Allow custom binary path or locate binary

lib/Context/Process.php

@@ -17,6 +17,9 @@ use function Amp\asyncCall;
 use function Amp\call;
 
 class Process implements Context {
+    /** @var string|null Cached path to located PHP binary. */
+    private static $binaryPath;
+
     /** @var \Amp\Process\Process */
     private $process;
 
@@ -26,10 +29,11 @@ class Process implements Context {
     /**
      * @param string|array $script Path to PHP script or array with first element as path and following elements options
      *     to the PHP script (e.g.: ['bin/worker', '-eOptionValue', '-nOptionValue'].
+     * @param string $binary Path to PHP binary. Null will attempt to automatically locate the binary.
      * @param string $cwd Working directory.
      * @param mixed[] $env Array of environment variables.
      */
-    public function __construct($script, string $cwd = "", array $env = []) {
+    public function __construct($script, string $binary = null, string $cwd = "", array $env = []) {
         $options = [
             "html_errors" => "0",
             "display_errors" => "0",
@@ -42,19 +46,35 @@ class Process implements Context {
             $script = \escapeshellarg($script);
         }
 
-        $options = (\PHP_SAPI === "phpdbg" ? " -b -qrr " : " ") . $this->formatOptions($options);
-        $separator = \PHP_SAPI === "phpdbg" ? " -- " : " ";
-        $command = \escapeshellarg(\PHP_BINARY) . $options . $separator . $script;
-
-        $processOptions = [];
-
-        if (\strncasecmp(\PHP_OS, "WIN", 3) === 0) {
-            $processOptions = ["bypass_shell" => true];
+        if ($binary === null) {
+            $binary = \PHP_BINARY;
         }
 
+        // Locate PHP executable when running under non-cli SAPI and no custom binary path was provided.
+        if ($binary === \PHP_BINARY && \PHP_SAPI !== "cli") {
+            $binary = self::$binaryPath ?? self::locateBinary();
+        } elseif (!\is_executable($binary)) {
+            throw new \Error(\sprintf("The PHP binary path '%s' was not found or is not executable", $binary));
+        }
+
+        $command = \escapeshellarg($binary) . " " . $this->formatOptions($options) . " " . $script;
+        $processOptions = \strncasecmp(\PHP_OS, "WIN", 3) === 0 ? ["bypass_shell" => true] : [];
+
         $this->process = new BaseProcess($command, $cwd, $env, $processOptions);
     }
 
+    private static function locateBinary(): string {
+        $executable = \strncasecmp(\PHP_OS, "WIN", 3) === 0 ? "php.exe" : "php";
+        foreach (\explode(\PATH_SEPARATOR, \getenv("PATH")) as $path) {
+            $path .= \DIRECTORY_SEPARATOR . $executable;
+            if (\is_executable($path)) {
+                return self::$binaryPath = $path;
+            }
+        }
+
+        throw new \Error("Could not locate PHP executable binary");
+    }
+
     private function formatOptions(array $options) {
         $result = [];
 

lib/Worker/DefaultWorkerFactory.php

@@ -22,6 +22,9 @@ class DefaultWorkerFactory implements WorkerFactory {
             return new WorkerThread;
         }
 
-        return new WorkerProcess;
+        return new WorkerProcess(
+            \getenv("AMP_PHP_BINARY") ?:
+            \defined("AMP_PHP_BINARY") ? \AMP_PHP_BINARY : null
+        );
     }
 }

lib/Worker/WorkerProcess.php

@@ -9,17 +9,18 @@ use Amp\Parallel\Context\Process;
  */
 class WorkerProcess extends AbstractWorker {
     /**
+     * @param string|null $binary Path to PHP binary. Null will attempt to automatically locate the binary.
      * @param string $envClassName Name of class implementing \Amp\Parallel\Worker\Environment to instigate.
      *     Defaults to \Amp\Parallel\Worker\BasicEnvironment.
      * @param mixed[] $env Array of environment variables to pass to the worker. Empty array inherits from the current
      *     PHP process. See the $env parameter of \Amp\Process\Process::__construct().
      */
-    public function __construct(string $envClassName = BasicEnvironment::class, array $env = []) {
+    public function __construct(string $binary = null, string $envClassName = BasicEnvironment::class, array $env = []) {
         $dir = \dirname(__DIR__, 2) . '/bin';
         $script = [
             $dir . "/worker",
             "-e" . $envClassName,
         ];
-        parent::__construct(new Process($script, $dir, $env));
+        parent::__construct(new Process($script, $binary, $dir, $env));
     }
 }

test/Context/ProcessTest.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace Amp\Parallel\Test\Context;
+
+use Amp\Parallel\Context\Process;
+use Amp\PHPUnit\TestCase;
+use Amp\Promise;
+
+class ProcessTest extends TestCase {
+    public function testBasicProcess() {
+        $process = new Process([
+            dirname(__DIR__) . "/bin/process",
+            "-sTest"
+        ]);
+        $process->start();
+        $this->assertSame("Test", Promise\wait($process->join()));
+    }
+}

test/bin/process

@@ -0,0 +1,61 @@
+#!/usr/bin/env php
+<?php
+
+use Amp\Parallel\Sync;
+
+// Doesn't exist in phpdbg...
+if (function_exists("cli_set_process_title")) {
+    @cli_set_process_title("process-test");
+}
+
+// Redirect all output written using echo, print, printf, etc. to STDERR.
+ob_start(function ($data) {
+    fwrite(STDERR, $data);
+    return '';
+}, 1, PHP_OUTPUT_HANDLER_CLEANABLE | PHP_OUTPUT_HANDLER_FLUSHABLE);
+
+(function () {
+    $paths = [
+        dirname(__DIR__, 2) . "/vendor/autoload.php",
+    ];
+
+    foreach ($paths as $path) {
+        if (file_exists($path)) {
+            $autoloadPath = $path;
+            break;
+        }
+    }
+
+    if (!isset($autoloadPath)) {
+        fwrite(STDERR, "Could not locate autoload.php");
+        exit(1);
+    }
+
+    require $autoloadPath;
+})();
+
+Amp\Loop::run(function () {
+    $channel = new Sync\ChannelledSocket(STDIN, STDOUT);
+
+    try {
+        $value = (function (): string {
+            $options = getopt("s:");
+
+            if (!isset($options["s"])) {
+                throw new Error("No string provided");
+            }
+
+            return $options["s"];
+        })();
+
+        $result = new Sync\ExitSuccess($value);
+    } catch (Throwable $exception) {
+        $result = new Sync\ExitFailure($exception);
+    }
+
+    try {
+        yield $channel->send($result);
+    } catch (Throwable $exception) {
+        exit(1); // Parent context died, simply exit.
+    }
+});