AT&T 2.0.19 Code drop, stage 2
[aaf/authz.git] / cadi / client / src / main / java / org / onap / aaf / cadi / locator / HotPeerLocator.java
diff --git a/cadi/client/src/main/java/org/onap/aaf/cadi/locator/HotPeerLocator.java b/cadi/client/src/main/java/org/onap/aaf/cadi/locator/HotPeerLocator.java
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+/**
+ * ============LICENSE_START====================================================
+ * org.onap.aaf
+ * ===========================================================================
+ * Copyright (c) 2018 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.aaf.cadi.locator;
+
+import org.onap.aaf.cadi.Access;
+import org.onap.aaf.cadi.Locator;
+import org.onap.aaf.cadi.LocatorException;
+import org.onap.aaf.cadi.Access.Level;
+import org.onap.aaf.cadi.routing.GreatCircle;
+import org.onap.aaf.misc.env.util.Split;
+
+/**
+ * This Locator is to handle Hot Peer load protection, when the Servers are 
+ *     1) Static
+ *     2) Well known client URL
+ * 
+ * The intention is to change traffic over to the Hot Peer, if a server goes down, and reinstate
+ * when it is back up.
+ * 
+ * Example of this kind of Service is a MS Certificate Server
+ * 
+ * @author Jonathan
+ *
+ * @param <CLIENT>
+ */
+public abstract class HotPeerLocator<CLIENT> implements Locator<CLIENT> {
+               private final String[] urlstrs;
+               private final CLIENT[] clients;
+               private final long[] failures;
+               private final double[] distances;
+               private int preferred;
+               private long invalidateTime;
+               private Thread refreshThread;
+               protected Access access;
+
+               /**
+                * Construct:  Expect one or more Strings in the form:
+                *              192.555.112.223:39/38.88087/-77.30122
+                *    separated by commas
+                * 
+                * @param trans
+                * @param urlstr
+                * @param invalidateTime
+                * @param localLatitude
+                * @param localLongitude
+                * @throws LocatorException
+                */
+               @SuppressWarnings("unchecked")
+               protected HotPeerLocator(Access access, final String urlstr, final long invalidateTime, final String localLatitude, final String localLongitude) throws LocatorException {
+                       this.access = access;
+                       urlstrs = Split.split(',', urlstr);
+                       clients = (CLIENT[])new Object[urlstrs.length];
+                       failures = new long[urlstrs.length];
+                       distances= new double[urlstrs.length];
+                       this.invalidateTime = invalidateTime;
+                       
+                       double distance = Double.MAX_VALUE;
+                       for(int i=0;i<urlstrs.length;++i) {
+                               String[] info = Split.split('/', urlstrs[i]);
+                               if(info.length<3) {
+                                       throw new LocatorException("Configuration needs LAT and LONG, i.e. ip:port/lat/long");
+                               }
+                               try {
+                                       clients[i] = _newClient(urlstrs[i]);
+                                       failures[i] = 0L;
+                               } catch(LocatorException le) {
+                                       failures[i] = System.currentTimeMillis()+invalidateTime;
+                               }
+                               
+                               double d = GreatCircle.calc(info[1],info[2],localLatitude,localLongitude);
+                               distances[i]=d;
+                               
+                               // find preferred server
+                               if(d<distance) {
+                                       preferred = i;
+                                       distance=d;
+                               }
+                       }
+                       
+                       access.printf(Level.INIT,"Preferred Client is %s",urlstrs[preferred]);
+                       for(int i=0;i<urlstrs.length;++i) {
+                               if(i!=preferred) {
+                                       access.printf(Level.INIT,"Alternate Client is %s",urlstrs[i]);
+                               }
+                       }
+               }
+               
+               protected abstract CLIENT _newClient(String hostInfo) throws LocatorException;
+               /**
+                * If client can reconnect, then return.  Otherwise, destroy and return null;
+                * @param client
+                * @return
+                * @throws LocatorException
+                */
+               protected abstract CLIENT _invalidate(CLIENT client);
+               
+               protected abstract void _destroy(CLIENT client);
+               
+               @Override
+               public Item best() throws LocatorException {
+                       if(failures[preferred]==0L) {
+                               return new HPItem(preferred);
+                       } else {
+                               long now = System.currentTimeMillis();
+                               double d = Double.MAX_VALUE;
+                               int best = -1;
+                               boolean tickle = false;
+                               // try for best existing client
+                               for(int i=0;i<urlstrs.length;++i) {
+                                       if(failures[i]<now && distances[i]<d) {
+                                               if(clients[i]!=null) {
+                                                       best = i;
+                                                       break;
+                                               } else {
+                                                       tickle = true; // There's some failed clients which can be restored
+                                               }
+                                       }
+                               }
+                               if(best<0 && tickle) {
+                                       tickle=false;
+                                       if(refresh()) {
+                                               // try again
+                                               for(int i=0;i<urlstrs.length;++i) {
+                                                       if(failures[i]==0L && distances[i]<d) {
+                                                               if(clients[i]!=null) {
+                                                                       best = i;
+                                                                       break;
+                                                               }
+                                                       }
+                                               }
+                                       }
+                               }
+                       
+                               /*
+                                * If a valid client is available, but there are some that can refresh, return the client immediately
+                                * but start a Thread to do the background Client setup.
+                                */
+                               if(tickle) {
+                                       synchronized(clients) {
+                                               if(refreshThread==null) {
+                                                       refreshThread = new Thread(new Runnable(){
+                                                               @Override
+                                                               public void run() {
+                                                                       refresh();
+                                                                       refreshThread = null;
+                                                               }
+                                                       });
+                                                       refreshThread.setDaemon(true);
+                                                       refreshThread.start();
+                                               }
+                                       }
+                               }
+                               
+                               if(best<0) {
+                                       throw new LocatorException("No Clients available");
+                               }
+
+                               
+                               return new HPItem(best);
+                       }
+               }
+               
+
+               @Override
+               public CLIENT get(Item item) throws LocatorException {
+                       HPItem hpi = (HPItem)item;
+                       CLIENT c = clients[hpi.idx];
+                       if(c==null) {
+                               if(failures[hpi.idx]>System.currentTimeMillis()) {
+                                       throw new LocatorException("Client requested is invalid");      
+                               } else {
+                                       synchronized(clients) {
+                                               c = _newClient(urlstrs[hpi.idx]);
+                                               failures[hpi.idx]=0L;
+                                       }
+                               }
+                       } else if(failures[hpi.idx]>0){
+                               throw new LocatorException("Client requested is invalid");
+                       }
+                       return c;
+               }
+               
+               public String info(Item item) {
+                       HPItem hpi = (HPItem)item;
+                       if(hpi!=null && hpi.idx<urlstrs.length) {
+                               return urlstrs[hpi.idx];
+                       } else {
+                               return "Invalid Item";
+                       }
+               }
+
+               @Override
+               public boolean hasItems() {
+                       for(int i=0;i<clients.length;++i) {
+                               if(clients[i]!=null && failures[i]==0L) {
+                                       return true;
+                               }
+                       }
+                       return false;
+               }
+               
+               @Override
+               public synchronized void invalidate(Item item) throws LocatorException {
+                       HPItem hpi = (HPItem)item;
+                       failures[hpi.idx] = System.currentTimeMillis() + invalidateTime;
+                       CLIENT c = clients[hpi.idx];
+                       clients[hpi.idx] = _invalidate(c);
+               }
+               
+               @Override
+               public Item first() throws LocatorException {
+                       return new HPItem(0);
+               }
+               
+               @Override
+               public Item next(Item item) throws LocatorException {
+                       HPItem hpi = (HPItem)item;
+                       if(++hpi.idx>=clients.length) {
+                               return null;
+                       }
+                       return hpi;
+               }
+               
+               @Override
+               public boolean refresh() {
+                       boolean force = !hasItems(); // If no Items at all, reset
+                       boolean rv = true;
+                       long now = System.currentTimeMillis();
+                       for(int i=0;i<clients.length;++i) {
+                               if(failures[i]>0L && (failures[i]<now || force)) { // retry
+                                       try {
+                                               synchronized(clients) {
+                                                       if(clients[i]==null) {
+                                                               clients[i]=_newClient(urlstrs[i]);
+                                                       }
+                                                       failures[i]=0L;
+                                               }
+                                       } catch (LocatorException e) {
+                                               failures[i]=now+invalidateTime;
+                                               rv = false;
+                                       }
+                               }
+                       }
+                       return rv;
+               }
+               
+               @Override
+               public void destroy() {
+                       for(int i=0;i<clients.length;++i) {
+                               if(clients[i]!=null) {
+                                       _destroy(clients[i]);
+                                       clients[i] = null;
+                               }
+                       }
+               }
+
+               private static class HPItem implements Item {
+                       private int idx;
+
+                       public HPItem(int i) {
+                               idx = i;
+                       }
+               }
+               
+
+               /*
+                * Convenience Functions
+                */
+               public CLIENT bestClient() throws LocatorException {
+                       return get(best());
+               }
+
+               public boolean invalidate(CLIENT client) throws LocatorException {
+                       for(int i=0;i<clients.length;++i) {
+                               if(clients[i]==client) { // yes, "==" is appropriate here.. Comparing Java Object Reference
+                                       invalidate(new HPItem(i));
+                                       return true;
+                               }
+                       }
+                       return false;
+               }
+
+       }
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