/ 
Nginx-Engine-0.10
/ Nginx::Engine

NAME

Nginx::Engine - Asynchronous framework based on nginx

SYNOPSIS

use Nginx::Engine;

# Creating event loop with 4096 connetions
# and ngxe-error.log as error log.
ngxe_init("./ngxe-error.log", 4096);

# Server that accepts new connection, 
# sends "hi" and closes it.
ngxe_server('*', 55555, sub {
    ngxe_writer($_[0], 1, 1000, "hi", sub {
        # $_[1] is error and return on error is always required
        # and it's there so you can do some cleanup if you need to.
        return if $_[1];

        ngxe_close($_[0]);
    });
});

# Server that reads whatever comes first
# sends it back and closes connection.  
# 
ngxe_server('*', 55555, sub {
    ngxe_writer)$_[0], 0, 5000, '', sub {
        return if $_[1];

        ngxe_close($_[0]);
    });

    ngxe_reader($_[0], NGXE_START, 5000, sub {
        return if $_[1];

        $_[3] = $_[2]; # write_buffer = read_buffer 
        #_[2] = '';    # read_buffer = ''
        
        # writer starts automatically if there is 
        # data in the write buffer after this sub
        # returns
    });
});

# Connecting to 127.0.0.1:80 and disconnecting.
ngxe_client('*', '127.0.0.1', 80, 2000, sub {
    if ($_[1]) {
        warn "$_[1]\n";
        return;
    }

    print "Connected, closing\n";
    ngxe_close($_[0]);
});

# Saying "N. Hello, World!" every second
ngxe_interval_set(1000, sub { 
    print "$_[2]. Hello, $_[1]!\n"; 
    $_[2]++ 
}, "World", 1);

# Saying "Hello World!" once after 5000 ms.
ngxe_timeout_set(5000, sub { 
    print "Hello, $_[1]!"; 
}, "World");


# Server that echoes everyhing back to the client.
ngxe_server('*', 55555, sub {

    ngxe_writer($_[0], 0, 5000, '', sub {
        return if $_[1];

        # write buffer sent and cleared for us 

        # writer stops automatically if there is
        # no data in the write buffer after this sub
        # returns
    });

    ngxe_reader($_[0], NGXE_START, 5000, sub {
        return if $_[1];

        $_[3] = $_[2]; # copying read buffer to the write buffer
        $_[2] = '';    # clearing read buffer

        # writer starts automatically if there is 
        # data in the write buffer after this sub
        # returns
    });

});

ngxe_loop;

DESCRIPTION

Nginx::Engine is a simple high-performance asynchronous networking framework. It's intended to bring nodejs-like performance and nginx's stability into Perl. It's almost as fast as nginx itself. And it can easily handle thousands or even tens of thousands of concurrent connections. Well, just like nginx.

Internally it initializes nginx to access event loop, event modules and a lot of other core functions nginx provides. For every connection Engine allocates a memory pool and destroys it whenever connection is closed. Engine registers a cleanup function for stored perl arguments and callbacks to decrease their reference count with the destruction of the memory pool. This way memory leaks are not possible even though two different memory allocators are used.

To achieve stability Nginx::Engine doesn't implement IO functions but rather simply reuses nginx's internal IO. This gives a huge performance boost as well by avoiding as much IO in perl as possible.

LIMITATIONS

fork() won't work properly in XS implementation. You should not use it after ngxe_init() at all.

Perl's signal handling won't work either after ngxe_init(). And there are no signal handlers right now.

DEPENDENCIES

No dependencies. Everything comes with the package.

SUPPORTED OPERATING SYSTEMS

Any unix or linux with working gcc, sh, perl and nginx should be ok. It mostly depends on the ability to build nginx in a way that it can be linked as a shared library. If there is a problem you can build nginx manually. Configure it without http module and with compiler option, that allows it to be linked as a shared library (not required for gcc on x86 and -fPIC for gcc on amd64).

For other systems there is a pure-perl fallback based on select().

EXPORT

The following functions are exported by default:

ngxe_init

ngxe_timeout_set
ngxe_timeout_clear

ngxe_interval_set
ngxe_interval_clear

ngxe_server

ngxe_client

ngxe_reader
ngxe_reader_start
ngxe_reader_stop
ngxe_reader_stop_writer_start
ngxe_reader_timeout

ngxe_writer
ngxe_writer_start
ngxe_writer_stop
ngxe_writer_stop_reader_start
ngxe_writer_timeout
ngxe_writer_buffer_set

ngxe_close

ngxe_loop

NGXE_START

INITIALIZATION

Before you can do anything you have to initialize the engine by calling ngxe_init() at the very beginning of your code. You cannot call any other fuction before that.

ngxe_init(ERROR_LOG[, CONNECTIONS])

Nginx requires error log to start. It is important to log error if some system call fails or nginx runs out of some resource, like number of connections or open files. You should always use log. But you can leave it empty if you want to.

Number of connections must be less than number of open files and sockets per process allowed by the system. You probably would need to tune your system anyway to use more then a couple of thousands.

So, I suggest to start with something like this:

ngxe_init("./ngxe-error.log", 4096);

TIMER

ngxe_timeout_set(TIMEOUT, CALLBACK, ...)

ngxe_timeout_set creates new timer event to execute a callback after TIMEOUT ms. Takes any number of extra arguments after CALLBACK and stores them internally. CALLBACK must be a CODE reference.

Returns timer identifier which can be used to remove event from the loop with ngxe_timeout_clear.

First argument passed to the callback is timer identifier and the rest are all those extra arguments you set.

$_[0] - timer
@_[1..$#_] - extra args

For example, here is how to say "Hello, World" in 5 seconds, where "World" is an extra argument:

ngxe_timeout_set(5000, sub { print "Hello, $_[1]!"; }, "World");

ngxe_timeout_clear(TIMER)

Prevents TIMER event from happening, removes from the loop.

INTERVAL

ngxe_interval_set(TIMEOUT, CALLBACK, ...)

Ceates new timer event to execute a callback after TIMEOUT ms. Resets timer every time until ngxe_interval_clear is called. Takes any number of extra arguments after CALLBACK and stores them internally. CALLBACK must be a CODE reference.

Returns timer identifier which can be used to remove event from the loop with ngxe_interval_clear.

First argument passed to the callback is timer identifier and the rest are all those extra arguments you set.

$_[0] - timer
@_[1..$#_] - extra args

For example, here is how to say "N. Hello, World" every second, where "World" and "N" are extra arguments:

ngxe_interval_set(1000, sub { 
    print "$_[2]. Hello, $_[1]!\n"; 
    $_[2]++; 
}, "World", 1);

ngxe_interval_clear(TIMER)

Stops interval identified as TIMER, removes from the loop.

SERVER

ngxe_server(BIND_ADDRESS, BIND_PORT, CALLBACK, ...)

Creates new server connection, binds to the BIND_ADDRESS:BIND_PORT, listens, accept new connections and executes CALLBACK on them with extra arguments if any. Empty or '*' BIND_ADDRESS will result in using INADDR_ANY instead.

First and second arguments passed to the callback are connection identifier and IP address of the remote host. All the rest - extra arguments you set.

$_[0] - connection
$_[1] - IP address connected
@_[2..$#_] - extra args

For example, to accept new connection, print its address and close it you need to create server and call ngxe_close right inside the callback:

ngxe_server('*', 55555, sub {
    print "$_[1] connected and discarded\n";
    ngxe_close($_[0]);
});

CLIENT

ngxe_client(BIND_ADDR, REMOTE_ADDR, REMOTE_PORT, TIMEOUT, CALLBACK, ...)

Creates new client connection, binds to the BIND_ADDR, connects to the REMOTE_ADDR:REMOTE_PORT. And tries to do all of it in TIMEOUT ms. Executes CALLBACK after with any extra arguments.

Returns connection.

First argument passed to the callback is connection identifier, second - error variable and the rest are extra arguments.

$_[0] - connection
$_[1] - error indicator
@_[2..$#_] - extra args

If error is set and TRUE than callback must return without any other ngxe_* functions beign called on this connection.

Example, connecting to 127.0.0.1:80 and immediately closing connection:

ngxe_client('127.0.0.1', '127.0.0.1', 80, 2000, sub {
    if ($_[1]) {
        warn "$_[1]\n";
        return;
    }

    print "Connected, closing\n";
    ngxe_close($_[0]);
});

Notice, we are returning from callback on error. This is required behaviour.

READER AND WRITER

Reader is a way to receive data from connection asynchronously. It executes callback every time new data arrives. You should do whatever you need with the read buffer and clear it afterwards to avoid too much memory consumption. If you put some data into the write buffer it will stop the reader and start the writer after. You can call ngxe_reader_stop($_[0]) if you need to do something else before you can actually respond to the client.

Writer is a bit different and it will execute a callback only when entire write buffer has been sent. Writer clears write buffer for you. You can modify it inside the callback and writer will send it again. You can achieve streaming this way. Writer is automatically stops itself and starts the reader if write buffer is empty after the callback; You can call ngxe_writer_stop($_[0]) if you need to deal with the connection later.

It doen't seem very clear and structured but speed is more important here.

Read and write buffers can be used in both reader and writer. You can save references to the read \$_[2] or write buffer \$_[3] if you want to access them later. Or you can use ngxe_writer_buffer_set(CONNECTION, DATA) to put something into the write buffer if you have a connection already stored somewhere.

And both reader and writer can be recreated to achieve different processing schemes and if you can afford to slow things down.

ngxe_reader(CONN, FLAGS, TIMEOUT, CALLBACK, ...)

Creates a reader for connection identified as CONN. Starts it immediately if NGXE_START is given as a flag. If no data has been received in TIMEOUT ms executes CALLBACK with error identifier set to timeout. Extra args can be placed after CALLBACK, as usual.

If TIMEOUT is set to 0 it is not going to be used at all.

Returns undef on error.

First argument paseed to the callback is connection identifier. Second is error.variable. Third and 4th are read and write buffers. And the fifth argument is an amount of data required for callback. Usefule to read data with known length.

$_[0] - connection
$_[1] - error indicator
$_[2] - read buffer
$_[3] - write buffer
$_[4] - min length
@_[5..$#_] - extra args

If error is set you must return from the subroutine avoiding any ngxe_* calls on current connection $_[0].

For example, let's create server, read a few bytes from new connection and close it:

ngxe_server('*', 55555, sub {
    ngxe_reader($_[0], NGXE_START, 1000, sub {
        if ($_[1]) {
            return;
        }

        print "got $_[2]\n";
        ngxe_close($_[0]);
    });
});

ngxe_reader_start(CONN)

Starts reader for connection CONN.

ngxe_reader_stop(CONN)

Stops reader for connection CONN.

ngxe_reader_stop_writer_start(CONN)

Stops reader and starts writer for connection CONN. Saves unnecessary perl --> XSUB --> perl transition.

ngxe_reader_timeout(CONN[, TIMEOUT])

Returns current timeout for the reader and sets it to TIMEOUT if specified.

ngxe_writer(CONN, FLAGS, TIMEOUT, DATA, CALLBACK, ...)

Creates a writer for connection identified as CONN. Starts it immediately if NGXE_START is given as a flag. If no data has been send in TIMEOUT ms executes CALLBACK with error flag set to timeout. Extra args can be placed after CALLBACK, as usual. Puts DATA into the write buffer.

If TIMEOUT is set to 0 timeout is not going to be used at all.

Returns undef on error.

First argument paseed to the callback is connection identifier. Second is error.variable. Third and 4th are read and write buffers.

$_[0] - connection
$_[1] - error indicator
$_[2] - read buffer
$_[3] - write buffer
@_[4..$#_] - extra args

If error is set you must return from the subroutine avoiding any ngxe_* calls on current connection $_[0].

For example, let's create server, send a few bytes to new connection and close it:

ngxe_server('*', 55555, sub {
    ngxe_writer($_[0], NGXE_START, 1000, "hi", sub {
        if ($_[1]) {
            return;
        }

        ngxe_close($_[0]);
    });
});

ngxe_writer_start(CONN)

Starts writer for connection CONN.

ngxe_writer_stop(CONN)

Stops writer for connection CONN

ngxe_writer_stop_reader_start(CONN)

Stops writer and starts reader for connection CONN. Saves unnecessary perl --> XSUB --> perl transition.

ngxe_writer_timeout(CONN[, TIMEOUT])

Returns current timeout for the writer and sets it to TIMEOUT if specified.

ngxe_writer_buffer_set(CONN, DATA)

Puts DATA.into the write buffer of the connection CONN replacing old data. Calls ngxe_writer_start() afterwards.

CLOSE

ngxe_close(CONN)

Destroys reader, writer, closes socket and removes connection from the loop.

EXAMPLES

There are quite a few examples in the examples/ directory.

EXAMPLE: ECHO SERVER

A bit more complex example involving manipulation with the buffers.

use Nginx::Engine;

ngxe_init("", 64);

ngxe_server("*", 55555, sub {

    ngxe_reader($_[0], 0, 5000, sub { 

        # $_[0] - connection
        # $_[1] - error indicator
        # $_[2] - read buffer
        # $_[3] - write buffer
        # $_[4] - min length
        # @_[5..$#_] -- args, but we didn't set any

        if ($_[1]) {
            return;
        }

        # copying read buffer to the write buffer
        $_[3] = $_[2];

        # clearing read buffer
        $_[2] = '';

        # calls ngxe_reader_stop_writer_start if write
        # buffers is not empty

    });

    ngxe_writer($_[0], 0, 1000, "", sub {

        # $_[0] - connection
        # $_[1] - error indicator
        # $_[2] - read buffer
        # $_[3] - write buffer
        # @_[4..$#_] -- args, but we didn't set any

        if ($_[1]) {
            return;
        }

        # calls ngxe_writer_stop_reader_start if there is no
        # more data in the buffer

    });

    ngxe_reader_start($_[0]);
});

ngxe_loop;

SEE ALSO

node.js http://nodejs.org/, nginx http://nginx.org/, POE, AnyEvent

AUTHOR

Alexandr Gomoliako <zzz@zzz.org.ua>

LICENSE

Copyright 2010 Alexandr Gomoliako. All rights reserved.

FreeBSD License. Take a look at LICENSE and nginx/LICENSE files.