From 2ea68fec4b4b722c04803394cc6c70b636fee34d Mon Sep 17 00:00:00 2001
From: Matthew Turland <tobias382@gmail.com>
Date: Mon, 21 Feb 2022 10:50:27 -0600
Subject: [PATCH] Add LoggingCompositeBuffer

---
 README.md                            |  18 ++++
 src/LoggingCompositeBuffer.php       |  84 ++++++++++++++++
 tests/LoggingCompositeBufferTest.php | 140 +++++++++++++++++++++++++++
 3 files changed, 242 insertions(+)
 create mode 100644 src/LoggingCompositeBuffer.php
 create mode 100644 tests/LoggingCompositeBufferTest.php

diff --git a/README.md b/README.md
index f4a1c6f..e72a8f9 100644
--- a/README.md
+++ b/README.md
@@ -366,6 +366,24 @@ $logger = new Logger;
 ServiceLocator::set(LoggerInterface::class, $logger);
 ```
 
+[Core buffer implementations](#buffering) do not implement logging. However, as of Flystream 0.4.0, a buffer instance can be wrapped in an instance of the `LoggingCompositeBuffer` class to log calls to its methods. An example of doing this with the default `MemoryBuffer` buffer implementation is shown below.
+
+```php
+<?php
+
+use Elazar\Flystream\BufferInterface;
+use Elazar\Flystream\LoggingCompositeBuffer;
+use Elazar\Flystream\MemoryBuffer;
+use Elazar\Flystream\ServiceLocator;
+use Monolog\Logger;
+use Psr\Log\LoggerInterface;
+
+$logger = new Logger;
+// configure $logger here
+$buffer = new LoggingCompositeBuffer(new MemoryBuffer, $logger);
+ServiceLocator::set(BufferInterface::class, $buffer);
+```
+
 ## Design
 
 ### Service Locator
diff --git a/src/LoggingCompositeBuffer.php b/src/LoggingCompositeBuffer.php
new file mode 100644
index 0000000..48bcb72
--- /dev/null
+++ b/src/LoggingCompositeBuffer.php
@@ -0,0 +1,84 @@
+<?php
+
+namespace Elazar\Flystream;
+
+use League\Flysystem\FilesystemOperator;
+use Psr\Log\LoggerInterface;
+
+class LoggingCompositeBuffer implements BufferInterface
+{
+    private BufferInterface $buffer;
+
+    private LoggerInterface $logger;
+
+    public function __construct(
+        BufferInterface $buffer,
+        LoggerInterface $logger
+    ) {
+        $this->buffer = $buffer;
+        $this->logger = $logger;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function write(string $data)
+    {
+        $context = $this->getContext([
+            'data' => $data,
+        ]);
+
+        $context['when'] = 'before';
+        $this->logger->info(__METHOD__, $context);
+
+        $return = $context['return'] = $this->buffer->write($data);
+
+        $context['when'] = 'after';
+        $this->logger->info(__METHOD__, $context);
+
+        return $return;
+    }
+
+    public function flush(
+        FilesystemOperator $filesystem,
+        string $path,
+        array $context
+    ): void {
+        $context = $this->getContext([
+            'filesystem_class' => get_class($filesystem),
+            'filesystem_id' => spl_object_id($filesystem),
+            'path' => $path,
+            'context' => $context,
+        ]);
+
+        $context['when'] = 'before';
+        $this->logger->info(__METHOD__, $context);
+
+        $this->buffer->flush($filesystem, $path, $context);
+
+        $context['when'] = 'after';
+        $this->logger->info(__METHOD__, $context);
+    }
+
+    public function close(): void
+    {
+        $context = $this->getContext();
+
+        $context['when'] = 'before';
+        $this->logger->info(__METHOD__, $context);
+
+        $this->buffer->close();
+
+        $context['when'] = 'after';
+        $this->logger->info(__METHOD__, $context);
+    }
+
+    private function getContext(array $add = []): array
+    {
+        $default = [
+            'buffer_class' => get_class($this->buffer),
+            'buffer_id' => spl_object_id($this->buffer),
+        ];
+        return array_merge($default, $add);
+    }
+}
diff --git a/tests/LoggingCompositeBufferTest.php b/tests/LoggingCompositeBufferTest.php
new file mode 100644
index 0000000..cc5e889
--- /dev/null
+++ b/tests/LoggingCompositeBufferTest.php
@@ -0,0 +1,140 @@
+<?php
+
+use Elazar\Flystream\BufferInterface;
+use Elazar\Flystream\LoggingCompositeBuffer;
+use League\Flysystem\Filesystem;
+use League\Flysystem\FilesystemOperator;
+use League\Flysystem\InMemory\InMemoryFilesystemAdapter;
+use Monolog\Handler\TestHandler;
+use Monolog\Logger;
+
+beforeEach(function () {
+    $this->logger = new Logger(__FILE__);
+    $this->logger->pushHandler(new TestHandler());
+
+    $this->nestedBuffer = new class implements BufferInterface {
+        public bool $flushCalled = false;
+        public bool $closeCalled = false;
+        public function write(string $data) {
+            return strlen($data);
+        }
+        public function flush(
+            FilesystemOperator $filesystem,
+            string $path,
+            array $context
+        ): void {
+            $this->flushCalled = true;
+        }
+        public function close(): void {
+            $this->closeCalled = true;
+        }
+    };
+
+    $this->buffer = new LoggingCompositeBuffer($this->nestedBuffer, $this->logger);
+    $this->filesystem = new Filesystem(new InMemoryFilesystemAdapter());
+});
+
+it('logs writes', function () {
+    $result = $this->buffer->write('foo');
+    expect($result)->toBe(3);
+
+    $records = $this->logger->popHandler()->getRecords();
+    expect($records)
+        ->toBeArray()
+        ->toHaveCount(2)
+        ->toHaveKeys([0, 1])
+        ->each
+        ->toBeArray()
+        ->toHaveKeys(['message', 'context', 'level_name']);
+
+    expect($records[0]['message'])->toBe('Elazar\Flystream\LoggingCompositeBuffer::write');
+    expect($records[0]['context'])
+        ->toHaveKeys(['buffer_class', 'buffer_id'])
+        ->toMatchArray([
+            'data' => 'foo',
+            'when' => 'before',
+        ]);
+    expect($records[0]['level_name'])->toBe('INFO');
+
+    expect($records[1]['message'])->toBe('Elazar\Flystream\LoggingCompositeBuffer::write');
+    expect($records[1]['context'])
+        ->toHaveKeys(['buffer_class', 'buffer_id'])
+        ->toMatchArray([
+            'data' => 'foo',
+            'when' => 'after',
+            'return' => 3,
+        ]);
+    expect($records[1]['level_name'])->toBe('INFO');
+});
+
+it('logs flushes', function () {
+    expect($this->nestedBuffer->flushCalled)->toBeFalse();
+    $this->buffer->flush(
+        $this->filesystem,
+        '/foo',
+        ['bar' => 'baz']
+    );
+    expect($this->nestedBuffer->flushCalled)->toBeTrue();
+
+    $records = $this->logger->popHandler()->getRecords();
+    expect($records)
+        ->toBeArray()
+        ->toHaveCount(2)
+        ->toHaveKeys([0, 1])
+        ->each
+        ->toBeArray()
+        ->toHaveKeys(['message', 'context', 'level_name']);
+
+    expect($records[0]['message'])->toBe('Elazar\Flystream\LoggingCompositeBuffer::flush');
+    expect($records[0]['context'])
+        ->toHaveKeys(['buffer_class', 'buffer_id', 'filesystem_id'])
+        ->toMatchArray([
+            'filesystem_class' => 'League\Flysystem\Filesystem',
+            'path' => '/foo',
+            'context' => ['bar' => 'baz'],
+            'when' => 'before',
+        ]);
+    expect($records[0]['level_name'])->toBe('INFO');
+
+    expect($records[1]['message'])->toBe('Elazar\Flystream\LoggingCompositeBuffer::flush');
+    expect($records[1]['context'])
+        ->toHaveKeys(['buffer_class', 'buffer_id', 'filesystem_id'])
+        ->toMatchArray([
+            'filesystem_class' => 'League\Flysystem\Filesystem',
+            'path' => '/foo',
+            'context' => ['bar' => 'baz'],
+            'when' => 'after',
+        ]);
+    expect($records[1]['level_name'])->toBe('INFO');
+});
+
+it('logs closes', function () {
+    expect($this->nestedBuffer->closeCalled)->toBeFalse();
+    $this->buffer->close();
+    expect($this->nestedBuffer->closeCalled)->toBeTrue();
+
+    $records = $this->logger->popHandler()->getRecords();
+    expect($records)
+        ->toBeArray()
+        ->toHaveCount(2)
+        ->toHaveKeys([0, 1])
+        ->each
+        ->toBeArray()
+        ->toHaveKeys(['message', 'context', 'level_name']);
+
+    expect($records[0]['message'])->toBe('Elazar\Flystream\LoggingCompositeBuffer::close');
+    expect($records[0]['context'])
+        ->toHaveKeys(['buffer_class', 'buffer_id'])
+        ->toMatchArray([
+            'when' => 'before',
+        ]);
+    expect($records[0]['level_name'])->toBe('INFO');
+
+    expect($records[1]['message'])->toBe('Elazar\Flystream\LoggingCompositeBuffer::close');
+    expect($records[1]['context'])
+        ->toHaveKeys(['buffer_class', 'buffer_id'])
+        ->toMatchArray([
+            'when' => 'after',
+        ]);
+    expect($records[1]['level_name'])->toBe('INFO');
+});