# this program was written by Philip Greenspun (philg@mit.edu)
# it is free to everyone under the standard GNU Public License 
# Modified by Hugh Brock hbrock@arsdigita.com 3/30/00 so keepalive could
# write monitor information into the server error log before restarting.

set connections [ns_server active]

# let's build an ns_set just to figure out how many distinct elts; kind of a kludge
# but I don't see how it would be faster in raw Tcl

set scratch [ns_set new scratch]
foreach connection $connections {
    ns_set cput $scratch [lindex $connection 1] 1
}

set distinct [ns_set size $scratch]

# run standard Unix uptime command to get load average (crude measure of 
# system health)

if [catch {set uptime_output [exec /usr/bin/uptime]} errmsg] {
   # whoops something wrong with uptime (check path)
   set uptime_output "ERROR running uptime, check path in script"
}

set connection_block ""

foreach connection $connections {
    append connection_block "[join $connection " : "]
"
}


ns_log error "Keepalive restarted the [ns_info server] server.

Server status just before restart:

There are a total of [llength $connections] requests being served
right now (to $distinct distinct IP addresses).  Note that this number
seems to include only the larger requests.  Smaller requests, e.g.,
for .html files and in-line images, seem to come and go too fast for
this program to catch.

AOLserver says that the max number of threads spawned since server
startup is [ns_totalstats HWM-threads].  The max threads since the
last interval reset (every 5 minutes or so by default):
[ns_intervalstats HWM-threads].  This final number is probably the
best estimate of current server activity.

Here's what uptime has to say about the box:

$uptime_output

conn # : client IP : state : method : url : n seconds : bytes

$connection_block
"