Provided by: libdancer-perl_1.3120+dfsg-1_all bug

NAME

       Dancer::Deployment - common ways to put your Dancer app into use

DESCRIPTION

       Dancer has been designed to be flexible, and this flexibility extends to your choices when
       deploying your Dancer app.

   Running as a cgi-script (or fast-cgi) under Apache
       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.

       Start by adding the following to your apache configuration (httpd.conf or
       sites-available/*site*):

           <VirtualHost *:80>
               ServerName www.example.com

               # /srv/www.example.com is the root of your
               # dancer application
               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>

               ScriptAlias / /srv/www.example.com/public/dispatch.cgi/

               ErrorLog  /var/log/apache2/www.example.com-error.log
               CustomLog /var/log/apache2/www.example.com-access_log common
           </VirtualHost>

       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 lines:

               AddHandler cgi-script .cgi

           ...

           ScriptAlias / /srv/www.example.com/public/dispatch.cgi

       To:

               AddHandler fastcgi-script .fcgi

           ...

           ScriptAlias / /srv/www.example.com/public/dispatch.fcgi

   Running stand-alone
       At the simplest, your Dancer 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.

       Running on Perl webservers with plackup

       A number of Perl web servers supporting PSGI are available on cpan:

       Starman
           "Starman" is a high performance web server, with support for preforking, signals and
           more.

       Twiggy
           "Twiggy" is an "AnyEvent" web server, it's light and fast.

       Corona
           "Corona" is a "Coro" based web server.

           WARNING: "Dancer"'s use of global variables and "Coro"'s threaded behaviors can cause
           some unexpected behaviors. See this GitHub issue
           <https://github.com/PerlDancer/Dancer/issues/929> for more details.  Unless you have
           really, really strongly compelling reasons to use Corona, consider using "Twiggy" or
           "Starman" instead.

       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.

       Enabling content compression

       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 Dancer to add Plack::Middleware::Deflater to the list of middlewares to
       pass to Plack::Builder, when wrapping the Dancer 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"

       Hosting on DotCloud

       The simplest way to achieve this is to push your main application directory to dotcloud
       with your "bin/app.pl" file copied to (or symlinked from) "app.psgi".

       Beware that the dotcloud service enforces one environment only, named "deployment". So
       instead of having "environments/development.yml" or "environments/production.yml" you must
       have a file named "environments/deployment.yml".

       Also make sure that your "Makefile.PL" (or other dependency mechanism) includes both
       Dancer and Plack::Request.

       The default in-memory session handler won't work, and instead you should switch to
       something persistent. Edit "config.yml" to change "session: 'Simple'" to (for example)
       "session: 'YAML'".

       In case you have issues with Template::Toolkit on Dotcloud

       If you use the Template::Toolkit and its "INCLUDE" or "PROCESS" directives, you might need
       to add the search path of your view files to the config. This is probably going to be
       something like "INCLUDE_PATH: '/home/dotcloud/current/views'" in "config.yml".

       An alternative implementation is to use a variation of the above Plack::Builder template:

        use Plack::Builder;
        use Dancer ':syntax';
        use Dancer::Handler;
        use lib 'lib';

        my $app1 = sub {
            setting appdir => '/home/dotcloud/current';
            load_app "My::App";
            Dancer::App->set_running_app("My::App");
            my $env = shift;
            Dancer::Handler->init_request_headers($env);
            my $req = Dancer::Request->new(env => $env);
            Dancer->dance($req);
        };

        builder {
            mount "/app1" => $app1;
        };

       This also supports hosting multiple apps, but you probably also need to specify the
       specific Environment configuration to use in your application.

       When mounting under a path on dotcloud, as in the above example, always create links using
       the "uri_for()" method for Dancer routes, and a "uri_base" variable for static content as
       shown in Dancer::Cookbook. This means whatever base path your app is mounted under, links
       and form submissions will continue to work.

       Creating a service

       You can turn your app into proper service running in background using one of the following
       examples:

       Using Ubic

       Ubic is a polymorphic 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);

           __PACKAGE__->new(
               server => 'Starman',
               app => '/path/to/your/application/app.pl',
               port => 5000,
               user => 'www-data',
           );

       Run "ubic start application" to start the service.

       Using daemontools

       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

       Running stand-alone behind a proxy / load balancer

       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:

       Using Apache's mod_proxy

       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/
           <Location /mywebapp/>
               RequestHeader set Request-Base /mywebapp
           </Location>

       HTTP header "Request-Base" is taken into account by Dancer, only when "behind_proxy"
       setting is set to true.

       It is important for you to note that the Apache2 modules mod_headers, mod_proxy and
       mod_proxy_http must be enabled.

           a2enmod headers
           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>

       Using perlbal

       "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/>

       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 my_webapp

       Using balance

       "balance" is a simple load-balancer from Inlab Software, available from
       <http://www.inlab.de/balance.html>.

       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

       Using Lighttpd

       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.

       Using Nginx

       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_set_header X-Forwarded-Proto $scheme;
                   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.

       Using HAProxy

       "HAProxy" is a reliable high-performance TCP/HTTP load balancer written in C available
       from <http://haproxy.1wt.eu/>.

       Suppose we want to run an application at "app.example.com:80" and would to use two
       backends listen on hosts "app-be1.example.com:3000" and "app-be2.example.com:3000".

       Here is HAProxy configuration file (haproxy.conf):

           global
               nbproc  1
               maxconn 4096
               user    nobody
               group   nobody
               # haproxy logs will be collected by syslog
               # syslog: unix socket path or tcp pair (ipaddress:port)
               log     /var/run/log local0
               daemon
               # enable compression (haproxy v1.5-dev13 and above required)
               tune.comp.maxlevel  5

           defaults
               log     global
               option  httpclose
               option  httplog
               option  dontlognull
               option  forwardfor
               option  abortonclose
               mode    http
               balance roundrobin
               retries 3
               timeout connect         5s
               timeout server          30s
               timeout client          30s
               timeout http-keep-alive 200m
               # enable compression (haproxy v1.5-dev13 and above required)
               compression algo gzip
               compression type text/html application/javascript text/css application/x-javascript text/javascript

           # application frontend (available at http://app.example.com)
           frontend app.example.com
               bind                  :80
               # modify request headers
               reqadd                X-Forwarded-Proto:\ http
               reqadd                X-Forwarded-Port:\ 80
               # modify response headers
               rspdel                ^Server:.*
               rspdel                ^X-Powered-By:.*
               rspadd                Server:\ Dethklok\ (Unix/0.2.3)
               rate-limit sessions   1024
               acl is-haproxy-stats  path_beg /stats
               # uncomment if you'd like to get haproxy usage statistics
               # use_backend haproxy   if is-haproxy-stats
               default_backend       dynamic

           # haproxy statistics (available at http://app.example.com/stats)
           backend haproxy
               stats uri             /stats
               stats refresh         180s
               stats realm           app.example.com\ haproxy\ statistics
               # change credentials
               stats auth            admin1:password1
               stats auth            admin2:password2
               stats hide-version
               stats show-legends

           # application backends
           backend dynamic
               # change path_info to check and value of the Host header sent to application server
               option httpchk HEAD / HTTP/1.1\r\nHost:\ app.example.com
               server app1 app-be1.example.com:3000 check inter 30s
               server app2 app-be2.example.com:3000 check inter 30s

       We will need to start the workers on each backend of our application. This can be done by
       starman utility:

           # on app-be1.example.com
           $ starman --workers=2 --listen :3000 /path/to/app.pl
           # on app-be2.example.com
           $ starman --workers=2 --listen :3000 /path/to/app.pl

       Then start the haproxy itself:

           # check the configuration..
           $ sudo haproxy -c -f haproxy.conf
           # now really start it..
           $ sudo haproxy -f haproxy.conf

       Plackup Chef Cookbook

       A psgi chef cookbook supporting Dancer (as well as Catalyst) written by Alexey Melezhik is
       available at <http://community.opscode.com/cookbooks/psgi>.

   Running from Apache
       You can run your Dancer app from Apache using the following examples:

       Running from Apache with Plack

       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 /websites/myapp.example.com>
                   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>

       NOTE: Only a single Dancer application can be deployed using the "Plack::Handler::Apache2"
       method. Multiple Dancer applications will not work properly (The routes will be mixed-up
       between the applications).

       It's recommended to start each app with "plackup" using your favorite server (Starman, for
       example) and then put a web server (Apache, Nginx, Perlbal, etc.) as a frontend server for
       both apps using reverse proxy (HTTP based, no fastcgi).

       Running from Apache under appdir

       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.

   Running on lighttpd (CGI)
       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

   Running on lighttpd (FastCGI)
       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",
                       )
                   )
               )
           }

       Launch your application:

           plackup -s FCGI --listen /tmp/fcgi.sock bin/app.pl