From 652123931c1d5c6c877f31a7af70047af322e27f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20Schr=C3=B6er?= <code@sweikenb.com>
Date: Sat, 3 Aug 2024 18:27:41 +0200
Subject: [PATCH] WIP add PoolManager

---
 src/Api/ProcessManagerInterface.php |  8 ++--
 src/PoolManager.php                 | 70 +++++++++++++++++++++++++++++
 src/ProcessManager.php              | 10 +++--
 3 files changed, 81 insertions(+), 7 deletions(-)
 create mode 100644 src/PoolManager.php

diff --git a/src/Api/ProcessManagerInterface.php b/src/Api/ProcessManagerInterface.php
index ab94483..3c96c6e 100644
--- a/src/Api/ProcessManagerInterface.php
+++ b/src/Api/ProcessManagerInterface.php
@@ -22,12 +22,12 @@ public function runProcess(callable $callback, ?ProcessOutputInterface $output =
     /**
      * By default, it waits until all child-processes are returned and calls the optional callback for each of them.
      * The callback will receive the return-status and the pid of the child process as arguments.
-     * If the callback returns FALSE (boolean), the method will not wait for further children to exit and returns early,
-     * any other or none value (including NULL) will continue to wait if remaining children are present.
-     * The callback will be executed before any other registered callback.
+     * If the callback returns FALSE (boolean) or $block is set to FALSE (boolean), the method will not wait for further
+     * children to exit and returns early, any other or none value (including NULL) will continue to wait if remaining
+     * children are present. The callback will be executed before any other registered callback.
      * Only works in the parent-process.
      */
-    public function wait(?callable $callback = null): void;
+    public function wait(?callable $callback = null, bool $block = true): void;
 
     /**
      * Registers a callback for when a child process gets created. Multiple callbacks can be registered.
diff --git a/src/PoolManager.php b/src/PoolManager.php
new file mode 100644
index 0000000..2936802
--- /dev/null
+++ b/src/PoolManager.php
@@ -0,0 +1,70 @@
+<?php
+namespace Sweikenb\Library\Pcntl;
+
+use Sweikenb\Library\Pcntl\Api\ChildProcessInterface;
+use Sweikenb\Library\Pcntl\Api\ProcessManagerInterface;
+
+class PoolManager
+{
+    const DEFAULT_KILL_TIMEOUT = 1.0;
+    private ProcessManagerInterface $pm;
+    private bool $interrupted = false;
+    private array $processes = [];
+
+    public function __construct(?ProcessManagerInterface $processManager = null,)
+    {
+        // create the process manager instance if not provided
+        $this->pm = $processManager ?? new ProcessManager();
+
+        // register/override interrupt handler for the main-process
+        pcntl_signal(SIGINT, [$this, 'handleInterrupt']);
+
+        // register events
+        $this->pm->onThreadCreate(function (ChildProcessInterface $process) {
+            $this->processes[$process->getId()] = $process;
+        });
+        $this->pm->onThreadExit(function (int $status, int $pid) {
+            unset($this->processes[$pid]);
+        });
+    }
+
+    public function handleInterrupt(): void
+    {
+        $this->interrupted = true;
+        $this->pm->sendSignalToChildren(SIGTERM);
+    }
+
+    public function execute(int $poolSize, callable $mainLoop, callable $processLoop, ?float $killTimeout = null): int
+    {
+        while (!$this->interrupted) {
+            // ensure we have enough threads
+            $this->pm->wait(block: false);
+            $missing = $poolSize - count($this->processes);
+            for ($i = 0; $i < $missing; $i++) {
+                $this->pm->runProcess($processLoop);
+            }
+
+            // call the main-loop
+            $this->pm->wait(block: false);
+            call_user_func($mainLoop, $this->processes, $this->pm);
+        }
+
+        // wait for children to exit after sending the SIGTERM by the SIGINT handler
+        // send a SIGKILL to forcefully terminate the child after the kill-timeout is reached
+        $status = 0;
+        $waitStart = microtime(true);
+        while (!empty($this->processes)) {
+            if ((microtime(true) - $waitStart) >= ($killTimeout ?? self::DEFAULT_KILL_TIMEOUT)) {
+                $this->pm->sendSignalToChildren(SIGKILL);
+                $status = 1;
+                break;
+            }
+            $this->pm->unblock();
+        }
+
+        // final wait until all children exited after the KILL
+        $this->pm->wait();
+
+        return $status;
+    }
+}
diff --git a/src/ProcessManager.php b/src/ProcessManager.php
index 4fe626d..dde777b 100644
--- a/src/ProcessManager.php
+++ b/src/ProcessManager.php
@@ -176,7 +176,7 @@ public function runProcess(callable $callback, ?ProcessOutputInterface $output =
         }
     }
 
-    public function wait(?callable $callback = null): void
+    public function wait(?callable $callback = null, bool $block = true): void
     {
         if ($this->isChildProcess) {
             return;
@@ -188,14 +188,15 @@ public function wait(?callable $callback = null): void
         }
 
         // wait for all children to exit
-        while (!empty($this->childProcesses)) {
+        $wait = true;
+        while ($wait && !empty($this->childProcesses)) {
             // process the exit-queue
             foreach ($this->childExitQueue as $pid => $status) {
                 if ($pid > 0) {
                     unset($this->childExitQueue[$pid], $this->childProcesses[$pid]);
                     foreach ($callbackStack as $callback) {
                         if (call_user_func($callback, $status, $pid) === false) {
-                            return;
+                            $block = false;
                         }
                     }
                 }
@@ -203,6 +204,9 @@ public function wait(?callable $callback = null): void
 
             // unblock the system and dispatch queued signals
             $this->unblock();
+
+            // continue to wait?
+            $wait = $block;
         }
     }