NAME¶
Mojo::IOLoop - Minimalistic event loop
SYNOPSIS¶
use Mojo::IOLoop;
# Listen on port 3000
Mojo::IOLoop->server({port => 3000} => sub {
my ($loop, $stream) = @_;
$stream->on(read => sub {
my ($stream, $bytes) = @_;
# Process input chunk
say $bytes;
# Write response
$stream->write('HTTP/1.1 200 OK');
});
});
# Connect to port 3000
my $id = Mojo::IOLoop->client({port => 3000} => sub {
my ($loop, $err, $stream) = @_;
$stream->on(read => sub {
my ($stream, $bytes) = @_;
# Process input
say "Input: $bytes";
});
# Write request
$stream->write("GET / HTTP/1.1\x0d\x0a\x0d\x0a");
});
# Add a timer
Mojo::IOLoop->timer(5 => sub {
my $loop = shift;
$loop->remove($id);
});
# Start event loop if necessary
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
DESCRIPTION¶
Mojo::IOLoop is a very minimalistic event loop based on Mojo::Reactor, it has
been reduced to the absolute minimal feature set required to build solid and
scalable non-blocking TCP clients and servers.
Depending on operating system, the default per-process and system-wide file
descriptor limits are often very low and need to be tuned for better
scalability. The "LIBEV_FLAGS" environment variable should also be
used to select the best possible EV backend, which usually defaults to the not
very scalable "select".
LIBEV_FLAGS=1 # select
LIBEV_FLAGS=2 # poll
LIBEV_FLAGS=4 # epoll (Linux)
LIBEV_FLAGS=8 # kqueue (*BSD, OS X)
The event loop will be resilient to time jumps if a monotonic clock is available
through Time::HiRes. A TLS certificate and key are also built right in, to
make writing test servers as easy as possible. Also note that for convenience
the "PIPE" signal will be set to "IGNORE" when
Mojo::IOLoop is loaded.
For better scalability (epoll, kqueue) and to provide IPv6, SOCKS5 as well as
TLS support, the optional modules EV (4.0+), IO::Socket::IP (0.20+),
IO::Socket::Socks (0.64+) and IO::Socket::SSL (1.84+) will be used
automatically if they are installed. Individual features can also be disabled
with the "MOJO_NO_IPV6", "MOJO_NO_SOCKS" and
"MOJO_NO_TLS" environment variables.
See "REAL-TIME WEB" in Mojolicious::Guides::Cookbook for more.
ATTRIBUTES¶
Mojo::IOLoop implements the following attributes.
accept_interval¶
my $interval = $loop->accept_interval;
$loop = $loop->accept_interval(0.5);
Interval in seconds for trying to reacquire the accept mutex, defaults to 0.025.
Note that changing this value can affect performance and idle CPU usage.
lock¶
my $cb = $loop->lock;
$loop = $loop->lock(sub {...});
A callback for acquiring the accept mutex, used to sync multiple server
processes. The callback should return true or false. Note that exceptions in
this callback are not captured.
$loop->lock(sub {
my $blocking = shift;
# Got the accept mutex, start accepting new connections
return 1;
});
max_accepts¶
my $max = $loop->max_accepts;
$loop = $loop->max_accepts(1000);
The maximum number of connections this event loop is allowed to accept before
shutting down gracefully without interrupting existing connections, defaults
to 0. Setting the value to 0 will allow this event loop to accept new
connections indefinitely. Note that up to half of this value can be subtracted
randomly to improve load balancing between multiple server processes.
max_connections¶
my $max = $loop->max_connections;
$loop = $loop->max_connections(1000);
The maximum number of concurrent connections this event loop is allowed to
handle before stopping to accept new incoming connections, defaults to 1000.
Setting the value to 0 will make this event loop stop accepting new
connections and allow it to shut down gracefully without interrupting existing
connections.
multi_accept¶
my $multi = $loop->multi_accept;
$loop = $loop->multi_accept(100);
Number of connections to accept at once, defaults to 50.
reactor¶
my $reactor = $loop->reactor;
$loop = $loop->reactor(Mojo::Reactor->new);
Low-level event reactor, usually a Mojo::Reactor::Poll or Mojo::Reactor::EV
object with a default subscriber to the event "error" in
Mojo::Reactor.
# Watch if handle becomes readable or writable
$loop->reactor->io($handle => sub {
my ($reactor, $writable) = @_;
say $writable ? 'Handle is writable' : 'Handle is readable';
});
# Change to watching only if handle becomes writable
$loop->reactor->watch($handle, 0, 1);
unlock¶
my $cb = $loop->unlock;
$loop = $loop->unlock(sub {...});
A callback for releasing the accept mutex, used to sync multiple server
processes. Note that exceptions in this callback are not captured.
METHODS¶
Mojo::IOLoop inherits all methods from Mojo::Base and implements the following
new ones.
acceptor¶
my $server = Mojo::IOLoop->acceptor($id);
my $server = $loop->acceptor($id);
my $id = $loop->acceptor(Mojo::IOLoop::Server->new);
Get Mojo::IOLoop::Server object for id or turn object into an acceptor.
client¶
my $id
= Mojo::IOLoop->client(address => '127.0.0.1', port => 3000, sub {...});
my $id = $loop->client(address => '127.0.0.1', port => 3000, sub {...});
my $id = $loop->client({address => '127.0.0.1', port => 3000} => sub {...});
Open TCP connection with Mojo::IOLoop::Client, takes the same arguments as
"connect" in Mojo::IOLoop::Client.
# Connect to localhost on port 3000
Mojo::IOLoop->client({port => 3000} => sub {
my ($loop, $err, $stream) = @_;
...
});
delay¶
my $delay = Mojo::IOLoop->delay;
my $delay = $loop->delay;
my $delay = $loop->delay(sub {...});
my $delay = $loop->delay(sub {...}, sub {...});
Build Mojo::IOLoop::Delay object to manage callbacks and control the flow of
events for this event loop, which can help you avoid deep nested closures and
memory leaks that often result from continuation-passing style. Callbacks will
be passed along to "steps" in Mojo::IOLoop::Delay.
# Synchronize multiple events
my $delay = Mojo::IOLoop->delay(sub { say 'BOOM!' });
for my $i (1 .. 10) {
my $end = $delay->begin;
Mojo::IOLoop->timer($i => sub {
say 10 - $i;
$end->();
});
}
$delay->wait;
# Sequentialize multiple events
Mojo::IOLoop->delay(
# First step (simple timer)
sub {
my $delay = shift;
Mojo::IOLoop->timer(2 => $delay->begin);
say 'Second step in 2 seconds.';
},
# Second step (concurrent timers)
sub {
my $delay = shift;
Mojo::IOLoop->timer(1 => $delay->begin);
Mojo::IOLoop->timer(3 => $delay->begin);
say 'Third step in 3 seconds.';
},
# Third step (the end)
sub { say 'And done after 5 seconds total.' }
)->wait;
# Handle exceptions in all steps
Mojo::IOLoop->delay(
sub {
my $delay = shift;
die 'Intentional error';
},
sub {
my ($delay, @args) = @_;
say 'Never actually reached.';
}
)->catch(sub {
my ($delay, $err) = @_;
say "Something went wrong: $err";
})->wait;
is_running¶
my $bool = Mojo::IOLoop->is_running;
my $bool = $loop->is_running;
Check if event loop is running.
exit unless Mojo::IOLoop->is_running;
next_tick¶
my $undef = Mojo::IOLoop->next_tick(sub {...});
my $undef = $loop->next_tick(sub {...});
Invoke callback as soon as possible, but not before returning, always returns
"undef".
# Perform operation on next reactor tick
Mojo::IOLoop->next_tick(sub {
my $loop = shift;
...
});
one_tick¶
Mojo::IOLoop->one_tick;
$loop->one_tick;
Run event loop until an event occurs. Note that this method can recurse back
into the reactor, so you need to be careful.
# Don't block longer than 0.5 seconds
my $id = Mojo::IOLoop->timer(0.5 => sub {});
Mojo::IOLoop->one_tick;
Mojo::IOLoop->remove($id);
recurring¶
my $id = Mojo::IOLoop->recurring(3 => sub {...});
my $id = $loop->recurring(0 => sub {...});
my $id = $loop->recurring(0.25 => sub {...});
Create a new recurring timer, invoking the callback repeatedly after a given
amount of time in seconds.
# Perform operation every 5 seconds
Mojo::IOLoop->recurring(5 => sub {
my $loop = shift;
...
});
remove¶
Mojo::IOLoop->remove($id);
$loop->remove($id);
Remove anything with an id, connections will be dropped gracefully by allowing
them to finish writing all data in their write buffers.
reset¶
Mojo::IOLoop->reset;
$loop->reset;
Remove everything and stop the event loop.
server¶
my $id = Mojo::IOLoop->server(port => 3000, sub {...});
my $id = $loop->server(port => 3000, sub {...});
my $id = $loop->server({port => 3000} => sub {...});
Accept TCP connections with Mojo::IOLoop::Server, takes the same arguments as
"listen" in Mojo::IOLoop::Server.
# Listen on port 3000
Mojo::IOLoop->server({port => 3000} => sub {
my ($loop, $stream, $id) = @_;
...
});
# Listen on random port
my $id = Mojo::IOLoop->server({address => '127.0.0.1'} => sub {
my ($loop, $stream, $id) = @_;
...
});
my $port = Mojo::IOLoop->acceptor($id)->handle->sockport;
singleton¶
my $loop = Mojo::IOLoop->singleton;
The global Mojo::IOLoop singleton, used to access a single shared event loop
object from everywhere inside the process.
# Many methods also allow you to take shortcuts
Mojo::IOLoop->timer(2 => sub { Mojo::IOLoop->stop });
Mojo::IOLoop->start;
# Restart active timer
my $id = Mojo::IOLoop->timer(3 => sub { say 'Timeout!' });
Mojo::IOLoop->singleton->reactor->again($id);
start¶
Mojo::IOLoop->start;
$loop->start;
Start the event loop, this will block until "stop" is called. Note
that some reactors stop automatically if there are no events being watched
anymore.
# Start event loop only if it is not running already
Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
stop¶
Mojo::IOLoop->stop;
$loop->stop;
Stop the event loop, this will not interrupt any existing connections and the
event loop can be restarted by running "start" again.
stream¶
my $stream = Mojo::IOLoop->stream($id);
my $stream = $loop->stream($id);
my $id = $loop->stream(Mojo::IOLoop::Stream->new);
Get Mojo::IOLoop::Stream object for id or turn object into a connection.
# Increase inactivity timeout for connection to 300 seconds
Mojo::IOLoop->stream($id)->timeout(300);
timer¶
my $id = Mojo::IOLoop->timer(3 => sub {...});
my $id = $loop->timer(0 => sub {...});
my $id = $loop->timer(0.25 => sub {...});
Create a new timer, invoking the callback after a given amount of time in
seconds.
# Perform operation in 5 seconds
Mojo::IOLoop->timer(5 => sub {
my $loop = shift;
...
});
DEBUGGING¶
You can set the "MOJO_IOLOOP_DEBUG" environment variable to get some
advanced diagnostics information printed to "STDERR".
MOJO_IOLOOP_DEBUG=1
SEE ALSO¶
Mojolicious, Mojolicious::Guides, <
http://mojolicio.us>.