#
# Freelance client - Model 2
# Uses DEALER socket to blast one or more services
#
lappend auto_path .
package require TclOO
package require zmq
package require mdp
if {[llength $argv] == 0} {
puts "Usage: flclient2.tcl <endpoint> …"
exit 1
}
# If not a single service replies within this time, give up
set GLOBAL_TIMEOUT 2500
oo::class create FLClient {
variable ctx socket servers sequence
constructor {} {
set ctx [zmq context mdcli_context_[::mdp::contextid]]
set socket [zmq socket mdcli_socket_[::mdp::socketid] $ctx DEALER]
set servers 0
set sequence 0
}
destructor {
$socket setsockopt LINGER 0
$socket close
$ctx term
}
method connect {endpoint} {
$socket connect $endpoint
incr servers
}
# Send request, get reply
method request {request} {
# Prefix request with sequence number and empty envelope
set request [zmsg push $request [incr sequence]]
set request [zmsg push $request ""]
# Blast the request to all connected servers
for {set server 0} {$server < $servers} {incr server} {
zmsg send $socket $request
}
# Wait for a matching reply to arrive from anywhere
# Since we can poll several times, calculate each one
set reply {}
set endtime [expr {[clock milliseconds] + $::GLOBAL_TIMEOUT}]
while {[clock milliseconds] < $endtime} {
set rpoll_set [zmq poll [list [list $socket {POLLIN}]] [expr {($endtime - [clock milliseconds])}]]
if {[llength $rpoll_set] && "POLLIN" in [lindex $rpoll_set 0 1]} {
# Reply is [empty][sequence][OK]
set reply [zmsg recv $socket]
if {[llength $reply] != 3} {
error "expected reply with length 3"
}
zmsg pop reply
set rsequence [zmsg pop reply]
if {$rsequence == $sequence} {
break
}
}
}
return $reply
}
}
# Create new freelance client object
set client [FLClient new]
# Connect to each endpoint
foreach endpoint $argv {
$client connect $endpoint
}
# Send a bunch of name resolution 'requests', measure time
set requests 100
set start [clock microseconds]
for {set i 0} {$i < $requests} {incr i} {
set request {}
set request [zmsg add $request "random name"]
set reply [$client request $request]
if {[llength $reply] == 0} {
puts "E: name service not available, aborting"
break
}
}
puts "Average round trip cost: [expr {([clock microseconds] - $start) / $requests}] usec"
$client destroy