Extract database health check

src/main/kotlin/de/ruvnox/tactical/Database.kt

@@ -0,0 +1,68 @@
+package de.ruvnox.tactical
+
+import java.sql.Connection
+import java.sql.DriverManager
+import kotlin.system.measureTimeMillis
+
+data class DatabaseConfig(
+    val host: String,
+    val port: Int,
+    val name: String,
+    val user: String,
+    val password: String
+)
+
+data class DatabaseCheckResult(
+    val status: String,
+    val host: String,
+    val port: Int,
+    val name: String,
+    val latencyMs: Long?
+)
+
+object Database {
+    fun configFromEnvironment(): DatabaseConfig {
+        return DatabaseConfig(
+            host = System.getenv("DB_HOST") ?: "unset",
+            port = System.getenv("DB_PORT")?.toIntOrNull() ?: 5432,
+            name = System.getenv("DB_NAME") ?: "unset",
+            user = System.getenv("DB_USER") ?: "",
+            password = System.getenv("DB_PASSWORD") ?: ""
+        )
+    }
+
+    fun connection(config: DatabaseConfig = configFromEnvironment()): Connection {
+        return DriverManager.getConnection(
+            "jdbc:postgresql://${config.host}:${config.port}/${config.name}",
+            config.user,
+            config.password
+        )
+    }
+
+    fun check(): DatabaseCheckResult {
+        val config = configFromEnvironment()
+        var ok = false
+
+        val latency = try {
+            measureTimeMillis {
+                connection(config).use { connection ->
+                    connection.createStatement().use { statement ->
+                        statement.executeQuery("select 1").use { result ->
+                            ok = result.next()
+                        }
+                    }
+                }
+            }
+        } catch (_: Exception) {
+            null
+        }
+
+        return DatabaseCheckResult(
+            status = if (ok) "online" else "offline",
+            host = config.host,
+            port = config.port,
+            name = config.name,
+            latencyMs = latency
+        )
+    }
+}

src/main/kotlin/de/ruvnox/tactical/Main.kt

@@ -13,7 +13,6 @@ import io.ktor.server.routing.routing
 import io.ktor.serialization.kotlinx.json.json
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.Json
-import java.sql.DriverManager
 
 @Serializable
 data class ServiceStatusResponse(
@@ -28,7 +27,8 @@ data class DatabaseStatusResponse(
     val status: String,
     val host: String,
     val port: Int,
-    val name: String
+    val name: String,
+    val latencyMs: Long?
 )
 
 fun main() {
@@ -83,32 +83,13 @@ fun Application.module() {
 }
 
 fun checkDatabaseStatus(): DatabaseStatusResponse {
-    val dbHost = System.getenv("DB_HOST") ?: "unset"
-    val dbPort = System.getenv("DB_PORT")?.toIntOrNull() ?: 5432
-    val dbName = System.getenv("DB_NAME") ?: "unset"
-    val dbUser = System.getenv("DB_USER") ?: ""
-    val dbPassword = System.getenv("DB_PASSWORD") ?: ""
-
-    val status = try {
-        DriverManager.getConnection(
-            "jdbc:postgresql://$dbHost:$dbPort/$dbName",
-            dbUser,
-            dbPassword
-        ).use { connection ->
-            connection.createStatement().use { statement ->
-                statement.executeQuery("select 1").use { result ->
-                    if (result.next()) "online" else "error"
-                }
-            }
-        }
-    } catch (_: Exception) {
-        "offline"
-    }
+    val result = Database.check()
 
     return DatabaseStatusResponse(
-        status = status,
-        host = dbHost,
-        port = dbPort,
-        name = dbName
+        status = result.status,
+        host = result.host,
+        port = result.port,
+        name = result.name,
+        latencyMs = result.latencyMs
     )
 }