Add sql_idle_timeout

etc/glance.conf.sample

@@ -42,3 +42,12 @@ bind_port = 9191
 # registry server. Any valid SQLAlchemy connection string is fine.
 # See: http://www.sqlalchemy.org/docs/05/reference/sqlalchemy/connections.html#sqlalchemy.create_engine
 sql_connection = sqlite:///glance.sqlite
+
+# Period in seconds after which SQLAlchemy should reestablish its connection
+# to the database.
+#
+# MySQL uses a default `wait_timeout` of 8 hours, after which it will drop
+# idle connections. This can result in 'MySQL Gone Away' exceptions. If you
+# notice this, you can lower this value to ensure that SQLAlchemy reconnects
+# before MySQL can drop the connection.
+sql_idle_timeout = 3600

glance/common/config.py

@@ -293,3 +293,24 @@ def load_paste_app(app_name, options, args):
                            "configuration file %(conf_file)s."
                            "\nGot: %(e)r" % locals())
     return conf, app
+
+
+def get_option(options, option, **kwargs):
+    if option in options:
+        value = options[option]
+        type_ = kwargs.get('type', 'str')
+        if type_ == 'bool':
+            if hasattr(value, 'lower'):
+                return value.lower() == 'true'
+            else:
+                return value
+        elif type_ == 'int':
+            return int(value)
+        elif type_ == 'float':
+            return float(value)
+        else:
+            return value
+    elif 'default' in kwargs:
+        return kwargs['default']
+    else:
+        raise KeyError("option '%s' not found" % option)

glance/registry/db/api.py

@@ -27,6 +27,7 @@ from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import joinedload
 from sqlalchemy.orm import sessionmaker
 
+from glance.common import config
 from glance.common import exception
 from glance.common import utils
 from glance.registry.db import models
@@ -52,8 +53,14 @@ def configure_db(options):
     """
     global _ENGINE
     if not _ENGINE:
+        verbose = config.get_option(
+            options, 'verbose', type='bool', default=False)
+        timeout = config.get_option(
+            options, 'sql_idle_timeout', type='int', default=3600)
         _ENGINE = create_engine(options['sql_connection'],
-                                echo=options['verbose'])
+                                echo=verbose,
+                                echo_pool=verbose,
+                                pool_recycle=timeout)
         register_models()