Deploying Perl apps

Deploying a Hello World Perl application

Azure Web Apps doesn't have direct support for Perl, but it's possible to get it working with some manual steps:

• Create a Web App.
• Go to Kudu Console to easily drop files into your site.
• Go to http://strawberryperl.com/releases.html and download the "32bit ZIP edition".
• Create a perl folder under D:\home\site.
• Drag and drop the perl zip file into that folder, making sure to drop it in the special area that expands zip files. It's a big file, so it could take several minutes.
• Go into the D:\home\site\perl\perl\lib folder, and create a subfolder named FCGI.
• On your machine, download http://search.cpan.org/CPAN/authors/id/C/CO/COSMICNET/FCGI-IIS-0.05.tar.gz
• Using a tool like 7zip, extract the file IIS.pm out of it (it's under FCGI-IIS-0.05\lib\FCGI).
• Copy that file into the FCGI folder you create above in the Kudu Console.
• Go to the Azure Portal and go to you site's Configure page.
• Under Handler Mappings, add one for: Extension: *.pl, Script processor path: D:\home\site\perl\perl\bin\perl.exe, Additional arguments: -MFCGI::IIS=do.

Other FastCGI operation modes for reference:

-MFCGI::IIS=test This is a simple test routine, that displays a counter that increments by 1 each time the script is called as a FastCGI.

-MFCGI::IIS=carp In this mode, CGI::Carp qw(fatalsToBrowser) is invoked before running the do method.

-MFCGI::IIS=eval With this mode eval is used instead of the do operator. Slower run time, but allows you to trap errors.

-MFCGI::IIS=evalhead With this mode eval is used instead of the do operator, also the Content-Type: text/html header is returned first, allowing you to trap wrong header errors.

-MFCGI::IIS=do Production Mode. This is the default mode, and will be called if no arguments are given, i.e. perl -MFCGI::IIS. The calling script is loaded into the FastCGI using the do operator.

• Using Kudu console, copy a Perl file into D:\home\site\wwwroot. e.g. hello.pl.
• Request http://{yoursite}.azurewebsites.net/hello.pl to run it.

Here is an example hello.pl file you can start with:

print "Content-type: text/plain\n\n";
print "Hello from Perl on Windows!\n";

If you're using CGI.pm to write to disk (or anything that uses File::Temp for that matter), be aware that Perl does not get the right temporary location in its $ENV{TMPDIR}. You'll need to specify it yourself at the top of your script.

Example:

BEGIN { $ENV{TMPDIR} = "d:\\local\\temp"; }

use CGI;
my $q = new CGI;
print $q->header(-type => "text/plain");

print "Temporary folder set to $ENV{TMPDIR}\n";

Output:

Temporary folder set to d:\local\temp

See this issue for more details on File::Temp: https://github.com/projectkudu/kudu/issues/1700

Adding MySQL database connectivity

• Copy D:\home\site\perl\c\bin\libmysql_.dll to D:\home\site\perl\perl\vendor\lib\auto\DBD\mysql
  (See this StackOverflow thread for the "Why")

• Add BEGIN { $ENV{SYSTEMROOT} = "D:\\Windows"; } at the top of your .pl script
  (See this StackOverflow thread for the "Why")

• At this point, running your Perl script in the Kudu console should be successful.

Example:

BEGIN
{
    $ENV{TMPDIR} = "d:\\local\\temp";
    $ENV{SYSTEMROOT} = "D:\\Windows";
}

use DBI;
print "Content-type: text/plain\n\n";

$db="wordpress";
$host="a-mysql-db.cloudapp.net";
$user="db_user";
$password="db_pass";

# Connect to MySQL database
my $dbhandle = DBI->connect ("DBI:mysql:database=$db:host=$host",
                           $user,
                           $password) 
                           or die "Can't connect to database: $DBI::errstr\n";

# Execute 'SHOW TABLES'
my $statement=$dbhandle->prepare("SHOW TABLES");
$statement->execute();

while (my @row=$statement->fetchrow_array)
{
  print $row[0]."\n";
}
$statement->finish;

# Disconnect from database
$db->disconnect or warn "Disconnection error: $DBI::errstr\n";
exit;

D:\home\site\wwwroot> d:\home\site\perl\perl\bin\perl.exe TestMySQL.pl

Content-type: text/plain

wp_commentmeta
wp_comments
wp_links
wp_options
wp_postmeta
wp_posts
wp_term_relationships
wp_term_taxonomy
wp_terms
wp_usermeta
wp_users

• With the console test successful, accessing the script over FastCGI should now also render the expected results: