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#
# Author:: Serdar Sutay (<serdar@chef.io>)
# Copyright:: Copyright 2012-2016, Chef Software Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# == net-ssh-multi gem patch for concurrency
# net-ssh-multi gem has 2 bugs associated with the use of
# :concurrent_connections option.
# 1-) There is a race condition while fetching the next_session when
# :concurrent_connections are set. @open_connections is being
# incremented by the connection thread and sometimes
# realize_pending_connections!() method can create more than required
# connection threads before the @open_connections is set by the
# previously created threads.
# 2-) When :concurrent_connections is set, server classes are setup
# with PendingConnection objects that always return true to busy?
# calls. If a connection fails when :concurrent_connections is set,
# server ends up returning true to all busy? calls since the session
# object is not replaced. Due to this, main event loop (process()
# function) never gets terminated.
#
# See: https://github.com/net-ssh/net-ssh-multi/pull/4
require "net/ssh/multi/version"
if Net::SSH::Multi::Version::STRING == "1.1.0" || Net::SSH::Multi::Version::STRING == "1.2.0"
require "net/ssh/multi"
module Net
module SSH
module Multi
class Server
# Make sure that server returns false if the ssh connection
# has failed.
def busy?(include_invisible=false)
!failed? && session && session.busy?(include_invisible)
end
end
class Session
def next_session(server, force=false) #:nodoc:
# don't retry a failed attempt
return nil if server.failed?
@session_mutex.synchronize do
if !force && concurrent_connections && concurrent_connections <= open_connections
connection = PendingConnection.new(server)
@pending_sessions << connection
return connection
end
# ===== PATCH START
# Only increment the open_connections count if the connection
# is not being forced. Incase of a force, it will already be
# incremented.
if !force
@open_connections += 1
end
# ===== PATCH END
end
begin
server.new_session
# I don't understand why this should be necessary--StandardError is a
# subclass of Exception, after all--but without explicitly rescuing
# StandardError, things like Errno::* and SocketError don't get caught
# here!
rescue Exception, StandardError => e
server.fail!
@session_mutex.synchronize { @open_connections -= 1 }
case on_error
when :ignore then
# do nothing
when :warn then
warn("error connecting to #{server}: #{e.class} (#{e.message})")
when Proc then
go = catch(:go) { on_error.call(server); nil }
case go
when nil, :ignore then # nothing
when :retry then retry
when :raise then raise
else warn "unknown 'go' command: #{go.inspect}"
end
else
raise
end
return nil
end
end
def realize_pending_connections! #:nodoc:
return unless concurrent_connections
server_list.each do |server|
server.close if !server.busy?(true)
server.update_session!
end
@connect_threads.delete_if { |t| !t.alive? }
count = concurrent_connections ? (concurrent_connections - open_connections) : @pending_sessions.length
count.times do
session = @pending_sessions.pop or break
# ===== PATCH START
# Increment the open_connections count here to prevent
# creation of connection thread again before that is
# incremented by the thread.
@session_mutex.synchronize { @open_connections += 1 }
# ===== PATCH END
@connect_threads << Thread.new do
session.replace_with(next_session(session.server, true))
end
end
end
end
end
end
end
end
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