Cessna

Cessna is a lightweight, TCP based socket acceptor pool for Erlang/OTP.

Goals

Cessna aims to provide a simple and lightweight approach to accepting TCP while you have heavy loads. Mostly, It helps when you have live connections like a Chat or an AMPQ server. For example, try to imagine this scenario: While your server has a 100K socket connection, it goes down (for some reason like deployment) and gets back up; you face heavy socket accept requests concurrently.

Installation

Pre Requirement: Use Erlang/OTP +18.

Step 1: Add cessna to rebar.config.

{deps, [
 ....
{cessna,  {git,  "git@github.com:amoein/cessna.git"}},
 ....
]}.

Step 2: Make sure cessna starts in your_app.erl:

-module(your_app).

start(_StartType, _StartArgs)  ->
....
application:ensure_started(cessna),
...

Step 3:
```
rebar3 deps
```

Usage

First of all you should include cessna/include/cessna.hrl in your module like this:

-include_lib("cessna/include/cessna.hrl").

For add new acceptor you should use cessna_sup:add_new_pool:

{ok,  _}  =  cessna_sup:add_new_pool(your_pool_name,  #option{}),

Spec
- your_pool_name: It's your acceptor pool name and it's atom()
- #option{}: It's record define by cessne contains:
```
#option{type  =  tcp,
        port  =  8080,
        handler_module  =  your_server_socket,
        handler_func  =  your_server_function,
        number_of_worker  =  10,
        ips  =  [{0,0,0,0}],
        socket_option  =  [binary]}
```
  - handler_module and handler_func:
    
    There are simple MFA(minus part of A). The Arity part is an array contain [Socket :: inet:socket(), PoolPID :: pid()], for example:
```
 -module(my_module).

 my_function([Socket , PID])->
 .....
 end.
```
    To get socket messages, you must provide a listening loop in your function. For more handy usage, it's better to be used on starting gen_serve like this:
```
- module(handler_module).

-behaviour(gen_server).

start_link([Socket, PoolPID]) ->
    gen_server:start_link(?MODULE, [Socket, PoolPID], []).
```
  - type:
    
    Currently it is tcp, but im ganna implement ssl soon.
  - port:
    
    non_neg_integer from 0 to 65535.
  - number_of_worker:
    
    Number of concurrent listener: non_neg_integer from 0
  - ips:
    
    Cessna can listen to multiple interface and ip for same port. array() :: [ip_address()]
  - socket_option:
    
    Erlang socket option. array() :: [socket_setopt()]

Version History

0.2.1 (3 March 2023)
- Fix bug in cessna_worker_tcp and cessna.hrl
0.2.0 (2 March 2023)
- Remove extra code
- Improve documentation
- Improve test
0.1.0(8 JUl 2019)
- Initial Release