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.
In providing ultimate flexibility in terms of deployment, your Dancer app can be run as a simple cgi-script out-of-the-box. No additional web-server configuration needed. Your web server should recognize .cgi files and be able to serve Perl scripts. The Perl module Plack::Runner is required. Access your app from the browser:
http://localhost/myapp/dispatch.cgi 500 Internal Server Error - Wrong http://localhost/myapp/dispatch.cgi/ 200 OK - Right
Enable Pretty-URLs if your web server supports .htaccess files and mod_rewrite. Place this code in a file called .htaccess in your application's root folder:
# BEGIN dancer application htaccess DirectoryIndex dispatch.cgi/ AddHandler cgi-script .cgi Options +ExecCGI +FollowSymLinks -Indexes RewriteEngine On RewriteCond %{SCRIPT_FILENAME} !-d RewriteCond %{SCRIPT_FILENAME} !-f RewriteRule (.*) /dispatch.cgi/$1 [L] # END dancer application htaccess
Now you can access your dancer application URLs as if you were using the embedded web server.
http://localhost/myapp/
This option is a no-brainer, easy to setup, low maintenance but serves requests slower than all other options.
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.
Plackup can also be used to start your application. A number of Perl web server supporting PSGI are available on cpan:
Plackup
Starman is a high performance web server, with support for preforking, signals, ...
Starman
Twiggy is an AnyEvent web server, it's light and fast.
Twiggy
AnyEvent
Corona is a Coro based web server.
Corona
Coro
To start you application using Plackup, all you need to do is
$ plackup -s Twiggy -p 5000 <YOURAPP>.pl
As you can see, the scaffolded Perl script for your app can be used as a PSGI startup file.
daemontools is a collection of tools for managing UNIX services. You can use it to easily start/restart/stop services.
A basic script to start an application: (in /service/application/run)
#!/bin/sh # if your application is not installed in @INC path: export PERL5LIB='/path/to/your/application/lib' exec 2>&1 \ /usr/local/bin/plackup -s Starman -a /path/to/your/application/app.pl -p 5000
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 use Lighttp's mod_proxy:
$HTTP["url"] =~ "/application" { proxy.server = ( "/" => ( "application" => ( "host" => "127.0.0.1", "port" => 3000 ) ) ) }
This configuration will proxy all request to the /application path to the path / on localhost:3000.
with Nginx:
upstream backend { server 10.0.0.1:8080; server 10.0.0.2:8080; ... } server { location / { proxy_pass http://backend; } }
You can run your Dancer app from Apache using the following examples:
You can run your app from Apache using PSGI (Plack), with a config like the following:
<VirtualHost myapp.example.com> ServerName www.myapp.example.com ServerAlias myapp.example.com DocumentRoot /websites/myapp.example.com <Directory /home/myapp/myapp> AllowOverride None Order allow,deny Allow from all </Directory> <Location /> SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /websites/myapp.example.com/app.pl </Location> ErrorLog /websites/myapp.example.com/logs/error_log CustomLog /websites/myapp.example.com/logs/access_log common </VirtualHost>
You can run your Dancer app from Apache via FastCGI using the dispatch.fcgi script written by the dancer helper script when you create your application scaffolding:
<VirtualHost *:80> ServerName localhost DocumentRoot "/tmp/TestApp/public" <Directory "/tmp/TestApp/public"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all AddHandler fastcgi-script .fcgi </Directory> RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ /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.
You can use Plack::Builder to mount multiple Dancer's application and run a Plack webserver like Starman in front.
Start by creating a simple app.psgi file:
use Dancer; use Plack::Builder; load_app 'MyApp1', 'MyApp2'; use Dancer::Config 'setting'; setting apphandler => 'PSGI'; Dancer::Config->load; my $app1 = sub { my $env = shift; my $request = Dancer::Request->new( $env ); Dancer->dance( $request ); }; my $app2 = sub { my $env = shift; my $request = Dancer::Request->new( $env ); Dancer->dance( $request ); }; builder { mount "/app1" => builder {$app1}; mount "/app2" => builder {$app2}; };
and now use Starman
plackup -a app.psgi -s Starman
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.