- The server is started first. It reads a file with the description of the various jobs that need to be done
- One or more clients (just start the client script multiple times) connect to the server and receive the information about the job at hand.
- Once the client is finished with that job, it asks for the next one (by sending a message to the server)
# server.tcl --
# Server application that distributes work among interested clients
#
# General information:
# This script sets up a server that listens to a socket.
# Clients connect to it and are then passed a "job" that
# they should process. The jobs are found in the file "server.inp"
#
# setUp --
# Create the server
# Arguments:
# None
# Return value:
# None
#
proc setUp { } {
global srvsock
set port 8085
set timeout 60000
set srvsock [socket -server [list acceptClient $timeout] $port]
}
# acceptClient --
# Accept the service request
#
# Arguments:
# timelimit Maximum time to wait
# socket Name of the socket we listen to
# ip IP address of client
# args (Possibly) all other arguments
#
# Return value:
# None
#
proc acceptClient { timelimit socket ip args } {
fconfigure $socket -block false
fileevent $socket readable [list sendJob $socket]
}
# sendJob --
# Send the description of a newjob to the client
#
# Arguments:
# socket Name of the socket we listen to
#
# Return value:
# None
#
proc sendJob { socket } {
global jobfile
global srvsock
if { ! [eof $socket] } {
gets $socket line
puts "Client: $line"
#
# Get the next job description
#
set end 1
while { [gets $jobfile job] >= 0 } {
set end 0
if { [lindex [split $job] 0] == "job" } {
puts $socket [join [lrange [split $job] 1 end]]
puts " Sent: $job"
flush $socket
break
}
}
#
# If end of job file ...
#
if { $end } {
close $jobfile
close $srvsock
puts "Server done!"
exit
}
} else {
close $socket
}
}
# main --
# Open the file with jobs and get the server going ...
#
set ::jobfile [open "server.inp" "r"]
setUp
puts "Server up and running ..."
vwait forever # client.tcl --
# Client application that takes work from a server
#
# General information:
# This script connects to the server and accepts a job to be done
#
# setUp --
# Connect to the server
# Arguments:
# None
# Return value:
# None
#
proc setUp { {host localhost} } {
global channel
set port 8085
set channel [socket $host $port]
puts $channel "client-[pid]"
flush $channel
fileevent $channel readable [list acceptJob $channel]
}
# acceptJob --
# Receive the job that is to be done from the server
#
# Arguments:
# None
# Return value:
# None
#
proc acceptJob {channel} {
if { [gets $channel line] >= 0 } {
puts "Received job: $line"
#
# Wait a while ...
#
after [expr {int(10000*rand())}]
#
# Send a string to say we are ready
#
puts $channel "client-[pid]"
flush $channel
} else {
#
# No more jobs ...
#
close $channel
puts "Done"
exit
}
}
# main --
# Get the client going ...
#
if { [llength $argv] > 0 } {
setUp [lindex $argv 0]
} else {
setUp
}
vwait forever# server.inp -- # Input for the server: # Lines that represent jobs ... # job "Test 1" job "Test 2" job "Test 3" job "Test 4" job "Test 5" job "Test 6" job "Test 7" job "Test 8" job "Test 9" job "Test 10"
"Distributed computation"
