merge(01-05): server /health + Flyway + HOCON + fail-loud DB boot

server/src/main/kotlin/dev/ulfrx/recipe/Application.kt

@@ -1,20 +1,36 @@
 package dev.ulfrx.recipe
 
-import io.ktor.server.application.*
-import io.ktor.server.engine.*
-import io.ktor.server.netty.*
-import io.ktor.server.response.*
-import io.ktor.server.routing.*
+import io.ktor.serialization.kotlinx.json.json
+import io.ktor.server.application.Application
+import io.ktor.server.application.install
+import io.ktor.server.engine.embeddedServer
+import io.ktor.server.netty.Netty
+import io.ktor.server.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.server.response.respond
+import io.ktor.server.routing.get
+import io.ktor.server.routing.routing
+import kotlinx.serialization.Serializable
 
 fun main() {
     embeddedServer(Netty, port = SERVER_PORT, host = "0.0.0.0", module = Application::module)
         .start(wait = true)
 }
 
+@Serializable
+private data class Health(val status: String)
+
 fun Application.module() {
+    install(ContentNegotiation) {
+        json()
+    }
+    Database.migrate(this)
+    configureRouting()
+}
+
+fun Application.configureRouting() {
     routing {
-        get("/") {
-            call.respondText("Ktor: ${Greeting().greet()}")
+        get("/health") {
+            call.respond(Health(status = "ok"))
         }
     }
-}
+}

server/src/main/kotlin/dev/ulfrx/recipe/Database.kt

@@ -0,0 +1,31 @@
+package dev.ulfrx.recipe
+
+import io.ktor.server.application.Application
+import org.flywaydb.core.Flyway
+import org.slf4j.LoggerFactory
+
+object Database {
+    private val log = LoggerFactory.getLogger(Database::class.java)
+
+    fun migrate(app: Application) {
+        val url = app.environment.config.property("database.url").getString()
+        val user = app.environment.config.property("database.user").getString()
+        val password = app.environment.config.property("database.password").getString()
+
+        log.info("Connecting to {} as {} and running Flyway migrations", url, user)
+
+        runCatching {
+            Flyway.configure()
+                .dataSource(url, user, password)
+                .locations("classpath:db/migration")
+                .baselineOnMigrate(true)
+                .validateOnMigrate(true)
+                .cleanDisabled(true)
+                .load()
+                .migrate()
+        }.onFailure { ex ->
+            log.error("Flyway migration failed — cannot start server", ex)
+            throw IllegalStateException("Database unreachable or migration failed", ex)
+        }
+    }
+}

server/src/main/resources/application.conf

@@ -0,0 +1,18 @@
+ktor {
+    deployment {
+        port = 8080
+        port = ${?PORT}
+    }
+    application {
+        modules = [ dev.ulfrx.recipe.ApplicationKt.module ]
+    }
+}
+
+database {
+    url = "jdbc:postgresql://localhost:5432/recipe"
+    url = ${?DATABASE_URL}
+    user = "recipe"
+    user = ${?DATABASE_USER}
+    password = "recipe"
+    password = ${?DATABASE_PASSWORD}
+}

server/src/test/kotlin/dev/ulfrx/recipe/ApplicationTest.kt

@@ -1,20 +1,30 @@
 package dev.ulfrx.recipe
 
-import io.ktor.client.request.*
-import io.ktor.client.statement.*
-import io.ktor.http.*
-import io.ktor.server.testing.*
-import kotlin.test.*
+import io.ktor.client.request.get
+import io.ktor.client.statement.bodyAsText
+import io.ktor.http.HttpStatusCode
+import io.ktor.serialization.kotlinx.json.json
+import io.ktor.server.application.install
+import io.ktor.server.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.server.testing.testApplication
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 class ApplicationTest {
 
     @Test
-    fun testRoot() = testApplication {
+    fun `health endpoint returns 200 with status ok`() = testApplication {
         application {
-            module()
+            install(ContentNegotiation) {
+                json()
+            }
+            configureRouting()
         }
-        val response = client.get("/")
+        val response = client.get("/health")
         assertEquals(HttpStatusCode.OK, response.status)
-        assertEquals("Ktor: ${Greeting().greet()}", response.bodyAsText())
+        val body = response.bodyAsText()
+        assertTrue(body.contains("\"status\""), "expected body to contain status field, was: $body")
+        assertTrue(body.contains("\"ok\""), "expected body to contain ok value, was: $body")
     }
-}
+}