AppEngine に Ktor アプリをデプロイする

1. Google Cloud SDK をインストールする

https://cloud.google.com/sdk/docs/install

2. 認証 & プロジェクト選択

> gcloud init

3. Ktor アプリを作る

IntelliJ IDEA に Ktor plugin を入れて、New Project wizard から Ktor プロジェクトを作る

4. AppEngine の設定を追加する

build.gradle.kts ... plugins { ... // ↓ 追加 id("com.google.cloud.tools.appengine") version "2.2.0" // ↓ 追加 war } ... dependencies { ... // ↓ 追加 implementation("io.ktor:ktor-server-servlet:$ktor_version") // ↓ 追加 compileOnly("com.google.appengine:appengine:$appengine_version") } // ↓ 追加 appengine { deploy { projectId = "GCLOUD_CONFIG" version = "GCLOUD_CONFIG" } } // ↓ 追加 tasks.named("run") { dependsOn(":appengineRun") } settings.gradle.kts ... // https://stackoverflow.com/questions/48502220/how-to-configure-appengine-gradle-plugin-using-kotlin-dsl/48510049#48510049 // ↓ 追加 pluginManagement { repositories { gradlePluginPortal() google() } resolutionStrategy { eachPlugin { if (requested.id.id == "com.google.cloud.tools.appengine") { useModule("com.google.cloud.tools:appengine-gradle-plugin:${requested.version}") } } } } src/main/webapp/WEB-INF/web.xml <?xml version="1.0" encoding="ISO-8859-1" ?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <!-- path to application.conf file, required --> <!-- note that this file is always loaded as an absolute path from the classpath --> <context-param> <param-name>io.ktor.ktor.config</param-name> <param-value>application.conf</param-value> </context-param> <servlet> <display-name>KtorServlet</display-name> <servlet-name>KtorServlet</servlet-name> <servlet-class>io.ktor.server.servlet.ServletApplicationEngine</servlet-class> <!-- required! --> <async-supported>true</async-supported> <!-- 100mb max file upload, optional --> <multipart-config> <max-file-size>304857600</max-file-size> <max-request-size>304857600</max-request-size> <file-size-threshold>0</file-size-threshold> </multipart-config> </servlet> <servlet-mapping> <servlet-name>KtorServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app> src/main/webapp/WEB-INF/appengine-web.xml <?xml version="1.0" encoding="utf-8"?> <appengine-web-app xmlns="http://appengine.google.com/ns/1.0"> <threadsafe>true</threadsafe> <runtime>java8</runtime> </appengine-web-app>

5. ローカルで実行する

> ./gradlew appengineRun // 止めるとき > ./gradlew appengineStop

6. デプロイする

> ./gradlew appengineDeploy


参考

• Run a Kotlin Ktor app on App Engine standard environment （注 Groovy なのとちょっと内容が古いです。（2021/3/9現在））
• https://ktor.io/docs/war.html （web.xml の設定)
• https://ktor.io/docs/google-app-engine.html
• https://github.com/ktorio/ktor-documentation/tree/main/codeSnippets/snippets/google-appengine-standard