NONRTRIC - Implement DMaaP mediator producer service in Java

[nonrtric.git] / dmaap-adaptor-java / src / main / java / org / oran / dmaapadapter / tasks / KafkaJobDataConsumer.java

diff --git a/dmaap-adaptor-java/src/main/java/org/oran/dmaapadapter/tasks/KafkaJobDataConsumer.java b/dmaap-adaptor-java/src/main/java/org/oran/dmaapadapter/tasks/KafkaJobDataConsumer.java
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+/*-
+ * ========================LICENSE_START=================================
+ * O-RAN-SC
+ * %%
+ * Copyright (C) 2021 Nordix Foundation
+ * %%
+ * 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.oran.dmaapadapter.tasks;
+
+import org.oran.dmaapadapter.repository.Job;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.web.reactive.function.client.WebClientResponseException;
+
+import reactor.core.Disposable;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.publisher.Sinks.Many;
+
+/**
+ * The class streams data from a multi cast sink and sends the data to the Job
+ * owner via REST calls.
+ */
+@SuppressWarnings("squid:S2629") // Invoke method(s) only conditionally
+
+public class KafkaJobDataConsumer {
+    private static final Logger logger = LoggerFactory.getLogger(KafkaJobDataConsumer.class);
+    private final Many<String> input;
+    private final Job job;
+    private Disposable subscription;
+    private int errorCounter = 0;
+
+    KafkaJobDataConsumer(Many<String> input, Job job) {
+        this.input = input;
+        this.job = job;
+    }
+
+    public synchronized void start() {
+        stop();
+        this.subscription = getMessagesFromKafka(job) //
+                .doOnNext(data -> logger.debug("Sending to consumer {} {} {}", job.getId(), job.getCallbackUrl(), data))
+                .flatMap(body -> job.getConsumerRestClient().post("", body), job.getParameters().getMaxConcurrency()) //
+                .onErrorResume(this::handleError) //
+                .subscribe(this::handleConsumerSentOk, //
+                        this::handleErrorInStream, //
+                        () -> logger.debug("KafkaMessageConsumer stopped, jobId: {}, type: {}", job.getId(),
+                                job.getType().getId()));
+    }
+
+    public synchronized void stop() {
+        if (this.subscription != null) {
+            subscription.dispose();
+            subscription = null;
+        }
+    }
+
+    public synchronized boolean isRunning() {
+        return this.subscription != null;
+    }
+
+    private Flux<String> getMessagesFromKafka(Job job) {
+        Flux<String> result = input.asFlux() //
+                .filter(job::isFilterMatch);
+
+        if (job.isBuffered()) {
+            result = result.bufferTimeout( //
+                    job.getParameters().getBufferTimeout().getMaxSize(), //
+                    job.getParameters().getBufferTimeout().getMaxTime()) //
+                    .map(Object::toString);
+        }
+        return result;
+    }
+
+    private Mono<String> handleError(Throwable t) {
+        logger.warn("exception: {} job: {}", t.getMessage(), job);
+
+        final int STOP_AFTER_ERRORS = 5;
+        if (t instanceof WebClientResponseException) {
+            if (++this.errorCounter > STOP_AFTER_ERRORS) {
+                logger.error("Stopping job {}", job);
+                return Mono.error(t);
+            } else {
+                return Mono.empty(); // Discard
+            }
+        } else {
+            // This can happen if there is an overflow.
+            return Mono.empty();
+        }
+    }
+
+    private void handleConsumerSentOk(String data) {
+        this.errorCounter = 0;
+    }
+
+    private void handleErrorInStream(Throwable t) {
+        logger.error("KafkaMessageConsumer jobId: {}, error: {}", job.getId(), t.getMessage());
+        this.subscription = null;
+    }
+
+}