Tatsumaki
non-blocking web framework built on Plack/AnyEvent
Tatsuhiko Miyagawa
Nov. 30th, 2009 / Shibuya.pm Tech Talks #12

PSGI

Perl Web Server
Gateway Interface

Python’s WSGI
Ruby’s Rack

my $app = sub {
my $env = shift;
return [ $status, $headers, $body ];
};

Plain Old Perl

Servers
CGI, FastCGI, mod_perl1&2
Standalone, Prefork, AnyEvent, Coro, POE,
Danga::Socket, nginx, mod_psgi, evhttpd, Perlbal

Frameworks
Catalyst, Mason, Maypole, CGI::Application, Jifty
Dancer, HTTP::Engine, Sqauatting, Continuity
WebGUI, Movable Type, Ark, Angelos, Noe

Middleware
Static, ConditionalGET, AccessLog, Chunked, Deflater,
NYTProf, FCGIDispatcher, JSONP, StackTrace,
Auth::Basic, XSendfile, Rewrite, JSConcat ...

Servers
CGI, FastCGI, mod_perl1&2
Standalone, Prefork, AnyEvent, Coro, POE,
Danga::Socket, nginx, mod_psgi, evhttpd, Perlbal

Non-blocking?

psgi.streaming

# delayed response
my $app = sub {
my $env = shift;
return sub {
my $respond = shift;
$respond->([ $status, $headers, $body ]);
};

# streaming content
my $app = sub {
my $env = shift;
return sub {
my $respond = shift;
my $w = $respond->([ $status, $headers ]);
some_event_loop(sub {
$w->write($content);
$w->close;
});
};

WARNING
psgi.streaming is an interface
Servers may not work if event loop is not shared
(Recommended to use AnyEvent in your app)

Frameworks?

Most frameworks do not
support non-blocking interface.
(Mojo 0.99 has IOLoop and Client)

Let’s make one!

Tatsumaki
http://www.flickr.com/photos/88699006@N00/679056142/

Port of Tornado

Plack and AnyEvent
All the way from the bottom to the top
Handle thousands of connections with EV/epoll

Works with
AnyEvent, POE, Coro, Danga::Socket and perlbal
Because it’s AnyEvent!

You can use
Any of AnyEvent::* libraries to do
asynchronous tasks (unlike Mojo)

The first and only framework
that uses psgi.streaming

package MainHandler;
use base qw(Tatsumaki::Handler);
sub get {
my $self = shift;
$self->write(“Hello World”);
}
package main;
use Tatsumaki::Application;
my $app = Tatsumaki::Application->new([
‘/’ => ‘MainHandler’,
]);

Tatsumaki::HTTPClient
AnyEvent::HTTP wrapper
non-blocking HTTP client for Tatsumaki

package HTTPClientHandler;
use base qw(Tatsumaki::Handler);
__PACKAGE__->asynchronous(1);
use Tatsumaki::HTTPClient;
sub get {
my $self = shift;
my $client = Tatsumaki::HTTPClient->new;
$client->get($api_url, sub {
my $res = shift;
my $body = $res->content;
$self->write(...);
$self->finish;
});
}

Long-poll (comet)

package AsyncHandler;
use base qw(Tatsumaki::Handler);
__PACKAGE__->asynchronous(1);
sub get {
my $self = shift;
my $t; $t = AE::timer 3, 0, sub {
undef $t;
$self->write(“Hello World”);
$self->finish;
});
}
package main;
use Tatsumaki::Application;
my $app = Tatsumaki::Application->new([
‘/’ => ‘AsyncHandler’,
]);

Tatsumaki::MessageQueue
Pure perl MQ (in AnyEvent)

package LongPollHandler;
use base qw(Tatsumaki::Handler);
__PACKAGE__->asynchronous(1);
use Tatsumaki::MessageQueue;
sub get {
my $self = shift;
my $mq = Tatsumaki::MessageQueue-
>instance(‘ch-name’);
$mq->poll_once($client_id, sub {
my @events = @_;
$self->write(@events);
$self->finish;
});
}

package EventPostHandler;
use base qw(Tatsumaki::Handler);
sub post {
my $self = shift;
my $mq = Tatsumaki::MessageQueue-
>instance(‘ch-name’);
$mq->publish({
name => “NewComment”, ...
});
$self->write({ success => 1 });
}

Multipart XHR
JavaScript hack to emulate server push

package MXHRPollHandler;
use base qw(Tatsumaki::Handler);
__PACKAGE__->asynchronous(1);
use Tatsumaki::MessageQueue;
sub get {
my $self = shift;
$self->multipart_xhr_push(1);
my $mq = Tatsumaki::MessageQueue-
>instance(‘ch-name’);
$mq->poll($client_id, sub {
my @events = @_;
$self->stream_write(@events);
});
}

JS Client libraries
jquery.ev
DUI.Stream
raphaeljs

DEMO

http://192.168.100.50:5000/chat/demo

Other apps
github.com/gugod/Social
github.com/miyagawa/Subfeedr
github.com/audreyt/socialcalc
github.com/clkao/Finance-GeniusTrader-Chart
github.com/lestrrat/Hamaki
github.com/yusukebe/Nagare

WHY

Web server resource

I/O bound
!CPU bound

I/O bound web apps
HTTP API proxy (e.g. OpenSocial)
Mash up (XML, REST API)
Real-time Web (Comet)

CPU bound jobs
Database Servers
Job Workers (TheSchwartz etc.)

Tatsumaki for
I/O bound web

✓ Non-blocking HTTP client
✓ Pure perl Message Queue
✓ I/O libraries (AnyEvent::*)
✓ DB libraries (AnyEvent::DBI)
✓ Job dispatcher (AE::Gearman)

Status
0.1.x on CPAN, considered beta
AnyEvent server has bugs on Linux

Plans

Tatsumaki::Service
Inspired by Google AppEngine Email/XMPP service
Webhook pattern

XMPP/IRC
Write Jabber/IRC bot as a web application

# see Tatsumaki-Service-XMPP/eg/translate.psgi
package XMPPTranslateHandler;
use base qw(Tatsumaki::Handler::XMPP);
sub post {
my $self = shift;
my $msg = $self->xmpp_message;
my $uri = “http://ajax.googleapis.com/...”;
my $client = Tatsumaki::HTTPClient->new;
$client->get($uri, $self->async_cb(sub {
my $res = shift;
my $r = JSON::decode_json($res->content);
$msg->reply($r->{translatedText});
$self->finish;
}));
}

Standard Comet Interface
a.k.a Stardust

Bayeux
HTTP push relay

“Real” PubSub interface
for Tatsumaki::MQ

Pluggable MQ
using “real” MQ like ActiveMQ or RabbitMQ

DataStore interface
using AnyEvent::DBI, Redis etc.

See Subfeedr
for Redis integration
http://github.com/miyagawa/Subfeedr

cpan> install Tatsumaki
http://github.com/miyagawa/Tatsumaki
irc://irc.perl.org/#plack

That’s it!
Questions?