Keep flavor information in system_metadata

This patch copies the instance_type information into an
instance's system_metadata on creation. This provides a way
for us to recall the attributes used to create the instance
even after the type may have been deleted.

This adds db migration 153, which generates flavor information in
system_metadata for existing instances in the database, as well as
brings a test to make sure that works.

Change-Id: Iad9d640b44df5f3831de58f9e800bcf42bc0610e

2 files changed, 89 insertions, 0 deletions

diff --git a/nova/tests/compute/test_compute.py b/nova/tests/compute/test_compute.py
index dc381d800..d51c7c842 100644
--- a/nova/tests/compute/test_compute.py
+++ b/nova/tests/compute/test_compute.py
@@ -3780,6 +3780,28 @@ class ComputeAPITestCase(BaseTestCase):
         finally:
             db.instance_destroy(self.context, ref[0]['uuid'])
 
+    def test_create_saves_type_in_system_metadata(self):
+        instance_type = instance_types.get_default_instance_type()
+        (ref, resv_id) = self.compute_api.create(
+                self.context,
+                instance_type=instance_type,
+                image_href=None)
+        try:
+            sys_metadata = db.instance_system_metadata_get(self.context,
+                    ref[0]['uuid'])
+
+            instance_type_props = ['name', 'memory_mb', 'vcpus', 'root_gb',
+                                   'ephemeral_gb', 'flavorid', 'swap',
+                                   'rxtx_factor', 'vcpu_weight']
+            for key in instance_type_props:
+                sys_meta_key = "instance_type_%s" % key
+                self.assertTrue(sys_meta_key in sys_metadata)
+                self.assertEqual(str(instance_type[key]),
+                                 str(sys_metadata[sys_meta_key]))
+
+        finally:
+            db.instance_destroy(self.context, ref[0]['uuid'])
+
     def test_create_instance_associates_security_groups(self):
         # Make sure create associates security groups.
         group = self._create_group()
diff --git a/nova/tests/test_migrations.py b/nova/tests/test_migrations.py
index 3b67e6439..8c18d5511 100644
--- a/nova/tests/test_migrations.py
+++ b/nova/tests/test_migrations.py
@@ -24,6 +24,7 @@ properly both upgrading and downgrading, and that no data loss occurs
 if possible.
 """
 
+import collections
 import commands
 import ConfigParser
 import os
@@ -452,3 +453,69 @@ class TestMigrations(test.TestCase):
         self.assertEqual("", volume.deleted)
         volume = volumes.select(volumes.c.id == "second").execute().first()
         self.assertEqual(volume.id, volume.deleted)
+
+    # migration 153, copy flavor information into system_metadata
+    def _prerun_153(self, engine):
+        fake_types = [
+            dict(id=10, name='type1', memory_mb=128, vcpus=1,
+                 root_gb=10, ephemeral_gb=0, flavorid="1", swap=0,
+                 rxtx_factor=1.0, vcpu_weight=1, disabled=False,
+                 is_public=True),
+            dict(id=11, name='type2', memory_mb=512, vcpus=1,
+                 root_gb=10, ephemeral_gb=5, flavorid="2", swap=0,
+                 rxtx_factor=1.5, vcpu_weight=2, disabled=False,
+                 is_public=True),
+            dict(id=12, name='type3', memory_mb=128, vcpus=1,
+                 root_gb=10, ephemeral_gb=0, flavorid="3", swap=0,
+                 rxtx_factor=1.0, vcpu_weight=1, disabled=False,
+                 is_public=False),
+            dict(id=13, name='type4', memory_mb=128, vcpus=1,
+                 root_gb=10, ephemeral_gb=0, flavorid="4", swap=0,
+                 rxtx_factor=1.0, vcpu_weight=1, disabled=True,
+                 is_public=True),
+            dict(id=14, name='type5', memory_mb=128, vcpus=1,
+                 root_gb=10, ephemeral_gb=0, flavorid="5", swap=0,
+                 rxtx_factor=1.0, vcpu_weight=1, disabled=True,
+                 is_public=False),
+            ]
+
+        fake_instances = [
+            dict(uuid='m153-uuid1', instance_type_id=10),
+            dict(uuid='m153-uuid2', instance_type_id=11),
+            dict(uuid='m153-uuid3', instance_type_id=12),
+            dict(uuid='m153-uuid4', instance_type_id=13),
+            # NOTE(danms): no use of type5
+            ]
+
+        instances = get_table(engine, 'instances')
+        instance_types = get_table(engine, 'instance_types')
+        engine.execute(instance_types.insert(), fake_types)
+        engine.execute(instances.insert(), fake_instances)
+
+        return fake_types, fake_instances
+
+    def _check_153(self, engine, data):
+        fake_types, fake_instances = data
+        # NOTE(danms): Fetch all the tables and data from scratch after change
+        instances = get_table(engine, 'instances')
+        instance_types = get_table(engine, 'instance_types')
+        sys_meta = get_table(engine, 'instance_system_metadata')
+
+        # Collect all system metadata, indexed by instance_uuid
+        metadata = collections.defaultdict(dict)
+        for values in sys_meta.select().execute():
+            metadata[values['instance_uuid']][values['key']] = values['value']
+
+        # Taken from nova/compute/api.py
+        instance_type_props = ['id', 'name', 'memory_mb', 'vcpus',
+                               'root_gb', 'ephemeral_gb', 'flavorid',
+                               'swap', 'rxtx_factor', 'vcpu_weight']
+
+        for instance in fake_instances:
+            inst_sys_meta = metadata[instance['uuid']]
+            inst_type = fake_types[instance['instance_type_id'] - 10]
+            for prop in instance_type_props:
+                prop_name = 'instance_type_%s' % prop
+                self.assertIn(prop_name, inst_sys_meta)
+                self.assertEqual(str(inst_sys_meta[prop_name]),
+                                 str(inst_type[prop]))