Heroku log parser

heroku_parser.php

<?php

if (!class_exists('HerokuParser')):

/**
 *  A super-quick parser for Heroku logfiles
 */
class HerokuParser {

	/**
	 *  Filter a string against the specified criteria
	 *
	 *  @param  string  the input string
	 *  @param  string  (optional) the source of the message (e.g., "app")
	 *  @param  string  (optional) the process (e.g., "web.1")
	 *  @return string  the line, or blank if the filter failed
	 */
	protected function filter ($line, $source = '', $process = '') {

		$source_test = $process_test = '.*?';

		if ($source) {
			$source_test = "$source";
		}

		if ($process) {
			$process_test = "$process\.?[0-9]*";
		}
		
		$test = sprintf('#\s%s\[%s\]\:\s#', $source_test, $process_test);

		if (preg_match($test, $line)) {
			return $line;
		}

		return '';
	}

	/**
	 *  Parse the contents of a single line
	 *
	 *  Returns an associative array describing the contents of the line:
	 *
	 *  - timestamp: when the message was logged
	 *  - source: the source of the message
	 *  - process: the source process logging the message
	 *  - message: the message
	 *
	 *  @param  string  the input string
	 *  @return array
	 */
	protected function parse ($line) {

		// timestamp source[process]: message
		$components = explode(' ', $line);

		$timestamp = array_shift($components);
		$dyno = explode('[', array_shift($components));

		$message = implode(' ', $components);

		return array(
			'timestamp' => strtotime($timestamp),
			'source' => $dyno[0],
			'process' => substr($dyno[1], 0, -2),
			'message' => trim($message)
		);
	}

	/**
	 *  Parse a Heroku log file
	 *
	 *  @param  string  the source of the message (e.g. "app")  
	 *  @param  string  the process ID (e.g., "web.1")
	 *  @return an array of entries matching the filter criteria
	 */
	public function run ($logfile, $source = '', $process = '') {

		$entries = array();

		if (!($fp = fopen($logfile, 'r'))) {
			die('failed opening logfile:' . $fp);
		}

		while(($line = fgets($fp)) !== false) {

			// compare the current line against any source/process filters
			if ($line = $this->filter($line, $source, $process)) {

				// parse coarse
				$line = $this->parse($line);

				if ($line['message']) {
					$entries[] = $line;
				}
			}
		}

		return $entries;

		fclose($fp);
	}
}

endif; // class_exists