Made DmaapMessageConsumer asynchronuous

Change-Id: Ib3d4951f3f9b2061353b5e50f427559a3781b10e
Issue-ID: CCSDK-2502
Signed-off-by: PatrikBuhr <patrik.buhr@est.tech>

3 files changed, 105 insertions, 86 deletions

diff --git a/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/clients/AsyncRestClient.java b/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/clients/AsyncRestClient.java
index 8409f45c..7f453a27 100644
--- a/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/clients/AsyncRestClient.java
+++ b/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/clients/AsyncRestClient.java
@@ -188,7 +188,7 @@ public class AsyncRestClient {
             logger.debug("{} HTTP error status = '{}', body '{}'", traceTag, exception.getStatusCode(),
                     exception.getResponseBodyAsString());
         } else {
-            logger.debug("{} HTTP error", traceTag, t);
+            logger.debug("{} HTTP error {}", traceTag, t.getMessage());
         }
     }
 
diff --git a/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageConsumer.java b/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageConsumer.java
index 3a365178..f948e5f5 100644
--- a/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageConsumer.java
+++ b/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageConsumer.java
@@ -20,7 +20,6 @@
 
 package org.onap.ccsdk.oran.a1policymanagementservice.dmaap;
 
-import com.google.common.collect.Iterables;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonArray;
@@ -37,15 +36,17 @@ import java.util.ServiceLoader;
 import org.onap.ccsdk.oran.a1policymanagementservice.clients.AsyncRestClient;
 import org.onap.ccsdk.oran.a1policymanagementservice.clients.AsyncRestClientFactory;
 import org.onap.ccsdk.oran.a1policymanagementservice.configuration.ApplicationConfig;
-import org.onap.ccsdk.oran.a1policymanagementservice.exceptions.ServiceException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.http.HttpStatus;
-import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Component;
 
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.FluxSink;
+import reactor.core.publisher.Mono;
+
 /**
  * The class fetches incoming requests from DMAAP. It uses the timeout parameter
  * that lets the MessageRouter keep the connection with the Kafka open until
@@ -74,60 +75,82 @@ public class DmaapMessageConsumer {
 
     private final AsyncRestClientFactory restClientFactory;
 
+    private final InfiniteFlux infiniteSubmitter = new InfiniteFlux();
+
     @Value("${server.http-port}")
     private int localServerHttpPort;
 
+    private static class InfiniteFlux {
+        private FluxSink<Integer> sink;
+        private int counter = 0;
+
+        public synchronized Flux<Integer> start() {
+            stop();
+            return Flux.create(this::next).doOnRequest(this::onRequest);
+        }
+
+        public synchronized void stop() {
+            if (this.sink != null) {
+                this.sink.complete();
+                this.sink = null;
+            }
+        }
+
+        void onRequest(long no) {
+            logger.debug("InfiniteFlux.onRequest {}", no);
+            for (long i = 0; i < no; ++i) {
+                sink.next(counter++);
+            }
+        }
+
+        void next(FluxSink<Integer> sink) {
+            logger.debug("InfiniteFlux.next");
+            this.sink = sink;
+            sink.next(counter++);
+        }
+
+    }
+
     @Autowired
     public DmaapMessageConsumer(ApplicationConfig applicationConfig) {
         this.applicationConfig = applicationConfig;
         GsonBuilder gsonBuilder = new GsonBuilder();
         ServiceLoader.load(TypeAdapterFactory.class).forEach(gsonBuilder::registerTypeAdapterFactory);
-        gson = gsonBuilder.create();
+        this.gson = gsonBuilder.create();
         this.restClientFactory = new AsyncRestClientFactory(applicationConfig.getWebClientConfig());
     }
 
     /**
-     * Starts the consumer. If there is a DMaaP configuration, it will start polling
-     * for messages. Otherwise it will check regularly for the configuration.
+     * Starts the DMAAP consumer. If there is a DMaaP configuration, it will start
+     * polling for messages. Otherwise it will check regularly for the
+     * configuration.
      *
-     * @return the running thread, for test purposes.
      */
-    public Thread start() {
-        Thread thread = new Thread(this::messageHandlingLoop);
-        thread.start();
-        return thread;
+    public void start() {
+        infiniteSubmitter.stop();
+
+        createTask().subscribe(//
+                value -> logger.debug("DmaapMessageConsumer next: {}", value), //
+                throwable -> logger.error("DmaapMessageConsumer error: {}", throwable), //
+                () -> logger.warn("DmaapMessageConsumer stopped") //
+        );
     }
 
-    private void messageHandlingLoop() {
-        while (!isStopped()) {
-            try {
-                if (isDmaapConfigured()) {
-                    Iterable<DmaapRequestMessage> dmaapMsgs = fetchAllMessages();
-                    if (dmaapMsgs != null && Iterables.size(dmaapMsgs) > 0) {
-                        logger.debug("Fetched all the messages from DMAAP and will start to process the messages");
-                        for (DmaapRequestMessage msg : dmaapMsgs) {
-                            processMsg(msg);
-                        }
-                    }
-                } else {
-                    sleep(TIME_BETWEEN_DMAAP_RETRIES); // wait for configuration
-                }
-            } catch (Exception e) {
-                logger.warn("{}", e.getMessage());
-                sleep(TIME_BETWEEN_DMAAP_RETRIES);
-            }
-        }
+    protected Flux<String> createTask() {
+        return infiniteFlux() //
+                .flatMap(notUsed -> fetchFromDmaap(), 1) //
+                .doOnNext(message -> logger.debug("Message Reveived from DMAAP : {}", message)) //
+                .flatMap(this::parseReceivedMessage, 1)//
+                .flatMap(this::handleDmaapMsg, 1) //
+                .onErrorResume(throwable -> Mono.empty());
     }
 
-    protected boolean isStopped() {
-        return false;
+    protected Flux<Integer> infiniteFlux() {
+        return infiniteSubmitter.start();
     }
 
-    protected boolean isDmaapConfigured() {
-        String producerTopicUrl = applicationConfig.getDmaapProducerTopicUrl();
-        String consumerTopicUrl = applicationConfig.getDmaapConsumerTopicUrl();
-        return (producerTopicUrl != null && consumerTopicUrl != null && !producerTopicUrl.isEmpty()
-                && !consumerTopicUrl.isEmpty());
+    protected Mono<Object> delay() {
+        return Mono.delay(TIME_BETWEEN_DMAAP_RETRIES).flatMap(o -> Mono.empty());
     }
 
     private <T> List<T> parseList(String jsonString, Class<T> clazz) {
@@ -146,7 +169,36 @@ public class DmaapMessageConsumer {
         return result;
     }
 
-    private void sendErrorResponse(String response) {
+    protected boolean isDmaapConfigured() {
+        String producerTopicUrl = applicationConfig.getDmaapProducerTopicUrl();
+        String consumerTopicUrl = applicationConfig.getDmaapConsumerTopicUrl();
+        return (producerTopicUrl != null && consumerTopicUrl != null && !producerTopicUrl.isEmpty()
+                && !consumerTopicUrl.isEmpty());
+    }
+
+    protected Mono<String> handleDmaapMsg(DmaapRequestMessage dmaapRequestMessage) {
+        return getDmaapMessageHandler().handleDmaapMsg(dmaapRequestMessage);
+    }
+
+    protected Mono<String> getFromMessageRouter(String topicUrl) {
+        logger.trace("getFromMessageRouter {}", topicUrl);
+        AsyncRestClient c = restClientFactory.createRestClient("");
+        return c.get(topicUrl);
+    }
+
+    protected Flux<DmaapRequestMessage> parseReceivedMessage(String jsonString) {
+        try {
+            logger.trace("parseMessages {}", jsonString);
+            return Flux.fromIterable(parseList(jsonString, DmaapRequestMessage.class));
+        } catch (Exception e) {
+            logger.error("parseMessages error {}", jsonString);
+            return sendErrorResponse("Could not parse: " + jsonString) //
+                    .flatMapMany(s -> Flux.empty());
+        }
+    }
+
+    protected Mono<String> sendErrorResponse(String response) {
+        logger.debug("sendErrorResponse {}", response);
         DmaapRequestMessage fakeRequest = ImmutableDmaapRequestMessage.builder() //
                 .apiVersion("") //
                 .correlationId("") //
@@ -158,37 +210,23 @@ public class DmaapMessageConsumer {
                 .timestamp("") //
                 .url("URL") //
                 .build();
-        getDmaapMessageHandler().sendDmaapResponse(response, fakeRequest, HttpStatus.BAD_REQUEST).block();
+        return getDmaapMessageHandler().sendDmaapResponse(response, fakeRequest, HttpStatus.BAD_REQUEST) //
+                .onErrorResume(e -> Mono.empty());
     }
 
-    List<DmaapRequestMessage> parseMessages(String jsonString) throws ServiceException {
-        try {
-            return parseList(jsonString, DmaapRequestMessage.class);
-        } catch (Exception e) {
-            sendErrorResponse("Not parsable request received, reason:" + e.toString() + ", input :" + jsonString);
-            throw new ServiceException("Could not parse incomming request. Reason :" + e.getMessage());
+    private Mono<String> fetchFromDmaap() {
+        if (!this.isDmaapConfigured()) {
+            logger.debug("fetchFromDmaap, no action DMAAP not configured");
+            return delay().flatMap(o -> Mono.empty());
         }
-    }
-
-    protected Iterable<DmaapRequestMessage> fetchAllMessages() throws ServiceException {
+        logger.debug("fetchFromDmaap");
         String topicUrl = this.applicationConfig.getDmaapConsumerTopicUrl();
-        AsyncRestClient consumer = getMessageRouterConsumer();
-        ResponseEntity<String> response = consumer.getForEntity(topicUrl).block();
-        logger.debug("DMaaP consumer received {} : {}", response.getStatusCode(), response.getBody());
-        if (response.getStatusCode().is2xxSuccessful()) {
-            return parseMessages(response.getBody());
-        } else {
-            throw new ServiceException("Cannot fetch because of Error respons: " + response.getStatusCode().toString()
-                    + " " + response.getBody());
-        }
-    }
 
-    private void processMsg(DmaapRequestMessage msg) {
-        logger.debug("Message Reveived from DMAAP : {}", msg);
-        getDmaapMessageHandler().handleDmaapMsg(msg);
+        return getFromMessageRouter(topicUrl) //
+                .onErrorResume(throwable -> delay().flatMap(o -> Mono.empty()));
     }
 
-    protected DmaapMessageHandler getDmaapMessageHandler() {
+    private DmaapMessageHandler getDmaapMessageHandler() {
         if (this.dmaapMessageHandler == null) {
             String pmsBaseUrl = "http://localhost:" + this.localServerHttpPort;
             AsyncRestClient pmsClient = restClientFactory.createRestClient(pmsBaseUrl);
@@ -199,16 +237,4 @@ public class DmaapMessageConsumer {
         return this.dmaapMessageHandler;
     }
 
-    protected void sleep(Duration duration) {
-        try {
-            Thread.sleep(duration.toMillis());
-        } catch (Exception e) {
-            logger.error("Failed to put the thread to sleep", e);
-        }
-    }
-
-    protected AsyncRestClient getMessageRouterConsumer() {
-        return restClientFactory.createRestClient("");
-    }
-
 }
diff --git a/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageHandler.java b/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageHandler.java
index 967cab1d..c77087a5 100644
--- a/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageHandler.java
+++ b/a1-policy-management/src/main/java/org/onap/ccsdk/oran/a1policymanagementservice/dmaap/DmaapMessageHandler.java
@@ -54,20 +54,13 @@ public class DmaapMessageHandler {
         this.dmaapClient = dmaapClient;
     }
 
-    public void handleDmaapMsg(DmaapRequestMessage msg) {
-        try {
-            String result = this.createTask(msg).block();
-            logger.debug("handleDmaapMsg: {}", result);
-        } catch (Exception throwable) {
-            logger.warn("handleDmaapMsg failure {}", throwable.getMessage());
-        }
-    }
-
-    Mono<String> createTask(DmaapRequestMessage dmaapRequestMessage) {
+    public Mono<String> handleDmaapMsg(DmaapRequestMessage dmaapRequestMessage) {
         return this.invokePolicyManagementService(dmaapRequestMessage) //
                 .onErrorResume(t -> handlePolicyManagementServiceCallError(t, dmaapRequestMessage)) //
                 .flatMap(response -> sendDmaapResponse(response.getBody(), dmaapRequestMessage,
-                        response.getStatusCode()));
+                        response.getStatusCode()))
+                .doOnError(t -> logger.warn("Failed to handle DMAAP message : {}", t.getMessage()))//
+                .onErrorResume(t -> Mono.empty());
     }
 
     private Mono<ResponseEntity<String>> handlePolicyManagementServiceCallError(Throwable error,