Addition of Active-Standby Feature

Patch 1: Adds the active-standby feature to drools-pdp.
This feature provides the state control of the
drools-pdp nodes controlling failover with a site
and across sites. Patch 2: Resolve merge conflict in
packages/install/pom.xml and pom.xml. Patch 3: Resolved
comments from Pamela Dragosh and Jorge Hernandez.

Issue-ID: POLICY-156
Change-Id: I922b3d5d8a464006e9675924bcbc7409d68c08d5
Signed-off-by: Kevin McKiou <km097d@att.com>

1 files changed, 240 insertions, 0 deletions

diff --git a/feature-active-standby-management/src/main/java/org/onap/policy/drools/activestandby/ActiveStandbyFeature.java b/feature-active-standby-management/src/main/java/org/onap/policy/drools/activestandby/ActiveStandbyFeature.java
new file mode 100644
index 00000000..d40a9e0f
--- /dev/null
+++ b/feature-active-standby-management/src/main/java/org/onap/policy/drools/activestandby/ActiveStandbyFeature.java
@@ -0,0 +1,240 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * feature-active-standby-management
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.policy.drools.activestandby;
+
+import java.io.IOException;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.onap.policy.drools.core.PolicySessionFeatureAPI;
+import org.onap.policy.drools.features.PolicyEngineFeatureAPI;
+import org.onap.policy.drools.statemanagement.StateManagementFeatureAPI;
+import org.onap.policy.drools.system.PolicyEngine;
+import org.onap.policy.drools.utils.PropertyUtil;
+
+/**
+ * If this feature is supported, there is a single instance of it.
+ * It adds persistence to Drools sessions, but it is also intertwined with
+ * active/standby state management and IntegrityMonitor. For now, they are
+ * all treated as a single feature, but it would be nice to separate them.
+ *
+ * The bulk of the code here was once in other classes, such as
+ * 'PolicyContainer' and 'Main'. It was moved here as part of making this
+ * a separate optional feature.
+ */
+public class ActiveStandbyFeature implements ActiveStandbyFeatureAPI, 
+				PolicySessionFeatureAPI, PolicyEngineFeatureAPI
+{
+	// get an instance of logger
+	private static final Logger logger =
+			LoggerFactory.getLogger(ActiveStandbyFeature.class);
+	
+	private static DroolsPdp myPdp;
+	private static Object myPdpSync = new Object();
+	private static DroolsPdpsElectionHandler electionHandler;
+	
+	private StateManagementFeatureAPI stateManagementFeature;
+	
+	public static final int SEQ_NUM = 1;
+	
+
+	/**************************/
+	/* 'FeatureAPI' interface */
+	/**************************/
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public int getSequenceNumber()
+	{
+		return(SEQ_NUM);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public void globalInit(String args[], String configDir)
+	{
+		// This must come first since it initializes myPdp
+		initializePersistence(configDir);
+		
+		for (StateManagementFeatureAPI feature : StateManagementFeatureAPI.impl.getList())
+		{
+			if (feature.getResourceName().equals(myPdp.getPdpId()))
+			{
+				if(logger.isDebugEnabled()){
+					logger.debug("ActiveStandbyFeature.globalInit: Found StateManagementFeature"
+						+ " with resourceName: {}", myPdp.getPdpId());
+				}
+				stateManagementFeature = feature;
+				break;
+			}
+		}
+		if(stateManagementFeature == null){
+			if(logger.isDebugEnabled()){
+				logger.debug("ActiveStandbyFeature failed to initialize.  "
+					+ "Unable to get instance of StateManagementFeatureAPI "
+					+ "with resourceID: {}", myPdp.getPdpId());
+			}
+			logger.error("ActiveStandbyFeature failed to initialize.  "
+					+ "Unable to get instance of StateManagementFeatureAPI "
+					+ "with resourceID: {}", myPdp.getPdpId());
+		}
+
+
+
+		//Create an instance of the Observer
+		PMStandbyStateChangeNotifier pmNotifier = new PMStandbyStateChangeNotifier();
+
+		//Register the PMStandbyStateChangeNotifier Observer
+		stateManagementFeature.addObserver(pmNotifier);
+		if(logger.isDebugEnabled()){
+			logger.debug("ActiveStandbyFeature.globalInit() exit");
+		}
+	}
+
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public boolean afterStart(PolicyEngine engine) 
+	{
+		// ASSERTION: engine == PolicyEngine.manager
+		PolicyEngine.manager.lock();
+		return false;
+	}
+
+	/**
+	 * Read in the persistence properties, determine whether persistence is
+	 * enabled or disabled, and initialize persistence if enabled.
+	 */
+	private static void initializePersistence(String configDir)
+	{
+		//Get the Active Standby properties
+		try {
+				Properties activeStandbyProperties = 
+						PropertyUtil.getProperties(configDir + "/feature-active-standby-management.properties");
+				ActiveStandbyProperties.initProperties(activeStandbyProperties);
+				logger.info("initializePersistence: ActiveStandbyProperties success");
+		} catch (IOException e) {
+			logger.error("ActiveStandbyFeature: initializePersistence ActiveStandbyProperties", e);
+		}
+		
+		DroolsPdpsConnector conn = getDroolsPdpsConnector("activeStandbyPU");
+		String resourceName = ActiveStandbyProperties.getProperty(ActiveStandbyProperties.NODE_NAME);
+		if(resourceName == null){
+			throw new NullPointerException();
+		}
+
+		/*
+		 * In a JUnit test environment, one or more PDPs may already have been
+		 * inserted in the DB, so we need to check for this.
+		 */
+		DroolsPdp existingPdp = conn.getPdp(resourceName);
+		if (existingPdp != null) {
+			System.out.println("Found existing PDP record, pdpId="
+					+ existingPdp.getPdpId() + ", isDesignated="
+					+ existingPdp.isDesignated() + ", updatedDate="
+					+ existingPdp.getUpdatedDate());
+			myPdp = existingPdp;
+		}
+
+		synchronized(myPdpSync){
+			if(myPdp == null){
+
+				myPdp = new DroolsPdpImpl(resourceName,false,4,new Date());	
+			}
+			if(myPdp != null){
+				String site_name = ActiveStandbyProperties.getProperty(ActiveStandbyProperties.SITE_NAME);
+				if (site_name == null) {
+					site_name = "";
+				}else{
+					site_name = site_name.trim();
+				}
+				myPdp.setSiteName(site_name);
+			}
+			if(electionHandler == null){
+				electionHandler = new DroolsPdpsElectionHandler(conn,myPdp);
+			}
+		}
+		System.out.println("\n\nThis controller is a standby, waiting to be chosen as primary...\n\n");
+		logger.info("\n\nThis controller is a standby, waiting to be chosen as primary...\n\n");
+	}
+
+
+	/*
+	 * Moved code to instantiate a JpaDroolsPdpsConnector object from main() to
+	 * this method, so it can also be accessed from StandbyStateChangeNotifier
+	 * class.
+	 */
+	public static DroolsPdpsConnector getDroolsPdpsConnector(String pu) {
+
+		Map<String, Object> propMap = new HashMap<String, Object>();
+		propMap.put("javax.persistence.jdbc.driver", ActiveStandbyProperties
+				.getProperty(ActiveStandbyProperties.DB_DRIVER));
+		propMap.put("javax.persistence.jdbc.url",
+				ActiveStandbyProperties.getProperty(ActiveStandbyProperties.DB_URL));
+		propMap.put("javax.persistence.jdbc.user", ActiveStandbyProperties
+				.getProperty(ActiveStandbyProperties.DB_USER));
+		propMap.put("javax.persistence.jdbc.password",
+				ActiveStandbyProperties.getProperty(ActiveStandbyProperties.DB_PWD));
+
+		EntityManagerFactory emf = Persistence.createEntityManagerFactory(
+				pu, propMap);
+		DroolsPdpsConnector conn = new JpaDroolsPdpsConnector(emf);
+
+		return conn;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String getPdpdNowActive(){
+		return electionHandler.getPdpdNowActive();
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String getPdpdLastActive(){
+		return electionHandler.getPdpdLastActive();
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String getResourceName() {
+		return myPdp.getPdpId();
+	}
+}