Adding persistence to the gossip application store.

Change-Id: Ib1382f9d1009297dde902f0d3e0daf27596587c5

@@ -121,6 +121,17 @@ public class ApplicationArchive
     }
 
     /**
+     * Returns the timestamp in millis since start of epoch, of when the
+     * specified application was last modified or changed state.
+     *
+     * @param appName application name
+     * @return number of millis since start of epoch
+     */
+    public long getUpdateTime(String appName) {
+        return appFile(appName, APP_XML).lastModified();
+    }
+
+    /**
      * Loads the application descriptor from the specified application archive
      * stream and saves the stream in the appropriate application archive
      * directory.
@@ -313,7 +324,7 @@ public class ApplicationArchive
      */
     protected boolean setActive(String appName) {
         try {
-            return appFile(appName, "active").createNewFile();
+            return appFile(appName, "active").createNewFile() && updateTime(appName);
         } catch (IOException e) {
             throw new ApplicationException("Unable to mark app as active", e);
         }
@@ -326,7 +337,17 @@ public class ApplicationArchive
      * @return true if file was deleted
      */
     protected boolean clearActive(String appName) {
-        return appFile(appName, "active").delete();
+        return appFile(appName, "active").delete() && updateTime(appName);
+    }
+
+    /**
+     * Updates the time-stamp of the app descriptor file.
+     *
+     * @param appName application name
+     * @return true if the app descriptor was updated
+     */
+    private boolean updateTime(String appName) {
+        return appFile(appName, APP_XML).setLastModified(System.currentTimeMillis());
     }
 
     /**

@@ -18,7 +18,6 @@ package org.onosproject.store.app;
 import com.google.common.base.Charsets;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.util.concurrent.ListenableFuture;
-
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
@@ -31,6 +30,7 @@ import org.onosproject.app.ApplicationEvent;
 import org.onosproject.app.ApplicationException;
 import org.onosproject.app.ApplicationState;
 import org.onosproject.app.ApplicationStore;
+import org.onosproject.app.ApplicationStoreDelegate;
 import org.onosproject.cluster.ClusterService;
 import org.onosproject.cluster.ControllerNode;
 import org.onosproject.common.app.ApplicationArchive;
@@ -47,6 +47,8 @@ import org.onosproject.store.ecmap.EventuallyConsistentMap;
 import org.onosproject.store.ecmap.EventuallyConsistentMapEvent;
 import org.onosproject.store.ecmap.EventuallyConsistentMapImpl;
 import org.onosproject.store.ecmap.EventuallyConsistentMapListener;
+import org.onosproject.store.impl.ClockService;
+import org.onosproject.store.impl.MultiValuedTimestamp;
 import org.onosproject.store.impl.WallclockClockManager;
 import org.onosproject.store.serializers.KryoNamespaces;
 import org.slf4j.Logger;
@@ -59,6 +61,7 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.atomic.AtomicLong;
 
 import static com.google.common.io.ByteStreams.toByteArray;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
@@ -105,10 +108,13 @@ public class GossipApplicationStore extends ApplicationArchive
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ApplicationIdStore idStore;
 
+    private final AtomicLong sequence = new AtomicLong();
+
     @Activate
     public void activate() {
-        KryoNamespace.Builder intentSerializer = KryoNamespace.newBuilder()
+        KryoNamespace.Builder serializer = KryoNamespace.newBuilder()
                 .register(KryoNamespaces.API)
+                .register(MultiValuedTimestamp.class)
                 .register(InternalState.class);
 
         executor = Executors.newSingleThreadScheduledExecutor(groupedThreads("onos/app", "store"));
@@ -118,35 +124,48 @@ public class GossipApplicationStore extends ApplicationArchive
 
         clusterCommunicator.addSubscriber(APP_BITS_REQUEST, new InternalBitServer(), messageHandlingExecutor);
 
+        // FIXME: Consider consolidating into a single map.
+
+        ClockService<ApplicationId, Application> appsClockService = (appId, app) ->
+                new MultiValuedTimestamp<>(getUpdateTime(appId.name()),
+                                           sequence.incrementAndGet());
+
         apps = new EventuallyConsistentMapImpl<>("apps", clusterService,
                                                  clusterCommunicator,
-                                                 intentSerializer,
-                                                 new WallclockClockManager<>());
+                                                 serializer,
+                                                 appsClockService);
+
+        ClockService<Application, InternalState> statesClockService = (app, state) ->
+                new MultiValuedTimestamp<>(getUpdateTime(app.id().name()),
+                                           sequence.incrementAndGet());
 
         states = new EventuallyConsistentMapImpl<>("app-states",
                                                    clusterService,
                                                    clusterCommunicator,
-                                                   intentSerializer,
-                                                   new WallclockClockManager<>());
+                                                   serializer,
+                                                   statesClockService);
         states.addListener(new InternalAppStatesListener());
 
         permissions = new EventuallyConsistentMapImpl<>("app-permissions",
                                                         clusterService,
                                                         clusterCommunicator,
-                                                        intentSerializer,
+                                                        serializer,
                                                         new WallclockClockManager<>());
 
-        // FIXME: figure out load from disk; this will require resolving the dual authority problem
-
-        executor.schedule(this::pruneUninstalledApps, LOAD_TIMEOUT_MS, MILLISECONDS);
-
         log.info("Started");
     }
 
+    /**
+     * Loads the application inventory from the disk and activates apps if
+     * they are marked to be active.
+     */
     private void loadFromDisk() {
         for (String name : getApplicationNames()) {
-            create(getApplicationDescription(name));
-            // load app permissions
+            Application app = create(getApplicationDescription(name));
+            if (app != null && isActive(app.id().name())) {
+                activate(app.id());
+                // load app permissions
+            }
         }
     }
 
@@ -162,6 +181,13 @@ public class GossipApplicationStore extends ApplicationArchive
     }
 
     @Override
+    public void setDelegate(ApplicationStoreDelegate delegate) {
+        super.setDelegate(delegate);
+        loadFromDisk();
+//        executor.schedule(this::pruneUninstalledApps, LOAD_TIMEOUT_MS, MILLISECONDS);
+    }
+
+    @Override
     public Set<Application> getApplications() {
         return ImmutableSet.copyOf(apps.values());
     }
@@ -403,5 +429,6 @@ public class GossipApplicationStore extends ApplicationArchive
                                       appDesc.origin(), appDesc.permissions(),
                                       appDesc.featuresRepo(), appDesc.features());
     }
+
 }