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PhutilDaemonOverseer.php
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Sun, Jul 20, 17:05

PhutilDaemonOverseer.php
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<?php
/*
* Copyright 2011 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* Oversees a daemon and restarts it if it fails.
*
* @group daemon
*/
class PhutilDaemonOverseer {
private $captureBufferSize = 65536;
private $deadline;
private $deadlineTimeout = 300;
private $restartDelay = 30;
private $killDelay = 3;
private $daemon;
private $argv;
private $childPID;
private $signaled;
private static $instance;
public function __construct($daemon, array $argv) {
$this->daemon = $daemon;
$this->argv = array_slice($argv, 1);
if (self::$instance) {
throw new Exception(
"You may not instantiate more than one Overseer per process.");
}
self::$instance = $this;
declare(ticks = 1);
pcntl_signal(SIGUSR1, array($this, 'didReceiveKeepaliveSignal'));
pcntl_signal(SIGINT, array($this, 'didReceiveTerminalSignal'));
pcntl_signal(SIGTERM, array($this, 'didReceiveTerminalSignal'));
}
public function run() {
$root = phutil_get_library_root('phutil');
$root = dirname($root);
$exec_daemon = $root.'/scripts/daemon/exec/exec_daemon.php';
$argv = $this->argv;
array_unshift($argv, $exec_daemon, $this->daemon);
foreach ($argv as $k => $arg) {
$argv[$k] = escapeshellarg($arg);
}
$command = 'exec '.implode(' ', $argv);
while (true) {
$this->logMessage('[INIT] Starting process.');
$future = new ExecFuture($command);
$future->setStdoutSizeLimit($this->captureBufferSize);
$future->setStderrSizeLimit($this->captureBufferSize);
$this->deadline = time() + $this->deadlineTimeout;
$future->isReady();
$this->childPID = $future->getPID();
do {
do {
// $memuse = number_format(memory_get_usage() / 1024, 1);
// $this->logMessage('[STAT] Memory Usage: '.$memuse.' KB');
// We need a shortish timeout here so we can run the tick handler
// frequently in order to process signals.
$result = $future->resolve(1);
if ($result !== null) {
list($err) = $result;
if ($err) {
$this->logMessage('[FAIL] Process edited with error '.$err.'.');
} else {
$this->logMessage('[DONE] Process exited successfully.');
}
break 2;
}
} while (time() < $this->deadline);
$this->logMessage('[HANG] Hang detected. Restarting process.');
$this->annihilateProcessGroup();
} while (false);
$this->logMessage('[WAIT] Waiting to restart process.');
sleep($this->restartDelay);
}
}
public function didReceiveKeepaliveSignal($signo) {
$this->deadline = time() + $this->deadlineTimeout;
}
public function didReceiveTerminalSignal($signo) {
if ($this->signaled) {
exit(128 + $signo);
}
echo "\n>>> Shutting down...\n";
$this->signaled = true;
$this->annihilateProcessGroup();
exit(128 + $signo);
}
private function logMessage($message) {
echo date('Y-m-d g:i:s A').' '.$message."\n";
}
private function annihilateProcessGroup() {
$pid = $this->childPID;
$pgid = posix_getpgid($pid);
if ($pid && $pgid) {
exec("kill -TERM -- -{$pgid}");
sleep($this->killDelay);
exec("kill -KILL -- -{$pgid}");
$this->childPID = null;
}
}
}

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