chore: initial commit

Signed-off-by: Alan Brault <alan.brault@visus.io>

src/main/kotlin/io/visus/demos/kotlinapi/controller/HealthController.kt

@@ -0,0 +1,63 @@
+package io.visus.demos.kotlinapi.controller
+
+import io.swagger.v3.oas.annotations.Operation
+import io.swagger.v3.oas.annotations.media.Content
+import io.swagger.v3.oas.annotations.media.Schema
+import io.swagger.v3.oas.annotations.responses.ApiResponse
+import io.swagger.v3.oas.annotations.tags.Tag
+import io.visus.demos.kotlinapi.api.dto.HealthResponse
+import io.visus.demos.kotlinapi.domain.model.HealthStatus
+import io.visus.demos.kotlinapi.domain.model.Status
+import io.visus.demos.kotlinapi.domain.service.HealthService
+import org.springframework.http.HttpStatus
+import org.springframework.http.MediaType
+import org.springframework.http.ResponseEntity
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RestController
+
+@RestController
+@Tag(name = "Health", description = "Health check endpoints")
+class HealthController(
+    private val healthCheckServices: List<HealthService>,
+) {
+    @GetMapping("/health", produces = [MediaType.APPLICATION_JSON_VALUE])
+    @Operation(
+        summary = "Health check",
+        description = "Returns the health status of the API",
+        responses = [
+            ApiResponse(
+                responseCode = "200",
+                description = "API is healthy",
+                content = [
+                    Content(
+                        mediaType = MediaType.APPLICATION_JSON_VALUE,
+                        schema = Schema(implementation = HealthResponse::class),
+                    ),
+                ],
+            ),
+            ApiResponse(
+                responseCode = "503",
+                description = "API is down or degraded",
+                content = [
+                    Content(
+                        mediaType = MediaType.APPLICATION_JSON_VALUE,
+                        schema = Schema(implementation = HealthResponse::class),
+                    ),
+                ],
+            ),
+        ],
+    )
+    fun health(): ResponseEntity<HealthResponse> {
+        val componentHealths = healthCheckServices.map { it.check() }
+        val healthStatus = HealthStatus.fromComponents(componentHealths)
+        val response = HealthResponse.from(healthStatus)
+
+        val httpStatus =
+            when (healthStatus.status) {
+                Status.UP -> HttpStatus.OK
+                Status.DOWN, Status.DEGRADED -> HttpStatus.SERVICE_UNAVAILABLE
+            }
+
+        return ResponseEntity.status(httpStatus).body(response)
+    }
+}