raspisms/daemons/AbstractDaemon.php

203 lines
5.5 KiB
PHP

<?php
namespace daemons;
/**
* Class defining the global structur of a Linux Daemon
*/
abstract class AbstractDaemon
{
protected $name;
protected $uniq;
protected $logger;
private $is_running = true;
private $signals = array (
SIGTERM,
SIGINT,
SIGCHLD,
SIGHUP
);
/**
* Class used to handle POSIX signals and fork from the current process
*
* @param string $name : The name of the class
* @param object $logger : A PSR3 logger instance
* @param string $pid_dir : Directory for the pid files
* @param array $signals :An array containing additional POSIX signals to handle [optionel]
* @param bool $uniq : Must the process be uniq ?
*/
protected function __construct (string $name, object $logger, string $pid_dir = '/var/run', array $signals = [], bool $uniq = false)
{
$this->name = $name;
$this->logger = $logger;
$this->signals = array_merge($this->signals, $signals);
$this->uniq = $uniq;
$this->pid_dir = $pid_dir;
//Allow script to run indefinitly
set_time_limit(0);
//Register signals
$this->register_signals();
}
/**
* Used to register POSIX signals
*/
private function register_signals()
{
//Enable a tick at every 1 instruction, allowing us to run a function frequently, for exemple looking at signal status
declare(ticks = 1);
foreach ($this->signals as $signal)
{
//For each signal define the method handle_signal of the current class as the way to handle it
@pcntl_signal($signal, [
'self',
'handle_signal'
]);
}
}
/**
* Used to handle properly SIGINT, SIGTERM, SIGCHLD and SIGHUP
*
* @param int $signal
* @param mixed $signinfo
*/
protected function handle_signal(int $signal, $signinfo)
{
if ($signal == SIGTERM || $signal == SIGINT) //Stop the daemon
{
$this->is_running = false;
}
else if ($signal == SIGHUP) //Restart the daemon
{
$this->on_stop();
$this->on_start();
}
else if ($signal == SIGCHLD) //On daemon child stopping
{
pcntl_waitpid(-1, $status, WNOHANG);
}
else //All the other signals
{
$this->handle_other_signals($signal);
}
}
/**
* Launch the infinite loop executing the "run" abstract method
*/
protected function start ()
{
//If process must be uniq and a process with the same pid file is already running
if (file_exists($this->pid_dir . '/' . $this->name . '.pid') && $this->uniq)
{
$this->logger->info("Another process named " . $this->name . " is already running.");
return false;
}
$pid = pcntl_fork(); //Fork current process into a child, so we will be able to later make the child indepedant, kill current process and keep only the child
if ($pid == -1) //Impossible to run script
{
$this->logger->critical("Impossible to create a subprocess.");
return false;
}
elseif ($pid) //Current script
{
return true;
}
$this->logger->info("Process $this->name started as a child with pid $pid.");
//Child script
$sid = posix_setsid(); //Try to make the child process a main process
if ($sid == -1) //Error
{
$this->logger->critical("Cannot make the child process with pid $pid independent.");
exit(1);
}
$this->logger->info("The child process with pid $pid is now independent.");
//Create pid dir if not exists
if (!file_exists($this->pid_dir))
{
$success = mkdir($this->pid_dir, 0777, true);
if (!$success)
{
$this->logger->critical('Cannot create PID directory : ' . $this->pid_dir);
exit(2);
}
}
//Set process name
cli_set_process_title($this->name);
//Write the pid of the process into a file
file_put_contents($this->pid_dir . '/' . $this->name . '.pid', getmypid());
$this->on_start();
try
{
while ($this->is_running)
{
pcntl_signal_dispatch(); //Call dispatcher for signals
$this->run();
}
}
catch (\Exception $e)
{
$this->logger->critical('Exception : ' . $e->getMessage() . " in " . $e->getFile() . " line " . $e->getLine());
}
$this->on_stop();
//Delete pid file
if (file_exists($this->pid_dir . '/' . $this->name . '.pid'))
{
unlink($this->pid_dir . '/' . $this->name . '.pid');
}
}
/**
* True if the daemon is running
*/
public function is_running()
{
return $this->is_running;
}
/**
* Override to implement the code that run infinetly (actually, it run one time but repeat the operation infinetly
*/
protected abstract function run();
/**
* Override to execute code before the ''run'' method on daemon start
*/
protected abstract function on_start();
/**
* Override to execute code after the ''run'' method on daemon shutdown
*/
protected abstract function on_stop();
/**
* Override to handle additional POSIX signals
*
* @param int $signal : Signal sent by interrupt
*/
protected abstract function handle_other_signals(int $signal);
}