io.github.microcks.minion.async.producer.GooglePubSubProducerManager Maven / Gradle / Ivy

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/*
 * Licensed to Laurent Broudoux (the "Author") under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Author licenses this
 * file to you 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.
 */
package io.github.microcks.minion.async.producer;


import io.github.microcks.domain.EventMessage;
import io.github.microcks.domain.Header;
import io.github.microcks.minion.async.AsyncMockDefinition;
import io.github.microcks.util.el.TemplateEngine;

import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutureCallback;
import com.google.api.core.ApiFutures;
import com.google.api.gax.core.CredentialsProvider;
import com.google.api.gax.core.ExecutorProvider;
import com.google.api.gax.core.FixedCredentialsProvider;
import com.google.api.gax.core.InstantiatingExecutorProvider;
import com.google.api.gax.core.NoCredentialsProvider;
import com.google.api.gax.rpc.NotFoundException;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.cloud.pubsub.v1.TopicAdminClient;
import com.google.cloud.pubsub.v1.TopicAdminSettings;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.PubsubMessage;
import com.google.pubsub.v1.TopicName;
import org.eclipse.microprofile.config.inject.ConfigProperty;
import org.jboss.logging.Logger;

import javax.annotation.PostConstruct;
import javax.enterprise.context.ApplicationScoped;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;

/**
 * Google Cloud PubSub implementation of producer for async event messages.
 * @author laurent
 */
@ApplicationScoped
public class GooglePubSubProducerManager {

   /** Get a JBoss logging logger. */
   private final Logger logger = Logger.getLogger(getClass());

   private static final String CLOUD_OAUTH_SCOPE = "https://www.googleapis.com/auth/cloud-platform";

   /**
    * As {@link Publisher} is bound to topic, default would be to create it at each invocation.
    * We'll use this cache, that enforces only one {@link Publisher} per PubSub topic exists.
    */
   private final ConcurrentHashMap publishers = new ConcurrentHashMap<>();

   /**
    * As {@link Publisher} is by default associated to its own executor, we have to override
    * this to avoid wasting resources. As the push of mock messages is sequential, 1 thread is enough.
    */
   private final ExecutorProvider executorProvider = InstantiatingExecutorProvider
         .newBuilder().setExecutorThreadCount(1).build();

   CredentialsProvider credentialsProvider;

   @ConfigProperty(name = "googlepubsub.project")
   String project;

   @ConfigProperty(name = "googlepubsub.service-account-location")
   String serviceAccountLocation;

   /**
    * Initialize the PubSub connection post construction.
    * @throws Exception If connection to PubSub cannot be done.
    */
   @PostConstruct
   public void create() throws Exception {
      try {
         if (serviceAccountLocation != null && serviceAccountLocation.length() > 0) {
            FileInputStream is = new FileInputStream(serviceAccountLocation);
            credentialsProvider = FixedCredentialsProvider.create(GoogleCredentials.fromStream(is).createScoped(CLOUD_OAUTH_SCOPE));
         } else {
            credentialsProvider = NoCredentialsProvider.create();
         }
      } catch (Exception e) {
         logger.errorf("Cannot read Google Cloud credentials %s", serviceAccountLocation);
         throw e;
      }
   }

   /**
    * Publish a message on specified PubSub topic.
    * @param topic The short name of topic within the configured project
    * @param value The message payload
    * @param headers The headers if any (as rendered by renderEventMessageHeaders() method)
    */
   public void publishMessage(String topic, String value, Map headers) {
      logger.infof("Publishing on topic {%s}, message: %s ", topic, value);

      try {
         if (publishers.get(topic) == null) {
            // Ensure topic exists on PubSub.
            TopicName topicName = TopicName.of(project, topic);

            TopicAdminSettings topicAdminSettings = TopicAdminSettings.newBuilder()
                  .setCredentialsProvider(credentialsProvider).build();
            TopicAdminClient topicAdminClient = TopicAdminClient.create(topicAdminSettings);

            try {
               topicAdminClient.getTopic(topicName);
            } catch (NotFoundException nfe) {
               logger.infof("Topic {%s} does not exist yet, creating it", topic);
               topicAdminClient.createTopic(topicName);
            }
         }

         // Build a message for corresponding publisher.
         Publisher publisher = getPublisher(topic);
         ByteString data = ByteString.copyFromUtf8(value);
         PubsubMessage pubsubMessage = PubsubMessage.newBuilder()
               .setData(data)
               .putAllAttributes(headers)
               .build();

         // Publish the message.
         ApiFuture messageIdFuture = publisher.publish(pubsubMessage);
         ApiFutures.addCallback(messageIdFuture, new ApiFutureCallback<>() {
            // Wait for message submission and log the result
            public void onSuccess(String messageId) {
               logger.debugv("Published with message id {0}", messageId);
            }
            public void onFailure(Throwable t) {
               logger.debugv("Failed to publish: {0}", t);
            }
         }, MoreExecutors.directExecutor());
      } catch (IOException ioe) {
         logger.warnf("Message sending has thrown an exception", ioe);
         ioe.printStackTrace();
      }
   }

   /**
    * Render Microcks headers using the template engine.
    * @param engine The template engine to reuse (because we do not want to initialize and manage a context at the GooglePubSubProducerManager level.)
    * @param headers The Microcks event message headers definition.
    * @return A map of rendered headers for GCP Publisher.
    */
   public Map renderEventMessageHeaders(TemplateEngine engine, Set headers) {
      if (headers != null && !headers.isEmpty()) {
         return headers.stream().collect(Collectors.toMap(
               header -> header.getName(),
               header -> {
                  String firstValue = header.getValues().stream().findFirst().get();
                  if (firstValue.contains(TemplateEngine.DEFAULT_EXPRESSION_PREFIX)) {
                     try {
                        return engine.getValue(firstValue);
                     } catch (Throwable t) {
                        logger.error("Failing at evaluating template " + firstValue, t);
                        return firstValue;
                     }
                  }
                  return firstValue;
               }));
      }
      return null;
   }

   /**
    * Compute a topic name from async mock definition.
    * @param definition The mock definition
    * @param eventMessage The event message to get dynamic part from
    * @return The short name of a PubSub topic
    */
   public String getTopicName(AsyncMockDefinition definition, EventMessage eventMessage) {
      logger.debugf("AsyncAPI Operation {%s}", definition.getOperation().getName());

      // Produce service name part of topic name.
      String serviceName = definition.getOwnerService().getName().replace(" ", "");
      serviceName = serviceName.replace("-", "");
      // Produce version name part of topic name.
      String versionName = definition.getOwnerService().getVersion().replace(" ", "");
      // Produce operation name part of topic name.
      String operationName = definition.getOperation().getName();
      if (operationName.startsWith("SUBSCRIBE ") || operationName.startsWith("PUBLISH ")) {
         operationName = operationName.substring(operationName.indexOf(" ") + 1);
      }

      operationName = operationName.replace('/', '-');
      operationName = ProducerManager.replacePartPlaceholders(eventMessage, operationName);

      // Aggregate the 3 parts using '_' as delimiter.
      return serviceName + "-" + versionName + "-" + operationName;
   }

   private Publisher getPublisher(String topic) throws IOException {
      try {
         return publishers.computeIfAbsent(topic, this::createPublisher);
      } catch (RuntimeException re) {
         // Just unwrap the underlying IOException...
         throw (IOException) re.getCause();
      }
   }

   private Publisher createPublisher(String topic) {
      try {
         return Publisher.newBuilder(TopicName.of(project, topic))
               .setExecutorProvider(executorProvider)
               .setCredentialsProvider(credentialsProvider)
               .build();
      } catch (IOException ioe) {
         logger.errorf("IOException while creating a Publisher for topic %s", topic);
         throw new RuntimeException("IOException while creating a Publisher for topic ", ioe);
      }
   }
}