refactoring code, check connection in Listener. refer to Bug #943031

Code Issues Proposed changes

Change-Id: Ic04d1a918fedd5fd71f58af8e27b58deef070ee2

This commit is contained in:

Peng Yong

2012年03月11日 11:51:31 +08:00

parent 0cca58be35

commit 42a96d7ca0

2 changed files with 29 additions and 21 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download Patch File Download Diff File Expand all files Collapse all files

1
Authors

View File

@@ -149,6 +149,7 @@ Nirmal Ranganathan <rnirmal@gmail.com>

Ollie Leahy <oliver.leahy@hp.com>

Pádraig Brady <pbrady@redhat.com>

Paul Voccio <paul@openstack.org>

Peng Yong <ppyy@pubyun.com>

Philip Knouff <philip.knouff@mailtrust.com>

Renuka Apte <renuka.apte@citrix.com>

Ricardo Carrillo Cruz <emaildericky@gmail.com>

49
nova/db/sqlalchemy/session.py

View File

@@ -18,10 +18,11 @@

"""Session Handling for SQLAlchemy backend."""

import sqlalchemy.exc

import time

import sqlalchemy.interfaces

import sqlalchemy.orm

import time

from sqlalchemy.exc import DisconnectionError

import nova.exception

import nova.flags as flags

@@ -50,12 +51,34 @@ def get_session(autocommit=True, expire_on_commit=False):

class SynchronousSwitchListener(sqlalchemy.interfaces.PoolListener):

"""Switch sqlite connections to non-synchronous mode"""

def connect(self, dbapi_con, con_record):

dbapi_con.execute("PRAGMA synchronous = OFF")

class MySQLPingListener(object):

"""

Ensures that MySQL connections checked out of the

pool are alive.

Borrowed from:

http://groups.google.com/group/sqlalchemy/msg/a4ce563d802c929f

"""

def checkout(self, dbapi_con, con_record, con_proxy):

try:

dbapi_con.cursor().execute('select 1')

except dbapi_con.OperationalError, ex:

if ex.args[0] in (2006, 2013, 2014, 2045, 2055):

LOG.warn('Got mysql server has gone away: %s', ex)

raise DisconnectionError("Database server went away")

else:

raise

def get_engine():

"""Return a SQLAlchemy engine."""

connection_dict = sqlalchemy.engine.url.make_url(FLAGS.sql_connection)

@@ -70,26 +93,10 @@ def get_engine():

if not FLAGS.sqlite_synchronous:

engine_args["listeners"] = [SynchronousSwitchListener()]

engine = sqlalchemy.create_engine(FLAGS.sql_connection, **engine_args)

ensure_connection(engine)

return engine

if 'mysql' in connection_dict.drivername:

engine_args['listeners'] = [MySQLPingListener()]

def ensure_connection(engine):

remaining_attempts = FLAGS.sql_max_retries

while True:

try:

engine.connect()

return

except sqlalchemy.exc.OperationalError:

if remaining_attempts == 0:

raise

LOG.warning(_('SQL connection failed (%(connstring)s). '

'%(attempts)d attempts left.'),

{'connstring': FLAGS.sql_connection,

'attempts': remaining_attempts})

time.sleep(FLAGS.sql_retry_interval)

remaining_attempts -= 1

return sqlalchemy.create_engine(FLAGS.sql_connection, **engine_args)

def get_maker(engine, autocommit=True, expire_on_commit=False):