Feat: Add health check endpoints

Signed-off-by: Jordan Hall <[email protected]>

kafkakewl-deploy/src/main/scala/com/mwam/kafkakewl/deploy/endpoints/Endpoints.scala

@@ -18,18 +18,33 @@ class Endpoints(
 ) {
   private val metricsEndpoint: PublicEndpoint[Unit, Unit, String, Any] = endpoint.in("metrics").get.out(stringBody)
 
+  // Health check endpoints. As of now, just return 200 no preparation is done
+  // after the HTTP server starts.
+  private val livenessEndpoint: PublicEndpoint[Unit, Nothing, Unit, Any] =
+    infallibleEndpoint.in("health").in("live").get
+  private val readinessEndpoint: PublicEndpoint[Unit, Nothing, Unit, Any] =
+    infallibleEndpoint.in("health").in("ready").get
+  private val startupProbeEndpoint: PublicEndpoint[Unit, Nothing, Unit, Any] =
+    infallibleEndpoint.in("health").in("startup").get
+
   val endpoints: List[ZServerEndpoint[Any, Any]] = {
     val api = deploymentServerEndpoints.endpoints
     val docs = docsEndpoints(api)
     val metrics = List(metricsEndpoint.zServerLogic[Any](_ => getMetrics))
-    api ++ docs ++ metrics
+    val health =
+      List(livenessEndpoint, readinessEndpoint, startupProbeEndpoint)
+        .map(
+          _.zServerLogic[Any](_ => ZIO.succeed(()))
+        )
+    api ++ docs ++ metrics ++ health
   }
 
   private def docsEndpoints(apiEndpoints: List[ZServerEndpoint[Any, Any]]): List[ZServerEndpoint[Any, Any]] = SwaggerInterpreter()
     .fromServerEndpoints[Task](apiEndpoints, "kafkakewl-deploy", "1.0.0")
 
   private def getMetrics: ZIO[Any, Unit, String] =
     prometheusPublisher.get // TODO this adds the timestamp as well which isn't desirable due to prometheus's staleness handling
+
 }
 
 object Endpoints {