Merge pull request #116 from bobthecow/feature/logging

Add logging

src/Mustache/Engine.php

@@ -34,12 +34,13 @@ class Mustache_Engine
     // Environment
     private $templateClassPrefix = '__Mustache_';
     private $cache = null;
+    private $cacheFileMode = null;
     private $loader;
     private $partialsLoader;
     private $helpers;
     private $escape;
     private $charset = 'UTF-8';
-    private $cacheFileMode = null;
+    private $logger;
 
     /**
      * Mustache class constructor.
@@ -81,6 +82,11 @@ class Mustache_Engine
      *
      *         // Character set for `htmlspecialchars`. Defaults to 'UTF-8'. Use 'UTF-8'.
      *         'charset' => 'ISO-8859-1',
+     *
+     *         // A Mustache Logger instance. No logging will occur unless this is set. Using a PSR-3 compatible
+     *         // logging library -- such as Monolog -- is highly recommended. A simple stream logger implementation is
+     *         // available as well:
+     *         'logger' => new Mustache_StreamLogger('php://stderr'),
      *     );
      *
      * @param array $options (default: array())
@@ -126,6 +132,10 @@ class Mustache_Engine
         if (isset($options['charset'])) {
             $this->charset = $options['charset'];
         }
+
+        if (isset($options['logger'])) {
+            $this->setLogger($options['logger']);
+        }
     }
 
     /**
@@ -330,6 +340,30 @@ class Mustache_Engine
         $this->getHelpers()->remove($name);
     }
 
+    /**
+     * Set the Mustache Logger instance.
+     *
+     * @param Mustache_Logger|Psr\Log\LoggerInterface $logger
+     */
+    public function setLogger($logger = null)
+    {
+        if ($logger !== null && !($logger instanceof Mustache_Logger || is_a($logger, 'Psr\\Log\\LoggerInterface'))) {
+            throw new InvalidArgumentException('Expected an instance of Mustache_Logger or Psr\\Log\\LoggerInterface.');
+        }
+
+        $this->logger = $logger;
+    }
+
+    /**
+     * Get the current Mustache Logger instance.
+     *
+     * @return Mustache_Logger|Psr\Log\LoggerInterface
+     */
+    public function getLogger()
+    {
+        return $this->logger;
+    }
+
     /**
      * Set the Mustache Tokenizer instance.
      *
@@ -453,7 +487,12 @@ class Mustache_Engine
         try {
             return $this->loadSource($this->getPartialsLoader()->load($name));
         } catch (InvalidArgumentException $e) {
-            // If the named partial cannot be found, return null.
+            // If the named partial cannot be found, log then return null.
+            $this->log(
+                Mustache_Logger::WARNING,
+                'Partial not found: "{name}"',
+                array('name' => $name)
+            );
         }
     }
 
@@ -496,15 +535,33 @@ class Mustache_Engine
             if (!class_exists($className, false)) {
                 if ($fileName = $this->getCacheFilename($source)) {
                     if (!is_file($fileName)) {
+                        $this->log(
+                            Mustache_Logger::DEBUG,
+                            'Writing "{className}" class to template cache: "{fileName}"',
+                            array('className' => $className, 'fileName' => $fileName)
+                        );
+
                         $this->writeCacheFile($fileName, $this->compile($source));
                     }
 
                     require_once $fileName;
                 } else {
+                    $this->log(
+                        Mustache_Logger::WARNING,
+                        'Template cache disabled, evaluating "{className}" class at runtime',
+                        array('className' => $className)
+                    );
+
                     eval('?>'.$this->compile($source));
                 }
             }
 
+            $this->log(
+                Mustache_Logger::DEBUG,
+                'Instantiating template: "{className}"',
+                array('className' => $className)
+            );
+
             $this->templates[$className] = new $className($this);
         }
 
@@ -553,6 +610,12 @@ class Mustache_Engine
         $tree = $this->parse($source);
         $name = $this->getTemplateClassName($source);
 
+        $this->log(
+            Mustache_Logger::INFO,
+            'Compiling template to "{className}" class',
+            array('className' => $name)
+        );
+
         return $this->getCompiler()->compile($source, $tree, $name, isset($this->escape), $this->charset);
     }
 
@@ -573,7 +636,7 @@ class Mustache_Engine
     /**
      * Helper method to dump a generated Mustache Template subclass to the file cache.
      *
-     * @throws RuntimeException if unable to create the cache directory or write $fileName
+     * @throws RuntimeException if unable to create the cache directory or write to $fileName.
      *
      * @param string $fileName
      * @param string $source
@@ -584,12 +647,25 @@ class Mustache_Engine
     {
         $dirName = dirname($fileName);
         if (!is_dir($dirName)) {
+            $this->log(
+                Mustache_Logger::INFO,
+                'Creating Mustache template cache directory: "{dirName}"',
+                array('dirName' => $dirName)
+            );
+
             @mkdir($dirName, 0777, true);
             if (!is_dir($dirName)) {
                 throw new RuntimeException(sprintf('Failed to create cache directory "%s".', $dirName));
             }
+
         }
 
+        $this->log(
+            Mustache_Logger::DEBUG,
+            'Caching compiled template to "{fileName}"',
+            array('fileName' => $fileName)
+        );
+
         $tempFile = tempnam($dirName, basename($fileName));
         if (false !== @file_put_contents($tempFile, $source)) {
             if (@rename($tempFile, $fileName)) {
@@ -598,8 +674,28 @@ class Mustache_Engine
 
                 return;
             }
+
+            $this->log(
+                Mustache_Logger::ERROR,
+                'Unable to rename Mustache temp cache file: "{tempName}" -> "{fileName}"',
+                array('tempName' => $tempFile, 'fileName' => $fileName)
+            );
         }
 
         throw new RuntimeException(sprintf('Failed to write cache file "%s".', $fileName));
     }
+
+    /**
+     * Add a log record if logging is enabled.
+     *
+     * @param  integer $level   The logging level
+     * @param  string  $message The log message
+     * @param  array   $context The log context
+     */
+    private function log($level, $message, array $context = array())
+    {
+        if (isset($this->logger)) {
+            $this->logger->log($level, $message, $context);
+        }
+    }
 }

src/Mustache/Logger.php

@@ -0,0 +1,135 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Describes a Mustache logger instance
+ *
+ * This is identical to the Psr\Log\LoggerInterface.
+ *
+ * The message MUST be a string or object implementing __toString().
+ *
+ * The message MAY contain placeholders in the form: {foo} where foo
+ * will be replaced by the context data in key "foo".
+ *
+ * The context array can contain arbitrary data, the only assumption that
+ * can be made by implementors is that if an Exception instance is given
+ * to produce a stack trace, it MUST be in a key named "exception".
+ *
+ * See https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-3-logger-interface.md
+ * for the full interface specification.
+ */
+interface Mustache_Logger
+{
+    /**
+     * Psr\Log compatible log levels
+     */
+    const EMERGENCY = 'emergency';
+    const ALERT     = 'alert';
+    const CRITICAL  = 'critical';
+    const ERROR     = 'error';
+    const WARNING   = 'warning';
+    const NOTICE    = 'notice';
+    const INFO      = 'info';
+    const DEBUG     = 'debug';
+
+    /**
+     * System is unusable.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function emergency($message, array $context = array());
+
+    /**
+     * Action must be taken immediately.
+     *
+     * Example: Entire website down, database unavailable, etc. This should
+     * trigger the SMS alerts and wake you up.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function alert($message, array $context = array());
+
+    /**
+     * Critical conditions.
+     *
+     * Example: Application component unavailable, unexpected exception.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function critical($message, array $context = array());
+
+    /**
+     * Runtime errors that do not require immediate action but should typically
+     * be logged and monitored.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function error($message, array $context = array());
+
+    /**
+     * Exceptional occurrences that are not errors.
+     *
+     * Example: Use of deprecated APIs, poor use of an API, undesirable things
+     * that are not necessarily wrong.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function warning($message, array $context = array());
+
+    /**
+     * Normal but significant events.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function notice($message, array $context = array());
+
+    /**
+     * Interesting events.
+     *
+     * Example: User logs in, SQL logs.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function info($message, array $context = array());
+
+    /**
+     * Detailed debug information.
+     *
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function debug($message, array $context = array());
+
+    /**
+     * Logs with an arbitrary level.
+     *
+     * @param mixed $level
+     * @param string $message
+     * @param array $context
+     * @return null
+     */
+    public function log($level, $message, array $context = array());
+}

src/Mustache/Logger/AbstractLogger.php

@@ -0,0 +1,121 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * This is a simple Logger implementation that other Loggers can inherit from.
+ *
+ * This is identical to the Psr\Log\AbstractLogger.
+ *
+ * It simply delegates all log-level-specific methods to the `log` method to
+ * reduce boilerplate code that a simple Logger that does the same thing with
+ * messages regardless of the error level has to implement.
+ */
+abstract class Mustache_Logger_AbstractLogger implements Mustache_Logger
+{
+    /**
+     * System is unusable.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function emergency($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::EMERGENCY, $message, $context);
+    }
+
+    /**
+     * Action must be taken immediately.
+     *
+     * Example: Entire website down, database unavailable, etc. This should
+     * trigger the SMS alerts and wake you up.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function alert($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::ALERT, $message, $context);
+    }
+
+    /**
+     * Critical conditions.
+     *
+     * Example: Application component unavailable, unexpected exception.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function critical($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::CRITICAL, $message, $context);
+    }
+
+    /**
+     * Runtime errors that do not require immediate action but should typically
+     * be logged and monitored.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function error($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::ERROR, $message, $context);
+    }
+
+    /**
+     * Exceptional occurrences that are not errors.
+     *
+     * Example: Use of deprecated APIs, poor use of an API, undesirable things
+     * that are not necessarily wrong.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function warning($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::WARNING, $message, $context);
+    }
+
+    /**
+     * Normal but significant events.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function notice($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::NOTICE, $message, $context);
+    }
+
+    /**
+     * Interesting events.
+     *
+     * Example: User logs in, SQL logs.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function info($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::INFO, $message, $context);
+    }
+
+    /**
+     * Detailed debug information.
+     *
+     * @param string $message
+     * @param array $context
+     */
+    public function debug($message, array $context = array())
+    {
+        $this->log(Mustache_Logger::DEBUG, $message, $context);
+    }
+}

src/Mustache/Logger/StreamLogger.php

@@ -0,0 +1,188 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * A Mustache Stream Logger.
+ *
+ * The Stream Logger wraps a file resource instance (such as a stream) or a
+ * stream URL. All log messages over the threshold level will be appended to
+ * this stream.
+ *
+ * Hint: Try `php://stderr` for your stream URL.
+ */
+class Mustache_Logger_StreamLogger extends Mustache_Logger_AbstractLogger
+{
+    protected static $levels = array(
+        self::DEBUG     => 100,
+        self::INFO      => 200,
+        self::NOTICE    => 250,
+        self::WARNING   => 300,
+        self::ERROR     => 400,
+        self::CRITICAL  => 500,
+        self::ALERT     => 550,
+        self::EMERGENCY => 600,
+    );
+
+    protected $stream = null;
+    protected $url    = null;
+
+    /**
+     * @throws InvalidArgumentException if the logging level is unknown.
+     *
+     * @param string  $stream Resource instance or URL
+     * @param integer $level  The minimum logging level at which this handler will be triggered
+     */
+    public function __construct($stream, $level = Mustache_Logger::ERROR)
+    {
+        $this->setLevel($level);
+
+        if (is_resource($stream)) {
+            $this->stream = $stream;
+        } else {
+            $this->url = $stream;
+        }
+    }
+
+    /**
+     * Close stream resources.
+     */
+    public function __destruct()
+    {
+        if (is_resource($this->stream)) {
+            fclose($this->stream);
+        }
+    }
+
+    /**
+     * Set the minimum logging level.
+     *
+     * @throws InvalidArgumentException if the logging level is unknown.
+     *
+     * @param  integer $level The minimum logging level which will be written
+     */
+    public function setLevel($level)
+    {
+        if (!array_key_exists($level, self::$levels)) {
+            throw new InvalidArgumentException('Unexpected logging level: ' . $level);
+        }
+
+        $this->level = $level;
+    }
+
+    /**
+     * Get the current minimum logging level.
+     *
+     * @return integer
+     */
+    public function getLevel()
+    {
+        return $this->level;
+    }
+
+    /**
+     * Logs with an arbitrary level.
+     *
+     * @throws InvalidArgumentException if the logging level is unknown.
+     *
+     * @param mixed $level
+     * @param string $message
+     * @param array $context
+     */
+    public function log($level, $message, array $context = array())
+    {
+        if (!array_key_exists($level, self::$levels)) {
+            throw new InvalidArgumentException('Unexpected logging level: ' . $level);
+        }
+
+        if (self::$levels[$level] >= self::$levels[$this->level]) {
+            $this->writeLog($level, $message, $context);
+        }
+    }
+
+    /**
+     * Write a record to the log.
+     *
+     * @param  integer $level   The logging level
+     * @param  string  $message The log message
+     * @param  array   $context The log context
+     */
+    protected function writeLog($level, $message, array $context = array())
+    {
+        if (!is_resource($this->stream)) {
+            if (!isset($this->url)) {
+                throw new LogicException('Missing stream url, the stream can not be opened. This may be caused by a premature call to close().');
+            }
+
+            $this->stream = fopen($this->url, 'a');
+            if (!is_resource($this->stream)) {
+                // @codeCoverageIgnoreStart
+                throw new UnexpectedValueException(sprintf('The stream or file "%s" could not be opened.', $this->url));
+                // @codeCoverageIgnoreEnd
+            }
+        }
+
+        fwrite($this->stream, self::formatLine($level, $message, $context));
+    }
+
+    /**
+     * Gets the name of the logging level.
+     *
+     * @throws InvalidArgumentException if the logging level is unknown.
+     *
+     * @param  integer $level
+     *
+     * @return string
+     */
+    protected static function getLevelName($level)
+    {
+        return strtoupper($level);
+    }
+
+    /**
+     * Format a log line for output.
+     *
+     * @param  integer $level   The logging level
+     * @param  string  $message The log message
+     * @param  array   $context The log context
+     *
+     * @return string
+     */
+    protected static function formatLine($level, $message, array $context = array())
+    {
+        return sprintf(
+            "%s: %s\n",
+            self::getLevelName($level),
+            self::interpolateMessage($message, $context)
+        );
+    }
+
+    /**
+     * Interpolate context values into the message placeholders.
+     *
+     * @param  string $message
+     * @param  array  $context
+     *
+     * @return string
+     */
+    protected static function interpolateMessage($message, array $context = array())
+    {
+        $message = (string) $message;
+
+        // build a replacement array with braces around the context keys
+        $replace = array();
+        foreach ($context as $key => $val) {
+            $replace['{' . $key . '}'] = $val;
+        }
+
+        // interpolate replacement values into the the message and return
+        return strtr($message, $replace);
+    }
+}

test/Mustache/Test/EngineTest.php

@@ -27,11 +27,14 @@ class Mustache_Test_EngineTest extends PHPUnit_Framework_TestCase
 
     public function testConstructor()
     {
+        $logger         = new Mustache_Logger_StreamLogger(tmpfile());
         $loader         = new Mustache_Loader_StringLoader;
         $partialsLoader = new Mustache_Loader_ArrayLoader;
         $mustache       = new Mustache_Engine(array(
             'template_class_prefix' => '__whot__',
-            'cache' => self::$tempDir,
+            'cache'  => self::$tempDir,
+            'cache_file_mode' => 777,
+            'logger' => $logger,
             'loader' => $loader,
             'partials_loader' => $partialsLoader,
             'partials' => array(
@@ -45,6 +48,7 @@ class Mustache_Test_EngineTest extends PHPUnit_Framework_TestCase
             'charset' => 'ISO-8859-1',
         ));
 
+        $this->assertSame($logger, $mustache->getLogger());
         $this->assertSame($loader, $mustache->getLoader());
         $this->assertSame($partialsLoader, $mustache->getPartialsLoader());
         $this->assertEquals('{{ foo }}', $partialsLoader->load('foo'));
@@ -85,12 +89,17 @@ class Mustache_Test_EngineTest extends PHPUnit_Framework_TestCase
 
     public function testSettingServices()
     {
+        $logger    = new Mustache_Logger_StreamLogger(tmpfile());
         $loader    = new Mustache_Loader_StringLoader;
         $tokenizer = new Mustache_Tokenizer;
         $parser    = new Mustache_Parser;
         $compiler  = new Mustache_Compiler;
         $mustache  = new Mustache_Engine;
 
+        $this->assertNotSame($logger, $mustache->getLogger());
+        $mustache->setLogger($logger);
+        $this->assertSame($logger, $mustache->getLogger());
+
         $this->assertNotSame($loader, $mustache->getLoader());
         $mustache->setLoader($loader);
         $this->assertSame($loader, $mustache->getLoader());
@@ -222,6 +231,74 @@ class Mustache_Test_EngineTest extends PHPUnit_Framework_TestCase
         $mustache->setHelpers('monkeymonkeymonkey');
     }
 
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testSetLoggerThrowsExceptions()
+    {
+        $mustache = new Mustache_Engine;
+        $mustache->setLogger(new StdClass);
+    }
+
+    public function testPartialLoadFailLogging()
+    {
+        $name     = tempnam(sys_get_temp_dir(), 'mustache-test');
+        $mustache = new Mustache_Engine(array(
+            'logger'   => new Mustache_Logger_StreamLogger($name, Mustache_Logger::WARNING),
+            'partials' => array(
+                'foo' => 'FOO',
+                'bar' => 'BAR',
+            ),
+        ));
+
+        $result = $mustache->render('{{> foo }}{{> bar }}{{> baz }}', array());
+        $this->assertEquals('FOOBAR', $result);
+
+        $this->assertContains('WARNING: Partial not found: "baz"', file_get_contents($name));
+    }
+
+    public function testCacheWarningLogging()
+    {
+        $name     = tempnam(sys_get_temp_dir(), 'mustache-test');
+        $mustache = new Mustache_Engine(array(
+            'logger'   => new Mustache_Logger_StreamLogger($name, Mustache_Logger::WARNING)
+        ));
+
+        $result = $mustache->render('{{ foo }}', array('foo' => 'FOO'));
+        $this->assertEquals('FOO', $result);
+
+        $this->assertContains('WARNING: Template cache disabled, evaluating', file_get_contents($name));
+    }
+
+    public function testLoggingIsNotTooAnnoying()
+    {
+        $name     = tempnam(sys_get_temp_dir(), 'mustache-test');
+        $mustache = new Mustache_Engine(array(
+            'logger'   => new Mustache_Logger_StreamLogger($name)
+        ));
+
+        $result = $mustache->render('{{ foo }}{{> bar }}', array('foo' => 'FOO'));
+        $this->assertEquals('FOO', $result);
+
+        $this->assertEmpty(file_get_contents($name));
+    }
+
+    public function testVerboseLoggingIsVerbose()
+    {
+        $name     = tempnam(sys_get_temp_dir(), 'mustache-test');
+        $mustache = new Mustache_Engine(array(
+            'logger'   => new Mustache_Logger_StreamLogger($name, Mustache_Logger::DEBUG)
+        ));
+
+        $result = $mustache->render('{{ foo }}{{> bar }}', array('foo' => 'FOO'));
+        $this->assertEquals('FOO', $result);
+
+        $log = file_get_contents($name);
+
+        $this->assertContains("DEBUG: Instantiating template: ", $log);
+        $this->assertContains("WARNING: Partial not found: \"bar\"", $log);
+    }
+
     private static function rmdir($path)
     {
         $path = rtrim($path, '/').'/';

test/Mustache/Test/Logger/AbstractLoggerTest.php

@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * @group unit
+ */
+class Mustache_Test_Logger_AbstractLoggerTest extends PHPUnit_Framework_TestCase
+{
+    public function testEverything()
+    {
+        $logger = new Mustache_Test_Logger_TestLogger;
+
+        $logger->emergency('emergency message');
+        $logger->alert('alert message');
+        $logger->critical('critical message');
+        $logger->error('error message');
+        $logger->warning('warning message');
+        $logger->notice('notice message');
+        $logger->info('info message');
+        $logger->debug('debug message');
+
+        $expected = array(
+            array(Mustache_Logger::EMERGENCY, 'emergency message', array()),
+            array(Mustache_Logger::ALERT, 'alert message', array()),
+            array(Mustache_Logger::CRITICAL, 'critical message', array()),
+            array(Mustache_Logger::ERROR, 'error message', array()),
+            array(Mustache_Logger::WARNING, 'warning message', array()),
+            array(Mustache_Logger::NOTICE, 'notice message', array()),
+            array(Mustache_Logger::INFO, 'info message', array()),
+            array(Mustache_Logger::DEBUG, 'debug message', array()),
+        );
+
+        $this->assertEquals($expected, $logger->log);
+    }
+}
+
+class Mustache_Test_Logger_TestLogger extends Mustache_Logger_AbstractLogger
+{
+    public $log = array();
+
+    /**
+     * Logs with an arbitrary level.
+     *
+     * @param mixed $level
+     * @param string $message
+     * @param array $context
+     */
+    public function log($level, $message, array $context = array())
+    {
+        $this->log[] = array($level, $message, $context);
+    }
+}

test/Mustache/Test/Logger/StreamLoggerTest.php

@@ -0,0 +1,206 @@
+<?php
+
+/*
+ * This file is part of Mustache.php.
+ *
+ * (c) 2012 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * @group unit
+ */
+class Mustache_Test_Logger_StreamLoggerTest extends PHPUnit_Framework_TestCase
+{
+    public function testAcceptsFilename()
+    {
+        $name   = tempnam(sys_get_temp_dir(), 'mustache-test');
+        $logger = new Mustache_Logger_StreamLogger($name);
+        $logger->log(Mustache_Logger::CRITICAL, 'message');
+
+        $this->assertEquals("CRITICAL: message\n", file_get_contents($name));
+    }
+
+    public function testAcceptsResource()
+    {
+        $name   = tempnam(sys_get_temp_dir(), 'mustache-test');
+        $file   = fopen($name, 'a');
+        $logger = new Mustache_Logger_StreamLogger($file);
+        $logger->log(Mustache_Logger::CRITICAL, 'message');
+
+        $this->assertEquals("CRITICAL: message\n", file_get_contents($name));
+    }
+
+    /**
+     * @expectedException LogicException
+     */
+    public function testPrematurelyClosedStreamThrowsException()
+    {
+        $stream = tmpfile();
+        $logger = new Mustache_Logger_StreamLogger($stream);
+        fclose($stream);
+
+        $logger->log(Mustache_Logger::CRITICAL, 'message');
+    }
+
+    /**
+     * @dataProvider getLevels
+     */
+    public function testLoggingThresholds($logLevel, $level, $shouldLog)
+    {
+        $stream = tmpfile();
+        $logger = new Mustache_Logger_StreamLogger($stream, $logLevel);
+        $logger->log($level, "logged");
+
+        rewind($stream);
+        $result = fread($stream, 1024);
+
+        if ($shouldLog) {
+            $this->assertContains("logged", $result);
+        } else {
+            $this->assertEmpty($result);
+        }
+    }
+
+    public function getLevels()
+    {
+        // $logLevel, $level, $shouldLog
+        return array(
+            // identities
+            array(Mustache_Logger::EMERGENCY, Mustache_Logger::EMERGENCY, true),
+            array(Mustache_Logger::ALERT,     Mustache_Logger::ALERT,     true),
+            array(Mustache_Logger::CRITICAL,  Mustache_Logger::CRITICAL,  true),
+            array(Mustache_Logger::ERROR,     Mustache_Logger::ERROR,     true),
+            array(Mustache_Logger::WARNING,   Mustache_Logger::WARNING,   true),
+            array(Mustache_Logger::NOTICE,    Mustache_Logger::NOTICE,    true),
+            array(Mustache_Logger::INFO,      Mustache_Logger::INFO,      true),
+            array(Mustache_Logger::DEBUG,     Mustache_Logger::DEBUG,     true),
+
+            // one above
+            array(Mustache_Logger::ALERT,     Mustache_Logger::EMERGENCY, true),
+            array(Mustache_Logger::CRITICAL,  Mustache_Logger::ALERT,     true),
+            array(Mustache_Logger::ERROR,     Mustache_Logger::CRITICAL,  true),
+            array(Mustache_Logger::WARNING,   Mustache_Logger::ERROR,     true),
+            array(Mustache_Logger::NOTICE,    Mustache_Logger::WARNING,   true),
+            array(Mustache_Logger::INFO,      Mustache_Logger::NOTICE,    true),
+            array(Mustache_Logger::DEBUG,     Mustache_Logger::INFO,      true),
+
+            // one below
+            array(Mustache_Logger::EMERGENCY, Mustache_Logger::ALERT,     false),
+            array(Mustache_Logger::ALERT,     Mustache_Logger::CRITICAL,  false),
+            array(Mustache_Logger::CRITICAL,  Mustache_Logger::ERROR,     false),
+            array(Mustache_Logger::ERROR,     Mustache_Logger::WARNING,   false),
+            array(Mustache_Logger::WARNING,   Mustache_Logger::NOTICE,    false),
+            array(Mustache_Logger::NOTICE,    Mustache_Logger::INFO,      false),
+            array(Mustache_Logger::INFO,      Mustache_Logger::DEBUG,     false),
+        );
+    }
+
+    /**
+     * @dataProvider getLogMessages
+     */
+    public function testLogging($level, $message, $context, $expected)
+    {
+        $stream = tmpfile();
+        $logger = new Mustache_Logger_StreamLogger($stream, Mustache_Logger::DEBUG);
+        $logger->log($level, $message, $context);
+
+        rewind($stream);
+        $result = fread($stream, 1024);
+
+        $this->assertEquals($expected, $result);
+    }
+
+    public function getLogMessages()
+    {
+        // $level, $message, $context, $expected
+        return array(
+            array(Mustache_Logger::DEBUG,     'debug message',     array(),  "DEBUG: debug message\n"),
+            array(Mustache_Logger::INFO,      'info message',      array(),  "INFO: info message\n"),
+            array(Mustache_Logger::NOTICE,    'notice message',    array(),  "NOTICE: notice message\n"),
+            array(Mustache_Logger::WARNING,   'warning message',   array(),  "WARNING: warning message\n"),
+            array(Mustache_Logger::ERROR,     'error message',     array(),  "ERROR: error message\n"),
+            array(Mustache_Logger::CRITICAL,  'critical message',  array(),  "CRITICAL: critical message\n"),
+            array(Mustache_Logger::ALERT,     'alert message',     array(),  "ALERT: alert message\n"),
+            array(Mustache_Logger::EMERGENCY, 'emergency message', array(),  "EMERGENCY: emergency message\n"),
+
+            // with context
+            array(
+                Mustache_Logger::ERROR,
+                'error message',
+                array('name' => 'foo', 'number' => 42),
+                "ERROR: error message\n"
+            ),
+
+            // with interpolation
+            array(
+                Mustache_Logger::ERROR,
+                'error {name}-{number}',
+                array('name' => 'foo', 'number' => 42),
+                "ERROR: error foo-42\n"
+            ),
+
+            // with iterpolation false positive
+            array(
+                Mustache_Logger::ERROR,
+                'error {nothing}',
+                array('name' => 'foo', 'number' => 42),
+                "ERROR: error {nothing}\n"
+            ),
+
+            // with interpolation injection
+            array(
+                Mustache_Logger::ERROR,
+                '{foo}',
+                array('foo' => '{bar}', 'bar' => 'FAIL'),
+                "ERROR: {bar}\n"
+            ),
+        );
+    }
+
+    public function testChangeLoggingLevels()
+    {
+        $stream = tmpfile();
+        $logger = new Mustache_Logger_StreamLogger($stream);
+
+        $logger->setLevel(Mustache_Logger::ERROR);
+        $this->assertEquals(Mustache_Logger::ERROR, $logger->getLevel());
+
+        $logger->log(Mustache_Logger::WARNING, 'ignore this');
+
+        $logger->setLevel(Mustache_Logger::INFO);
+        $this->assertEquals(Mustache_Logger::INFO, $logger->getLevel());
+
+        $logger->log(Mustache_Logger::WARNING, 'log this');
+
+        $logger->setLevel(Mustache_Logger::CRITICAL);
+        $this->assertEquals(Mustache_Logger::CRITICAL, $logger->getLevel());
+
+        $logger->log(Mustache_Logger::ERROR, 'ignore this');
+
+        rewind($stream);
+        $result = fread($stream, 1024);
+
+        $this->assertEquals("WARNING: log this\n", $result);
+    }
+
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testThrowsInvalidArgumentExceptionWhenSettingUnknownLevels()
+    {
+        $logger = new Mustache_Logger_StreamLogger(tmpfile());
+        $logger->setLevel('bacon');
+    }
+
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testThrowsInvalidArgumentExceptionWhenLoggingUnknownLevels()
+    {
+        $logger = new Mustache_Logger_StreamLogger(tmpfile());
+        $logger->log('bacon', 'CODE BACON ERROR!');
+    }
+}