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plackup - Man Page

Run PSGI application with Plack handlers


  # read your app from app.psgi file

  # choose .psgi file from ARGV[0] (or with -a option)
  plackup hello.psgi

  # switch server implementation with --server (or -s)
  plackup --server HTTP::Server::Simple --port 9090 --host test.psgi

  # use UNIX socket to run FCGI daemon
  plackup -s FCGI --listen /tmp/fcgi.sock myapp.psgi

  # launch FCGI external server on port 9090
  plackup -s FCGI --port 9090


plackup is a command line utility to run PSGI applications from the command line.

plackup automatically figures out the environment it is run in, and runs your application in that environment. FastCGI, CGI, AnyEvent and others can all be detected. See Plack::Loader for the authoritative list.

plackup assumes you have an app.psgi script in your current directory. The last statement of app.psgi should be a code reference that is a PSGI application:

  use MyApp;
  my $application = MyApp->new;
  my $app = sub { $application->run_psgi(@_) };


  plackup --host --port 9090 /path/to/app.psgi

The first non-option argument is used as a .psgi file path. You can also set this path with -a or --app. If omitted, the default file path is app.psgi in the current directory.


-a,  --app

Specifies the full path to a .psgi script. You may alternately provide this path as the first argument to plackup.


Evaluates the given perl code as a PSGI app, much like perl's -e option:

  plackup -e 'sub { my $env = shift; return [ ... ] }'

It is also handy when you want to run a custom application like Plack::App::*.

  plackup -MPlack::App::File -e 'Plack::App::File->new(...)->to_app'

You can also specify -e option with .psgi file path to wrap the application with middleware configuration from the command line. You can also use Plack::Builder DSL syntax inside -e code. For example:

  plackup -e 'enable "Auth::Basic", authenticator => ...;' myapp.psgi

is equivalent to the PSGI application:

  use Plack::Builder;
  use Plack::Util;
  builder {
      enable "Auth::Basic", authenticator => ...;

Note that when you use -e option to enable middleware, plackup doesn't assume the implicit app.psgi path. You must either pass the path to your .psgi file in the command line arguments or load the application inside -e after the enable.

  plackup                                # Runs app.psgi
  plackup -e 'enable "Foo"'              # Doesn't work!
  plackup -e 'enable "Foo"' app.psgi     # Works
  plackup -e 'enable "Foo"; sub { ... }' # Works
-o,  --host

Binds to a TCP interface. Defaults to undef, which lets most server backends bind to the any (*) interface. This option is only valid for servers which support TCP sockets.

-p,  --port

Binds to a TCP port. Defaults to 5000. This option is only valid for servers which support TCP sockets.

Note: default port 5000 may conflict with AirPlay server on MacOS 12 (Monterey) or later.

-s,  --server, the PLACK_SERVER environment variable

Selects a specific server implementation to run on. When provided, the -s or --server flag will be preferred over the environment variable.

If no option is given, plackup will try to detect the best server implementation based on the environment variables as well as modules loaded by your application in %INC. See Plack::Loader for details.

-S,  --socket

Listens on a UNIX domain socket path. Defaults to undef. This option is only valid for servers which support UNIX sockets.

-l,  --listen

Listens on one or more addresses, whether "HOST:PORT", ":PORT", or "PATH" (without colons). You may use this option multiple times to listen on multiple addresses, but the server will decide whether it supports multiple interfaces.

-D,  --daemonize

Makes the process run in the background. It's up to the backend server/handler implementation whether this option is respected or not.


Specifies Perl library include paths, like perl's -I option. You may add multiple paths by using this option multiple times.


Loads the named modules before loading the app's code. You may load multiple modules by using this option multiple times.

In combination with -r or -R may not have the desired restart effect when the loaded module is changed in the development directory. To avoid this problem you need to load the module with the app code using -e.

-E,  --env, the PLACK_ENV environment variable.

Specifies the environment option. Setting this value with -E or --env also writes to the PLACK_ENV environment variable. This allows applications or frameworks to tell which environment setting the application is running on.

  # These two are the same
  plackup -E deployment
  env PLACK_ENV=deployment plackup

Common values are development, deployment, and test. The default value is development, which causes plackup to load the middleware components: AccessLog, StackTrace, and Lint unless --no-default-middleware is set.


This prevents loading the default middleware stack even when Plack environment (i.e. -E or PLACK_ENV) is set to development.

-r,  --reload

Makes plackup restart the server whenever a file in your development directory changes. This option by default watches the lib directory and the base directory where .psgi file is located. Use -R to watch other directories.

Reloading will delay the compilation of your application. Automatic server detection (see -s above) may not behave as you expect, if plackup needs to scan your application for the modules it uses. Avoid problems by specifying -s explicitly when using -r or -R.

To avoid problems with changes to preloaded modules see documentation for -M.

-R,  --Reload

Makes plackup restart the server whenever a file in any of the given directories changes. -R and --Reload take a comma-separated list of paths:

  plackup -R /path/to/project/lib,/path/to/project/templates

To avoid problems with changes to preloaded modules see documentation for -M.

-L,  --loader

Specifies the server loading subclass that implements how to run the server. Available options are Plack::Loader (default), Restarter (automatically set when -r or -R is used), Delayed, and Shotgun.

See Plack::Loader::Delayed and Plack::Loader::Shotgun for more details.


Specifies the pathname of a file where the access log should be written.  By default, in the development environment access logs will go to STDERR.


Specify the root path of your app (SCRIPT_NAME in PSGI env) to run. The following two commands are roughly the same.

  plackup --path /foo app.psgi
  plackup -e 'mount "/foo" => Plack::Util::load_psgi("app.psgi")'

Other options that starts with -- are passed through to the backend server. See each Plack::Handler backend's documentation for more details on their available options.

See Also

Plack::Runner Plack::Loader


2024-01-25 perl v5.38.2 User Contributed Perl Documentation