RPC Implementation using multiple relays to enable async communication (

#25)

composer.json

@@ -75,7 +75,7 @@
     "scripts": {
         "test": "phpunit --no-coverage --colors=always",
         "test-cover": "phpunit --coverage-clover=coverage.xml",
-        "test-static": "psalm",
+        "test-static": "psalm --no-cache",
         "test-mutations": "infection"
     },
     "minimum-stability": "dev",

src/ConnectedRelayInterface.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace Spiral\Goridge;
+
+use Spiral\Goridge\Exception\RelayException;
+
+/**
+ * This interface describes a Relay that explictily establishes a connection.
+ * That connection can also be re-established on the fly (in comparison to StreamRelay, which relies on the existence of the streams).
+ * The object is also clonable, i.e. supports cloning without data errors due to shared state.
+ */
+interface ConnectedRelayInterface extends RelayInterface
+{
+    /**
+     * Returns true if the underlying connection is already established
+     */
+    public function isConnected(): bool;
+
+    /**
+     * Establishes the underlying connection and returns true on success, false on failure, or throws an exception in case of an error.
+     *
+     * @throws RelayException
+     */
+    public function connect(): bool;
+
+    /**
+     * Closes the underlying connection.
+     */
+    public function close(): void;
+
+    /**
+     * Enforce implementation of __clone magic method
+     * @psalm-return void
+     */
+    public function __clone();
+}

src/MultiRelayHelper.php

@@ -0,0 +1,115 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Spiral\Goridge;
+
+use Spiral\Goridge\RPC\Exception\RPCException;
+use function socket_select;
+
+class MultiRelayHelper
+{
+    /**
+     * @param array<array-key, RelayInterface> $relays
+     * @return array-key[]|false
+     * @internal
+     * Returns either
+     *  - an array of array keys, even if only one
+     *  - or false if none
+     */
+    public static function findRelayWithMessage(array $relays, int $timeoutInMicroseconds = 0): array|false
+    {
+        if (count($relays) === 0) {
+            return false;
+        }
+
+        if ($relays[array_key_first($relays)] instanceof SocketRelay) {
+            $sockets = [];
+            $socketIdToRelayIndexMap = [];
+            foreach ($relays as $relayIndex => $relay) {
+                assert($relay instanceof SocketRelay);
+
+                // Enforce connection
+                if ($relay->socket === null) {
+                    // Important: Do not force reconnect here as it would otherwise completely ruin further handling
+                    continue;
+                }
+
+                $sockets[] = $relay->socket;
+                $socketIdToRelayIndexMap[spl_object_id($relay->socket)] = $relayIndex;
+            }
+
+            if (count($sockets) === 0) {
+                return false;
+            }
+
+            $writes = null;
+            $except = null;
+            $changes = socket_select($sockets, $writes, $except, 0, $timeoutInMicroseconds);
+
+            if ($changes > 0) {
+                $indexes = [];
+                foreach ($sockets as $socket) {
+                    $indexes[] = $socketIdToRelayIndexMap[spl_object_id($socket)] ?? throw new RPCException("Invalid socket??");
+                }
+
+                return $indexes;
+            } else {
+                return false;
+            }
+        }
+
+        if ($relays[array_key_first($relays)] instanceof StreamRelay) {
+            $streams = [];
+            $streamNameToRelayIndexMap = [];
+            foreach ($relays as $relayIndex => $relay) {
+                assert($relay instanceof StreamRelay);
+
+                $streams[] = $relay->in;
+                $streamNameToRelayIndexMap[(string)$relay->in] = $relayIndex;
+            }
+
+            $writes = null;
+            $except = null;
+            $changes = stream_select($streams, $writes, $except, 0, $timeoutInMicroseconds);
+
+            if ($changes > 0) {
+                $indexes = [];
+                foreach ($streams as $stream) {
+                    $indexes[] = $streamNameToRelayIndexMap[(string)$stream] ?? throw new RPCException("Invalid stream??");
+                }
+
+                return $indexes;
+            } else {
+                return false;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @param array<array-key, RelayInterface> $relays
+     * @return array-key[]|false
+     * @internal
+     * Returns either
+     *  - an array of array keys, even if only one
+     *  - or false if none
+     */
+    public static function checkConnected(array $relays): array|false
+    {
+        if (count($relays) === 0) {
+            return false;
+        }
+
+        $keysNotConnected = [];
+        foreach ($relays as $key => $relay) {
+            if ($relay instanceof ConnectedRelayInterface && !$relay->isConnected()) {
+                $relay->connect();
+                $keysNotConnected[] = $key;
+            }
+        }
+
+        return $keysNotConnected;
+    }
+}

src/RPC/AbstractRPC.php

@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Spiral\Goridge\RPC;
+
+use Spiral\Goridge\Frame;
+use Spiral\Goridge\RelayInterface;
+use Spiral\Goridge\RPC\Exception\ServiceException;
+use Stringable;
+use function sprintf;
+use function strlen;
+use function substr;
+use function ucfirst;
+
+abstract class AbstractRPC implements RPCInterface
+{
+    /**
+     * RPC calls service prefix.
+     *
+     * @var non-empty-string|null
+     */
+    protected ?string $service = null;
+
+    /**
+     * @var positive-int
+     */
+    protected static int $seq = 1;
+
+    public function __construct(
+        protected CodecInterface $codec
+    ) {
+    }
+
+    /**
+     * @psalm-pure
+     */
+    public function withServicePrefix(string $service): self
+    {
+        /** @psalm-suppress ImpureVariable */
+        $rpc = clone $this;
+        $rpc->service = $service;
+
+        return $rpc;
+    }
+
+    /**
+     * @psalm-pure
+     */
+    public function withCodec(CodecInterface $codec): self
+    {
+        /** @psalm-suppress ImpureVariable */
+        $rpc = clone $this;
+        $rpc->codec = $codec;
+
+        return $rpc;
+    }
+
+    /**
+     * @throws Exception\ServiceException
+     */
+    protected function decodeResponse(Frame $frame, RelayInterface $relay, mixed $options = null): mixed
+    {
+        // exclude method name
+        $body = substr((string)$frame->payload, $frame->options[1]);
+
+        if ($frame->hasFlag(Frame::ERROR)) {
+            $name = $relay instanceof Stringable
+                ? (string)$relay
+                : $relay::class;
+
+            throw new ServiceException(sprintf("Error '%s' on %s", $body, $name));
+        }
+
+        return $this->codec->decode($body, $options);
+    }
+
+    /**
+     * @param non-empty-string $method
+     */
+    protected function packFrame(string $method, mixed $payload): Frame
+    {
+        if ($this->service !== null) {
+            $method = $this->service . '.' . ucfirst($method);
+        }
+
+        $body = $method . $this->codec->encode($payload);
+        return new Frame($body, [self::$seq, strlen($method)], $this->codec->getIndex());
+    }
+}

src/RPC/AsyncRPCInterface.php

@@ -0,0 +1,69 @@
+<?php
+
+namespace Spiral\Goridge\RPC;
+
+use Spiral\Goridge\Exception\GoridgeException;
+use Spiral\Goridge\Exception\RelayException;
+use Spiral\Goridge\RPC\Exception\RPCException;
+use Spiral\Goridge\RPC\Exception\ServiceException;
+
+interface AsyncRPCInterface extends RPCInterface
+{
+    /**
+     * Invoke remote RoadRunner service method using given payload (free form) non-blockingly and ignore the response.
+     *
+     * @param non-empty-string $method
+     *
+     * @throws GoridgeException
+     */
+    public function callIgnoreResponse(string $method, mixed $payload): void;
+
+    /**
+     * Invoke remote RoadRunner service method using given payload (free form) non-blockingly but accept a response.
+     *
+     * @param non-empty-string $method
+     * @return positive-int An "ID" to check whether a response has been received and to fetch said response.
+     *
+     * @throws GoridgeException
+     */
+    public function callAsync(string $method, mixed $payload): int;
+
+    /**
+     * Check whether a response has been received using the "ID" obtained through @see AsyncRPCInterface::callAsync() .
+     *
+     * @param positive-int $seq
+     * @return bool
+     */
+    public function hasResponse(int $seq): bool;
+
+    /**
+     * Checks the "ID"s obtained through @see AsyncRPCInterface::callAsync() if they've got a response yet.
+     * Returns an array of "ID"s that do.
+     *
+     * @param positive-int[] $seqs
+     * @return positive-int[]
+     */
+    public function hasResponses(array $seqs): array;
+
+    /**
+     * Fetch the response for the "ID" obtained through @see AsyncRPCInterface::callAsync() .
+     * @param positive-int $seq
+     * @throws RPCException
+     * @throws ServiceException
+     * @throws RelayException
+     */
+    public function getResponse(int $seq, mixed $options = null): mixed;
+
+    /**
+     * Fetches the responses for the "ID"s obtained through @see AsyncRPCInterface::callAsync()
+     * and returns a map of "ID" => Response.
+     * @throws RelayException
+     * @throws ServiceException
+     * @throws RPCException
+     *
+     * @param array<array-key, positive-int> $seqs
+     * @return iterable<positive-int, mixed>
+     *
+     */
+    public function getResponses(array $seqs, mixed $options = null): iterable;
+}