Dancer2::Deployment - Common ways to put your Dancer2 app into use
version 0.06
Dancer2 has been designed to be flexible, and this flexibility extends to your choices when deploying your Dancer2 app.
In providing ultimate flexibility in terms of deployment, your Dancer2 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.
Start by adding the following to your apache configuration (httpd.conf or sites-available/*site*):
<VirtualHost *:80> ServerName www.example.com DocumentRoot /srv/www.example.com/public ServerAdmin you@example.com <Directory "/srv/www.example.com/public"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all AddHandler cgi-script .cgi </Directory> RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ /dispatch.cgi$1 [QSA,L] ErrorLog /var/log/apache2/www.example.com-error.log CustomLog /var/log/apache2/www.example.com-access_log common </VirtualHost>
Note that when using fast-cgi your rewrite rule should be:
RewriteRule ^(.*)$ /dispatch.fcgi$1 [QSA,L]
Here, the mod_rewrite magic for Pretty-URLs is directly put in Apache's configuration. But if your web server supports .htaccess files, you can drop those lines in a .htaccess file.
To check if your server supports mod_rewrite type apache2 -l to list modules. To enable mod_rewrite (Debian), run a2enmod rewrite. Place following code in a file called .htaccess in your application's root folder:
apache2 -l
a2enmod rewrite
# BEGIN dancer application htaccess 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/
This option is a no-brainer, easy to setup, low maintenance but serves requests slower than all other options.
You can use the same technique to deploy with FastCGI, by just changing the line:
AddHandler cgi-script .cgi
By:
AddHandler fastcgi-script .fcgi
Of course remember to update your rewrite rules, if you have set any:
RewriteRule (.*) /dispatch.fcgi$1 [L]
At the simplest, your Dancer2 app can run standalone, operating as its own webserver using HTTP::Server::Simple::PSGI.
Simply fire up your app:
$ perl bin/app.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.
A number of Perl web servers supporting PSGI are available on cpan:
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 your application, just run plackup (see Plack and specific servers above for all available options):
$ plackup bin/app.pl $ plackup -E deployment -s Starman --workers=10 -p 5001 -a bin/app.pl
As you can see, the scaffolded Perl script for your app can be used as a PSGI startup file.
Content compression (gzip, deflate) can be easily enabled via a Plack middleware (see Plack#Plack::Middleware): Plack::Middleware::Deflater. It's a middleware to encode the response body in gzip or deflate, based on Accept-Encoding HTTP request header.
Enable it as you would enable any Plack middleware. First you need to install Plack::Middleware::Deflater, then in the configuration file (usually environments/development.yml), add these lines:
plack_middlewares: - - Plack::Middleware::Deflater - ...
These lines tell Dancer2 to add Plack::Middleware::Deflater to the list of middlewares to pass to Plack::Builder, when wrapping the Dancer2 app. The syntax is :
as key: the name of the Plack middleware to use
as value: the options to pass it as a list. In our case, there is no option to specify to Plack::Middleware::Deflater, so we use an empty YAML list.
To test if content compression works, trace the HTTP request and response before and after enabling this middleware. Among other things, you should notice that the response is gzip or deflate encoded, and contains a header Content-Encoding set to gzip or deflate
Content-Encoding
gzip
deflate
You can use Plack::Builder to mount multiple Dancer2 applications on a PSGI webserver like Starman.
Start by creating a simple app.psgi file:
use Dancer2 ':syntax'; use Plack::Builder; setting apphandler => 'PSGI'; my $app1 = sub { my $env = shift; local $ENV{DANCER_APPDIR} = '/Users/franck/tmp/app1'; load_app "app1"; Dancer2::App->set_running_app('app1'); setting appdir => '/Users/franck/tmp/app1'; Dancer2::Config->load; my $request = Dancer2::Request->new( env => $env ); Dancer2->dance($request); }; my $app2 = sub { my $env = shift; local $ENV{DANCER_APPDIR} = '/Users/franck/tmp/app2'; load_app "app2"; Dancer2::App->set_running_app('app2'); setting appdir => '/Users/franck/tmp/app2'; Dancer2::Config->load; my $request = Dancer2::Request->new( env => $env ); Dancer2->dance($request); }; builder { mount "/app1" => builder {$app1}; mount "/app2" => builder {$app2}; };
and now use Starman
plackup -a app.psgi -s Starman
You can turn your app into proper service running in background using one of the following examples:
Ubic is an extensible perlish service manager. You can use it to start and stop any services, automatically start them on reboots or daemon failures, and implement custom status checks.
A basic PSGI service description (usually in /etc/ubic/service/application):
use parent qw(Ubic::Service::Plack); # if your application is not installed in @INC path: sub start { my $self = shift; $ENV{PERL5LIB} = '/path/to/your/application/lib'; $self->SUPER::start(@_); } __PACKAGE__->new( server => 'Starman', app => '/path/to/your/application/app.pl', port => 5000, user => 'www-data', );
Run ubic start application to start the service.
ubic start application
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 Dancer2 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/
It is important for you to note that the Apache2 modules mod_proxy and mod_proxy_http must be enabled.
a2enmod proxy a2enmod proxy_http
It is also important to set permissions for proxying for security purposes, below is an example.
<Proxy *> Order allow,deny Allow from all </Proxy>
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 Dancer2 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 my_webapp
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 Dancer2 app. You could even run several instances of your Dancer2 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 Dancer2 app on port 3000:
balance http localhost:3000
To listen on a specified IP only on port 80, and distribute requests between multiple Dancer2 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 backendurl { server unix:THE_PATH_OF_YOUR_PLACKUP_SOCKET_HERE.sock; } server { listen 80; server_name YOUR_HOST_HERE; access_log /var/log/YOUR_ACCESS_LOG_HERE.log; error_log /var/log/YOUR_ERROR_LOG_HERE.log info; root YOUR_ROOT_PROJECT/public; location / { try_files $uri @proxy; access_log off; expires max; } location @proxy { proxy_set_header Host $http_host; proxy_set_header X-Forwarded-Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_pass http://backendurl; } }
You will need plackup to start a worker listening on a socket :
cd YOUR_PROJECT_PATH sudo -u www plackup -E production -s Starman --workers=2 -l THE_PATH_OF_YOUR_PLACKUP_SOCKET_HERE.sock -a bin/app.pl
A good way to start this is to use daemontools and place this line with all environments variables in the "run" file.
daemontools
You can run your Dancer2 app from Apache using the following examples:
You can run your app from Apache using PSGI (Plack), with a config like the following:
<VirtualHost myapp.example.com> ServerName www.myapp.example.com ServerAlias myapp.example.com DocumentRoot /websites/myapp.example.com <Directory /home/myapp/myapp> AllowOverride None Order allow,deny Allow from all </Directory> <Location /> SetHandler perl-script PerlHandler Plack::Handler::Apache2 PerlSetVar psgi_app /websites/myapp.example.com/app.pl </Location> ErrorLog /websites/myapp.example.com/logs/error_log CustomLog /websites/myapp.example.com/logs/access_log common </VirtualHost>
To set the environment you want to use for your application (production or development), you can set it this way:
<VirtualHost> ... SetEnv DANCER_ENVIRONMENT "production" ... </VirtualHost>
If you want to deploy multiple applications under the same VirtualHost, using one application per directory for example, you can do the following.
This example uses the FastCGI dispatcher that comes with Dancer2, but you should be able to adapt this to use any other way of deployment described in this guide. The only purpose of this example is to show how to deploy multiple applications under the same base directory/virtualhost.
<VirtualHost *:80> ServerName localhost DocumentRoot "/path/to/rootdir" RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f <Directory "/path/to/rootdir"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all AddHandler fastcgi-script .fcgi </Directory> RewriteRule /App1(.*)$ /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 run as a CGI app on lighttpd, just create a soft link to the dispatch.cgi script (created when you run dancer -a MyApp) inside your system's cgi-bin folder. Make sure mod_cgi is enabled.
ln -s /path/to/MyApp/public/dispatch.cgi /usr/lib/cgi-bin/mycoolapp.cgi
Make sure mod_fcgi is enabled. You also must have FCGI installed.
This example configuration uses TCP/IP:
$HTTP["url"] == "^/app" { fastcgi.server += ( "/app" => ( "" => ( "host" => "127.0.0.1", "port" => "5000", "check-local" => "disable", ) ) ) }
Launch your application:
plackup -s FCGI --port 5000 bin/app.pl
This example configuration uses a socket:
$HTTP["url"] =~ "^/app" { fastcgi.server += ( "/app" => ( "" => ( "socket" => "/tmp/fcgi.sock", "check-local" => "disable", ) ) ) }
plackup -s FCGI --listen /tmp/fcgi.sock bin/app.pl
Dancer Core Developers
This software is copyright (c) 2013 by Alexis Sukrieh.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install Dancer2, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Dancer2
CPAN shell
perl -MCPAN -e shell install Dancer2
For more information on module installation, please visit the detailed CPAN module installation guide.