, ['%s_id' % model_name, 'category_id'])
                 db.commit_transaction()
+                if verbosity:
+                    print "Added Many2Many table between %s and %s" % (model_name, 'category')
             except DatabaseError, e:
                 db.rollback_transaction()
                 if "already exists" in str(e):
-                    print "Already exists"
+                    if verbosity > 1:
+                        print "Many2Many table between %s and %s already exists" % (model_name, 'category')
                 else:
+                    sys.stderr = org_stderror
                     raise e
+    sys.stderr = org_stderror
 
 
 def drop_field(app_name, model_name, field_name):
@@ -67,6 +77,8 @@ def drop_field(app_name, model_name, field_name):
     """
     # Table is typically appname_modelname, but it could be different
     #   always best to be sure.
+    from .fields import CategoryM2MField, CategoryFKField
+    from .settings import FIELD_REGISTRY
     try:
         from south.db import db
     except ImportError:
@@ -95,9 +107,3 @@ def drop_field(app_name, model_name, field_name):
         except DatabaseError, e:
             db.rollback_transaction()
             raise e
-
-try:
-    from south.signals import post_migrate
-    post_migrate.connect(migrate_app)
-except ImportError:
-    pass