run_with_exit.php

run_with_exit.php

<?php

/**
 * Self-contained monitoring system for system signals
 * returns true if a 'graceful exit' like signal is received.
 *
 * We don't listen for SIGKILL as that needs to be an immediate exit,
 * which PHP already provides.
 * @return bool
 */
function checkSignalsForExit()
{
    static $initialised = false;
    static $needToExit = false;

    $fnSignalHandler = function ($signalNumber) use (&$needToExit) {
        $needToExit = true;
    };

    if ($initialised === false) {
        pcntl_signal(SIGINT, $fnSignalHandler, false);
        pcntl_signal(SIGQUIT, $fnSignalHandler, false);
        pcntl_signal(SIGTERM, $fnSignalHandler, false);
        pcntl_signal(SIGHUP, $fnSignalHandler, false);
        pcntl_signal(SIGUSR1, $fnSignalHandler, false);
        $initialised = true;
    }

    pcntl_signal_dispatch();

    return $needToExit;
}


/**
 * Repeatedly calls a callable until it's time to stop
 *
 * @param callable $callable - the thing to run
 * @param int $secondsBetweenRuns - the minimum time between runs
 * @param int $sleepTime - the time to sleep between runs
 * @param int $maxRunTime - the max time to run for, before returning
 */
function continuallyExecuteCallable($callable, int $secondsBetweenRuns, int $sleepTime, int $maxRunTime)
{
    $startTime = microtime(true);
    $lastRuntime = 0;
    $finished = false;

    echo "starting continuallyExecuteCallable \n";
    while ($finished === false) {
        $shouldRunThisLoop = false;
        if ($secondsBetweenRuns === 0) {
            $shouldRunThisLoop = true;
        }
        else if ((microtime(true) - $lastRuntime) > $secondsBetweenRuns) {
            $shouldRunThisLoop = true;
        }

        if ($shouldRunThisLoop === true) {
            $callable();
            $lastRuntime = microtime(true);
        }

        if (checkSignalsForExit()) {
            break;
        }

        if ($sleepTime > 0) {
            sleep($sleepTime);
        }

        if ((microtime(true) - $startTime) > $maxRunTime) {
            echo "Reach maxRunTime - finished = true\n";
            $finished = true;
        }
    }

    echo "Finishing continuallyExecuteCallable\n";
}