Full-stack Kotlin in one deploy

It assumes you have deployed a single server before. If not, start with Deploy a Ktor server.

The project

shop/
├── gradlew
├── settings.gradle.kts
├── gradle.properties
├── api/            Ktor server: the public API
├── admin/          Ktor server: an internal admin tool
├── composeApp/     Compose Multiplatform: wasmJs web app
└── androidApp/     Android app

settings.gradle.kts includes every module:

include(":api", ":admin", ":composeApp", ":androidApp")

Each module only needs its usual Gradle setup. See Ktor servers, Web apps and Android apps for what the platform looks for.

Pick the primary server

Both :api and :admin are Ktor servers at the same depth. Without a setting, :admin would get the bare host, because it comes first in alphabetical order. Put :api there instead, in gradle.properties:

atoll.primary=:api

See The primary module.

Tell the web app where the API is

The web app is static: it learns the API URL when it is built. Set a build-only variable:

atoll env set API_URL=https://shop.atoll.app --no-runtime --project shop

Then read it in composeApp/build.gradle.kts and turn it into a constant, for example with a small generated source:

val apiUrl = providers.environmentVariable("API_URL").orElse("http://localhost:8080")

val generateConfig by tasks.registering {
    val out = layout.buildDirectory.dir("generated/config")
    val url = apiUrl
    outputs.dir(out)
    doLast {
        val file = out.get().file("Config.kt").asFile
        file.parentFile.mkdirs()
        file.writeText("const val API_URL = \"${url.get()}\"\n")
    }
}

kotlin {
    sourceSets.commonMain {
        kotlin.srcDir(generateConfig)
    }
}

The web app and the API are on different hosts, so the API needs Ktor’s CORS plugin to allow requests from the web app’s host.

Deploy

atoll deploy --name shop

Deployment 3c9e41a0-5d2b-4f7e-9a61-0b8d2c7e4f15 READY

  KTOR     :api         READY  primary  https://shop.atoll.app/
  KTOR     :admin       READY           https://shop--admin.atoll.app/
  WEB      :composeApp  READY  primary  https://shop-web.atoll.app/
  ANDROID  :androidApp  READY
      note: Debug build: for a signed release APK and App Bundle, set ANDROID_KEYSTORE_BASE64, ANDROID_KEYSTORE_PASSWORD, ANDROID_KEY_ALIAS, ANDROID_KEY_PASSWORD in the project's build env vars.
      androidApp-debug.apk (6.1 MB)  https://atoll.example.com/api/deployments/3c9e41a0-…/artifacts/androidApp-debug.apk

All four targets build in one deployment. If one fails, the others still go live and the deployment is PARTIAL.

Previews with their own API

When you link the repository, every pull request gets a preview with its own hosts. Point the preview web app at a preview-safe API by setting API_URL for the preview environment:

atoll env set API_URL=https://staging-api.example.com --env preview --no-runtime --project shop

Add your domains

atoll domains add api.shop.example --project shop
atoll domains add shop.example --web --project shop

Then update API_URL to the new API domain and deploy again. See Custom domains.

​The project

​Pick the primary server

​Tell the web app where the API is

​Deploy

​Previews with their own API

​Add your domains