#
# Suicidal Snail
#
package require zmq
if {[llength $argv] == 0} {
set argv [list driver]
} elseif {[llength $argv] != 1} {
puts "Usage: suisnail.tcl <driver|sub|pub>"
exit 1
}
lassign $argv what
set MAX_ALLOWED_DELAY 1000 ;# msecs
set tclsh [info nameofexecutable]
expr {srand([pid])}
switch -exact -- $what {
sub {
# This is our subscriber
# It connects to the publisher and subscribes to everything. It
# sleeps for a short time between messages to simulate doing too
# much work. If a message is more than 1 second late, it croaks.
zmq context context
zmq socket subpipe context PAIR
subpipe connect "ipc://subpipe.ipc"
# Subscribe to everything
zmq socket subscriber context SUB
subscriber setsockopt SUBSCRIBE ""
subscriber connect "tcp://localhost:5556"
# Get and process messages
while {1} {
set string [subscriber recv]
puts "$string (delay = [expr {[clock milliseconds] - $string}])"
if {[clock milliseconds] - $string > $::MAX_ALLOWED_DELAY} {
puts stderr "E: subscriber cannot keep up, aborting"
break
}
after [expr {1+int(rand()*2)}]
}
subpipe send "gone and died"
subscriber close
subpipe close
context term
}
pub {
# This is our server task
# It publishes a time-stamped message to its pub socket every 1ms.
zmq context context
zmq socket pubpipe context PAIR
pubpipe connect "ipc://pubpipe.ipc"
# Prepare publisher
zmq socket publisher context PUB
publisher bind "tcp://*:5556"
while {1} {
# Send current clock (msecs) to subscribers
publisher send [clock milliseconds]
if {"POLLIN" in [pubpipe getsockopt EVENTS]} {
break
}
after 1 ;# 1msec wait
}
publisher close
pubpipe close
context term
}
driver {
zmq context context
zmq socket pubpipe context PAIR
pubpipe bind "ipc://pubpipe.ipc"
zmq socket subpipe context PAIR
subpipe bind "ipc://subpipe.ipc"
puts "Start publisher, output redirected to publisher.log"
exec $tclsh suisnail.tcl pub > publisher.log 2>@1 &
puts "Start subscriber, output redirected to subscriber.log"
exec $tclsh suisnail.tcl sub > subscriber.log 2>@1 &
subpipe recv
pubpipe send "break"
after 100
pubpipe close
subpipe close
context term
}
}