[FEATURE] Log filter

README.md

@@ -117,6 +117,56 @@ Laravel's (`>= 5.0, < 5.1`) exception logger doesn't use event dispatcher (https
 php artisan vendor:publish --provider="Understand\UnderstandLaravel5\UnderstandLaravel5ServiceProvider"
 ```
 
+### Log Filter
+To filter out specific log types a custom log filter can be provided.
+
+**Example filter class**
+```php
+// app/Logging/UnderstandLogFilter.php
+<?php
+
+declare(strict_types=1);
+
+namespace App\Logging;
+
+use Illuminate\Support\Str;
+
+class UnderstandLogFilter
+{
+    public function __invoke($level, $message, $context): bool
+    {
+        if ($level === 'warning' && Str::contains(strtolower($message), 'deprecated')) {
+            return true;
+        }
+
+        return false;
+    }
+}
+```
+and then it can be configured in `understand-laravel.php`
+```php
+<?php
+// ...
+// config/understand-laravel.php
+'log_filter' => \App\Logging\UnderstandLogFilter::class,
+```
+
+The `log_filter` config value must be a callable type:
+- https://www.php.net/manual/en/function.is-callable.php  
+  or a callable dependency from the service container:
+- https://laravel.com/docs/9.x/container#the-make-method
+
+The suggested way would be to create an invokable class since it's hard to serialise anonymous functions (Laravel config cache):
+- https://www.php.net/manual/en/language.oop5.magic.php#object.invoke
+
+The log filter interface must be as follows: `$callable($level, $message, $context)`.
+The result of the filter must be a boolean value:
+- `TRUE`, the log should be ignored and NOT delivered to Understand.io
+- `FALSE`, the log should be delivered to Understand.io
+
+The `ignored_logs` config value has higher precedence than `log_filter`.
+
+
 ### Requirements 
 ##### UTF-8
 This package uses the json_encode function, which only supports UTF-8 data, and you should therefore ensure that all of your data is correctly encoded. In the event that your log data contains non UTF-8 strings, then the json_encode function will not be able to serialize the data.

src/Understand/UnderstandLaravel5/UnderstandLaravel5ServiceProvider.php

@@ -434,22 +434,29 @@ protected function handleEvent($level, $message, $context)
         }
     }
 
-    /**
-     * @param $level
-     * @param $message
-     * @param $context
-     * @return bool
-     */
     protected function shouldIgnoreEvent($level, $message, $context)
     {
         $ignoredEventTypes = (array)$this->app['config']->get('understand-laravel.ignored_logs');
+        $logFilter = $this->app['config']->get('understand-laravel.log_filter');
+
+        // check if the log should be ignored by its level (info, warning, etc.)
+        if ($ignoredEventTypes)
+        {
+            return in_array($level, $ignoredEventTypes, true);
+        }
 
-        if ( ! $ignoredEventTypes)
+        // check if a custom filter is set and whether the log should be ignored
+        // true - the log should be ignored
+        // false - the log should be delivered to Understand
+        if ($logFilter)
         {
-            return false;
+            $factory = is_callable($logFilter) ? $logFilter : $this->app->make($logFilter);
+
+            return (bool)$factory($level, $message, $context);
         }
 
-        return in_array($level, $ignoredEventTypes, true);
+        // by default logs are not ignored
+        return false;
     }
 
     /**

src/config/understand-laravel.php

@@ -66,6 +66,27 @@
         //'emergency',
     ],
 
+    /**
+     * Log filter.
+     *
+     * The configuration value (filter) must be a callable type:
+     * - https://www.php.net/manual/en/function.is-callable.php
+     * or a callable dependency from the service container:
+     * - https://laravel.com/docs/9.x/container#the-make-method
+     *
+     * The suggested way would be to create an invokable class since it's hard to serialise anonymous functions (Laravel config cache):
+     * - https://www.php.net/manual/en/language.oop5.magic.php#object.invoke
+     *
+     * The log (callable) filter interface is as follows: `$callable($level, $message, $context)`.
+     *
+     * The result of the filter must be a boolean value:
+     * - TRUE, the log should be ignored and NOT delivered to Understand.io
+     * - FALSE, the log should be delivered to Understand.io
+     *
+     * The `ignored_logs` config value has higher precedence than `log_filter`.
+     */
+    'log_filter' => null,
+
     /**
      * Field names which values should not be sent to Understand.io
      * It applies to POST and GET request parameters

tests/LogFilterTest.php

@@ -0,0 +1,144 @@
+<?php
+
+use Understand\UnderstandLaravel5\Logger;
+use Understand\UnderstandLaravel5\Handlers\CallbackHandler;
+use Understand\UnderstandLaravel5\UnderstandLaravel5ServiceProvider;
+
+class LogFilterTest extends Orchestra\Testbench\TestCase
+{
+
+    /**
+     * Setup service provider
+     *
+     * @param object $app
+     * @return void
+     */
+    protected function getPackageProviders($app)
+    {
+        return [UnderstandLaravel5ServiceProvider::class];
+    }
+
+    /**
+     * @return void
+     */
+    public function testLogFilterAllowsDelivery()
+    {
+        $logsSent = 0;
+
+        $callback = function() use(&$logsSent)
+        {
+            $logsSent++;
+        };
+
+        $this->app['config']->set('understand-laravel.log_filter', function() {
+            // FALSE, logs should not be filtered
+            return false;
+        });
+
+        $handler = new CallbackHandler($callback);
+        $this->app['understand.logger'] = new Logger($this->app['understand.fieldProvider'], $handler);
+
+        // trigger error
+        $this->app['Psr\Log\LoggerInterface']->error('test');
+        $this->app['Psr\Log\LoggerInterface']->warning('test2');
+
+        $this->assertEquals(2, $logsSent);
+    }
+
+    /**
+     * @return void
+     */
+    public function testServiceContainerDependency()
+    {
+        $logsSent = 0;
+
+        $callback = function() use(&$logsSent)
+        {
+            $logsSent++;
+        };
+
+        $dependencyName = 'service-container-dependency';
+        $dependencyCalled = false;
+
+        $this->app->bind($dependencyName, function() use(&$dependencyCalled) {
+            return function() use(&$dependencyCalled) {
+                $dependencyCalled = true;
+                // FALSE, logs should not be filtered
+                return false;
+            };
+        });
+
+        $this->app['config']->set('understand-laravel.log_filter', $dependencyName);
+
+        $handler = new CallbackHandler($callback);
+        $this->app['understand.logger'] = new Logger($this->app['understand.fieldProvider'], $handler);
+
+        // trigger error
+        $this->app['Psr\Log\LoggerInterface']->error('test');
+
+        $this->assertTrue($dependencyCalled);
+        $this->assertEquals(1, $logsSent);
+    }
+
+    /**
+     * @return void
+     */
+    public function testLogFilterFiltersOneLog()
+    {
+        $logsSent = 0;
+
+        $callback = function() use(&$logsSent)
+        {
+            $logsSent++;
+        };
+
+        $this->app['config']->set('understand-laravel.log_filter', function($level, $message, $context) {
+            if ($message === 'test2') {
+                // TRUE, log should be filtered
+                return true;
+            }
+
+            // FALSE, logs should not be filtered
+            return false;
+        });
+
+        $handler = new CallbackHandler($callback);
+        $this->app['understand.logger'] = new Logger($this->app['understand.fieldProvider'], $handler);
+
+        // trigger error
+        $this->app['Psr\Log\LoggerInterface']->error('test');
+        $this->app['Psr\Log\LoggerInterface']->warning('test2');
+
+        $this->assertEquals(1, $logsSent);
+    }
+
+    /**
+     * @return void
+     */
+    public function testLogFilterReceivesAllData()
+    {
+        $logsSent = 0;
+
+        $callback = function() use(&$logsSent)
+        {
+            $logsSent++;
+        };
+
+        $this->app['config']->set('understand-laravel.log_filter', function($level, $message, $context) {
+            $this->assertEquals('error', $level);
+            $this->assertEquals('test', $message);
+            $this->assertEquals(['context' => 'value'], $context);
+
+            // FALSE, logs should not be filtered
+            return false;
+        });
+
+        $handler = new CallbackHandler($callback);
+        $this->app['understand.logger'] = new Logger($this->app['understand.fieldProvider'], $handler);
+
+        // trigger error
+        $this->app['Psr\Log\LoggerInterface']->error('test', ['context' => 'value']);
+
+        $this->assertEquals(1, $logsSent);
+    }
+}