Dancer::Deployment - common ways to put your Dancer app into use
Dancer has been designed to be flexible, and this flexibility extends to your choices when deploying your Dancer app.
At the simplest, your Dancer app can run standalone, operating as its own webserver using HTTP::Simple::PSGI.
Simply fire up your app:
$ perl ./mysuperwebapp.pl >> Listening on 0.0.0.0:3000 == Entering the dance floor ...
Point your browser at it, and away you go!
This option can be useful for small personal web apps or internal apps, but if you want to make your app available to the world, it probably won't suit you.
Another option would be to run your app stand-alone as described above, but then use a proxy or load balancer to accept incoming requests (on the standard port 80, say) and feed them to your Dancer app.
This could be achieved using various software; examples would include:
You could set up a VirtualHost for your web app, and proxy all requests through to it:
<VirtualHost mywebapp.example.com:80> ProxyPass / http://localhost:3000/ ProxyPassReverse / http://localhost:3000/ </VirtualHost>
Or, if you want your webapp to share an existing VirtualHost, you could have it under a specified dir:
ProxyPass /mywebapp/ http://localhost:3000/ ProxyPassReverse /mywebapp/ http://localhost:3000/
perlbal is a single-threaded event-based server written in Perl supporting HTTP load balancing, web serving, and a mix of the two, available from http://www.danga.com/perlbal/
perlbal
It processes hundreds of millions of requests a day just for LiveJournal, Vox and TypePad and dozens of other "Web 2.0" applications.
It can also provide a management interface to let you see various information on requests handled etc.
It could easily be used to handle requests for your Dancer apps, too.
It can be easily installed from CPAN:
perl -MCPAN -e 'install Perlbal'
Once installed, you'll need to write a configuration file. See the examples provided with perlbal, but you'll probably want something like:
CREATE POOL my_dancers POOL my_dancers ADD 10.0.0.10:3030 POOL my_dancers ADD 10.0.0.11:3030 POOL my_dancers ADD 10.0.0.12:3030 POOL my_dancers ADD 10.0.0.13:3030 CREATE SERVICE my_webapp SET listen = 0.0.0.0:80 SET role = reverse_proxy SET pool = my_dancers SET persist_client = on SET persist_backend = on SET verify_backend = on ENABLE balancer
balance is a simple load-balancer from Inlab Software, available from http://www.inlab.de/balance.html.
balance
It could be used simply to hand requests to a standalone Dancer app. You could even run several instances of your Dancer app, on the same machine or on several machines, and use a machine running balance to distribute the requests between them, for some serious heavy traffic handling!
To listen on port 80, and send requests to a Dancer app on port 3000:
balance http localhost:3000
To listen on a specified IP only on port 80, and distribute requests between multiple Dancer apps on multiple other machines:
balance -b 10.0.0.1 80 10.0.0.2:3000 10.0.0.3:3000 10.0.0.4:3000
You can run your app from Apache using PSGI (Plack), with a config like the following:
<VirtualHost myapp.example.com> ServerName www.myapp.example.com ServerAlias myapp.example.com DocumentRoot /websites/myapp.example.com <Location /> SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /websites/myapp.example.com/app.psgi </Location> ErrorLog /websites/myapp.example.com/logs/error_log CustomLog /websites/myapp.example.com/logs/access_log common </VirtualHost>
You can run your Dancer app from Apache via FastCGI using the dispatch.fcgi script written by the dancer helper script when you create your application scaffolding:
<VirtualHost *:80> ServerName localhost DocumentRoot "/tmp/TestApp/public" <Directory "/tmp/TestApp/public"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all AddHandler fastcgi-script .fcgi </Directory> RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ /dispatch.fcgi [QSA,L] </VirtualHost>
If you want to deploy multiple applications under the same VirtualHost, using one application per directory for example, you can do the following.
This example uses the FastCGI dispatcher that comes with Dancer, but you should be able to adapt this to use any other way of deployment described in this guide. The only purpose of this example is to show how to deploy multiple applications under the same base directory/virtualhost.
<VirtualHost *:80> ServerName localhost DocumentRoot "/path/to/rootdir" RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f <Directory "/path/to/rootdir"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all AddHandler fastcgi-script .fcgi </Directory> RewriteRule /App1(.*)$ /App1/public/dispatch.fcgi$1 [QSA,L] RewriteRule /App2(.*)$ /App2/public/dispatch.fcgi$1 [QSA,L] ... RewriteRule /AppN(.*)$ /AppN/public/dispatch.fcgi$1 [QSA,L] </VirtualHost>
Of course, if your Apache configuration allows that, you can put the RewriteRules in a .htaccess file directly within the application's directory, which lets you add a new application without changing the Apache configuration.
To install Dancer, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Dancer
CPAN shell
perl -MCPAN -e shell install Dancer
For more information on module installation, please visit the detailed CPAN module installation guide.