Migrate question product tags to products M2M.

migrations/194-questions-product-migration.py

@@ -0,0 +1,43 @@
+from django.utils.encoding import smart_str
+
+from products.models import Product
+from taggit.models import Tag
+from questions.models import Question
+
+tags_to_migrate = {
+    # source tag -> product
+    'desktop': ['firefox'],
+    'mobile': ['mobile']
+}
+
+
+def assert_equals(a, b):
+    assert a == b, '%s != %s' % (a, b)
+
+
+def run():
+    # Get all the tags to migrate.
+    tags = list(Tag.objects.filter(slug__in=tags_to_migrate.keys()))
+
+    total_affected = 0
+
+    # For each tag, get the question and add a product for it.
+    for tag in tags:
+        for product_slug in tags_to_migrate[tag.slug]:
+            product = Product.objects.get(slug=product_slug)
+
+            # Assign the product to all the questions tagged with tag.
+            # Pull in 5000 at a time from the db.
+            n = 5000
+            qs = Question.objects.filter(tags__slug=tag.slug)
+            count = qs.count()
+            print '%s %s questions to work on...' % (count, product_slug)
+            for i in range(0, count, n):
+                for question in qs[i:i + n]:
+                    question.products.add(product)
+
+                    print 'Added product "%s" to question "%s"' % (
+                        smart_str(product.slug), smart_str(question.title))
+                    total_affected += 1
+
+    print 'Done! (%d)' % total_affected