Added LogViewer class and CLI command

CHANGELOG.md

@@ -3,6 +3,7 @@
 
 1. [](#new)
     * Added index file support for Flex Objects
+    * Added `LogViewer` helper class and CLI command: `bin/grav logviewer`
 1. [](#improved)
     * Improved error detection for broken Flex Objects
     * Removed apc and xcache support, made apc alias of apcu

bin/grav

@@ -45,5 +45,6 @@ $app->addCommands(array(
     new \Grav\Console\Cli\NewProjectCommand(),
     new \Grav\Console\Cli\SchedulerCommand(),
     new \Grav\Console\Cli\SecurityCommand(),
+    new \Grav\Console\Cli\LogViewerCommand(),
 ));
 $app->run();

system/src/Grav/Common/Helpers/LogViewer.php

@@ -0,0 +1,130 @@
+<?php
+
+/**
+ * @package    Grav\Common\Helpers
+ *
+ * @copyright  Copyright (C) 2015 - 2019 Trilby Media, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Common\Helpers;
+
+class LogViewer
+{
+    protected $pattern = '/\[(?P<date>.*)\] (?P<logger>\w+).(?P<level>\w+): (?P<message>.*[^ ]+) (?P<context>[^ ]+) (?P<extra>[^ ]+)/';
+
+    /**
+     * Get the objects of a tailed file
+     *
+     * @param $filepath
+     * @param int $lines
+     * @param bool $desc
+     * @return array
+     */
+    public function objectTail($filepath, $lines = 1, $desc = true)
+    {
+        $data = $this->tail($filepath, $lines);
+        $tailed_log = explode(PHP_EOL, $data);
+        $line_objects = [];
+
+        foreach ($tailed_log as $line) {
+            $line_objects[] = $this->parse($line);
+        }
+
+        return $desc ? $line_objects : array_reverse($line_objects);
+    }
+
+    /**
+     * Optimized way to get just the last few entries of a log file
+     *
+     * @param $filepath
+     * @param int $lines
+     * @return bool|string
+     */
+    public function tail($filepath, $lines = 1) {
+
+        $f = @fopen($filepath, "rb");
+        if ($f === false) return false;
+
+        else $buffer = ($lines < 2 ? 64 : ($lines < 10 ? 512 : 4096));
+
+        fseek($f, -1, SEEK_END);
+        if (fread($f, 1) != "\n") $lines -= 1;
+
+        // Start reading
+        $output = '';
+        $chunk = '';
+        // While we would like more
+        while (ftell($f) > 0 && $lines >= 0) {
+            // Figure out how far back we should jump
+            $seek = min(ftell($f), $buffer);
+            // Do the jump (backwards, relative to where we are)
+            fseek($f, -$seek, SEEK_CUR);
+            // Read a chunk and prepend it to our output
+            $output = ($chunk = fread($f, $seek)) . $output;
+            // Jump back to where we started reading
+            fseek($f, -mb_strlen($chunk, '8bit'), SEEK_CUR);
+            // Decrease our line counter
+            $lines -= substr_count($chunk, "\n");
+        }
+        // While we have too many lines
+        // (Because of buffer size we might have read too many)
+        while ($lines++ < 0) {
+            // Find first newline and remove all text before that
+            $output = substr($output, strpos($output, "\n") + 1);
+        }
+        // Close file and return
+        fclose($f);
+
+        return trim($output);
+    }
+
+    public static function levelColor($level)
+    {
+        $colors = [
+            'DEBUG'     => 'green',
+            'INFO'      => 'cyan',
+            'NOTICE'    => 'yellow',
+            'WARNING'   => 'yellow',
+            'ERROR'     => 'red',
+            'CRITICAL'  => 'red',
+            'ALERT'     => 'red',
+            'EMERGENCY' => 'magenta'
+        ];
+        return $colors[$level] ?? 'white';
+    }
+
+    /**
+     * Parse a monolog row into array bits
+     *
+     * @param $line
+     * @return array
+     */
+    public function parse($line)
+    {
+        if( !is_string($line) || strlen($line) === 0) {
+            return array();
+        }
+        preg_match($this->pattern, $line, $data);
+        if (!isset($data['date'])) {
+            return array();
+        }
+
+        preg_match('/(.*)- Trace:(.*)/', $data['message'], $matches);
+        if (is_array($matches) && isset($matches[1])) {
+            $data['message'] = trim($matches[1]);
+            $data['trace'] = trim($matches[2]);
+        }
+
+        return array(
+            'date' => \DateTime::createFromFormat('Y-m-d H:i:s', $data['date']),
+            'logger' => $data['logger'],
+            'level' => $data['level'],
+            'message' => $data['message'],
+            'trace' => $data['trace'] ?? null,
+            'context' => json_decode($data['context'], true),
+            'extra' => json_decode($data['extra'], true)
+        );
+    }
+
+}

system/src/Grav/Console/Cli/LogViewerCommand.php

@@ -0,0 +1,89 @@
+<?php
+
+/**
+ * @package    Grav\Console\Cli
+ *
+ * @copyright  Copyright (C) 2015 - 2019 Trilby Media, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Console\Cli;
+
+
+use Grav\Common\Grav;
+use Grav\Common\Helpers\LogViewer;
+use Grav\Common\Utils;
+use Grav\Console\ConsoleCommand;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Style\SymfonyStyle;
+
+class LogViewerCommand extends ConsoleCommand
+{
+    protected function configure()
+    {
+        $this
+            ->setName('logviewer')
+            ->addOption(
+                'file',
+                'f',
+                InputOption::VALUE_OPTIONAL,
+                'custom log file location (default = grav.log)'
+            )
+            ->addOption(
+                'lines',
+                'l',
+                InputOption::VALUE_OPTIONAL,
+                'number of lines (default = 10)'
+            )
+            ->setDescription('Display the last few entries of Grav log')
+            ->setHelp("Display the last few entries of Grav log");
+    }
+
+    /**
+     * @return int|null|void
+     */
+    protected function serve()
+    {
+        $grav = Grav::instance();
+        $grav->setup();
+
+        $file = $this->input->getOption('file') ?? 'grav.log';
+        $lines = $this->input->getOption('lines') ?? 20;
+        $verbose = $this->input->getOption('verbose', false);
+
+        $io = new SymfonyStyle($this->input, $this->output);
+
+        $io->title('Log Viewer');
+
+        $io->writeln(sprintf('viewing last %s entries in <white>%s</white>', $lines, $file));
+        $io->newLine();
+
+        $viewer = new LogViewer();
+
+        $logfile = $grav['locator']->findResource("log://" . $file);
+
+        if ($logfile) {
+            $rows = $viewer->objectTail($logfile, $lines, true);
+            foreach ($rows as $log) {
+                $date = $log['date'];
+                $level_color = LogViewer::levelColor($log['level']);
+
+                if ($date instanceof \DateTime) {
+                    $output = "<yellow>{$log['date']->format('Y-m-d h:i:s')}</yellow> [<{$level_color}>{$log['level']}</{$level_color}>]";
+                    if ($log['trace'] && $verbose) {
+                        $output .= " <white>{$log['message']}</white> - {$log['trace']}";
+                    } else {
+                        $output .= " {$log['message']}";
+                    }
+                    $io->writeln($output);
+                    if ($verbose) {
+                        $io->newLine();
+                    }
+                }
+            }
+        } else {
+            $io->error('cannot find the log file: logs/' . $file);
+        }
+
+    }
+}