From 04e7cab313650ed1bd966f149982c06a998c7a87 Mon Sep 17 00:00:00 2001
From: Jens-Uwe Mager <jum@anubis.han.de>
Date: Tue, 29 Jul 2025 17:46:44 +0200
Subject: [PATCH 1/3] Add a 'stdlog' log type.

The stdlog log type is similar to the errorlog log type, but it does
output to stderr and makes sure the output is formatted as JSON. This is
in particular useful for environments running in docker containers, with
the stderr being collected by log aggregation services like Grafana or
Google Cloud logging.
---
 lib/private/Log/LogFactory.php |  3 +-
 lib/private/Log/Stdlog.php     | 65 ++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 lib/private/Log/Stdlog.php

diff --git a/lib/private/Log/LogFactory.php b/lib/private/Log/LogFactory.php
index ee6054b81f8fd..84d7411c4f965 100644
--- a/lib/private/Log/LogFactory.php
+++ b/lib/private/Log/LogFactory.php
@@ -1,5 +1,4 @@
 <?php
-
 /**
  * SPDX-FileCopyrightText: 2018 Nextcloud GmbH and Nextcloud contributors
  * SPDX-License-Identifier: AGPL-3.0-or-later
@@ -26,6 +25,7 @@ public function __construct(
 	public function get(string $type):IWriter {
 		return match (strtolower($type)) {
 			'errorlog' => new Errorlog($this->systemConfig),
+			'stdlog' => new Stdlog($this->systemConfig),
 			'syslog' => $this->c->resolve(Syslog::class),
 			'systemd' => $this->c->resolve(Systemdlog::class),
 			'file' => $this->buildLogFile(),
@@ -36,6 +36,7 @@ public function get(string $type):IWriter {
 	protected function createNewLogger(string $type, string $tag, string $path): IWriter {
 		return match (strtolower($type)) {
 			'errorlog' => new Errorlog($this->systemConfig, $tag),
+			'stdlog' => new Stdlog($this->systemConfig, $tag),
 			'syslog' => new Syslog($this->systemConfig, $tag),
 			'systemd' => new Systemdlog($this->systemConfig, $tag),
 			default => $this->buildLogFile($path),
diff --git a/lib/private/Log/Stdlog.php b/lib/private/Log/Stdlog.php
new file mode 100644
index 0000000000000..83d7e36797ce9
--- /dev/null
+++ b/lib/private/Log/Stdlog.php
@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Log;
+
+use OC\SystemConfig;
+use OCP\Log\IWriter;
+
+class Stdlog extends LogDetails implements IWriter {
+	public function __construct(
+		SystemConfig $config,
+		protected string $tag = 'nextcloud',
+	) {
+		parent::__construct($config);
+	}
+
+	/**
+	 * Write a message in the log
+	 *
+	 * @param string|array $message
+	 */
+	public function write(string $app, $message, int $level): void {
+	    $detailsJson = $this->logDetailsAsJSON($app, $message, $level);
+	    $details = json_decode($detailsJson, true);
+
+	    if (json_last_error() !== JSON_ERROR_NONE || !is_array($details)) {
+		return;
+	    }
+
+	    $logEntry = array_merge([
+		'tag' => $this->tag,
+		'app' => $app,
+		'level' => $level,
+	    ], $details);
+	    // Check if 'message' field exists and is a string
+	    if (isset($logEntry['message']) && is_string($logEntry['message'])) {
+		$msg = $logEntry['message'];
+
+		if (strlen($msg) > 0 && $msg[0] === '{') {
+		    // Try decoding JSON
+		    $decoded = json_decode($msg, true);
+
+		    if (json_last_error() === JSON_ERROR_NONE && is_array($decoded)) {
+			// Remove original 'message' field
+			unset($logEntry['message']);
+
+			// Flatten decoded JSON into top-level logEntry
+			// This will overwrite existing keys if there are
+			// conflicts
+			$logEntry = array_merge($logEntry, $decoded);
+		    }
+		}
+	    }
+
+	    $json = json_encode($logEntry, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
+
+	    if ($json !== false) {
+		file_put_contents('php://stderr', $json . PHP_EOL);
+	    }
+	}
+}

From 60fe227b66ccecdb7ec86ee6b0d82942f727811a Mon Sep 17 00:00:00 2001
From: Jens-Uwe Mager <jum@anubis.han.de>
Date: Mon, 29 Dec 2025 12:58:04 -0500
Subject: [PATCH 2/3] Add traceparent support.

---
 lib/private/Log/Stdlog.php | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/private/Log/Stdlog.php b/lib/private/Log/Stdlog.php
index 83d7e36797ce9..65493d753a950 100644
--- a/lib/private/Log/Stdlog.php
+++ b/lib/private/Log/Stdlog.php
@@ -36,6 +36,17 @@ public function write(string $app, $message, int $level): void {
 		'app' => $app,
 		'level' => $level,
 	    ], $details);
+	    $traceparent = $_SERVER['HTTP_TRACEPARENT'];
+	    if (preg_match('/^00-([0-9a-f]{32})-([0-9a-f]{16})-([0-9a-f]{2})$/', $traceparent, $matches)) {
+		$gcp = getenv('GOOGLE_CLOUD_PROJECT');
+		if (!empty($gcp)) {
+		    $logEntry['logging.googleapis.com/trace'] = 'projects/' . $gcp . '/traces/' . $matches[1];
+		    $logEntry['logging.googleapis.com/spanId'] = $matches[2];
+		} else {
+		    $logEntry['traceId'] = $matches[1];
+		    $logEntry['spanId'] = $matches[2];
+		}
+	    }
 	    // Check if 'message' field exists and is a string
 	    if (isset($logEntry['message']) && is_string($logEntry['message'])) {
 		$msg = $logEntry['message'];

From d37edb563aa5ac61f972d01753e0ac4037b9e9af Mon Sep 17 00:00:00 2001
From: Jens-Uwe Mager <jum@anubis.han.de>
Date: Fri, 29 May 2026 16:27:18 -0400
Subject: [PATCH 3/3] If there is no trace parent, do nothing.

---
 lib/private/Log/Stdlog.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/private/Log/Stdlog.php b/lib/private/Log/Stdlog.php
index 65493d753a950..013881211aa5b 100644
--- a/lib/private/Log/Stdlog.php
+++ b/lib/private/Log/Stdlog.php
@@ -36,7 +36,7 @@ public function write(string $app, $message, int $level): void {
 		'app' => $app,
 		'level' => $level,
 	    ], $details);
-	    $traceparent = $_SERVER['HTTP_TRACEPARENT'];
+	    $traceparent = $_SERVER['HTTP_TRACEPARENT'] ?? '';
 	    if (preg_match('/^00-([0-9a-f]{32})-([0-9a-f]{16})-([0-9a-f]{2})$/', $traceparent, $matches)) {
 		$gcp = getenv('GOOGLE_CLOUD_PROJECT');
 		if (!empty($gcp)) {