Implementing Serverless PHP

Serverless applications have a number of benefits and JavaScript is the most common language to write serverless functions in. Why not PHP? In this talk, I will discuss how I implemented first class PHP support into the Apache OpenWhisk platform. I look at how OpenWhisk works, how the PHP supprt is implemented and then walk though an example PHP serverless Slack application.

Transcript

1. Implementing Serverless PHP Under the hood of OpenWhisk Rob Allen
2. Serverless? The first thing to know about serverless computing is that "serverless" is a pretty bad name to call it. - Brandon Butler, Network World Rob Allen ~ @akrabat
3. AKA: Functions as a Service • A runtime to execute your functions • No capacity planning or load balancing; just tasks being executed. • Pay for execution, not when idle Rob Allen ~ @akrabat
4. Common tasks • Microservices / API backends • Volatile workloads (that break down in pieces) • Data processing • Event processing (message queues) • Scheduled tasks • Chat bots Rob Allen ~ @akrabat
5. Challenges • Start up latency • Time limit • State is external • DevOps is still a thing Rob Allen ~ @akrabat
6. Serverless implementations Apache OpenWhisk (IBM, Adobe, RedHat) AWS Lambda Google Cloud Functions Microsoft Azure Cloud Functions Iron.io Rob Allen ~ @akrabat
7. OpenWhisk is Open Source Rob Allen ~ @akrabat
8. JavaScript Rob Allen ~ @akrabat
9. Hello world in JS hello.js: 1 function main(params) 2 { 3 name = params.name || "World" 4 return {msg: 'Hello ' + name} 5 } Create action: $ wsk action create helloJS hello.js --web true --kind nodejs:6 ok: updated action helloJS Rob Allen ~ @akrabat
10. Hello world in JS Execute: $ wsk action invoke -r helloJS -p name Rob { "msg": "Hello Rob" } or: $ curl -k https://192.168.33.13/api/v1/web/guest/default/helloJS.json { "msg": "Hello World" } Rob Allen ~ @akrabat
11. PHP Rob Allen ~ @akrabat
12. Hello world in PHP hello.php: 1 <?php 2 function main(array $args) : array 3 { 4 $name = $args["name"] ?? "World"; 5 return [ "msg" => "Hello $name" ]; 6 } Rob Allen ~ @akrabat
13. Dockerise exec: 1 #!/bin/bash 2 3 # Install PHP 4 if [ ! -f /usr/bin/php ]; then 5 echo "http://dl-cdn.alpinelinux.org/alpine/edge/community" \ 6 >> /etc/apk/repositories 7 apk add --update php7 php7-json 8 fi 9 10 # Run PHP action 11 /usr/bin/php -r 'require "/action/hello.php"; 12 echo json_encode(main(json_decode($argv[1], true)));' -- "$@" Rob Allen ~ @akrabat
14. Create & Execute action 1 $ zip -r hello.zip hello.php exec 2 3 $ wsk action create helloPHP hello.zip --web true --docker 4 ok: updated action helloPHP 5 6 $ wsk action invoke -r helloPHP -p name Rob 7 { 8 "msg": "Hello Rob" 9 } Rob Allen ~ @akrabat
15. Time to execute: 7 seconds Rob Allen ~ @akrabat
16. Solution: Write a PHP action runner! Rob Allen ~ @akrabat
17. OpenWhisk's Architecture Rob Allen ~ @akrabat
18. OpenWhisk's Architecture Rob Allen ~ @akrabat
19. Create an action Rob Allen ~ @akrabat
20. Invoke an action Rob Allen ~ @akrabat
21. Action container lifecycle • Hosts the user-written code • Controlled via two end points: /init & /run Rob Allen ~ @akrabat
22. Action Container API POST /init POST /run input { "value": { "name" : "helloPHP", "main" : "main", "binary": false, "code" : "<?php …", } } { "value": { "name" : "Rob", } } output { "OK": true} `{"msg": "Hello Rob" } Rob Allen ~ @akrabat
23. Writing a PHP action container We need: • A container • Code to handle endpoints (router) • Execute the user code (runner) Rob Allen ~ @akrabat
24. Dockerfile FROM php:7.1-alpine # copy required files ADD router.php /action ADD runner.php /action # Start webserver on port 8080 EXPOSE 8080 CMD [ "php", "-S", "0.0.0.0:8080", "/action/router.php" ] Rob Allen ~ @akrabat
25. router.php 1 <?php 2 if ($_SERVER['REQUEST_URI'] == '/init') { 3 $result = init(); 4 } elseif ($_SERVER['REQUEST_URI'] == '/run') { 5 $result = run(); 6 } 7 8 /* send response */ 9 header('Content-Type: application/json'); 10 echo json_encode((object)$result); Rob Allen ~ @akrabat
26. router.php: init() 1 function init() 2 { 3 $post = file_get_contents('php://input'); 4 $data = json_decode($post, true)['value']; 5 6 file_put_contents('index.php', $data['code']); 7 8 $config = ['function' => $data['main'], 'file' => 'index.php']; 9 file_put_contents('config.json', json_encode($config)); 10 11 return ["OK" => true]; 12 } Rob Allen ~ @akrabat
27. router.php: run() 1 function run() 2 { 3 $config = file_get_contents('config.json'); 4 $args = json_decode(file_get_contents('php://input'), true)['value']; 5 6 list($code, $out, $err) = runPHP('runner.php', $config, $args); 7 8 $pos = strrpos($stdout, PHP_EOL) + 1; 9 $lastLine = trim(substr($stdout, $pos)); 10 11 file_put_contents("php://stderr", $stderr); 12 file_put_contents("php://stdout", $stdout); 13 14 return $lastLine; 15 } Rob Allen ~ @akrabat
28. runner.php Runs the user's code in a separate process 1 <?php 2 $config = json_decode($argv[1], true); 3 $functionName = $config['function'] ?? 'main'; 4 5 $args = json_decode(file_get_contents('php://stdin') ?? [], true); 6 7 require '/action/vendor/autoload.php'; 8 require '/action/src/index.php'; 9 $result = $_functionName($args); 10 11 echo json_encode((object)$result); Rob Allen ~ @akrabat
29. Hello world in PHP hello.php: 1 <?php 2 function main(array $args) : array { 3 $name = $args["name"] ?? "World"; 4 return [ "msg" => "Hello $name" ]; 5 } $ wsk action create hello hello.php --web true --kind php:7.1 ok: updated action hello $ wsk action invoke -r hello -p name Rob { "msg": "Hello Rob" } Rob Allen ~ @akrabat
30. Time to execute: 500 milliseconds Rob Allen ~ @akrabat
31. Let's look at some code! Rob Allen ~ @akrabat
32. Summary Rob Allen ~ @akrabat
33. Resources • https://www.martinfowler.com/articles/serverless.html • http://www.openwhisk.org • https://medium.com/openwhisk • http://github.com/apache/incubator-openwhisk/pull/2415 • https://github.com/akrabat/ow-php-ftime Rob Allen ~ @akrabat
34. Thank you! Rob Allen ~ @akrabat