Table of Contents

mongoproxy is just like mysqlproxy:

(image from mysqlproxy)

why:

• load-balance on primary and secondary.
• mongo-php-drive is too heavy to create a connection
• too many php workers, too many connections
• client should not to know it's a replset(no slaveok for client)

what's better:

• single process, less ping to backend mongod
• avoid blocking ping before querys.
• one client => one server conn

TODO:

• print request_id into log done
• dump request & response done
• handler slave_ok done
• handler primary change
• client idle
• server side timeout. done
• close serverside conn when too many idle conns(easy to do).
• ssl support
• smart clients may use ismaster to find out backends, we should hide this

config

conf/mongoproxy.cfg :

MONGOPROXY_BIND = 0.0.0.0
MONGOPROXY_PORT = 9527

#replica set
MONGOPROXY_USE_REPLSET = 1

MONGOPROXY_REPLSET_NAME = cluster0
#select will go to slaves
MONGOPROXY_REPLSET_ENABLE_SLAVE = 1

#MONGOPROXY_BACKEND = 127.0.0.1:27017
MONGOPROXY_BACKEND = 127.0.0.1:30001,127.0.0.1:30003

usage

ning@ning-laptop ~/idning/blog_and_notes$ mongo --port 9527 
MongoDB shell version: 2.0.6
connecting to: 127.0.0.1:9527/test
SECONDARY> db.foo.find()
{ "_id" : ObjectId("506afa5300ee31bfddede23d"), "x" : 3 }
{ "_id" : ObjectId("506afa7a5428e4e2f65ce8fb"), "x" : 3 }
{ "_id" : ObjectId("506b30adf6f0dc3792367efe"), "3" : 5 }
{ "_id" : ObjectId("506b9f4cc50ba0162da625bf"), "x" : 3 }
SECONDARY> db.foo.insert({x:9})
PRIMARY> db.foo.find()
{ "_id" : ObjectId("506afa5300ee31bfddede23d"), "x" : 3 }
{ "_id" : ObjectId("506afa7a5428e4e2f65ce8fb"), "x" : 3 }
{ "_id" : ObjectId("506b30adf6f0dc3792367efe"), "3" : 5 }
{ "_id" : ObjectId("506b9f4cc50ba0162da625bf"), "x" : 3 }
{ "_id" : ObjectId("506ba7e74f1b2720690ce3c0"), "x" : 9 }
PRIMARY> 

test

use pymongo testcases:

git clone https://github.com/mongodb/mongo-python-driver
cd mongo-python-driver 
export DB_PORT=9527

nosetests -I test_ssl -vx

Reference

• http://www.mongodb.org/display/DOCS/Mongo+Wire+Protocol#MongoWireProtocol-OPQUERY
• https://github.com/interactive-matter/bson-c (MongoDB C Driver)
• https://github.com/mongodb/mongo-c-driver/tree/master/src (another MongoDB c driver, offical version)