在這場分享裡，將示範如何用 Kotlin 程式語言及 Ktor 框架，快速打造一個 API Mocking 的 Backend Application，並整合 Google Cloud Platform 上的 Cloud Build、Container Registry、Cloud Run 等服務完成一個完整的 CI/CD 開發流程。

1. otlin
Mobile Backend
—
(shengyou)
MOPCON 2020 Unconference
2020/10/25

2. —
• Developer Advocate
• Backend Developer
• Open Source Community Organizer

3. • General-purpose
• Static typing
• OOP + FP
• Developed by
JetBrains
• Open Source
(Apache 2.0)
https://kotlinlang.org/
Kotlin
Programing Language
—

4. Kotlin Multiplatform
—
Browser
Kotlin/JS
Server
Kotlin/JVM
iOS
Kotlin/Native
Android
Kotlin/JVM

5. Ktor Framework
—
https://ktor.io/
• Web Framework
• Asynchronous
• Servers + Clients
• Developed by
JetBrains
• Open Source
(Apache 2.0)

6. —
• Ktor
• Feature
• Routing
• Response JSON
• Application Call
• Deployment
•

7. —
Develop Build/Pack Upload/Store Host

8. Ktor
—
https://plugins.jetbrains.com/plugin/10823-ktor

9. Ktor Feature
—
Client
Ktor App
HTTP Server
Feature
Feature
Feature

10. —
// gradle.properties
jackson_version=1.0.1
javafaker_version=2.10.5
// build.gradle
dependencies {
//...
implementation "io.ktor:ktor-jackson:$version"
implementation "com.github.javafaker:javafaker:$version"
implementation "joda-time:joda-time:$version"
}

11. Feature
—
install(ContentNegotiation) {
jackson {
}
}

12. —
data class Contact(
)
{
"data": [
{
},
// ...
]
}

13. —
data class Contact(
val id: Long?,
)
{
"data": [
{
"id": 1,
},
// ...
]
}

14. —
data class Contact(
val id: Long?,
val name: String,
val email: String,
val mobile: String,
val address: String,
)
{
"data": [
{
"id": 1,
"name": "...",
"email": "...",
"mobile": "...",
"address": "...",
},
// ...
]
}

15. —
data class Contact(
val id: Long?,
val name: String,
val email: String,
val mobile: String,
val address: String,
val createdAt: String,
val updatedAt: String,
)
{
"data": [
{
"id": 1,
"name": "...",
"email": "...",
"mobile": "...",
"address": "...",
"createdAt": "yyyy-MM-dd HH:mm:ss",
"updatedAt": "yyyy-MM-dd HH:mm:ss"
},
// ...
]
}

16. Routing
—
routing {
get("/") {
call.respondText("Hello, Ktor")
}
}

17. Application Call
—
Server
Database
Client
Kotlin/JVM

18. JSON
a.k.a API Mocking
—
val faker = Faker(Locale("..."))
val contacts = mutableListOf<Contact>()
for (i in 1..10) {
contacts.add(Contact(
id = i.toLong(),
name = faker.name().fullName(),
email = faker.internet().emailAddress(),
mobile = faker.phoneNumber().cellPhone(),
address = faker.address().fullAddress(),
createdAt = DateTime.now().toString("yyyy-MM-dd HH:mm:ss"),
updatedAt = DateTime.now().toString("yyyy-MM-dd HH:mm:ss")
))
}
call.respond(mapOf("data" to contacts))

19. Jib
—
More on: https://github.com/GoogleContainerTools/jib
1.Apply the plugin
// build.gradle
plugins {
id 'com.google.cloud.tools.jib' version '2.6.0'
}
2.Run the command
$ gradle jib --image=<MY IMAGE>
Steps:

20. Behind the Jib
—
Video source: https://www.youtube.com/watch?v=H6gR_Cv4yWI
Build containers faster with Jib, a Google image build tool for Java applications

21. CI/CD
—
Cloud Build
Container Registry
Cloud Run
Trigger

22. CI/CD
—
Cloud Build
Container Registry
Cloud Run
Trigger
Push

23. CI/CD
—
Cloud Build
Container Registry
Cloud Run
Trigger
Push
Trigger

24. CI/CD
—
Cloud Build
Container Registry
Cloud Run
Trigger
Push
Trigger
Pull

25. CI/CD
—
Cloud Build
Container Registry
Cloud Run
Trigger
Push
Trigger
Pull
Serve

26. CI/CD
—
Cloud Build
Container Registry
Cloud Run
Trigger
Push
Trigger
Pull
Serve

27. cloudbuild.yaml
—
steps:
# Uses the Cloud Builders Gradle image.
- name: 'gcr.io/cloud-builders/gradle'
args:
# Uncomment for projects that do not include Jib as a plugin.
- '--init-script=auto-jib.gradle'
# Runs the Jib build.
# For advanced customizations, configure the plugin in the build.gradle.
- 'jib'
# Sets the target image reference to push to.
- '--image=gcr.io/${_PROJECT}/${_IMAGE}'

28. auto-jib.gradle
—
// Gradle init script that applies the Jib Gradle plugin.
initscript {
repositories {
maven {
url 'https://plugins.gradle.org/m2'
}
}
dependencies {
classpath 'gradle.plugin.com.google.cloud.tools:jib-gradle-plugin:+'
}
}
// Only applies the Jib plugin if the project does not apply it already.
rootProject {
afterEvaluate {
if (!project.plugins.hasPlugin('com.google.cloud.tools.jib')) {
project.apply plugin: com.google.cloud.tools.jib.gradle.JibPlugin
tasks.jib.dependsOn classes
}
}
}

29. cloudbuild.yaml
—
steps:
# Uses the Cloud Builders Gradle image.
...
# Deploy an image from Container Registry to Cloud Run
- name: 'gcr.io/google.com/cloudsdktool/cloud-sdk'
entrypoint: gcloud
args:
- 'run'
- 'deploy'
- '${_SERVICE}'
- '--image'
- 'gcr.io/${_PROJECT}/${_IMAGE}'
- '--region'
- '${_REGION}'
- '--platform'
- 'managed'
- '--allow-unauthenticated'

30. Google Cloud
—

31. —
Develop Build/Pack HostUpload/Store

32. —
Develop Build/Pack Host
Kotlin + Ktor
Upload/Store

33. —
Develop Build/Pack Host
Kotlin + Ktor Cloud Build Container Registry
Upload/Store

34. —
Develop Build/Pack Host
Kotlin + Ktor Cloud Build Container Registry Cloud Run
Upload/Store

35. —
• Kotlin + Ktor API Mocking
• Container Ktor App
• API
• Kotlin

36. kotlin.tips
Kotlin
—

37. Shengyou Fan ( )
shengyou.fan@jetbrains.com
Q&A
—
otlin
Mobile Backend