From 2148a0f33c078825b58d6b29d7a5c220abeb539a Mon Sep 17 00:00:00 2001
From: Erik van Velzen <erik@evanv.nl>
Date: Thu, 4 Jun 2020 04:28:00 +0200
Subject: [PATCH] Add priority field to processor tags

So that the order in which the processors are used by monolog can be
determined.
---
 .../Compiler/AddProcessorsPass.php            | 61 +++++++++++++------
 .../Compiler/AddProcessorsPassTest.php        | 21 +++++++
 2 files changed, 64 insertions(+), 18 deletions(-)

diff --git a/DependencyInjection/Compiler/AddProcessorsPass.php b/DependencyInjection/Compiler/AddProcessorsPass.php
index 7afaa06c..728ca80d 100644
--- a/DependencyInjection/Compiler/AddProcessorsPass.php
+++ b/DependencyInjection/Compiler/AddProcessorsPass.php
@@ -28,32 +28,57 @@ public function process(ContainerBuilder $container)
             return;
         }
 
+        $processors = [];
+
         foreach ($container->findTaggedServiceIds('monolog.processor') as $id => $tags) {
             foreach ($tags as $tag) {
-                if (!empty($tag['channel']) && !empty($tag['handler'])) {
-                    throw new \InvalidArgumentException(sprintf('you cannot specify both the "handler" and "channel" attributes for the "monolog.processor" tag on service "%s"', $id));
+                if (!isset($tag['priority'])) {
+                    $tag['priority'] = 0;
                 }
 
-                if (!empty($tag['handler'])) {
-                    $definition = $container->findDefinition(sprintf('monolog.handler.%s', $tag['handler']));
-                } elseif (!empty($tag['channel'])) {
-                    if ('app' === $tag['channel']) {
-                        $definition = $container->getDefinition('monolog.logger');
-                    } else {
-                        $definition = $container->getDefinition(sprintf('monolog.logger.%s', $tag['channel']));
-                    }
-                } else {
-                    $definition = $container->getDefinition('monolog.logger_prototype');
-                }
+                $processors[] = [
+                    'id' => $id,
+                    'tag' => $tag,
+                ];
+            }
+        }
+
+        // Sort by priority so that higher-prio processors are added last.
+        // The effect is the monolog will call the higher-prio processors first
+        usort(
+            $processors,
+            function (array $left, array $right) {
+               return $left['tag']['priority'] - $right['tag']['priority'];
+            }
+        );
+
+        foreach ($processors as $processor) {
+            $tag = $processor['tag'];
+            $id = $processor['id'];
+
+            if (!empty($tag['channel']) && !empty($tag['handler'])) {
+                throw new \InvalidArgumentException(sprintf('you cannot specify both the "handler" and "channel" attributes for the "monolog.processor" tag on service "%s"', $id));
+            }
 
-                if (!empty($tag['method'])) {
-                    $processor = [new Reference($id), $tag['method']];
+            if (!empty($tag['handler'])) {
+                $definition = $container->findDefinition(sprintf('monolog.handler.%s', $tag['handler']));
+            } elseif (!empty($tag['channel'])) {
+                if ('app' === $tag['channel']) {
+                    $definition = $container->getDefinition('monolog.logger');
                 } else {
-                    // If no method is defined, fallback to use __invoke
-                    $processor = new Reference($id);
+                    $definition = $container->getDefinition(sprintf('monolog.logger.%s', $tag['channel']));
                 }
-                $definition->addMethodCall('pushProcessor', [$processor]);
+            } else {
+                $definition = $container->getDefinition('monolog.logger_prototype');
+            }
+
+            if (!empty($tag['method'])) {
+                $processor = [new Reference($id), $tag['method']];
+            } else {
+                // If no method is defined, fallback to use __invoke
+                $processor = new Reference($id);
             }
+            $definition->addMethodCall('pushProcessor', [$processor]);
         }
     }
 }
diff --git a/Tests/DependencyInjection/Compiler/AddProcessorsPassTest.php b/Tests/DependencyInjection/Compiler/AddProcessorsPassTest.php
index 155e6cf0..02253ae5 100644
--- a/Tests/DependencyInjection/Compiler/AddProcessorsPassTest.php
+++ b/Tests/DependencyInjection/Compiler/AddProcessorsPassTest.php
@@ -34,6 +34,13 @@ public function testHandlerProcessors()
         $calls = $service->getMethodCalls();
         $this->assertCount(1, $calls);
         $this->assertEquals(['pushProcessor', [new Reference('test2')]], $calls[0]);
+
+        $service = $container->getDefinition('monolog.handler.priority_test');
+        $calls = $service->getMethodCalls();
+        $this->assertCount(3, $calls);
+        $this->assertEquals(['pushProcessor', [new Reference('processor-10')]], $calls[0]);
+        $this->assertEquals(['pushProcessor', [new Reference('processor+10')]], $calls[1]);
+        $this->assertEquals(['pushProcessor', [new Reference('processor+20')]], $calls[2]);
     }
 
     protected function getContainer()
@@ -45,9 +52,11 @@ protected function getContainer()
         $definition = $container->getDefinition('monolog.logger_prototype');
         $container->setDefinition('monolog.handler.test', new Definition('%monolog.handler.null.class%', [100, false]));
         $container->setDefinition('handler_test', new Definition('%monolog.handler.null.class%', [100, false]));
+        $container->setDefinition('monolog.handler.priority_test', new Definition('%monolog.handler.null.class%', [100, false]));
         $container->setAlias('monolog.handler.test2', 'handler_test');
         $definition->addMethodCall('pushHandler', [new Reference('monolog.handler.test')]);
         $definition->addMethodCall('pushHandler', [new Reference('monolog.handler.test2')]);
+        $definition->addMethodCall('pushHandler', [new Reference('monolog.handler.priority_test')]);
 
         $service = new Definition('TestClass', ['false', new Reference('logger')]);
         $service->addTag('monolog.processor', ['handler' => 'test']);
@@ -57,6 +66,18 @@ protected function getContainer()
         $service->addTag('monolog.processor', ['handler' => 'test2']);
         $container->setDefinition('test2', $service);
 
+        $service = new Definition('TestClass', ['false', new Reference('logger')]);
+        $service->addTag('monolog.processor', ['handler' => 'priority_test', 'priority' => 10]);
+        $container->setDefinition('processor+10', $service);
+
+        $service = new Definition('TestClass', ['false', new Reference('logger')]);
+        $service->addTag('monolog.processor', ['handler' => 'priority_test', 'priority' => -10]);
+        $container->setDefinition('processor-10', $service);
+
+        $service = new Definition('TestClass', ['false', new Reference('logger')]);
+        $service->addTag('monolog.processor', ['handler' => 'priority_test', 'priority' => 20]);
+        $container->setDefinition('processor+20', $service);
+
         $container->getCompilerPassConfig()->setOptimizationPasses([]);
         $container->getCompilerPassConfig()->setRemovingPasses([]);
         $container->addCompilerPass(new AddProcessorsPass());