From 62c924c4ab2f84ab08f257e72789701afcd81925 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Pedro=20Correia?=
 <jose.pedrocorreia@promptlyhealth.com>
Date: Tue, 23 Sep 2025 08:38:01 +0100
Subject: [PATCH] Add liveness and readiness probes

---
 .../resources/static-content/openapi.yml      | 35 +++++++++++++++++++
 src/jvmMain/kotlin/Module.kt                  |  2 ++
 .../kotlin/controller/health/HealthModule.kt  | 25 +++++++++++++
 .../ValidationServiceFactoryImpl.kt           | 23 ++++++------
 .../validation/ValidationServiceStatus.kt     | 14 ++++++++
 5 files changed, 88 insertions(+), 11 deletions(-)
 create mode 100644 src/jvmMain/kotlin/controller/health/HealthModule.kt
 create mode 100644 src/jvmMain/kotlin/controller/validation/ValidationServiceStatus.kt

diff --git a/src/commonMain/resources/static-content/openapi.yml b/src/commonMain/resources/static-content/openapi.yml
index c6f993c..347b121 100644
--- a/src/commonMain/resources/static-content/openapi.yml
+++ b/src/commonMain/resources/static-content/openapi.yml
@@ -184,6 +184,41 @@ paths:
             application/json:
               schema:
                 $ref: "#/components/schemas/packageServerStatus"
+  /health/ready:
+    get:
+      tags:
+        - Health
+      description: "Readiness probe. Returns 200 OK if all presets have been loaded and the validation service is ready, otherwise returns 503."
+      operationId: healthReady
+      responses:
+        "200":
+          description: OK
+          content:
+            text/plain:
+              schema:
+                type: string
+                example: OK
+        "503":
+          description: Service Unavailable
+          content:
+            text/plain:
+              schema:
+                type: string
+                example: ValidationService not ready
+  /health/live:
+    get:
+      tags:
+        - Health
+      description: "Liveness probe. Always returns OK if the service is running."
+      operationId: healthLive
+      responses:
+        "200":
+          description: OK
+          content:
+            text/plain:
+              schema:
+                type: string
+                example: OK
 
 
 components:
diff --git a/src/jvmMain/kotlin/Module.kt b/src/jvmMain/kotlin/Module.kt
index 0ed4a07..32d8216 100644
--- a/src/jvmMain/kotlin/Module.kt
+++ b/src/jvmMain/kotlin/Module.kt
@@ -1,5 +1,6 @@
 import io.ktor.serialization.gson.*
 import controller.debug.debugModule
+import controller.health.healthModule
 import controller.ig.igModule
 import controller.terminology.terminologyModule
 import controller.uptime.uptimeModule
@@ -96,6 +97,7 @@ fun Application.setup() {
         validationModule()
         terminologyModule()
         uptimeModule()
+        healthModule()
 
         get("/") {
             call.respondText(
diff --git a/src/jvmMain/kotlin/controller/health/HealthModule.kt b/src/jvmMain/kotlin/controller/health/HealthModule.kt
new file mode 100644
index 0000000..33829c8
--- /dev/null
+++ b/src/jvmMain/kotlin/controller/health/HealthModule.kt
@@ -0,0 +1,25 @@
+package controller.health
+
+import controller.validation.ValidationServiceStatus
+import io.ktor.server.application.*
+import io.ktor.server.response.*
+import io.ktor.server.routing.*
+import io.ktor.http.*
+
+fun Route.healthModule() {
+    route("/health/ready") {
+        get {
+            if (ValidationServiceStatus.isReady()) {
+                call.respond(HttpStatusCode.OK, "OK")
+            } else {
+                call.respond(HttpStatusCode.ServiceUnavailable, "ValidationService not ready")
+            }
+        }
+    }
+
+    route("/health/live") {
+        get {
+            call.respond(HttpStatusCode.OK, "OK")
+        }
+    }
+}
diff --git a/src/jvmMain/kotlin/controller/validation/ValidationServiceFactoryImpl.kt b/src/jvmMain/kotlin/controller/validation/ValidationServiceFactoryImpl.kt
index 8bad155..e451c1f 100644
--- a/src/jvmMain/kotlin/controller/validation/ValidationServiceFactoryImpl.kt
+++ b/src/jvmMain/kotlin/controller/validation/ValidationServiceFactoryImpl.kt
@@ -30,18 +30,19 @@ class ValidationServiceFactoryImpl : ValidationServiceFactory {
         val validationService =
             ValidationService(sessionCache);
         thread {
-        presets.forEach {
-            if (it.key != "CUSTOM") {
-                println("Loading preset: " + it.key)
-                try {
-                    validationService.putBaseEngine(it.key, it.validationContext)
-                } catch (e: Exception) {
-                    println("Error loading preset: " + it.key)
-                    e.printStackTrace()
+            presets.forEach {
+                if (it.key != "CUSTOM") {
+                    println("Loading preset: " + it.key)
+                    try {
+                        validationService.putBaseEngine(it.key, it.validationContext)
+                    } catch (e: Exception) {
+                        println("Error loading preset: " + it.key)
+                        e.printStackTrace()
+                    }
+                    println("Preset loaded: " + it.key);
                 }
-                println("Preset loaded: " + it.key);
             }
-        }
+            ValidationServiceStatus.setService(validationService)
         }
         return validationService
     }
@@ -71,7 +72,7 @@ class ValidationServiceFactoryImpl : ValidationServiceFactory {
         return Collections.unmodifiableList(presets)
     }
 
-    override fun getValidationService() : ValidationService {
+    override fun getValidationService(): ValidationService {
         if (java.lang.Runtime.getRuntime().freeMemory() < validationServiceConfig.engineReloadThreshold) {
             println(
                 "Free memory ${
diff --git a/src/jvmMain/kotlin/controller/validation/ValidationServiceStatus.kt b/src/jvmMain/kotlin/controller/validation/ValidationServiceStatus.kt
new file mode 100644
index 0000000..d17bb53
--- /dev/null
+++ b/src/jvmMain/kotlin/controller/validation/ValidationServiceStatus.kt
@@ -0,0 +1,14 @@
+package controller.validation
+
+import org.hl7.fhir.validation.service.ValidationService
+import java.util.concurrent.atomic.AtomicReference
+
+object ValidationServiceStatus {
+    private val serviceRef = AtomicReference<ValidationService?>(null)
+
+    fun setService(service: ValidationService) {
+        serviceRef.set(service)
+    }
+
+    fun isReady(): Boolean = serviceRef.get() != null
+}