<?php declare(strict_types=1);
/*
* This file is part of the Monolog package.
*
* (c) Jordi Boggiano <j.boggiano@seld.be>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Monolog\Handler;
use Monolog\Level;
use Monolog\Logger;
use Psr\Log\LogLevel;
use Monolog\LogRecord;
/**
* Simple handler wrapper that deduplicates log records across multiple requests
*
* It also includes the BufferHandler functionality and will buffer
* all messages until the end of the request or flush() is called.
*
* This works by storing all log records' messages above $deduplicationLevel
* to the file specified by $deduplicationStore. When further logs come in at the end of the
* request (or when flush() is called), all those above $deduplicationLevel are checked
* against the existing stored logs. If they match and the timestamps in the stored log is
* not older than $time seconds, the new log record is discarded. If no log record is new, the
* whole data set is discarded.
*
* This is mainly useful in combination with Mail handlers or things like Slack or HipChat handlers
* that send messages to people, to avoid spamming with the same message over and over in case of
* a major component failure like a database server being down which makes all requests fail in the
* same way.
*
* @author Jordi Boggiano <j.boggiano@seld.be>
*/
class DeduplicationHandler extends BufferHandler
{
protected string $deduplicationStore;
protected Level $deduplicationLevel;
protected int $time;
protected bool $gc = false;
/**
* @param HandlerInterface $handler Handler.
* @param string|null $deduplicationStore The file/path where the deduplication log should be kept
* @param int|string|Level|LogLevel::* $deduplicationLevel The minimum logging level for log records to be looked at for deduplication purposes
* @param int $time The period (in seconds) during which duplicate entries should be suppressed after a given log is sent through
* @param bool $bubble Whether the messages that are handled can bubble up the stack or not
*
* @phpstan-param value-of<Level::VALUES>|value-of<Level::NAMES>|Level|LogLevel::* $deduplicationLevel
*/
public function __construct(HandlerInterface $handler, ?string $deduplicationStore = null, int|string|Level $deduplicationLevel = Level::Error, int $time = 60, bool $bubble = true)
{
parent::__construct($handler, 0, Level::Debug, $bubble, false);
$this->deduplicationStore = $deduplicationStore === null ? sys_get_temp_dir() . '/monolog-dedup-' . substr(md5(__FILE__), 0, 20) .'.log' : $deduplicationStore;
$this->deduplicationLevel = Logger::toMonologLevel($deduplicationLevel);
$this->time = $time;
}
public function flush(): void
{
if ($this->bufferSize === 0) {
return;
}
$store = null;
if (file_exists($this->deduplicationStore)) {
$store = file($this->deduplicationStore, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
}
$passthru = null;
foreach ($this->buffer as $record) {
if ($record->level->value >= $this->deduplicationLevel->value) {
$passthru = $passthru === true || !is_array($store) || !$this->isDuplicate($store, $record);
if ($passthru) {
$line = $this->buildDeduplicationStoreEntry($record);
file_put_contents($this->deduplicationStore, $line . "\n", FILE_APPEND);
if (!is_array($store)) {
$store = [];
}
$store[] = $line;
}
}
}
// default of null is valid as well as if no record matches duplicationLevel we just pass through
if ($passthru === true || $passthru === null) {
$this->handler->handleBatch($this->buffer);
}
$this->clear();
if ($this->gc) {
$this->collectLogs();
}
}
/**
* If there is a store entry older than e.g. a day, this method should set `$this->gc` to `true` to trigger garbage collection.
* @param string[] $store The deduplication store
*/
protected function isDuplicate(array $store, LogRecord $record): bool
{
$timestampValidity = $record->datetime->getTimestamp() - $this->time;
$expectedMessage = preg_replace('{[\r\n].*}', '', $record->message);
$yesterday = time() - 86400;
for ($i = count($store) - 1; $i >= 0; $i--) {
list($timestamp, $level, $message) = explode(':', $store[$i], 3);
if ($level === $record->level->getName() && $message === $expectedMessage && $timestamp > $timestampValidity) {
return true;
}
if ($timestamp < $yesterday) {
$this->gc = true;
}
}
return false;
}
/**
* @return string The given record serialized as a single line of text
*/
protected function buildDeduplicationStoreEntry(LogRecord $record): string
{
return $record->datetime->getTimestamp() . ':' . $record->level->getName() . ':' . preg_replace('{[\r\n].*}', '', $record->message);
}
private function collectLogs(): void
{
if (!file_exists($this->deduplicationStore)) {
return;
}
$handle = fopen($this->deduplicationStore, 'rw+');
if (false === $handle) {
throw new \RuntimeException('Failed to open file for reading and writing: ' . $this->deduplicationStore);
}
flock($handle, LOCK_EX);
$validLogs = [];
$timestampValidity = time() - $this->time;
while (!feof($handle)) {
$log = fgets($handle);
if (is_string($log) && '' !== $log && substr($log, 0, 10) >= $timestampValidity) {
$validLogs[] = $log;
}
}
ftruncate($handle, 0);
rewind($handle);
foreach ($validLogs as $log) {
fwrite($handle, $log);
}
flock($handle, LOCK_UN);
fclose($handle);
$this->gc = false;
}
}