Feature: Add and expose frontend loglevel

This adds a new config variable `loglevel_frontend`,
allowing to configure the logging level of the
browser part as requested in nextcloud/nextcloud-logger#141

If not configured the `loglevel` is used as the fallback.

Signed-off-by: Ferdinand Thiessen <rpm@fthiessen.de>

config/config.sample.php

@@ -888,6 +888,15 @@ $CONFIG = [
  */
 'loglevel' => 2,
 
+/**
+ * Loglevel used by the frontend to start logging at. The same values as
+ * for ``loglevel`` can be used. If not set it defaults to the value
+ * configured for ``loglevel`` or Warning if that is not set either.
+ *
+ * Defaults to ``2``
+ */
+'loglevel_frontend' => 2,
+
 /**
  * If you maintain different instances and aggregate the logs, you may want
  * to distinguish between them. ``syslog_tag`` can be set per instance

lib/private/Template/JSConfigHelper.php

@@ -47,6 +47,7 @@ use OCP\IInitialStateService;
 use OCP\IL10N;
 use OCP\ISession;
 use OCP\IURLGenerator;
+use OCP\ILogger;
 use OCP\IUser;
 use OCP\User\Backend\IPasswordConfirmationBackend;
 use OCP\Util;
@@ -176,6 +177,9 @@ class JSConfigHelper {
 			'sharing.maxAutocompleteResults' => max(0, $this->config->getSystemValueInt('sharing.maxAutocompleteResults', Constants::SHARING_MAX_AUTOCOMPLETE_RESULTS_DEFAULT)),
 			'sharing.minSearchStringLength' => $this->config->getSystemValueInt('sharing.minSearchStringLength', 0),
 			'blacklist_files_regex' => FileInfo::BLACKLIST_FILES_REGEX,
+			'loglevel' => $this->config->getSystemValue('loglevel_frontend',
+				$this->config->getSystemValue('loglevel', ILogger::WARN)
+			),
 		];
 
 		$array = [