Updated ReplSetConnection docs

This commit is contained in:
Kyle Banker 2010-12-15 14:14:06 -05:00
parent fe897d077c
commit a825500784
2 changed files with 43 additions and 11 deletions

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@ -6,17 +6,17 @@ Here follow a few considerations for those using the MongoDB Ruby driver with [r
First, make sure that you've configured and initialized a replica set.
Use `Connection.multi` to connect to a replica set:
Use `ReplSetConnection.new` to connect to a replica set:
@connection = Connection.multi([['n1.mydb.net', 27017], ['n2.mydb.net', 27017], ['n3.mydb.net', 27017]])
@connection = ReplSetConnection.new(['n1.mydb.net', 27017], ['n2.mydb.net', 27017], ['n3.mydb.net', 27017])
The driver will attempt to connect to a master node and, when found, will replace all seed nodes with known members of the replica set.
### Read slaves
If you want to read from a seconday node, you can pass :read_secondary => true to Connection#multi.
If you want to read from a seconday node, you can pass :read_secondary => true to ReplSetConnection#new.
@connection = Connection.multi([['n1.mydb.net', 27017], ['n2.mydb.net', 27017], ['n3.mydb.net', 27017]],
@connection = ReplSetConnection.new(['n1.mydb.net', 27017], ['n2.mydb.net', 27017], ['n3.mydb.net', 27017],
:read_secondary => true)
A random secondary will be chosen to be read from. In a typical multi-process Ruby application, you'll have a good distribution of reads across secondary nodes.
@ -62,14 +62,12 @@ Of course, the proper way to handle connection failures will always depend on th
### Testing
The Ruby driver (>= 1.0.6) includes some unit tests for verifying replica set behavior. They reside in *tests/replica_sets*. You can run them individually with the following rake tasks:
The Ruby driver (>= 1.1.5) includes unit tests for verifying replica set behavior. They reside in *tests/replica_sets*. You can run them as a group with the following rake task:
rake test:replica_set_count
rake test:replica_set_insert
rake test:pooled_replica_set_insert
rake test:replica_set_query
rake test:rs
Make sure you have a replica set running on localhost before trying to run these tests.
The suite will set up a five-node replica set by itself and ensure that driver behaves correctly even in the face
of individual node failures. Node that the `mongod` executable must be in the search path for this to work.
### Further Reading

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@ -18,10 +18,44 @@
module Mongo
# Instantiates and manages connections to MongoDB.
# Instantiates and manages connections to a MongoDB replica set.
class ReplSetConnection < Connection
attr_reader :nodes, :secondaries, :arbiters, :read_pool, :secondary_pools
# Create a connection to a MongoDB replica set.
#
# Once connected to a replica set, you can find out which nodes are primary, secondary, and
# arbiters with the corresponding accessors: Connection#primary, Connection#secondaries, and
# Connection#arbiters. This is useful if your application needs to connect manually to nodes other
# than the primary.
#
# @param [Array] args A list of host-port pairs ending with a hash containing any options. See
# the examples below for exactly how to use the constructor.
#
# @option options [Boolean, Hash] :safe (false) Set the default safe-mode options
# propogated to DB objects instantiated off of this Connection. This
# default can be overridden upon instantiation of any DB by explicity setting a :safe value
# on initialization.
# @option options [Boolean] :read_secondary(false) If true, a random secondary node will be chosen,
# and all reads will be directed to that node.
# @option options [Logger, #debug] :logger (nil) Logger instance to receive driver operation log.
# @option options [Integer] :pool_size (1) The maximum number of socket connections allowed per
# connection pool. Note: this setting is relevant only for multi-threaded applications.
# @option options [Float] :timeout (5.0) When all of the connections a pool are checked out,
# this is the number of seconds to wait for a new connection to be released before throwing an exception.
# Note: this setting is relevant only for multi-threaded applications.
#
# @example Connect to a replica set and provide two seed nodes:
# ReplSetConnection.new(['localhost', 30000], ['localhost', 30001])
#
# @example Connect to a replica set providing two seed nodes and allowing reads from a
# secondary node:
# ReplSetConnection.new(['localhost', 30000], ['localhost', 30001], :read_secondary => true)
#
# @see http://api.mongodb.org/ruby/current/file.REPLICA_SETS.html Replica sets in Ruby
#
# @raise [ReplicaSetConnectionError] This is raised if a replica set name is specified and the
# driver fails to connect to a replica set with that name.
def initialize(*args)
if args.last.is_a?(Hash)
opts = args.pop