Update the unique constraint for the name of an api_key so that it only looks at api_keys that are not expired (or expiry_date is null).

This will allow clients to create a new api key with the same name.

migrations/versions/0295_api_key_constraint.py

@@ -0,0 +1,23 @@
+"""
+
+Revision ID: 0295_api_key_constraint
+Revises: 0294_add_verify_reply_to
+Create Date: 2019-06-04 13:49:50.685493
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = '0295_api_key_constraint'
+down_revision = '0294_add_verify_reply_to'
+
+
+def upgrade():
+    op.drop_constraint('uix_service_to_key_name', 'api_keys', type_='unique')
+    op.create_index('uix_service_to_key_name', 'api_keys', ['service_id', 'name'], unique=True,
+                    postgresql_where=sa.text('expiry_date IS NULL'))
+
+
+def downgrade():
+    op.drop_index('uix_service_to_key_name', table_name='api_keys')
+    op.create_unique_constraint('uix_service_to_key_name', 'api_keys', ['service_id', 'name'])