2 files changed, 175 insertions, 0 deletions
diff --git a/source/Exceptions/RoadRunnerException.php b/source/Exceptions/RoadRunnerException.php
new file mode 100644
index 00000000..fa7b8da3
--- /dev/null
+++ b/source/Exceptions/RoadRunnerException.php
@@ -0,0 +1,13 @@
+<?php
+/**
+ * High-performance PHP process supervisor and load balancer written in Go
+ *
+ * @author    Wolfy-J
+ */
+
+namespace Spiral\RoadRunner\Exceptions;
+
+class RoadRunnerException extends \RuntimeException
+{
+
+}
+\ No newline at end of file
diff --git a/source/Worker.php b/source/Worker.php
new file mode 100644
index 00000000..d31b48bd
--- /dev/null
+++ b/source/Worker.php
@@ -0,0 +1,162 @@
+<?php
+/**
+ * High-performance PHP process supervisor and load balancer written in Go
+ *
+ * @author Wolfy-J
+ */
+
+namespace Spiral\RoadRunner;
+
+use Spiral\Goridge\Exceptions\GoridgeException;
+use Spiral\Goridge\RelayInterface as Relay;
+use Spiral\RoadRunner\Exceptions\RoadRunnerException;
+
+/**
+ * Accepts connection from RoadRunner server over given Goridge relay.
+ *
+ * Example:
+ *
+ * $worker = new Worker(new Goridge\StreamRelay(STDIN, STDOUT));
+ * while ($task = $worker->receive($context)) {
+ *      $worker->send("DONE", json_encode($context));
+ * }
+ */
+class Worker
+{
+    // Must be set as context value in order to perform controlled demolition of worker
+    const TERMINATE = "TERMINATE";
+
+    // Must be set as context value in order to represent content as an error
+    const ERROR = "ERROR";
+
+    /** @var Relay */
+    private $relay;
+
+    /**
+     * @param Relay $relay
+     */
+    public function __construct(Relay $relay)
+    {
+        $this->relay = $relay;
+    }
+
+    /**
+     * Receive packet of information to process, returns null when process must be stopped. Might
+     * return Error to wrap error message from server.
+     *
+     * @param array $context Contains parsed context array send by the server.
+     *
+     * @return \Error|null|string
+     * @throws GoridgeException
+     */
+    public function receive(&$context)
+    {
+        $body = $this->relay->receiveSync($flags);
+
+        if ($flags & Relay::PAYLOAD_CONTROL) {
+            if ($this->handleControl($body, $context)) {
+                // wait for the next command
+                return $this->receive($context);
+            }
+
+            // Expect process termination
+            return null;
+        }
+
+        if ($flags & Relay::PAYLOAD_ERROR) {
+            return new \Error($body);
+        }
+
+        return $body;
+    }
+
+    /**
+     * Respond to the server with result of task execution and execution context.
+     *
+     * Example:
+     * $worker->respond((string)$response->getBody(), json_encode($response->getHeaders()));
+     *
+     * @param string $payload
+     * @param string $context
+     */
+    public function send(string $payload, string $context = null)
+    {
+        if (is_null($context)) {
+            $this->relay->send($context, Relay::PAYLOAD_CONTROL | Relay::PAYLOAD_NONE);
+        } else {
+            $this->relay->send($context, Relay::PAYLOAD_CONTROL | Relay::PAYLOAD_RAW);
+        }
+
+        $this->relay->send($payload, Relay::PAYLOAD_RAW);
+    }
+
+    /**
+     * Respond to the server with an error. Error must be treated as TaskError and might not cause
+     * worker destruction.
+     *
+     * Example:
+     *
+     * $worker->error("invalid payload");
+     *
+     * @param string $message
+     */
+    public function error(string $message)
+    {
+        $this->relay->send(
+            $message,
+            Relay::PAYLOAD_CONTROL | Relay::PAYLOAD_RAW | Relay::PAYLOAD_ERROR
+        );
+    }
+
+    /**
+     * Terminate the process. Server must automatically pass task to the next available process.
+     * Worker will receive TerminateCommand context after calling this method.
+     *
+     * @throws GoridgeException
+     */
+    public function terminate()
+    {
+        $this->send(null, self::TERMINATE);
+    }
+
+    /**
+     * Handles incoming control command payload and executes it if required.
+     *
+     * @param string $body
+     * @param array  $context Exported context (if any).
+     *
+     * @returns bool True when continue processing.
+     *
+     * @throws RoadRunnerException
+     */
+    private function handleControl(string $body = null, &$context = null): bool
+    {
+        if (is_null($body)) {
+            // empty prefix
+            return true;
+        }
+
+        $parsed = json_decode($body, true);
+        if ($parsed === false) {
+            throw new RoadRunnerException("invalid task context, JSON payload is expected");
+        }
+
+        // PID negotiation (socket connections only)
+        if (!empty($parsed['pid'])) {
+            $this->relay->send(json_encode([
+                'pid'    => getmypid(),
+                'parent' => $parsed['pid'],
+            ]), Relay::PAYLOAD_CONTROL);
+        }
+
+        // termination request
+        if (!empty($parsed['terminate'])) {
+            return false;
+        }
+
+        // not a command but execution context
+        $context = $parsed;
+
+        return true;
+    }
+}
+\ No newline at end of file