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Generate parallel network traffic to test a server
Apache httpd - log files and log tools example from a Well House Consultants training course
More on Apache httpd - log files and log tools [link]

This example is described in the following article(s):
   • Tuning Apache httpd and Tomcat to work well together - [link]

Source code: o10x Module: A606
#!/usr/bin/env perl

my $host = 'http://yourdomainfortest.co.uk';

my $queLength = 25; # Number of different jobs at same time
my $VERBOSE = 1;

# Read file of URLs to be tested
# Best extracted from a log file to mimic loading proportions and order

open ( URLS, "<$ARGV[0]" ) or die "Cannot open input file: $ARGV[0]\n$!\n";

$SIG{CHLD} = 'IGNORE'; # to avoid buildup of zombies
my @urls;
my @que;
chomp (@urls = <URLS>);

foreach my $url ( @urls ) {
        $url = $host . $url;
        next if $url =~ /\'/;

# Start off a new request via ab

        pipe (*{$url},RETHAND);
        print "Requesting $url\n" if $VERBOSE > 0;

# Starts in child process so that parent can continue

        if (!($pid = fork())) {
                # Could also use the LWP library in Perl ...
                my $cmd = "/usr/local/apache2/bin/ab -c 4 -n 4 '$url'";
                my $val=`$cmd`;

                # When child has completed, tell the parent
                print RETHAND "Completed $url\n";
                print RETHAND "$val\n" if $VERBOSE > 1;
                print RETHAND "xyzz\n";

# Parent queues up the child

        push @que, $url;

# If parent has less than maximum children, go start another straight away

        next if @que < $queLength;

# If parent has reached maximum children level, wait for oldest child to complete

# Note - if some children are very slow this may result in a temporary lower load
# as younger ones finish first

        my $waitfor = shift @que;
        while ($response = <$waitfor> ) {
                last if ($response =~ /xyz/);
                print "$response" if $VERBOSE > 0;

# Loop exits while the final batch is still running - add wait code?

Learn about this subject
This module and example are covered on the following public courses:
 * Deploying Apache and Tomcat
 * Deploying Java Applications on Linux / Unix
Also available on on site courses for larger groups

Books covering this topic
Yes. We have over 700 books in our library. Books covering Lamp deployment are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples
This example comes from our "Apache httpd - log files and log tools" training module. You'll find a description of the topic and some other closely related examples on the "Apache httpd - log files and log tools" module index page.

Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.

Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License.

Other resources
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre.
The Horse's mouth provides a daily tip or thought.
• Further resources are available via the resources centre.
• All of these resources can be searched through through our search engine
• And there's a global index here.

Purpose of this website
This is a sample program, class demonstration or answer from a training course. It's main purpose is to provide an after-course service to customers who have attended our public private or on site courses, but the examples are made generally available under conditions described below.

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This web site is written and maintained by Well House Consultants.

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Past attendees on our training courses are welcome to use individual examples in the course of their programming, but must check the examples they use to ensure that they are suitable for their job. Remember that some of our examples show you how not to do things - check in your notes. Well House Consultants take no responsibility for the suitability of these example programs to customer's needs.

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