Replica Set connection improvements for refresh and multi-threaded apps.

This commit is contained in:
Kyle Banker 2011-09-13 17:50:01 -04:00
parent a370f3abed
commit 83eaa4d51b
9 changed files with 128 additions and 80 deletions

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@ -53,7 +53,7 @@ module Mongo
def initialize(name, db, opts={})
if db.is_a?(String) && name.is_a?(Mongo::DB)
warn "Warning: the order of parameters to initialize a collection have changed. " +
"Please specify the collection name first, followed by the db. This will be made permanent"
"Please specify the collection name first, followed by the db. This will be made permanent" +
"in v2.0."
db, name = name, db
end

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@ -30,9 +30,6 @@ module Mongo
Mutex = ::Mutex
ConditionVariable = ::ConditionVariable
# Abort connections if a ConnectionError is raised.
Thread.abort_on_exception = true
DEFAULT_PORT = 27017
STANDARD_HEADER_SIZE = 16
RESPONSE_HEADER_SIZE = 20

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@ -23,7 +23,7 @@ module Mongo
# Instantiates and manages connections to a MongoDB replica set.
class ReplSetConnection < Connection
attr_reader :nodes, :secondaries, :arbiters, :secondary_pools,
:replica_set_name, :read_pool, :seeds, :tags_to_pools, :refresh_interval
:replica_set_name, :read_pool, :seeds, :tags_to_pools, :refresh_interval, :auto_refresh
# Create a connection to a MongoDB replica set.
#
@ -62,6 +62,8 @@ module Mongo
# prevent you from having to reconnect manually.
# @option opts [Integer] :refresh_interval (90) If :auto_refresh is enabled, this is the number of seconds
# that the background thread will sleep between calls to check the replica set's state.
# @option opts [Boolean] :require_primary (true) If true, require a primary node for the connection
# to succeed. Otherwise, connection will succeed as long as there's at least one secondary.
#
# @example Connect to a replica set and provide two seed nodes. Note that the number of seed nodes does
# not have to be equal to the number of replica set members. The purpose of seed nodes is to permit
@ -148,6 +150,9 @@ module Mongo
@replica_set_name = opts[:name]
end
# Require a primary node to connect?
@require_primary = opts.fetch(:require_primary, false)
setup(opts)
end
@ -158,6 +163,7 @@ module Mongo
# Initiate a connection to the replica set.
def connect
log(:debug, "Connecting.")
sync_synchronize(:EX) do
return if @connected
manager = PoolManager.new(self, @seeds)
@ -166,8 +172,10 @@ module Mongo
update_config(manager)
initiate_auto_refresh
if @primary.nil? #TODO: in v2.0, we'll let this be optional and do a lazy connect.
if @require_primary && @primary.nil? #TODO: in v2.0, we'll let this be optional and do a lazy connect.
raise ConnectionFailure, "Failed to connect to primary node."
elsif !@read_pool
raise ConnectionFailure, "Failed to connect to any node."
else
@connected = true
end
@ -205,11 +213,14 @@ module Mongo
end
background_manager = Thread.current[:background]
if background_manager.update_required?(@hosts)
sync_synchronize(:EX) do
background_manager.connect
update_config(background_manager)
end
# Return if another thread is already in the process of refreshing.
return if sync_exclusive?
sync_synchronize(:EX) do
log(:debug, "Refreshing...")
background_manager.connect
update_config(background_manager)
end
end
@ -259,35 +270,36 @@ module Mongo
# Close the connection to the database.
# TODO: we should get an exclusive lock here.
def close
@connected = false
sync_synchronize(:EX) do
@connected = false
super
super
if @refresh_thread
@refresh_thread.kill
@refresh_thread = nil
end
if @nodes
@nodes.each do |member|
member.disconnect
if @refresh_thread
@refresh_thread.kill
@refresh_thread = nil
end
end
@nodes = []
@read_pool = nil
if @secondary_pools
@secondary_pools.each do |pool|
pool.close
if @nodes
@nodes.each do |member|
member.disconnect
end
end
end
@secondaries = []
@secondary_pools = []
@arbiters = []
@tags_to_pools.clear
@sockets_to_pools.clear
@nodes = []
@read_pool = nil
if @secondary_pools
@secondary_pools.each do |pool|
pool.close
end
end
@secondaries = []
@secondary_pools = []
@arbiters = []
@tags_to_pools.clear
@sockets_to_pools.clear
end
end
# If a ConnectionFailure is raised, this method will be called
@ -342,17 +354,25 @@ module Mongo
# if no read pool has been defined.
def checkout_reader
connect unless connected?
socket = get_socket_from_pool(@read_pool)
sync_synchronize(:SH) do
socket = @read_pool.checkout
@sockets_to_pools[socket] = @read_pool
if !socket
refresh
socket = get_socket_from_pool(@primary_pool)
end
if socket
socket
else
raise ConnectionFailure.new("Could not connect to a node for reading.")
end
end
# Checkout a socket connected to a node with one of
# the provided tags. If no such node exists, raise
# an exception.
#
# NOTE: will be available in driver release v2.0.
def checkout_tagged(tags)
sync_synchronize(:SH) do
tags.each do |k, v|
@ -372,13 +392,33 @@ module Mongo
# Checkout a socket for writing (i.e., a primary node).
def checkout_writer
connect unless connected?
socket = get_socket_from_pool(@primary_pool)
sync_synchronize(:SH) do
if @primary_pool
socket = @primary_pool.checkout
@sockets_to_pools[socket] = @primary_pool
socket
if !socket
refresh
socket = get_socket_from_pool(@primary_pool)
end
if socket
socket
else
raise ConnectionFailure.new("Could not connect to primary node.")
end
end
def get_socket_from_pool(pool)
begin
sync_synchronize(:SH) do
if pool
socket = pool.checkout
@sockets_to_pools[socket] = pool
socket
end
end
rescue ConnectionFailure => ex
log(:info, "Failed to checkout from #{pool} with #{ex.class}; #{ex.message}")
return nil
end
end
@ -397,8 +437,12 @@ module Mongo
end
def checkin(socket)
if pool = @sockets_to_pools[socket]
pool.checkin(socket)
sync_synchronize(:SH) do
if pool = @sockets_to_pools[socket]
pool.checkin(socket)
elsif socket
socket.close
end
end
end
end

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@ -2,7 +2,7 @@ module Mongo
module Logging
# Log a message with the given level.
def log(level, message)
def log(level, msg)
return unless @logger
case level
when :debug then

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@ -20,6 +20,10 @@ module Mongo
end
alias :== :eql?
def close
self.socket.close if self.socket
end
def host_string
address
end

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@ -52,17 +52,19 @@ module Mongo
end
def close
@sockets.each do |sock|
begin
sock.close
rescue IOError => ex
warn "IOError when attempting to close socket connected to #{@host}:#{@port}: #{ex.inspect}"
@connection_mutex.synchronize do
(@sockets - @checked_out).each do |sock|
begin
sock.close
rescue IOError => ex
warn "IOError when attempting to close socket connected to #{@host}:#{@port}: #{ex.inspect}"
end
end
@host = @port = nil
@sockets.clear
@pids.clear
@checked_out.clear
end
@host = @port = nil
@sockets.clear
@pids.clear
@checked_out.clear
end
def inspect
@ -188,7 +190,7 @@ module Mongo
if @pids[socket] != Process.pid
@pids[socket] = nil
@sockets.delete(socket)
socket.close
socket.close if socket
checkout_new_socket
else
@checked_out << socket

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@ -23,31 +23,29 @@ module Mongo
@members = members
end
# Ensure that the view of the replica set is current by
# running the ismaster command and checking to see whether
# we've connected to all known nodes. If not, automatically
# connect to these unconnected nodes. This is handy when we've
# connected to a replica set with no primary or when a secondary
# node comes up after we've connected.
#
# If we're connected to nodes that are no longer part of the set,
# remove these from our set of secondary pools.
def update_required?(hosts)
if !@refresh_node || !@refresh_node.set_config
begin
@refresh_node = get_valid_seed_node
rescue ConnectionFailure
warn "Could not refresh config because no valid seed node was available."
return
end
end
hosts != @refresh_node.node_list
end
private
def initialize_data
begin
if @primary_pool
@primary_pool.close
end
if @secondary_pools
@secondary_pools.each do |pool|
pool.close
end
end
if @members
@members.each do |member|
member.close
end
end
rescue ConnectionFailure
end
@primary = nil
@primary_pool = nil
@read_pool = nil

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@ -6,6 +6,10 @@ require 'benchmark'
class ReplicaSetRefreshTest < Test::Unit::TestCase
include Mongo
def setup
@conn = nil
end
def teardown
RS.restart_killed_nodes
@conn.close if @conn
@ -98,7 +102,6 @@ class ReplicaSetRefreshTest < Test::Unit::TestCase
end
def test_adding_and_removing_nodes
puts "ADDING AND REMOVING"
@conn = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
[RS.host, RS.ports[2]], :refresh_interval => 2, :auto_refresh => true)

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@ -21,7 +21,7 @@ class ReplSetManager
@config = {"_id" => @name, "members" => []}
@durable = opts.fetch(:durable, false)
@path = File.join(File.expand_path(File.dirname(__FILE__)), "data")
@oplog_size = opts.fetch(:oplog_size, 512)
@oplog_size = opts.fetch(:oplog_size, 32)
@tags = [{"dc" => "ny", "rack" => "a", "db" => "main"},
{"dc" => "ny", "rack" => "b", "db" => "main"},
{"dc" => "sf", "rack" => "a", "db" => "main"}]