Remove Ratpack dependency for HV-VES health checks

In order to minimize complexity and possibly improve performance (thread count)
reactor-netty should be used instead of Ratpack. Also reorganize code to
be more consistent and differentiated readiness and liveness endpoints
(for future use in K8s Pod definition).

As an example I've defined health check probe in docker-compose YAML.

Change-Id: I1b5ce3d685e7ae5b0515b2146ae4fa88b3b41186
Issue-ID: DCAEGEN2-705
Signed-off-by: Piotr Jaszczyk <piotr.jaszczyk@nokia.com>

8 files changed, 128 insertions, 91 deletions

diff --git a/hv-collector-health-check/pom.xml b/hv-collector-health-check/pom.xml
index 1e77adb0..09515879 100644
--- a/hv-collector-health-check/pom.xml
+++ b/hv-collector-health-check/pom.xml
@@ -50,8 +50,8 @@
             <artifactId>kotlin-stdlib-jdk8</artifactId>
         </dependency>
         <dependency>
-            <groupId>io.ratpack</groupId>
-            <artifactId>ratpack-core</artifactId>
+            <groupId>io.projectreactor.ipc</groupId>
+            <artifactId>reactor-netty</artifactId>
         </dependency>
         <dependency>
             <groupId>io.arrow-kt</groupId>
diff --git a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthCheckApiServer.kt b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthCheckApiServer.kt
deleted file mode 100644
index b21d1871..00000000
--- a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthCheckApiServer.kt
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * ============LICENSE_START=======================================================
- * dcaegen2-collectors-veshv
- * ================================================================================
- * Copyright (C) 2018 NOKIA
- * ================================================================================
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- * ============LICENSE_END=========================================================
- */
-package org.onap.dcae.collectors.veshv.healthcheck.api
-
-import arrow.effects.IO
-import ratpack.handling.Chain
-import ratpack.server.RatpackServer
-import ratpack.server.ServerConfig
-import java.util.concurrent.atomic.AtomicReference
-
-/**
- * @author Jakub Dudycz <jakub.dudycz@nokia.com>
- * @since August 2018
- */
-class HealthCheckApiServer(private val healthStateProvider: HealthStateProvider) {
-
-    private val healthState: AtomicReference<HealthState> = AtomicReference(HealthState.STARTING)
-
-    fun start(port: Int): IO<RatpackServer> = IO {
-        healthStateProvider().subscribe(healthState::set)
-        RatpackServer
-                .start {
-                    it
-                            .serverConfig(ServerConfig.embedded().port(port).development(false))
-                            .handlers(this::configureHandlers)
-                }
-    }
-
-    private fun configureHandlers(chain: Chain) {
-        chain
-                .get("healthcheck") { ctx ->
-                    healthState.get().run {
-                        ctx.response.status(responseCode).send(message)
-                    }
-                }
-    }
-}
\ No newline at end of file
diff --git a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthStateProvider.kt b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthDescription.kt
index 5cc09ccc..8c69406c 100644
--- a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthStateProvider.kt
+++ b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthDescription.kt
@@ -19,21 +19,14 @@
  */
 package org.onap.dcae.collectors.veshv.healthcheck.api
 
-import org.onap.dcae.collectors.veshv.healthcheck.impl.HealthStateProviderImpl
-import reactor.core.publisher.Flux
 
 /**
  * @author Jakub Dudycz <jakub.dudycz@nokia.com>
  * @since August 2018
  */
-interface HealthStateProvider {
-
-    operator fun invoke(): Flux<HealthState>
-    fun changeState(healthState: HealthState)
-
-    companion object {
-        val INSTANCE: HealthStateProvider by lazy {
-            HealthStateProviderImpl()
-        }
-    }
+enum class HealthDescription(val message: String, val status: HealthStatus) {
+    HEALTHY("Healthy", HealthStatus.UP),
+    STARTING("Collector is starting", HealthStatus.OUT_OF_SERVICE),
+    RETRYING_FOR_CONSUL_CONFIGURATION("Consul configuration not available. Retrying.", HealthStatus.OUT_OF_SERVICE),
+    CONSUL_CONFIGURATION_NOT_FOUND("Consul configuration not found", HealthStatus.DOWN)
 }
diff --git a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthState.kt b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthState.kt
index 3dddf1e7..853cc00f 100644
--- a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthState.kt
+++ b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthState.kt
@@ -19,16 +19,21 @@
  */
 package org.onap.dcae.collectors.veshv.healthcheck.api
 
-import org.onap.dcae.collectors.veshv.utils.http.Status.Companion.OK
-import org.onap.dcae.collectors.veshv.utils.http.Status.Companion.SERVICE_UNAVAILABLE
+import org.onap.dcae.collectors.veshv.healthcheck.impl.HealthStateImpl
+import reactor.core.publisher.Flux
 
 /**
  * @author Jakub Dudycz <jakub.dudycz@nokia.com>
  * @since August 2018
  */
-enum class HealthState(val message: String, val responseCode: Int) {
-    HEALTHY("Healthy", OK),
-    STARTING("Collector is starting", SERVICE_UNAVAILABLE),
-    WAITING_FOR_CONSUL_CONFIGURATION("Waiting for consul configuration", SERVICE_UNAVAILABLE),
-    CONSUL_CONFIGURATION_NOT_FOUND("Consul configuration not found", SERVICE_UNAVAILABLE)
+interface HealthState {
+
+    operator fun invoke(): Flux<HealthDescription>
+    fun changeState(healthDescription: HealthDescription)
+
+    companion object {
+        val INSTANCE: HealthState by lazy {
+            HealthStateImpl()
+        }
+    }
 }
diff --git a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthStatus.kt b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthStatus.kt
new file mode 100644
index 00000000..79fc9321
--- /dev/null
+++ b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/api/HealthStatus.kt
@@ -0,0 +1,34 @@
+/*
+ * ============LICENSE_START=======================================================
+ * dcaegen2-collectors-veshv
+ * ================================================================================
+ * Copyright (C) 2018 NOKIA
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.collectors.veshv.healthcheck.api
+
+import org.onap.dcae.collectors.veshv.utils.http.Status.Companion.OK
+import org.onap.dcae.collectors.veshv.utils.http.Status.Companion.SERVICE_UNAVAILABLE
+
+/**
+ * @author Piotr Jaszczyk <piotr.jaszczyk@nokia.com>
+ * @since August 2018
+ */
+enum class HealthStatus(val httpResponseStatus: Int) {
+    UP(OK),
+    DOWN(SERVICE_UNAVAILABLE),
+    OUT_OF_SERVICE(SERVICE_UNAVAILABLE),
+    UNKNOWN(SERVICE_UNAVAILABLE)
+}
diff --git a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/factory/HealthCheckApiServer.kt b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/factory/HealthCheckApiServer.kt
new file mode 100644
index 00000000..7e9efac7
--- /dev/null
+++ b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/factory/HealthCheckApiServer.kt
@@ -0,0 +1,60 @@
+/*
+ * ============LICENSE_START=======================================================
+ * dcaegen2-collectors-veshv
+ * ================================================================================
+ * Copyright (C) 2018 NOKIA
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.collectors.veshv.healthcheck.factory
+
+import arrow.effects.IO
+import io.netty.handler.codec.http.HttpResponseStatus
+import org.onap.dcae.collectors.veshv.healthcheck.api.HealthDescription
+import org.onap.dcae.collectors.veshv.healthcheck.api.HealthState
+import org.onap.dcae.collectors.veshv.utils.NettyServerHandle
+import org.onap.dcae.collectors.veshv.utils.ServerHandle
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import reactor.ipc.netty.http.server.HttpServer
+import reactor.ipc.netty.http.server.HttpServerRequest
+import reactor.ipc.netty.http.server.HttpServerResponse
+import java.util.concurrent.atomic.AtomicReference
+
+/**
+ * @author Jakub Dudycz <jakub.dudycz@nokia.com>
+ * @since August 2018
+ */
+class HealthCheckApiServer(private val healthState: HealthState, private val port: Int) {
+
+    private val healthDescription: AtomicReference<HealthDescription> = AtomicReference(HealthDescription.STARTING)
+
+    fun start(): IO<ServerHandle> = IO {
+        healthState().subscribe(healthDescription::set)
+        val ctx = HttpServer.create(port).startRouter { routes ->
+            routes.get("/health/ready", ::readinessHandler)
+            routes.get("/health/alive", ::livenessHandler)
+        }
+        NettyServerHandle(ctx)
+    }
+
+    private fun readinessHandler(req: HttpServerRequest, resp: HttpServerResponse) =
+            healthDescription.get().run {
+                resp.status(status.httpResponseStatus).sendString(Flux.just(status.toString(), "\n", message))
+            }
+
+    private fun livenessHandler(req: HttpServerRequest, resp: HttpServerResponse) =
+                resp.status(HttpResponseStatus.NOT_IMPLEMENTED).sendString(Mono.just("Not implemented yet"))
+
+}
diff --git a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateProviderImpl.kt b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateImpl.kt
index 5056d2da..c273f0a0 100644
--- a/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateProviderImpl.kt
+++ b/hv-collector-health-check/src/main/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateImpl.kt
@@ -19,8 +19,8 @@
  */
 package org.onap.dcae.collectors.veshv.healthcheck.impl
 
-import org.onap.dcae.collectors.veshv.healthcheck.api.HealthStateProvider
 import org.onap.dcae.collectors.veshv.healthcheck.api.HealthState
+import org.onap.dcae.collectors.veshv.healthcheck.api.HealthDescription
 import reactor.core.publisher.Flux
 import reactor.core.publisher.FluxProcessor
 import reactor.core.publisher.UnicastProcessor
@@ -29,11 +29,11 @@ import reactor.core.publisher.UnicastProcessor
  * @author Jakub Dudycz <jakub.dudycz@nokia.com>
  * @since August 2018
  */
-internal class HealthStateProviderImpl : HealthStateProvider {
+internal class HealthStateImpl : HealthState {
 
-    private val healthStateStream: FluxProcessor<HealthState, HealthState> = UnicastProcessor.create()
+    private val healthDescriptionStream: FluxProcessor<HealthDescription, HealthDescription> = UnicastProcessor.create()
 
-    override fun invoke(): Flux<HealthState> = healthStateStream
+    override fun invoke(): Flux<HealthDescription> = healthDescriptionStream
 
-    override fun changeState(healthState: HealthState) = healthStateStream.onNext(healthState)
+    override fun changeState(healthDescription: HealthDescription) = healthDescriptionStream.onNext(healthDescription)
 }
diff --git a/hv-collector-health-check/src/test/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateProviderImplTest.kt b/hv-collector-health-check/src/test/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateProviderImplTest.kt
index e9c487bf..e3fced2d 100644
--- a/hv-collector-health-check/src/test/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateProviderImplTest.kt
+++ b/hv-collector-health-check/src/test/kotlin/org/onap/dcae/collectors/veshv/healthcheck/impl/HealthStateProviderImplTest.kt
@@ -21,10 +21,9 @@ package org.onap.dcae.collectors.veshv.healthcheck.impl
 
 import org.jetbrains.spek.api.Spek
 import org.jetbrains.spek.api.dsl.describe
-import org.jetbrains.spek.api.dsl.given
 import org.jetbrains.spek.api.dsl.it
 import org.jetbrains.spek.api.dsl.on
-import org.onap.dcae.collectors.veshv.healthcheck.api.HealthState
+import org.onap.dcae.collectors.veshv.healthcheck.api.HealthDescription
 import reactor.test.StepVerifier
 
 /**
@@ -33,20 +32,20 @@ import reactor.test.StepVerifier
  */
 object HealthStateProviderImplTest : Spek({
     describe("Health state provider") {
-            val healthStateProviderImpl = HealthStateProviderImpl()
+            val healthStateProviderImpl = HealthStateImpl()
             on("health state update") {
-                healthStateProviderImpl.changeState(HealthState.HEALTHY)
-                healthStateProviderImpl.changeState(HealthState.WAITING_FOR_CONSUL_CONFIGURATION)
-                healthStateProviderImpl.changeState(HealthState.WAITING_FOR_CONSUL_CONFIGURATION)
-                healthStateProviderImpl.changeState(HealthState.CONSUL_CONFIGURATION_NOT_FOUND)
+                healthStateProviderImpl.changeState(HealthDescription.HEALTHY)
+                healthStateProviderImpl.changeState(HealthDescription.RETRYING_FOR_CONSUL_CONFIGURATION)
+                healthStateProviderImpl.changeState(HealthDescription.RETRYING_FOR_CONSUL_CONFIGURATION)
+                healthStateProviderImpl.changeState(HealthDescription.CONSUL_CONFIGURATION_NOT_FOUND)
 
                 it("should push new health state to the subscriber") {
                     StepVerifier
                             .create(healthStateProviderImpl().take(4))
-                            .expectNext(HealthState.HEALTHY)
-                            .expectNext(HealthState.WAITING_FOR_CONSUL_CONFIGURATION)
-                            .expectNext(HealthState.WAITING_FOR_CONSUL_CONFIGURATION)
-                            .expectNext(HealthState.CONSUL_CONFIGURATION_NOT_FOUND)
+                            .expectNext(HealthDescription.HEALTHY)
+                            .expectNext(HealthDescription.RETRYING_FOR_CONSUL_CONFIGURATION)
+                            .expectNext(HealthDescription.RETRYING_FOR_CONSUL_CONFIGURATION)
+                            .expectNext(HealthDescription.CONSUL_CONFIGURATION_NOT_FOUND)
                             .verifyComplete()
                 }
             }