Play Framework on Google App Engine - Productivity Stack
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This document discusses using the Play Framework for web application development on Google App Engine (GAE). It provides an overview of Play and GAE, how they work together, and some tradeoffs. Specifically, it covers how Play abstracts away the GAE infrastructure, limitations of the GAE sandbox environment, options for running Play 2 applications on GAE including using a WAR file or custom runtime, and the pros and cons of the Play Framework on GAE approach.
Play Framework on Google App Engine - Productivity Stack
- 1. smart.biz.plsmart.biz.pl Play with GAE 1 Productivity stack: Play Framework on Google App Engine Polish Java User Group Kraków 2016-04-05 @marcinstepien www.smart.biz.pl
- 3. smart.biz.plsmart.biz.pl ❖ App Engine intro, scaling & limitations ❖ Play Framework stuff ❖ GAE abstraction ❖ How do this two things work together ❖ Play 2 on GAE? ❖ Trade-offs 3 Play Framework + GAE
- 6. smart.biz.pl Google Cloud Compute EngineApp Engine PaaS IaaS 6
- 7. smart.biz.pl Building blocks App Engine PaaS 7 Build tools Scalable Infrastructure
- 8. smart.biz.pl Scaling is simplified 8 One tier of servers Instances: - capacity - max / min # - manual / autoscale - warm up / decommission - traffic splitting Internet
- 9. smart.biz.pl Just a drawing 9 Internet load balancer frontend servers backed servers data store You will not deal with that
- 10. smart.biz.pl GAE Limitations 10 Security sandbox ● Java class whitelist ● Java 7 ● Servlet API 2.5 ○ no real async WS calls ● No raw socket connections ○ no SMTP etc. ○ Url Fetch service instead Scalability ● Frontend calls are limited to 30s ● Scheduled Jobs limited to 10min ● Url Fetch limited to max 60s ● Do not share object in session ● NoSQL datastore * ● 200 indexes
- 12. smart.biz.pl Play 1, Play 2, Ninja, Spark … Spring Boot, JHipster Java micro frameworks 12
- 13. smart.biz.pl Play 1 Play 2 2008 released 2013 Java first service Scala first, Java Groovy templates Scala 1 GAE module - by community maintenance mode* developed by authors and community by 3rd part. commerce support by authors and 3rd part. Play Framework versions 13
- 14. smart.biz.pl There is no HttpServletRequest, HttpSession etc. Not a JEE Framework 14 GAE module wraps Play app into .war file
- 15. smart.biz.pl There is no server side session Share Nothing 15
- 16. smart.biz.plsmart.biz.pl #pass value to next request in flash scope flash.put(“key”, object); #store in encrypted user cookie, Strings only, 4kb session.put(“key”, “value”); #store object in cache Cache.store(“key”, object, “1h”); 16 Share Nothing
- 17. smart.biz.pl hot swapping on dev, just hit F5 + auto scaling on prod Share Nothing 17
- 18. smart.biz.pl GAE gives 2 types. Transparent use for Play developer. Distributed Cache 18
- 19. smart.biz.pl But not on GAE with Servlet 2.5 spec Play is asynchronous 19
- 20. smart.biz.plsmart.biz.pl #com.ning.http.client.AsyncHttpClient #not on GAE servlet API 2.5 Promise<HttpResponse> res1, res2; res1 = WS.url("http://example1").getAsync(); res2 = WS.url("http://example2").getAsync(); ... #synchronous call works fine WS.url("http://example").get(); #Json parser WS.url("http://example").getJson(); 20 WS calls are wrapped in URL fetch
- 21. smart.biz.pl Siena module instead of GAE JPA Data store: Active Record pattern 21
- 22. smart.biz.plsmart.biz.pl public class Employee extends Model { @Id public Long id; public String fullName; public Department dep; } public class Department extends Model { @Id public Long id; @Url public String website; public Date launched; } 22 Data store abstraction
- 23. smart.biz.plsmart.biz.pl Employee adam = new Employee(“Adam”); Adam.dep = department; adam.save(); welcome(adam); 23 Active Record
- 24. smart.biz.plsmart.biz.pl public class Employee extends Model { @Id public Long id; public String fullName; #no Joins, dep stores only id field public Department dep; #retrieves and maps into object public String getDepWebsite() { #dep.website is null until you call .get() return dep.get().website; } } 24 Fetching data, no joins
- 25. smart.biz.plsmart.biz.pl public class Employee extends Model {... public static List<Employee> getAll(Long depId) { return all().filter(“dep”, new Department(depId)) .fetch(); } public static Query<Employee> all() { return all(Employee.class); } 25 Querying
- 26. smart.biz.pl Controller is tied to HTTP protocol RESTful 26
- 27. smart.biz.plsmart.biz.pl #http method, app url (regex), controller method GET /employee/{id} Employees.user POST /employee/ Employees.create PUT /employee/{id} Employees.update DELETE /employee/{id} Employees.delete GET /employee/show-{id} Employees.show GET /employee/list Employees.list 27 Routing
- 28. smart.biz.plsmart.biz.pl #controller methods are static for Play v. < 1.4 public class Employees extends App { public static void create(Employee em) { em.save(); show(em.id); #HTTP 302 redirect } #template is chosen by convention public static void show(Long id) { #object passed into Employees/show.html render(Employee.get(id)); } public static void list() { renderJSON(Employee.all()); } } 28 Controller
- 29. smart.biz.pl Data store, Logging, Cache, Gmail, WS calls etc. GAE Abstraction 29 Is implemented in Play. GAE SDK is hidden.
- 30. smart.biz.pl GAE tooling 30 BigQuery, Security scans, Performance scans, alerts .
- 31. smart.biz.pl 2. Environment (Java 8, Servlet 3.0 +) Play 2 on GAE ? 31 1. Deployable .war file
- 32. smart.biz.plsmart.biz.pl https://github.com/play2war/play2-war-plugin 32 Play 2 on GAE: war
- 33. smart.biz.plsmart.biz.pl https://cloud.google.com/appengine/docs/flexible/custom-runtimes/ https://cloud.google.com/appengine/docs/flexible/java/dev-jetty9-and-apis 33 Play 2 on GAE: run Services only via public APIs...Jetty 9 + docker configuration Flexible runtime Custom runtime
- 34. smart.biz.pl Trade-offs 34 Pros ● Faster deployment ● Scaling ● Google Infrastructure ● maintenance + analytic tools ○ BigQuery etc. ● Abstraction ○ You are not tied with GAE SDK Cons ● Sandbox limitations ● Not truly asynchronous on basic GAE ● Servlet container lowers application performance ● Watch out for test coverage