Lambda runtime entrypoint for PHP.Gt WebEngine

bootstrap

#!/opt/bin/php
<?php
require __DIR__ . "/vendor/autoload.php";

use Gt\Fetch\Http;
use Gt\Fetch\Response\BodyResponse;

while(true) {
	$payload = null;
	$invocationId = null;
	
	$http = new Http();
	$http->fetch(
		"http://" 
		. $_ENV["AWS_LAMBDA_RUNTIME_API"] 
		. "/2018-06-01/runtime/invocation/next"
	)->then(function(BodyResponse $response) use(&$invocationId) {
		$invocationId = $response->getHeaderLine("Lambda-Runtime-Aws-Request-Id");
		return $response->text();
	})->then(function(string $text) use(&$payload) {
		$payload = json_decode($text, true);
	});
	
	$http->wait();
	
	$handlerFunction = array_slice(explode(".", $_ENV["_HANDLER"]), -1)[0];
	require_once($_ENV["LAMBDA_TASK_ROOT"] . "/function/" . $handlerFunction . ".php");
	
	/*
	TODO: Once WebEngine is available in the handlerFunction context, the PSR-7 Response 
	will be returned, which needs to be converted into this object and json_encoded
	as the POST body.
	{
	    "isBase64Encoded": true|false,
	    "statusCode": httpStatusCode,
	    "headers": { "headerName": "headerValue", ... },
	    "multiValueHeaders": { "headerName": ["headerValue", "headerValue2", ...], ... },
	    "body": "..."
	}
	*/
	$response = $handlerFunction($payload);
	
	$http->fetch(
		"http://" 
		. $_ENV["AWS_LAMBDA_RUNTIME_API"] 
		. "/2018-06-01/runtime/invocation/" 
		. $invocationId 
		. "/response",
		[
			"method" => "POST",
			"body" => $response,
		]
	);
	
	$http->wait();
}

handler.php

<?php
/*
{
    "isBase64Encoded": true|false,
    "statusCode": httpStatusCode,
    "headers": { "headerName": "headerValue", ... },
    "multiValueHeaders": { "headerName": ["headerValue", "headerValue2", ...], ... },
    "body": "..."
}
*/
function handler($request) {
	$lambdaResponse = (object)[
		"isBase64Encoded" => false,
		"statusCode" => 200,
		"headers" => (object)[
			"Content-type" => "text/plain",
			"X-Test" => "My name is Greg",
		],
		"multiValueHeaders" => (object)[
			"X-Multi-Test" => [
				"First MVH",
				"Second MVH",
			],
		],
		"body" => "Mary had a little Lambda",
	];
	return json_encode($lambdaResponse);
}

trust-policy.json

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Effect": "Allow",
			"Principal": {
				"Service": "lambda.amazonaws.com"
			},
			"Action": "sts:AssumeRole"
		}
	]
}