Allow setting levels in Target constructor

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 2.1.2 under development
 
+- New #125: Add optional `$levels` parameter to `Target` constructor allowing log level filtering at instantiation (@samdark)
 - Chg #126: Add `ext-psr` to `conflict` section in `composer.json` (@samdark)
 
 ## 2.1.1 June 03, 2025
@@ -13,7 +14,7 @@
 
 - New #104: Add new static methods `Logger::assertLevelIsValid()`, `Logger::assertLevelIsString()` and
   `Logger::assertLevelIsSupported()` (@vjik)
-- New #108: Support of nested values in message templates' variables, e. g. `{foo.bar}` (@vjik)
+- New #108: Support of nested values in message templates' variables, e.g. `{foo.bar}` (@vjik)
 - New #109, #113, #116: Add context providers (@vjik)
 - New #111: Add `DateTime` and `DateTimeImmutable` support as time in log context (@vjik)
 - New #112: Add `Message::category()` method and `Message::DEFAULT_CATEGORY` constant, deprecate

src/PsrTarget.php

@@ -15,10 +15,11 @@ final class PsrTarget extends Target
      * Sets the PSR-3 logger used to save messages of this target.
      *
      * @param LoggerInterface $logger The logger instance to be used for messages processing.
+     * @param string[] $levels The {@see \Psr\Log\LogLevel log message levels} that this target is interested in.
      */
-    public function __construct(private LoggerInterface $logger)
+    public function __construct(private LoggerInterface $logger, array $levels = [])
     {
-        parent::__construct();
+        parent::__construct($levels);
     }
 
     /**

src/StreamTarget.php

@@ -27,10 +27,11 @@ final class StreamTarget extends Target
 {
     /**
      * @param resource|string $stream A string stream identifier or a stream resource.
+     * @param string[] $levels The {@see \Psr\Log\LogLevel log message levels} that this target is interested in.
      */
-    public function __construct(private $stream = 'php://stdout')
+    public function __construct(private $stream = 'php://stdout', array $levels = [])
     {
-        parent::__construct();
+        parent::__construct($levels);
     }
 
     protected function export(): void

src/Target.php

@@ -81,11 +81,14 @@ abstract protected function export(): void;
 
     /**
      * When defining a constructor in child classes, you must call `parent::__construct()`.
+     *
+     * @param string[] $levels The {@see \Psr\Log\LogLevel log message levels} that this target is interested in.
      */
-    public function __construct()
+    public function __construct(array $levels = [])
     {
         $this->categories = new CategoryFilter();
         $this->formatter = new Formatter();
+        $this->setLevels($levels);
     }
 
     /**
@@ -147,7 +150,7 @@ public function setExcept(array $except): self
     }
 
     /**
-     * Sets a list of log message levels that current target is interested in.
+     * Sets a list of {@see \Psr\Log\LogLevel log message levels} that current target is interested in.
      *
      * @param string[] $levels The list of log message levels.
      *

tests/PsrTargetTest.php

@@ -56,4 +56,30 @@ public function testPsrLogInterfaceMethods(string $level, string $message, array
         $this->target->collect([new Message($level, $message, $context)], true);
         $this->expectOutputString("{$level}: {$message}: " . json_encode($context, JSON_THROW_ON_ERROR));
     }
+
+    public function testSetLevelsViaConstructor(): void
+    {
+        $target = new PsrTarget(
+            new class () implements LoggerInterface {
+                use LoggerTrait;
+
+                public function log($level, $message, array $context = []): void
+                {
+                    echo "$level: $message";
+                }
+            },
+            [LogLevel::ERROR, LogLevel::INFO]
+        );
+
+        $target->collect(
+            [
+                new Message(LogLevel::INFO, 'message-1', ['foo' => 'bar']),
+                new Message(LogLevel::DEBUG, 'message-2', ['foo' => true]),
+                new Message(LogLevel::ERROR, 'message-3', ['foo' => 1]),
+            ],
+            true
+        );
+
+        $this->expectOutputString('info: message-1error: message-3');
+    }
 }

tests/StreamTargetTest.php

@@ -100,4 +100,21 @@ private function exportStreamTarget(StreamTarget $target): void
             true
         );
     }
+
+    public function testSetLevelsViaConstructor(): void
+    {
+        $target = new StreamTarget('php://output', [LogLevel::ERROR, LogLevel::INFO]);
+        $target->setFormat(static fn (Message $message) => "[{$message->level()}] {$message->message()}");
+
+        $target->collect(
+            [
+                new Message(LogLevel::INFO, 'message-1', ['foo' => 'bar']),
+                new Message(LogLevel::DEBUG, 'message-2', ['foo' => true]),
+                new Message(LogLevel::ERROR, 'message-3', ['foo' => 1]),
+            ],
+            true
+        );
+
+        $this->expectOutputString("[info] message-1\n[error] message-3\n");
+    }
 }

tests/TargetTest.php

@@ -461,6 +461,37 @@ public function testFormatMessageThrowExceptionForPrefixCallableReturnNotBoolean
         $this->target->formatMessages();
     }
 
+    public function testSetLevelsViaConstructor(): void
+    {
+        $target = new DummyTarget([LogLevel::ERROR, LogLevel::WARNING]);
+        $logger = new Logger([$target]);
+
+        $logger->setFlushInterval(1);
+        $logger->log(LogLevel::INFO, 'testInfo');
+        $logger->log(LogLevel::ERROR, 'testError');
+        $logger->log(LogLevel::WARNING, 'testWarning');
+        $logger->log(LogLevel::DEBUG, 'testDebug');
+
+        $messages = $target->getMessages();
+        $this->assertCount(2, $messages);
+        $this->assertSame('testError', $messages[0]->message());
+        $this->assertSame('testWarning', $messages[1]->message());
+    }
+
+    public function testSetLevelsViaConstructorWithEmptyArray(): void
+    {
+        $target = new DummyTarget([]);
+        $logger = new Logger([$target]);
+
+        $logger->setFlushInterval(1);
+        $logger->log(LogLevel::INFO, 'testInfo');
+        $logger->log(LogLevel::ERROR, 'testError');
+        $logger->log(LogLevel::DEBUG, 'testDebug');
+
+        $messages = $target->getMessages();
+        $this->assertCount(3, $messages);
+    }
+
     private function collectOneAndExport(string $level, string $message, array $context = []): void
     {
         $this->target->collect([new Message($level, $message, $context)], true);

tests/TestAsset/DummyTarget.php

@@ -14,9 +14,9 @@ final class DummyTarget extends Target
     private array $exportMessages = [];
     private Formatter $exportFormatter;
 
-    public function __construct()
+    public function __construct(array $levels = [])
     {
-        parent::__construct();
+        parent::__construct($levels);
         $this->exportFormatter = new Formatter();
     }