Event client to retry in case of failed connection

On initial creation of the event client consumer/publisher
handle a failure to connect to RMQ gracefully such that the
application can still start up and re-try connecting at a later
time

Change-Id: I4ba8e2d2a8b4e4e5a60255550bb74a501494c9bd
Issue-ID: AAI-2185
Signed-off-by: sblimkie <steven.blimkie@amdocs.com>

6 files changed, 364 insertions, 113 deletions

diff --git a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqApplicationMsgs.java b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqApplicationMsgs.java
new file mode 100644
index 0000000..22df2b6
--- /dev/null
+++ b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqApplicationMsgs.java
@@ -0,0 +1,39 @@
+/**
+ * ============LICENSE_START=======================================================
+ * org.onap.aai
+ * ================================================================================
+ * Copyright © 2019 AT&T Intellectual Property. All rights reserved.
+ * Copyright © 2019 European Software Marketing Ltd.
+ * ================================================================================
+ * 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.aai.event.client;
+
+import com.att.eelf.i18n.EELFResourceManager;
+import org.onap.aai.cl.eelf.LogMessageEnum;
+
+/**
+ * Logger messages
+ */
+public enum RabbitMqApplicationMsgs implements LogMessageEnum {
+
+    MESSAGE_ERROR, MESSAGE_INFO, MESSAGE_WARN;
+
+    /**
+     * Static initializer to ensure the resource bundles for this class are loaded...
+     */
+    static {
+        EELFResourceManager.loadMessageBundle("resources");
+    }
+}
diff --git a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqClientConfig.java b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqClientConfig.java
index d177989..108f730 100644
--- a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqClientConfig.java
+++ b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqClientConfig.java
@@ -29,6 +29,7 @@ import com.rabbitmq.client.BuiltinExchangeType;
 public class RabbitMqClientConfig {
     
     private static String BINDING_CONSUME_ALL = "#";
+    private static Integer DEFAULT_RETRY_INTERVAL = 15000;
 
     private String hosts;
     private String username;
@@ -46,6 +47,7 @@ public class RabbitMqClientConfig {
     private String sslKeyStorePassword;
     private String sslTrustStorePassword;
     private String connectionTimeout;
+    private Integer retryInterval;
     private String enableSsl;
     
     public String getUsername() {
@@ -181,6 +183,18 @@ public class RabbitMqClientConfig {
         this.connectionTimeout = connectionTimeout;
     }
 
+    public Integer getRetryInterval() {
+        if (retryInterval == null) {
+           return DEFAULT_RETRY_INTERVAL;
+        }
+        
+        return retryInterval;
+    }
+    
+    public void setRetryInterval(Integer retryInterval) {
+        this.retryInterval = retryInterval;
+    }
+    
     public Boolean getEnableSsl() {
         if (enableSsl != null) {
             return Boolean.valueOf(enableSsl);
diff --git a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventConsumer.java b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventConsumer.java
index c10b46c..340c68f 100644
--- a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventConsumer.java
+++ b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventConsumer.java
@@ -28,6 +28,7 @@ import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.TimeUnit;
 
 import javax.naming.ConfigurationException;
+import javax.naming.ServiceUnavailableException;
 
 import org.onap.aai.cl.api.Logger;
 import org.onap.aai.cl.eelf.LoggerFactory;
@@ -51,127 +52,185 @@ import com.rabbitmq.client.AMQP;
  *
  */
 public class RabbitMqEventConsumer implements EventConsumer {
-	private static Logger log = LoggerFactory.getInstance().getLogger(RabbitMqEventConsumer.class);
+    private static Logger log = LoggerFactory.getInstance().getLogger(RabbitMqEventConsumer.class);
 
-	private BlockingQueue<MessageWithOffset> messageQueue;
+    private BlockingQueue<MessageWithOffset> messageQueue;
+
+    private Connection connection;
+    private Channel channel;
+    private Long lastDeliveryTag;
+    private long timeout = 5000;
+    private RabbitMqClientConfig config;
+    private long lastConnectionAttempt = 0L; 
 
-	private final Connection connection;
-	private final Channel channel;
-	private Long lastDeliveryTag;
-	private long timeout = 5000;
-	private RabbitMqClientConfig config;
-	
-	
     /**
      * (intended for testing prupose only)
      * @param messageQueue
      */
-	public void setMessageQueue(BlockingQueue<MessageWithOffset> messageQueue) {
-		this.messageQueue = messageQueue;
-	}
+    public void setMessageQueue(BlockingQueue<MessageWithOffset> messageQueue) {
+        this.messageQueue = messageQueue;
+    }
 
     public RabbitMqEventConsumer(RabbitMqClientConfig config) throws Exception {
         this.config = config;
         this.messageQueue = new ArrayBlockingQueue<>(1000);
-        
+
         if (config.getQueue() == null) {
             throw new ConfigurationException("Mandatory config param queue not set");
         }
-        
-        this.connection = RabbitMqUtils.createConnection(config);
-        this.channel = connection.createChannel();
-        
-        if (config.getExchangeName() != null) {
-            channel.exchangeDeclare(config.getExchangeName(), config.getExchangeType(), true, false, config.getExchangeArguments());
-            channel.queueDeclare(config.getQueue(), true, false, false, config.getQueueArguments());
-            channel.queueBind(config.getQueue(), config.getExchangeName(), config.getBindingKey());
+
+        try {
+            createConnection();
+        }
+        catch (ConfigurationException ex) {
+            // If the configuration is bad, we may as well re-throw the exception and let the process die.
+            throw ex;
+        }
+        catch (Exception ex) {
+            // Otherwise, let the process live.  We can retry establishing a connection later.
+            log.error(RabbitMqApplicationMsgs.MESSAGE_ERROR, "Unable to connect to RMQ: " + ex.getMessage());
+            return;
+        }
+    }
+
+    private synchronized void createConnection() throws Exception {
+        if (connection != null) {
+            return;
+        }
+
+        long currentTime = System.currentTimeMillis();
+
+        if ( (currentTime - config.getRetryInterval()) < lastConnectionAttempt) {
+            log.warn(RabbitMqApplicationMsgs.MESSAGE_WARN, "No attempt to consume.  No connection to RMQ.");
+            throw new ServiceUnavailableException("Waiting for retry interval");
+        }
+
+        lastConnectionAttempt = currentTime;
+
+        try {
+            this.connection = RabbitMqUtils.createConnection(config);
+            this.channel = connection.createChannel();
+
+            if (config.getExchangeName() != null) {
+                channel.exchangeDeclare(config.getExchangeName(), config.getExchangeType(), true, false, config.getExchangeArguments());
+                channel.queueDeclare(config.getQueue(), true, false, false, config.getQueueArguments());
+                channel.queueBind(config.getQueue(), config.getExchangeName(), config.getBindingKey());
+            }
+            else {
+                channel.queueDeclare(config.getQueue(), true, false, false, config.getQueueArguments());
+            }
+
+            channel.basicConsume(config.getQueue(), false, new CallBackConsumer(channel)); //AutoAck is false
         }
-        else {
-            channel.queueDeclare(config.getQueue(), true, false, false, config.getQueueArguments());
+        catch (Exception ex) {
+            close();
+            throw ex;
         }
-         
-        channel.basicConsume(config.getQueue(), false, new CallBackConsumer(channel)); //AutoAck is false
+
+        log.info(RabbitMqApplicationMsgs.MESSAGE_INFO, "Event consumer successfully connected to RMQ");
     }
 
-	
-	@Override
-	public Iterable<String> consumeAndCommit() throws Exception {
-		Iterable<String> list = consume();
-		commitOffsets();
-		return list;
-	}
-
-	@Override
-	public Iterable<String> consume() throws Exception {
-		List<String> list = new ArrayList<>();
-		MessageWithOffset record = null;
-		if(messageQueue.peek()!=null) {
-			do
-			{
-				record = messageQueue.poll(1000, TimeUnit.MILLISECONDS);
-				lastDeliveryTag = record.getOffset();
-				list.add(record.getMessage());
-			}while(messageQueue.peek()!=null);
-		}
-		return list;
-	}
-
-	@Override
-	public Iterable<MessageWithOffset> consumeWithOffsets() throws Exception {
-		List<MessageWithOffset> list = new ArrayList<>();
-		MessageWithOffset record = null;
-		if(messageQueue.peek()!=null) {
-			do
-			{
-				record = messageQueue.poll(1000, TimeUnit.MILLISECONDS);
-				lastDeliveryTag = record.getOffset();
-				list.add(record);
-			}while(messageQueue.peek()!=null);
-		}
+    @Override
+    public Iterable<String> consumeAndCommit() throws Exception {
+        Iterable<String> list = consume();
+        commitOffsets();
         return list;
-	}
-
-	@Override
-	public void commitOffsets() throws Exception {
-		if(lastDeliveryTag != null)
-		{
-			channel.basicAck(lastDeliveryTag, true); //Ack messages upto lastDeliveryTag or offset so that they can be marked
-			lastDeliveryTag = null;
-		}
-	}
-
-	@Override
-	public void commitOffsets(long offset) throws Exception {
-		channel.basicAck(offset, true); //Ack messages upto lastDeliveryTag or offset so that they can be marked
-	}
-	
-	/**
-	 * Closes the channel
-	 * @throws Exception
-	 */
-	public void close() throws Exception {
-		channel.close();
-		connection.close();
-	}
-	
-	class CallBackConsumer extends DefaultConsumer{
-		CallBackConsumer(Channel channel) {
-			super(channel);
-		}
+    }
+
+    @Override
+    public Iterable<String> consume() throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+
+        List<String> list = new ArrayList<>();
+        MessageWithOffset record = null;
+        if(messageQueue.peek()!=null) {
+            do
+            {
+                record = messageQueue.poll(1000, TimeUnit.MILLISECONDS);
+                lastDeliveryTag = record.getOffset();
+                list.add(record.getMessage());
+            }while(messageQueue.peek()!=null);
+        }
+        return list;
+    }
+
+    @Override
+    public Iterable<MessageWithOffset> consumeWithOffsets() throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+
+        List<MessageWithOffset> list = new ArrayList<>();
+        MessageWithOffset record = null;
+        if(messageQueue.peek()!=null) {
+            do
+            {
+                record = messageQueue.poll(1000, TimeUnit.MILLISECONDS);
+                lastDeliveryTag = record.getOffset();
+                list.add(record);
+            }while(messageQueue.peek()!=null);
+        }
+        return list;
+    }
+
+    @Override
+    public void commitOffsets() throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+
+        if(lastDeliveryTag != null)
+        {
+            channel.basicAck(lastDeliveryTag, true); //Ack messages upto lastDeliveryTag or offset so that they can be marked
+            lastDeliveryTag = null;
+        }
+    }
+
+    @Override
+    public void commitOffsets(long offset) throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+
+        channel.basicAck(offset, true); //Ack messages upto lastDeliveryTag or offset so that they can be marked
+    }
+
+    /**
+     * Closes the channel
+     * @throws Exception
+     */
+    public void close() throws Exception {
+        if (channel != null) {
+            channel.close();
+            channel = null;
+        }
+
+        if (connection != null) {
+            connection.close();
+            connection = null;
+        }
+    }
+
+    class CallBackConsumer extends DefaultConsumer{
+        CallBackConsumer(Channel channel) {
+            super(channel);
+        }
         @Override
         public void handleDelivery(String consumerTag, Envelope envelope,
-	                                 AMQP.BasicProperties properties, byte[] body) throws IOException {
-	       String message = new String(body, "UTF-8");
-	       try
-	       {
-	    	   MessageWithOffset record = new MessageWithOffset(envelope.getDeliveryTag(), message);
-	    	   messageQueue.offer(record, timeout, TimeUnit.MILLISECONDS);
-	       }
-	       catch(Exception e)
-	       {
-	    	   log.debug(" Got exception while handling message="+e.getMessage()+" Will be reposting to queue");
-		       channel.basicNack(envelope.getDeliveryTag(), false, true); //Explicit Ack with requeue
-	       }
-	    }
-	}
+                AMQP.BasicProperties properties, byte[] body) throws IOException {
+            String message = new String(body, "UTF-8");
+            try
+            {
+                MessageWithOffset record = new MessageWithOffset(envelope.getDeliveryTag(), message);
+                messageQueue.offer(record, timeout, TimeUnit.MILLISECONDS);
+            }
+            catch(Exception e)
+            {
+                log.debug(" Got exception while handling message="+e.getMessage()+" Will be reposting to queue");
+                channel.basicNack(envelope.getDeliveryTag(), false, true); //Explicit Ack with requeue
+            }
+        }
+    }
 }
diff --git a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventPublisher.java b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventPublisher.java
index 614ae54..a4c6105 100644
--- a/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventPublisher.java
+++ b/event-client-rabbitmq/src/main/java/org/onap/aai/event/client/RabbitMqEventPublisher.java
@@ -24,6 +24,7 @@ package org.onap.aai.event.client;
 import java.util.Collection;
 
 import javax.naming.ConfigurationException;
+import javax.naming.ServiceUnavailableException;
 
 import org.onap.aai.cl.api.Logger;
 import org.onap.aai.cl.eelf.LoggerFactory;
@@ -41,29 +42,45 @@ import com.rabbitmq.client.Connection;
 public class RabbitMqEventPublisher implements EventPublisher {
     private static Logger log = LoggerFactory.getInstance().getLogger(RabbitMqEventPublisher.class);
 
-    private final Connection connection;
-    private final Channel channel;
+    private Connection connection;
+    private Channel channel;
 
     private RabbitMqClientConfig config;
+    
+    private long lastConnectionAttempt = 0L; 
 
     public RabbitMqEventPublisher(RabbitMqClientConfig config) throws Exception {
         this.config = config;
-        
+
         if (config.getExchangeName() == null) {
             throw new ConfigurationException("Mandatory config param exchangeName not set");
         }
-        
-        this.connection = RabbitMqUtils.createConnection(config);
-        this.channel = connection.createChannel();
 
-        //Durable exchange and non delete
-        channel.exchangeDeclare(config.getExchangeName(), config.getExchangeType(), true, false, config.getExchangeArguments());
+        try {
+            createConnection();
+        }
+        catch (ConfigurationException ex) {
+            // If the configuration is bad, we may as well re-throw the exception and let the process die.
+            throw ex;
+        }
+        catch (Exception ex) {
+            // Otherwise, let the process live.  We can retry establishing a connection later.
+            log.error(RabbitMqApplicationMsgs.MESSAGE_ERROR, "Unable to connect to RMQ: " + ex.getMessage());
+            return;
+        }
     }
 
     @Override
     public void close() throws Exception {
-        channel.close();
-        connection.close();
+        if (channel != null) {
+            channel.close();
+            channel = null;
+        }
+
+        if (connection != null) {
+            connection.close();
+            connection = null;
+        }
     }
 
     @Override
@@ -88,6 +105,10 @@ public class RabbitMqEventPublisher implements EventPublisher {
 
     @Override
     public int sendSync(String message) throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+        
         channel.basicPublish(config.getExchangeName(), config.getRoutingKey(), null, message.getBytes());
         log.debug(" [x] Sent '" + message + "'");		
         return 1;
@@ -95,6 +116,10 @@ public class RabbitMqEventPublisher implements EventPublisher {
 
     @Override
     public int sendSync(Collection<String> messages) throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+        
         log.debug("Publishing" + messages.size() + " messages ");
         for (String message : messages) {
             sendSync(message);
@@ -104,17 +129,54 @@ public class RabbitMqEventPublisher implements EventPublisher {
 
     @Override
     public int sendSync(String routingParam, String message) throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+        
         channel.basicPublish(config.getExchangeName(), routingParam, null, message.getBytes());
         return 1;	
     }
 
     @Override
     public int sendSync(String routingParam, Collection<String> messages) throws Exception {
+        if (connection == null) {
+            createConnection();
+        }
+        
         log.debug("Publishing" + messages.size() + " messages ");
         for (String message : messages) {
             sendSync(routingParam, message);
         }
         return messages.size();
     }
+    
+    private synchronized void createConnection() throws Exception {
+        if (connection != null) {
+            return;
+        }
+        
+        long currentTime = System.currentTimeMillis();
+
+        if ( (currentTime - config.getRetryInterval()) < lastConnectionAttempt) {
+            log.warn(RabbitMqApplicationMsgs.MESSAGE_WARN, "Drop event.  No connection to RMQ.");
+            throw new ServiceUnavailableException("Waiting for retry interval");
+        }
+        
+        lastConnectionAttempt = currentTime;
+        
+        try {
+            this.connection = RabbitMqUtils.createConnection(config);
+            this.channel = connection.createChannel();
+            
+            //Durable exchange and non delete
+            channel.exchangeDeclare(config.getExchangeName(), config.getExchangeType(), true, false, config.getExchangeArguments());
+        }
+        catch (Exception ex) {
+            close();
+            throw ex;
+        }
+        
+        log.info(RabbitMqApplicationMsgs.MESSAGE_INFO, "Event publisher successfully connected to RMQ");
+    }
 
 }
diff --git a/event-client-rabbitmq/src/main/resources/resources.properties b/event-client-rabbitmq/src/main/resources/resources.properties
new file mode 100644
index 0000000..1e148d2
--- /dev/null
+++ b/event-client-rabbitmq/src/main/resources/resources.properties
@@ -0,0 +1,38 @@
+#
+# ============LICENSE_START=======================================================
+# org.onap.aai
+# ================================================================================
+# Copyright © 2019 AT&T Intellectual Property. All rights reserved.
+# Copyright © 2019 European Software Marketing Ltd.
+# ================================================================================
+# 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=========================================================
+#
+
+MESSAGE_INFO=\
+    |\
+    {0}|\
+    |\
+    |\
+
+MESSAGE_ERROR=\
+    |\
+    {0}|\
+    |\
+    |\
+
+MESSAGE_WARN=\
+    |\
+    {0}|\
+    |\
+    |\
diff --git a/event-client-rabbitmq/src/test/java/org/onap/aai/event/client/TestRabbitMqApplicationMsgs.java b/event-client-rabbitmq/src/test/java/org/onap/aai/event/client/TestRabbitMqApplicationMsgs.java
new file mode 100644
index 0000000..5870a39
--- /dev/null
+++ b/event-client-rabbitmq/src/test/java/org/onap/aai/event/client/TestRabbitMqApplicationMsgs.java
@@ -0,0 +1,39 @@
+/**
+ * ============LICENSE_START=======================================================
+ * org.onap.aai
+ * ================================================================================
+ * Copyright © 2019 AT&T Intellectual Property. All rights reserved.
+ * Copyright © 2019 European Software Marketing Ltd.
+ * ================================================================================
+ * 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.aai.event.client;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertThat;
+
+import org.junit.Test;
+
+public class TestRabbitMqApplicationMsgs {
+
+    /**
+     * This test is used to ensure that the static initializer for ApplicationMsgs is invoked.
+     */
+    @Test
+    public void accessEnumValues() {
+        assertThat(RabbitMqApplicationMsgs.values().length, is(not(0)));
+    }
+
+}