Allow long error messages for nodes

Change type of error message attribute for nodes
from a 255 character long string, i.e., sa.String(255)
to a text of variable lenght -- sa.Text.

Change-Id: I5d1d83458d961302d4696ee5089197eacc420688
Closes-bug: #1578245

nailgun/nailgun/db/migration/alembic_migrations/versions/fuel_9_0_1.py

@@ -37,6 +37,7 @@ def upgrade():
     upgrade_transaction_names()
     upgrade_clusters_replaced_info_wrong_default()
     upgrade_tasks_snapshot()
+    upgrade_node_error_msg_to_allow_long_error_msg()
 
 
 def downgrade():
@@ -44,6 +45,7 @@ def downgrade():
     downgrade_clusters_replaced_info_wrong_default()
     downgrade_transaction_names()
     downgrade_deployment_history()
+    downgrade_node_error_msg_to_allow_long_error_msg()
 
 
 def upgrade_deployment_history():
@@ -143,6 +145,12 @@ def upgrade_transaction_names():
     )
 
 
+def upgrade_node_error_msg_to_allow_long_error_msg():
+    op.alter_column(table_name='nodes',
+                    column_name='error_msg',
+                    type_=sa.Text)
+
+
 def downgrade_transaction_names():
     upgrade_enum(
         'tasks',
@@ -151,3 +159,13 @@ def downgrade_transaction_names():
         transaction_names_new,
         transaction_names_old
     )
+
+
+def downgrade_node_error_msg_to_allow_long_error_msg():
+    connection = op.get_bind()
+    connection.execute(sa.text('''
+UPDATE nodes SET error_msg = substring(error_msg for 255);
+'''))
+    op.alter_column(table_name='nodes',
+                    column_name='error_msg',
+                    type_=sa.String(255))

nailgun/nailgun/db/sqlalchemy/models/node.py

@@ -90,7 +90,7 @@ class Node(Base):
     pending_deletion = Column(Boolean, default=False)
     changes = relationship("ClusterChanges", backref="node")
     error_type = Column(Enum(*consts.NODE_ERRORS, name='node_error_type'))
-    error_msg = Column(String(255))
+    error_msg = Column(Text)
     timestamp = Column(DateTime, nullable=False)
     online = Column(Boolean, default=True)
     labels = Column(

nailgun/nailgun/test/unit/test_migration_fuel_9_0_1.py

@@ -12,6 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import datetime
+
 import alembic
 
 from nailgun.db import db
@@ -117,3 +119,30 @@ class TestTransactionsNames(base.BaseAlembicMigrationTest):
                 }
             ]
         )
+
+
+class TestNodeErrorMessage(base.BaseAlembicMigrationTest):
+
+    def test_upgrade_node_error_msg_to_allow_long_error_msg(self):
+        nodes = self.meta.tables['nodes']
+        self.assertIsInstance(nodes.columns['error_msg'].type, sa.Text)
+
+        node_uuid = '26b508d0-0d76-4159-bce9-f67ec2765480'
+        long_error_msg = ''.join('a' for i in range(500))
+
+        db.execute(
+            nodes.insert(),
+            [{
+                'uuid': node_uuid,
+                'cluster_id': None,
+                'group_id': None,
+                'status': 'discover',
+                'meta': '{}',
+                'mac': 'aa:aa:aa:aa:aa:aa',
+                'error_msg': long_error_msg,
+                'timestamp': datetime.datetime.utcnow(),
+            }]
+        )
+
+        node = db.query(nodes).filter_by(uuid=node_uuid).first()
+        self.assertEqual(long_error_msg, node.error_msg)