[Mate] Add command to stop running server

demo/mcp.json

@@ -3,7 +3,8 @@
         "symfony-ai-mate": {
             "command": "./vendor/bin/mate",
             "args": [
-                "serve"
+                "serve",
+                "--force-keep-alive"
             ]
         }
     }

src/mate/CHANGELOG.md

@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+0.2
+---
+
+ * Add `StopCommand` to stop a running server
+ * Add `--force-keep-alive` option to `ServeCommand` to restart server if it was stopped
+
 0.1
 ---
 

src/mate/bin/mate

@@ -1,4 +1,63 @@
 #!/usr/bin/env php
 <?php
 
-include __DIR__ . '/mate.php';
+/*
+ * This script will decide if we should try to keep the process alive or not.
+ * When running ./vendor/bin/mate serve --force-keep-alive, it will spawn a child process.
+ */
+
+$keepAlive = false;
+if (($argv[1] ?? false) === 'serve') {
+    $keepAlive = $argv;
+    // try to detect "--force-keep-alive
+    for ($i = 2; $i < $argc; ++$i) {
+        if ($argv[$i] === '--force-keep-alive') {
+            unset($keepAlive[$i]);
+        }
+    }
+}
+
+if (false === $keepAlive || $argv === $keepAlive) {
+    include __DIR__ . '/mate.php';
+    return;
+}
+
+// Build the command as an array to avoid shell interpretation
+$command = $keepAlive;
+
+while (true) {
+    // Run child attached to parent's STDIN/STDOUT/STDERR so it can read from STDIN
+    // and interact as if it was run directly.
+    $descriptorSpec = [
+        0 => ['file', 'php://stdin', 'r'],
+        1 => ['file', 'php://stdout', 'w'],
+        2 => ['file', 'php://stderr', 'w'],
+    ];
+
+    $process = proc_open($command, $descriptorSpec, $pipes, null, null, [
+        'bypass_shell' => true,
+    ]);
+
+    if (!\is_resource($process)) {
+        fwrite(STDERR, "[mate][keep-alive] Failed to start process.\n");
+        exit(70); // EX_SOFTWARE
+    }
+
+    // Wait for the process to terminate and get its exit code
+    $exitCode = proc_close($process);
+
+    if ($exitCode === 0) {
+        fwrite(STDERR, "[mate][keep-alive] Process exited with code 0, restarting...\n");
+        sleep(1);
+        continue;
+    }
+
+    if ($exitCode >= 129 && $exitCode <= 192) {
+        $signal = $exitCode - 128;
+        fwrite(STDERR, sprintf("[mate][keep-alive] Process terminated by signal %d (exit %d), not restarting.\n", $signal, $exitCode));
+    } else {
+        fwrite(STDERR, sprintf("[mate][keep-alive] Process exited with code %d, not restarting.\n", $exitCode));
+    }
+
+    exit($exitCode);
+}

src/mate/resources/mcp.json

@@ -3,7 +3,8 @@
         "symfony-ai-mate": {
             "command": "./vendor/bin/mate",
             "args": [
-                "serve"
+                "serve",
+                "--force-keep-alive"
             ]
         }
     }

src/mate/src/App.php

@@ -11,11 +11,14 @@
 
 namespace Symfony\AI\Mate;
 
+use Mcp\Server\Transport\Stdio\RunnerControl;
+use Mcp\Server\Transport\Stdio\RunnerState;
 use Psr\Log\LoggerInterface;
 use Symfony\AI\Mate\Command\ClearCacheCommand;
 use Symfony\AI\Mate\Command\DiscoverCommand;
 use Symfony\AI\Mate\Command\InitCommand;
 use Symfony\AI\Mate\Command\ServeCommand;
+use Symfony\AI\Mate\Command\StopCommand;
 use Symfony\AI\Mate\Exception\UnsupportedVersionException;
 use Symfony\Component\Console\Application;
 use Symfony\Component\Console\Command\Command;
@@ -46,8 +49,15 @@ public static function build(ContainerBuilder $container): Application
         self::addCommand($application, new InitCommand($rootDir));
         self::addCommand($application, new ServeCommand($logger, $container));
         self::addCommand($application, new DiscoverCommand($rootDir, $logger));
+        self::addCommand($application, new StopCommand((string) $container->getParameter('mate.cache_dir')));
         self::addCommand($application, new ClearCacheCommand($cacheDir));
 
+        if (\defined('SIGUSR1') && class_exists(RunnerControl::class)) {
+            $application->getSignalRegistry()->register(\SIGUSR1, function () {
+                RunnerControl::$state = RunnerState::STOP;
+            });
+        }
+
         return $application;
     }
 

src/mate/src/Command/ServeCommand.php

@@ -25,6 +25,7 @@
 use Symfony\Component\Console\Attribute\AsCommand;
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 
@@ -59,8 +60,19 @@ public static function getDefaultDescription(): string
         return 'Starts the MCP server with stdio transport';
     }
 
+    protected function configure(): void
+    {
+        $this->addOption('force-keep-alive', null, InputOption::VALUE_NONE, 'Force a restart of the server if it stops.');
+    }
+
     protected function execute(InputInterface $input, OutputInterface $output): int
     {
+        if ($input->getOption('force-keep-alive')) {
+            $output->writeln('The option --force-keep-alive requires using the "bin/mate" file. Try running "./vendor/bin/mate serve --force-keep-alive"');
+
+            return Command::INVALID;
+        }
+
         $rootDir = $this->container->getParameter('mate.root_dir');
         \assert(\is_string($rootDir));
 
@@ -100,7 +112,14 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             ->setLogger($this->logger)
             ->build();
 
-        $server->run(new StdioTransport());
+        $pidFileName = \sprintf('%s/server_%d.pid', $cacheDir, getmypid());
+        file_put_contents($pidFileName, getmypid());
+
+        try {
+            $server->run(new StdioTransport());
+        } finally {
+            unlink($pidFileName);
+        }
 
         return Command::SUCCESS;
     }

src/mate/src/Command/StopCommand.php

@@ -0,0 +1,74 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Mate\Command;
+
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+use Symfony\Component\Finder\Finder;
+
+/**
+ * Stop all running servers. This will force the AI to restart the server. Can be combined with
+ * the "--force-keep-alive" option on the "serve" command to make sure the server is restarted
+ * and not killed.
+ *
+ * @author Tobias Nyholm <[email protected]>
+ */
+#[AsCommand('stop', 'Stop running servers to allow them to be restarted with new configuration')]
+class StopCommand extends Command
+{
+    public function __construct(private string $cacheDir)
+    {
+        parent::__construct(self::getDefaultName());
+    }
+
+    public static function getDefaultName(): string
+    {
+        return 'stop';
+    }
+
+    public static function getDefaultDescription(): string
+    {
+        return 'Stop running servers to allow them to be restarted with new configuration';
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $io = new SymfonyStyle($input, $output);
+
+        if (!\function_exists('posix_kill')) {
+            $io->error('The "stop" command require the posix php extension.');
+
+            return Command::FAILURE;
+        }
+
+        if (!\defined('SIGUSR1')) {
+            $io->error('The "stop" command require the pcntl php extension.');
+
+            return Command::FAILURE;
+        }
+
+        $finder = new Finder();
+        $finder->files()
+            ->in($this->cacheDir)
+            ->name('server_*.pid');
+
+        foreach ($finder as $file) {
+            $pid = (int) file_get_contents($file->getRealPath());
+            posix_kill($pid, \SIGUSR1);
+        }
+
+        return Command::SUCCESS;
+    }
+}