Wolf Digital file logging helper class and function

FileLogger.php

<?php

namespace WolfDigital;

use DateTime;
use DateTimeZone;
use Exception;

class FileLogger {

	/** @var FileLogger */
	private $parent_logger;

	/** @var string */
	private $log_dir;

	/** @var string */
	private $file_name;

	/** @var string */
	private $namespace;

	/** @var int */
	private $depth;

	private $timezone;

	/** @var array */
	private static $namespace_stack = [];

	/**
	 * @param string $log_dir
	 * @param string $file_name
	 * @param FileLogger|null $parent_logger An optional additional FileLogger to pass messages through to.
	 * @param string $namespace
	 */
	public function __construct( $log_dir, $file_name, FileLogger $parent_logger = null, $namespace = '', $timezone = '' ) {
		$this->log_dir = untrailingslashit( $log_dir );
		$this->file_name = trim( $file_name, '/' );
		$this->parent_logger = $parent_logger;
		$this->namespace = $namespace;
		$this->depth = 0;
		$this->timezone = $timezone ?: date_default_timezone_get();
		$this->createLogDir();
	}

	/**
	 * @param string $message
	 */
	public function log( $message ) {
		$stamp = '[' . $this->getTimestamp() . ']';

		if ( is_array( $message ) || is_object( $message ) ) {
			$message = print_r( $message, true );
		}

		if ( $this->depth > 0 ) {
			$multiplier = $this->depth == 1 ? 1 : 2;
			$message = str_repeat( ' ', $this->depth * $multiplier ) . '– ' . $message;
		}

		if ( $this->namespace ) {
			$message = "{$this->namespace} $message";
		}

		error_log( "$stamp $message \n", 3, $this->getPathToLogFile() );

		if ( $this->parent_logger ) {
			$this->parent_logger->log( $message );
		}
	}

	/**
	 * Add a blank line to the log file.
	 */
	public function logBlankLine() {
		error_log( "\n", 3, $this->getPathToLogFile() );

		if ( $this->parent_logger ) {
			$this->parent_logger->logBlankLine();
		}
	}

	/**
	 * Set the depth for the log message indentation.
	 *
	 * @param int $depth
	 */
	public function setDepth( $depth ) {
		$this->depth = $depth;
	}

	/**
	 * Set the namespace for log messages and push it onto the stack.
	 *
	 * @param string $namespace
	 */
	public function setNamespace( $namespace ) {
		self::$namespace_stack[] = $this->namespace;
		$this->namespace = $namespace;
	}

	/**
	 * Revert the namespace to the previous one in the stack.
	 */
	public function revertNamespace() {
		if ( ! empty( self::$namespace_stack ) ) {
			$this->namespace = array_pop( self::$namespace_stack );
		} else {
			$this->namespace = '';
		}
	}

	/**
	 * Get the current namespace stack.
	 *
	 * @return array
	 */
	public function getNamespaceStack() {
		return self::$namespace_stack;
	}

	/**
	 * @return string
	 */
	private function getPathToLogFile() {
		$dir = $this->log_dir;
		$name = $this->file_name;
		$extension = '.log';
		return "{$dir}/{$name}{$extension}";
	}

	private function getTimestamp() {
		try {
			$dt = new DateTime( "now", new DateTimeZone( $this->timezone ) );
			$dt->setTimestamp( time() );
			return $dt->format( 'Y-m-d h:i:sa' ) . ' ' . $this->timezone;
		} catch ( Exception $e ) {
			return date( 'Y-m-d h:i:sa' ) . ' ' . date_default_timezone_get();
		}
	}

	private function createLogDir() {
		if ( ! file_exists( $this->log_dir ) ) {
			wp_mkdir_p( $this->log_dir );
		}
	}
}

log-utils.php

<?php

namespace WolfDigital;

use DateTime;
use DateTimeZone;
use WolfDigital\FileLogger;

defined( 'WOLFD_CORE_LOG_DIR' ) or define( 'WOLFD_CORE_LOG_DIR', wp_get_upload_dir()['basedir'] . '/wolfdigital' );
defined( 'WOLFD_CORE_LOG_TZ' ) or define( 'WOLFD_CORE_LOG_TZ', 'Australia/Melbourne' );

/**
 * @param string $basename       Base name for the log file (e.g. 'jobfile-import')
 * @param string $date_prefix    'daily', 'monthly', 'none', or a custom DateTime format (e.g. 'Y-m')
 * @return FileLogger
 */
function logger( $basename = 'log', $date_prefix = 'monthly' ) {
	static $loggers = [];

	$key = "{$basename}|{$date_prefix}";
	if ( ! isset( $loggers[ $key ] ) ) {
		$prefix = '';
		try {
			$tz = new DateTimeZone( WOLFD_CORE_LOG_TZ );
			$now = new DateTime( 'now', $tz );

			switch ( $date_prefix ) {
				case 'daily':
					$prefix = $now->format( 'Ymd' );
					break;
				case 'monthly':
					$prefix = $now->format( 'Ym' );
					break;
				case 'none':
					$prefix = '';
					break;
				default:
					$prefix = $now->format( $date_prefix );
					break;
			}
		} catch ( \Exception $e ) {
			// fail silently
		}

		$filename = join( '-', array_filter( [ $prefix, $basename ] ) );

		$loggers[ $key ] = new FileLogger(
			WOLFD_CORE_LOG_DIR,
			$filename,
			null,
			'',
			WOLFD_CORE_LOG_TZ
		);
	}

	return $loggers[ $key ];
}