Add containerStats() and containerStatsStream() methods

README.md

@@ -321,6 +321,7 @@ a [`Stream`](https://github.com/reactphp/stream) instance instead:
 $stream = $client->imageCreateStream();
 $stream = $client->imagePushStream();
 $stream = $client->eventsStream();
+$stream = $client->containerStatsStream($container);
 ```
 
 The resulting stream will emit the following events:

examples/stats.php

@@ -0,0 +1,35 @@
+<?php
+
+// this example shows how the `containerStatsStream()` method can be used show live container stats.
+// demonstrates the JSON streaming API, individual stats events will be printed as they happen.
+
+use Clue\React\Docker\Client;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$container = isset($argv[1]) ? $argv[1] : 'asd';
+echo 'Monitoring "' . $container . '" (pass as argument to this example)' . PHP_EOL;
+
+$loop = React\EventLoop\Factory::create();
+$client = new Client($loop);
+
+$stream = $client->containerStatsStream($container);
+
+$stream->on('data', function ($progress) {
+    //echo 'progress: '. json_encode($progress, JSON_PRETTY_PRINT) . PHP_EOL;
+
+    $memory = $progress['memory_stats']['usage'] / $progress['memory_stats']['limit'] * 100;
+    $sent = $received = 0;
+    foreach ($progress['networks'] as $stats) {
+        $sent += $stats['tx_bytes'];
+        $received += $stats['rx_bytes'];
+    }
+
+    echo round($memory, 3) . '% memory and ' . $received . '/' . $sent . ' bytes network I/O' . PHP_EOL;
+});
+$stream->on('error', 'printf');
+$stream->on('close', function () {
+    echo 'stream closed' . PHP_EOL;
+});
+
+$loop->run();

src/Client.php

@@ -344,6 +344,61 @@ public function containerExportStream($container)
         );
     }
 
+    /**
+     * Returns a container’s resource usage statistics.
+     *
+     * This is a JSON API endpoint that resolves with a single stats info.
+     *
+     * If you want to monitor live stats events as they happen, you
+     * should consider using `imageStatsStream()` instead.
+     *
+     * @param string $container container ID
+     * @return PromiseInterface Promise<array> JSON stats
+     * @link https://docs.docker.com/engine/api/v1.40/#operation/ContainerStats
+     * @since 0.3.0 Available as of Docker Engine API v1.19 (Docker v1.7), use `containerStatsStream()` on legacy versions
+     * @see self::containerStatsStream()
+     */
+    public function containerStats($container)
+    {
+        return $this->browser->get(
+            $this->uri->expand(
+                '/containers/{container}/stats{?stream}',
+                array(
+                    'container' => $container,
+                    'stream' => 0
+                )
+            )
+        )->then(array($this->parser, 'expectJson'));
+    }
+
+    /**
+     * Returns a live stream of a container’s resource usage statistics.
+     *
+     * The resulting stream will emit the following events:
+     * - data:  for *each* element in the stats stream
+     * - error: once if an error occurs, will close() stream then
+     * - close: once the stream ends (either finished or after "error")
+     *
+     * @param string $container container ID
+     * @return ReadableStreamInterface JSON stats stream
+     * @link https://docs.docker.com/engine/api/v1.40/#operation/ContainerStats
+     * @since 0.3.0 Available as of Docker Engine API v1.17 (Docker v1.5)
+     * @see self::containerStats()
+     */
+    public function containerStatsStream($container)
+    {
+        return $this->streamingParser->parseJsonStream(
+            $this->browser->withOptions(array('streaming' => true))->get(
+                $this->uri->expand(
+                    '/containers/{container}/stats',
+                    array(
+                        'container' => $container
+                    )
+                )
+            )
+        );
+    }
+
     /**
      * Resize the TTY of container id
      *

tests/ClientTest.php

@@ -287,6 +287,23 @@ public function testContainerRemoveVolumeForce()
         $this->expectPromiseResolveWith('', $this->client->containerRemove(123, true, true));
     }
 
+    public function testContainerStats()
+    {
+        $this->expectRequestFlow('GET', '/containers/123/stats?stream=0', $this->createResponse(), 'expectJson');
+
+        $this->expectPromiseResolveWith('', $this->client->containerStats(123));
+    }
+
+    public function testContainerStatsStream()
+    {
+        $stream = $this->getMockBuilder('React\Stream\ReadableStreamInterface')->getMock();
+
+        $this->expectRequest('GET', '/containers/123/stats', $this->createResponse(''));
+        $this->streamingParser->expects($this->once())->method('parseJsonStream')->will($this->returnValue($stream));
+
+        $this->assertSame($stream, $this->client->containerStatsStream('123'));
+    }
+
     public function testContainerResize()
     {
         $this->expectRequestFlow('POST', '/containers/123/resize?w=800&h=600', $this->createResponse(), 'expectEmpty');