Google DevFest Kaohsiung 2019

Transcript

1. Kotlin Server-Side Development Using Ktor @chennevin
2. Agenda • Ktor • Kotlin tips • Friends: Armeria, Spring • Ktor on GAE • Android -> Backend
3. Ktor • Easy to Learn • Easy to Use • Client + Server • Features / Middleware • OAuth 2 - Firefox Account • Nice Architecture • Routing + Controller
5. start.ktor.io
6. start.ktor.io
8. Intellij Plugin
9. Auto Sync….
12. Android JVM Backend Jetty / Netty WAR Ktor / Spring WAR WAR WAR Roughly
 VS
13. My First Server
14. Respond Text
15. Respond… JSON?
16. Content Negotiation
17. Content Negotiation
19. Getting Parameters
20. Features (Middleware)
21. Firefox Account • Internal only— Coming soon! API DOC • OAuth 2.0 (authentication grand type) • authorization • token • profile
22. Ktor Auth (Oauth)
23. Ktor Auth (Oauth)
24. Retrofit :)
25. Architecture (MVC) • RSS API
26. Routing HelloRoute.kt
27. Architecture (Route)
 https://developer.mozilla.org/en-US/docs/Learn/Server-side/Express_Nodejs/routes •
28. Route VS Controller
29. Google App Engine • Build highly scalable applications on a fully managed serverless platform • Java 8 + Jetty9 • Java 11 (Beta)+Netty • Sample: Mobile app backend services • UnderstandApp Engine Gradle plugin will help your deployment
30. Google App Engine
31. Ktor on App Engine • Follow the document Follow Ktor Doc
32. Add GAE Manually(1)
33. Add GAE Manually(2)
34. Ktor Good Read • Mobile Backends (IO 2019)
 https://www.youtube.com/watch? v=zjWOMBdPbsI&t=517s • KotlinConf Ryan Harter 
 https://www.youtube.com/watch?v=V4PS3IjIzlw
35. Exception Handling[link]
36. • Don’t make exception a part of your business logic • Don’t abuse GlobalExceptionHandler • Use standard Exception • Kotlin doesn’t have checked exception • Cleaner code • Need to look into library method that throws Exception Handling[link]
37. Exception Handling • Don’t make exception a part of your business logic • Don’t abuse GlobalExceptionHandler • Use standard Exception • Kotlin doesn’t have checked exception • Cleaner code • Need to look into library method that throws
38. Armeria • HTTP/2 RPC/REST client/ server library • built on top of Java 8, Netty, Thrift and gRPC https://www.youtube.com/ watch?v=hLlctum1pIA
39. Annotation Use-site Targets •
53. Ktor Route Creation • Extension functions
54. Ktor Route Creation • Extension
55. Ktor Route Creation • Extension Configure
56. Spring Controller Creation
57. Spring Handling Request
58. Ktor Handling Request
59. Android v.s. Backend
60. Memory • Android: MB • Backend: G
61. Lifecycle • Android: Killed • Backend: Scale
62. Boot up time • Android: First Lunch • Backed: Affect scaling
63. Thread • Android: 1+ • Backed: 100+
64. Error Handling • Android: UncaughtExceptionHandler (Less) • Backed: Global Exception Handler (Often)
65. Good libraries • Guava Cache
66. (Android Dev)->Backend Dev Diff Same Memory IoC Lifecycle Testing Boot up time Application Context Error Handling Libraries SRE / Cloud Infra
67. GCP Training • https://cloud.google.com/training/
68. GCP Training • https://cloud.google.com/training/
69. Take away • Ktor • Introduction • Request / Respond • Features • Firefox Account • Architecture • Deploy to Google App Engine • Backend development for Android dev • Exception Handling • Annotation Use-site Targets • Final / Nullable • Spring / Armeria / Ktor
70. Suggestions… • Use Ktor GAE samples • Use Groovy Gradle build script for now • Be careful fo Intellij 2019.2 (don’t touch offline mode!)
71. Mozilla Tech Speaker • https://wiki.mozilla.org/TechSpeakers
72. Thank you! @chennevin