Trait_* models have incorrect type for key

Each of the TraitText, TraintInt, TraitFloat
and TraitDatetime have key column which has
its type defined incorrectly as Integer. The
migrate script correctly defines the type as
String(255).

This fix updates the sqlalchemy Trait* models
to define key as String(255).

Closes-Bug: 1449752

Change-Id: I5ac2e9b811e3baa53e329732233cd0011a4d25b9

ceilometer/event/storage/impl_sqlalchemy.py

@@ -93,25 +93,25 @@ class Connection(base.Connection):
         - TraitInt
           - int trait value
           - { event_id: event -> event.id
-              key: trait type
+              key: trait name
               value: integer value
               }
         - TraitDatetime
-          - int trait value
+          - datetime trait value
           - { event_id: event -> event.id
-              key: trait type
+              key: trait name
               value: datetime value
               }
         - TraitText
-          - int trait value
+          - text trait value
           - { event_id: event -> event.id
-              key: trait type
+              key: trait name
               value: text value
               }
         - TraitFloat
-          - int trait value
+          - float trait value
           - { event_id: event -> event.id
-              key: trait type
+              key: trait name
               value: float value
               }
 

ceilometer/storage/sqlalchemy/models.py

@@ -343,7 +343,7 @@ class TraitText(Base):
         Index('ix_trait_text_event_id_key', 'event_id', 'key'),
     )
     event_id = Column(Integer, ForeignKey('event.id'), primary_key=True)
-    key = Column(Integer, primary_key=True)
+    key = Column(String(255), primary_key=True)
     value = Column(Text)
 
 
@@ -355,7 +355,7 @@ class TraitInt(Base):
         Index('ix_trait_int_event_id_key', 'event_id', 'key'),
     )
     event_id = Column(Integer, ForeignKey('event.id'), primary_key=True)
-    key = Column(Integer, primary_key=True)
+    key = Column(String(255), primary_key=True)
     value = Column(Integer)
 
 
@@ -367,7 +367,7 @@ class TraitFloat(Base):
         Index('ix_trait_float_event_id_key', 'event_id', 'key'),
     )
     event_id = Column(Integer, ForeignKey('event.id'), primary_key=True)
-    key = Column(Integer, primary_key=True)
+    key = Column(String(255), primary_key=True)
     value = Column(Float(53))
 
 
@@ -379,5 +379,5 @@ class TraitDatetime(Base):
         Index('ix_trait_datetime_event_id_key', 'event_id', 'key'),
     )
     event_id = Column(Integer, ForeignKey('event.id'), primary_key=True)
-    key = Column(Integer, primary_key=True)
+    key = Column(String(255), primary_key=True)
     value = Column(PreciseTimestamp())