From 845075031a6a6fc720f4b5d587556aec65519f3c Mon Sep 17 00:00:00 2001
From: Steve Baker <sbaker@redhat.com>
Date: Tue, 21 Jun 2016 14:11:39 +1200
Subject: [PATCH] Remove the db object delete method

The HeatBase.delete method starts its own (sub) transaction with one
of three possible sessions. This change moves all delete calls to a
sqlalchemy.api function with the current context session. This will help with
bug #1479723 to always do deletes with a session provided by the
context manager.

Change-Id: I8dfd3bc6fdb44b0e3b06fab5d7dc8e06fa3d80a8
---
 heat/db/api.py               |  4 ++++
 heat/db/sqlalchemy/api.py    | 37 +++++++++++++++++++++++++-----------
 heat/db/sqlalchemy/models.py | 10 ----------
 heat/objects/resource.py     |  3 +--
 4 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/heat/db/api.py b/heat/db/api.py
index 899d83c3ec..9fbb9c7cb8 100644
--- a/heat/db/api.py
+++ b/heat/db/api.py
@@ -118,6 +118,10 @@ def resource_create(context, values):
     return IMPL.resource_create(context, values)
 
 
+def resource_delete(context, resource_id):
+    return IMPL.resource_delete(context, resource_id)
+
+
 def resource_exchange_stacks(context, resource_id1, resource_id2):
     return IMPL.resource_exchange_stacks(context, resource_id1, resource_id2)
 
diff --git a/heat/db/sqlalchemy/api.py b/heat/db/sqlalchemy/api.py
index 0c27409107..55a5f1ada7 100644
--- a/heat/db/sqlalchemy/api.py
+++ b/heat/db/sqlalchemy/api.py
@@ -125,14 +125,17 @@ def raw_template_update(context, template_id, values):
 def raw_template_delete(context, template_id):
     raw_template = raw_template_get(context, template_id)
     raw_tmpl_files_id = raw_template.files_id
-    raw_template.delete()
-    if raw_tmpl_files_id is None:
-        return
-    # If no other raw_template is referencing the same raw_template_files,
-    # delete that too
-    if context.session.query(models.RawTemplate).filter_by(
-            files_id=raw_tmpl_files_id).first() is None:
-        raw_template_files_get(context, raw_tmpl_files_id).delete()
+    session = context.session
+    with session.begin(subtransactions=True):
+        session.delete(raw_template)
+        if raw_tmpl_files_id is None:
+            return
+        # If no other raw_template is referencing the same raw_template_files,
+        # delete that too
+        if session.query(models.RawTemplate).filter_by(
+                files_id=raw_tmpl_files_id).first() is None:
+            raw_tmpl_files = raw_template_files_get(context, raw_tmpl_files_id)
+            session.delete(raw_tmpl_files)
 
 
 def raw_template_files_create(context, values):
@@ -221,6 +224,14 @@ def resource_update(context, resource_id, values, atomic_key,
         return bool(rows_updated)
 
 
+def resource_delete(context, resource_id):
+    session = context.session
+    with session.begin(subtransactions=True):
+        resource = session.query(models.Resource).get(resource_id)
+        if resource:
+            session.delete(resource)
+
+
 def resource_data_get_all(context, resource_id, data=None):
     """Looks up resource_data by resource.id.
 
@@ -276,7 +287,7 @@ def stack_tags_delete(context, stack_id):
         result = stack_tags_get(context, stack_id)
         if result:
             for tag in result:
-                tag.delete()
+                session.delete(tag)
 
 
 def stack_tags_get(context, stack_id):
@@ -334,7 +345,9 @@ def resource_exchange_stacks(context, resource_id1, resource_id2):
 
 def resource_data_delete(context, resource_id, key):
     result = resource_data_get_by_key(context, resource_id, key)
-    result.delete()
+    session = context.session
+    with session.begin(subtransactions=True):
+        session.delete(result)
 
 
 def resource_create(context, values):
@@ -1039,7 +1052,9 @@ def software_deployment_update(context, deployment_id, values):
 
 def software_deployment_delete(context, deployment_id):
     deployment = software_deployment_get(context, deployment_id)
-    deployment.delete()
+    session = context.session
+    with session.begin(subtransactions=True):
+        session.delete(deployment)
 
 
 def snapshot_create(context, values):
diff --git a/heat/db/sqlalchemy/models.py b/heat/db/sqlalchemy/models.py
index dd6d38ff66..3b360f7df1 100644
--- a/heat/db/sqlalchemy/models.py
+++ b/heat/db/sqlalchemy/models.py
@@ -46,16 +46,6 @@ class HeatBase(models.ModelBase, models.TimestampMixin):
                 session = get_session()
         session.expire(self, attrs)
 
-    def delete(self, session=None):
-        """Delete this object."""
-        if not session:
-            session = orm_session.Session.object_session(self)
-            if not session:
-                session = get_session()
-        session.begin(subtransactions=True)
-        session.delete(self)
-        session.commit()
-
     def update_and_save(self, values, session=None):
         if not session:
             session = orm_session.Session.object_session(self)
diff --git a/heat/objects/resource.py b/heat/objects/resource.py
index 656e221242..9b632a4828 100644
--- a/heat/objects/resource.py
+++ b/heat/objects/resource.py
@@ -125,8 +125,7 @@ class Resource(
 
     @classmethod
     def delete(cls, context, resource_id):
-        resource_db = db_api.resource_get(context, resource_id)
-        resource_db.delete()
+        db_api.resource_delete(context, resource_id)
 
     @classmethod
     def exchange_stacks(cls, context, resource_id1, resource_id2):