James Cicenia wrote on 4/11/07 10:06 AM:
Anyone know of a good cheap service to monitor my web apps when they
stop responding... i.e, no instance available, etc.
My Adaptor Settings/Redirection URL is a CGI script that sends
email (see below). You can also set up a cron-job to periodically
hit your site and, e.g. create a socket connection on ports 80 and
443 to make sure httpd is up (further below), or point curl at your
site to make you're not seeing "no instance available" in your
responses (i.e. httpd is up, but your app is down).
For a one-time $36 fee www.freeshell.org will give you a unix shell
account that, I believe, has cron access.
zak.
#!/usr/bin/perl -w
# --
# -- KB error page, displayed by WO when our application is
unavailable,
# -- sends email to the webmaster if $ENV{DOCUMENT_ROOT}/
i3pkb_error is
# -- more than 10 minutes old.
# --
# -- 2005-10-25, email@hidden
# --
use strict;
# recipient of email sent by this script
use constant RECIPIENT => "webmaster\@thei3p.org";
# sender of email sent by this script
use constant SENDER => "webmaster\@thei3p.org";
# gateway to send mail through
use constant MAILHOST => "mail.thei3p.org";
# full path to error file
# must be owned by the webserver user and chmod 700
use constant ERROR_FILE => "$ENV{'DOCUMENT_ROOT'}/i3pkb_error";
# --
# -- nothing to configure below
# --
BEGIN
{
use strict;
use CGI;
use Email::Send;
use File::stat;
}
main();
sub main
{
my ($cgi, $message, $content, $submitter, @list) = undef;
# send mail if it's been 10 minutes since the last time
# this error was recorded
my $stat = lstat(ERROR_FILE);
if ($stat && (time() - $stat->mtime) > 600) {
$message .= "The application i3pkb on $ENV{'SERVER_NAME'}
is not responding and must be restarted." ;
# message to registrar
send_mail($message, (time() - $stat->mtime), RECIPIENT,
SENDER);
}
# reset the error timestamp
my $error_file = ERROR_FILE;
`touch $error_file`;
# display error page in browser
$cgi = CGI->new();
print $cgi->header();
print template();
}
#
# send_mail
# send a message
sub send_mail
{
my ($message, $age, $recipient, $sender) = @_;
my $error_file = ERROR_FILE;
send SMTP => <<"EOT", MAILHOST;
To: $recipient
From: $sender
Subject: ERROR: i3pkb on $ENV{'SERVER_NAME'} MUST BE RESTARTED
$message
$error_file was $age seconds old.
EOT
}
# --
# --
# -- template
# -- return the WO error page to display in place of the
# -- requested page.
sub template
{
open FILE, "$ENV{'DOCUMENT_ROOT'}/index.html";
my @lines = <FILE>;
close FILE;
return join "\n", @lines;
}
#!/usr/bin/perl -w
#
# dead simple server monitoring script
# checks whether a TCP socket can be created on a given server:port
# sends mail when a socket connection fails
#
# email@hidden, 2007-02-28
#
#
use strict;
use IO::Socket;
use Email::Send;
use constant MAIL_SENDER => "webmaster\@thei3p.org";
use constant MAIL_RECIPIENT => ("webmaster\@thei3p.org");
use constant SMTP_SERVER => "mail.thei3p.org";
#
# hosts
# returns a \@list of hosts and their services to monitor
sub hosts
{
my @list;
# http, https, imaps, smtp
push @list, new_host("some.host.org", "80");
push @list, new_host("some.host.org", "443");
push @list, new_host("some.host.org", "993");
push @list, new_host("some.host.org", "25");
return \@list;
}
#
# NOTHING TO CONFIGURE BELOW
#
main();
sub main
{
my ($socket, $status);
for my $host (@{ hosts() }) {
print "testing $host->{host}:$host->{port}...\n";
$socket = IO::Socket::INET->new(
PeerAddr => $host->{host},
PeerPort => $host->{port},
Proto => 'tcp',
Type => SOCK_STREAM,
Timeout => 3,
);
if (! $socket) {
print STDERR "$host->{host}:$host->{port} is
unreachable.\n";
message_send("$host->{host}:$host->{port} is
unreachable.");
}
}
}
# --
#
# new_host
# shortcut to create a new hashref of server-name, server-ip and
server-port
sub new_host
{
my ($host, $port) = @_;
return {"host" => $host, "port" => $port};
}
# --
#
# message_send
# send a warning email
sub message_send
{
my ($subject) = @_;
for my $recip (MAIL_RECIPIENT)
{
my $sender = MAIL_SENDER;
send SMTP => <<"EOT", SMTP_SERVER;
To: $recip
From: $sender
Subject: $subject
$subject
EOT
}
}
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