Restart/Logging/Debug tweaks

src/main/java/org/jlab/epics2web/Application.java

@@ -62,6 +62,7 @@ public static Future<?> writeFromBlockingQueue(Session session) {
         return writerExecutor.submit(new Runnable() {
             @Override
             public void run() {
+                final String id = session.getId() + " / " + session.getUserProperties().get("ip");
                 final ArrayBlockingQueue<String> writequeue = (ArrayBlockingQueue<String>) session.getUserProperties().get("writequeue");
                 try {
                     while (true) {
@@ -72,7 +73,7 @@ public void run() {
                                 try {
                                     session.getBasicRemote().sendText(msg);
                                 } catch (IllegalStateException | IOException e) { // If session closes between time session.isOpen() and sentText(msg) then you'll get this exception.  Not an issue.
-                                    LOGGER.log(Level.FINEST, "Unable to send message: ", e);
+                                    LOGGER.log(Level.FINEST, "Unable to send message to " + id, e);
 
                                     if (!session.isOpen()) {
                                         LOGGER.log(Level.FINEST, "Session closed after write exception; shutting down write thread");
@@ -81,12 +82,12 @@ public void run() {
                                 }
                             }
                         } else {
-                            LOGGER.log(Level.FINEST, "Session closed; shutting down write thread");
+                            LOGGER.log(Level.FINEST, "Session {0} closed; shutting down write thread", id);
                             break;
                         }
                     }
                 } catch (InterruptedException e) {
-                    LOGGER.log(Level.FINEST, "Shutting down writer thread as requested", e);
+                    LOGGER.log(Level.FINEST, "Shutting down {0} writer thread as requested by InterruptException", id);
                 }
             }
         });

src/main/java/org/jlab/epics2web/controller/WebConsole.java

@@ -8,9 +8,9 @@
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-import javax.websocket.Session;
 import org.jlab.epics2web.Application;
 import org.jlab.epics2web.epics.ChannelMonitor;
+import org.jlab.epics2web.websocket.SessionInfo;
 import org.jlab.epics2web.websocket.WebSocketSessionManager;
 import org.jlab.epics2web.epics.ChannelManager;
 
@@ -40,7 +40,7 @@ protected void doGet(HttpServletRequest request, HttpServletResponse response)
 
 
         Map<String, ChannelMonitor> monitorMap = channelManager.getMonitorMap();
-        Map<Session, Set<String>> clientMap = sessionManager.getClientMap();
+        Map<SessionInfo, Set<String>> clientMap = sessionManager.getClientMap();
 
         request.setAttribute("monitorMap", monitorMap);
         request.setAttribute("clientMap", clientMap);

src/main/java/org/jlab/epics2web/epics/ChannelManager.java

@@ -130,7 +130,9 @@ public static String getDbrValueAsString(DBR dbr) {
 
     public void addValueToJSON(JsonObjectBuilder builder, DBR dbr) {
         try {
-            if (dbr.isDOUBLE()) {
+            if(dbr == null) {
+                builder.addNull("value"); // null happens on restart?
+            } else if (dbr.isDOUBLE()) {
                 double value = ((gov.aps.jca.dbr.DOUBLE) dbr).getDoubleValue()[0];
                 if (Double.isFinite(value)) {
                     builder.add("value", value);
@@ -380,7 +382,7 @@ public Map<String, ChannelMonitor> getMonitorMap() {
      *
      * @return The listener to PVs map
      */
-    public Map<PvListener, Set<String>> getClientMap() {
+    public Map<PvListener, Set<String>> getListenerMap() {
         return Collections.unmodifiableMap(clientMap);
     }
 }

src/main/java/org/jlab/epics2web/epics/ChannelMonitor.java

@@ -266,7 +266,7 @@ public void run() {
                                 handleRegularConnectionOrReconnect();
                             }
                         } else {
-                            LOGGER.log(Level.FINE, "Notifying clients of disconnect from channel: {0}", pv);
+                            LOGGER.log(Level.FINEST, "Notifying clients of disconnect from channel: {0}", pv);
 
                             state.set(MonitorState.DISCONNECTED);
                             notifyPvInfoAll(false);

src/main/java/org/jlab/epics2web/websocket/SessionInfo.java

@@ -0,0 +1,43 @@
+package org.jlab.epics2web.websocket;
+
+/**
+ * This class provides a snapshot of websocket information that will not throw Exceptions if you try to interrogate it
+ * after the session happens to have closed.  There is a race condition if you hand a list of javax.websocket.Session
+ * objects to a debug console for example as if the session happens to close between the time you return it and the
+ * time the debug console calls the userProperties method for example you get an exception.
+ */
+public class SessionInfo {
+    private String id;
+    private String ip;
+    private String name;
+    private String agent;
+    private long droppedMessageCount;
+
+    public SessionInfo(String id, String ip, String name, String agent, long droppedMessageCount) {
+        this.id = id;
+        this.ip = ip;
+        this.name = name;
+        this.agent = agent;
+        this.droppedMessageCount = droppedMessageCount;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public String getIp() {
+        return ip;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getAgent() {
+        return agent;
+    }
+
+    public long getDroppedMessageCount() {
+        return droppedMessageCount;
+    }
+}

src/main/java/org/jlab/epics2web/websocket/WebSocketSessionManager.java

@@ -229,14 +229,33 @@ public void removePvs(Session session, Set<String> pvSet) {
      *
      * @return The map
      */
-    public Map<Session, Set<String>> getClientMap() {
-        Map<PvListener, Set<String>> pvMap = Application.channelManager.getClientMap();
-        Map<Session, Set<String>> clientMap = new HashMap<>();
+    public Map<SessionInfo, Set<String>> getClientMap() {
+        Map<PvListener, Set<String>> pvMap = Application.channelManager.getListenerMap();
+        Map<SessionInfo, Set<String>> clientMap = new HashMap<>();
 
         for (Session session : listenerMap.keySet()) {
             WebSocketSessionMonitor listener = listenerMap.get(session);
             Set<String> pvSet = pvMap.get(listener);
-            clientMap.put(session, pvSet);
+
+            if(session.isOpen()) {
+                String id = null;
+
+                try {
+                    id = session.getId();
+                    String ip = (String)session.getUserProperties().get("ip");
+                    String name = (String)session.getUserProperties().get("name");
+                    String agent = (String)session.getUserProperties().get("agent");
+                    AtomicLong droppedMessageCount = (AtomicLong)session.getUserProperties().get("droppedMessageCount");
+
+                    SessionInfo info = new SessionInfo(id, ip, name, agent, droppedMessageCount.get());
+
+                    clientMap.put(info, pvSet);
+                } catch(Exception e) {
+                    // Even id may be null if closed before getId() called.  Oh well.
+                    LOGGER.log(Level.FINEST, "Session '{0}' closed while preparing info report", id);
+                    // Ignore
+                }
+            }
         }
 
         return clientMap;
@@ -316,14 +335,17 @@ public void sendUpdate(Session session, String pv, DBR dbr) {
     @SuppressWarnings("unchecked")
     public void send(Session session, String pv, String msg) {
         if (session.isOpen()) {
+            String id = session.toString();
             if (Application.WRITE_STRATEGY == WriteStrategy.ASYNC_QUEUE) {
                 ConcurrentLinkedQueue<String> writequeue = (ConcurrentLinkedQueue<String>) session.getUserProperties().get("writequeue");               
-
-                //System.out.println("Queue Size: " + writequeue.size());
+
                 if (writequeue.size() > Application.WRITE_QUEUE_SIZE_LIMIT) {
-                    //LOGGER.log(Level.INFO, "Dropping message: {0}", msg);
                     AtomicLong dropCount = (AtomicLong)session.getUserProperties().get("droppedMessageCount");
-                    dropCount.getAndIncrement();
+                    long count = dropCount.getAndIncrement() + 1; // getAndIncrement is actually returning previous value, not newly updated, so we add 1.
+                    // Limit log file output by only reporting when thresholds are reached
+                    if(count == 1 || count == 1000 || count == 10000 || count == 100000) {
+                        LOGGER.log(Level.FINEST, "Session {0} queue full (limit={1}); Dropping pv {2} message: {3}; total dropped: {4}", new Object[]{id, Application.WRITE_QUEUE_SIZE_LIMIT, pv, msg, count});
+                    }
                 } else {
                     writequeue.offer(msg);
                 }
@@ -336,9 +358,12 @@ public void send(Session session, String pv, String msg) {
                 boolean success = writequeue.offer(msg);              
 
                 if(!success) {
-                    //LOGGER.log(Level.INFO, "Dropping message: {0}", msg);    
                     AtomicLong dropCount = (AtomicLong)session.getUserProperties().get("droppedMessageCount");
-                    dropCount.getAndIncrement();                       
+                    long count = dropCount.getAndIncrement() + 1;  // getAndIncrement is actually returning previous value, not newly updated, so we add 1.
+                    // Limit log file output by only reporting when thresholds are reached
+                    if(count == 1 || count == 1000 || count == 10000 || count == 100000) {
+                        LOGGER.log(Level.FINEST, "Session {0} queue full (limit={1}); Dropping pv {2} message: {3}; total dropped: {4}", new Object[]{id, Application.WRITE_QUEUE_SIZE_LIMIT, pv, msg, count});
+                    }
                 }                
             } else {
                 try {

src/main/webapp/WEB-INF/views/console.jsp

@@ -49,11 +49,11 @@
                 <c:forEach items="${clientMap}" var="client">
                     <tr>
                         <td><c:out value="${client.key.id}"/></td>
-                        <td><c:out value="${client.key.userProperties.ip eq null ? client.key.remoteAddr : client.key.userProperties.ip}"/></td>
-                        <td><c:out value="${client.key.userProperties.agent}"/></td>
-                        <td><c:out value="${client.key.userProperties.name}"/></td>
+                        <td><c:out value="${client.key.ip}"/></td>
+                        <td><c:out value="${client.key.agent}"/></td>
+                        <td><c:out value="${client.key.name}"/></td>
                         <td>(${client.value == null ? '0' : client.value.size()}) <c:out value="${client.value}"/></td>
-                        <td><fmt:formatNumber value="${client.key.userProperties.droppedMessageCount}"/></td>
+                        <td><fmt:formatNumber value="${client.key.droppedMessageCount}"/></td>
                     </tr>
                 </c:forEach>
             </tbody>