[ONOS-5729] VirtualFlowRuleStore implementation

Changes
1. VirtualStore and AbstractVirtualStore are defined
2. SimpleFlowRuleStore is added
3. FlowRuleStoreDeligate is implemented

Change-Id: Ic1f3d25f8a52d8c9bb6bc4de67abc0d642f47c9c
diff --git a/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java b/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java
new file mode 100644
index 0000000..ff13ac2
--- /dev/null
+++ b/incubator/store/src/main/java/org/onosproject/incubator/store/virtual/impl/SimpleVirtualFlowRuleStore.java
@@ -0,0 +1,403 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.
+ */
+
+package org.onosproject.incubator.store.virtual.impl;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.RemovalListener;
+import com.google.common.cache.RemovalNotification;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.Sets;
+import com.google.common.util.concurrent.SettableFuture;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Modified;
+import org.apache.felix.scr.annotations.Property;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.util.Tools;
+import org.onosproject.incubator.net.virtual.NetworkId;
+import org.onosproject.incubator.net.virtual.VirtualNetworkFlowRuleStore;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.flow.CompletedBatchOperation;
+import org.onosproject.net.flow.DefaultFlowEntry;
+import org.onosproject.net.flow.FlowEntry;
+import org.onosproject.net.flow.FlowId;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.flow.FlowRuleBatchEntry;
+import org.onosproject.net.flow.FlowRuleBatchEvent;
+import org.onosproject.net.flow.FlowRuleBatchOperation;
+import org.onosproject.net.flow.FlowRuleBatchRequest;
+import org.onosproject.net.flow.FlowRuleEvent;
+import org.onosproject.net.flow.FlowRuleStoreDelegate;
+import org.onosproject.net.flow.StoredFlowEntry;
+import org.onosproject.net.flow.TableStatisticsEntry;
+import org.onosproject.store.service.StorageService;
+import org.osgi.service.component.ComponentContext;
+import org.slf4j.Logger;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Dictionary;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.onosproject.net.flow.FlowRuleEvent.Type.RULE_REMOVED;
+import static org.slf4j.LoggerFactory.getLogger;
+
+//TODO: support distributed flowrule store for virtual networks
+
+@Component(immediate = true)
+@Service
+public class SimpleVirtualFlowRuleStore
+        extends AbstractVirtualStore<FlowRuleBatchEvent, FlowRuleStoreDelegate>
+        implements VirtualNetworkFlowRuleStore {
+
+    private final Logger log = getLogger(getClass());
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected StorageService storageService;
+
+    private final ConcurrentMap<NetworkId,
+            ConcurrentMap<DeviceId, ConcurrentMap<FlowId, List<StoredFlowEntry>>>>
+            flowEntries = new ConcurrentHashMap<>();
+
+
+    private final AtomicInteger localBatchIdGen = new AtomicInteger();
+
+    private static final int DEFAULT_PENDING_FUTURE_TIMEOUT_MINUTES = 5;
+    @Property(name = "pendingFutureTimeoutMinutes", intValue = DEFAULT_PENDING_FUTURE_TIMEOUT_MINUTES,
+            label = "Expiration time after an entry is created that it should be automatically removed")
+    private int pendingFutureTimeoutMinutes = DEFAULT_PENDING_FUTURE_TIMEOUT_MINUTES;
+
+    private Cache<Integer, SettableFuture<CompletedBatchOperation>> pendingFutures =
+            CacheBuilder.newBuilder()
+                    .expireAfterWrite(pendingFutureTimeoutMinutes, TimeUnit.MINUTES)
+                    .removalListener(new TimeoutFuture())
+                    .build();
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        flowEntries.clear();
+        log.info("Stopped");
+    }
+
+    @Modified
+    public void modified(ComponentContext context) {
+
+        readComponentConfiguration(context);
+
+        // Reset Cache and copy all.
+        Cache<Integer, SettableFuture<CompletedBatchOperation>> prevFutures = pendingFutures;
+        pendingFutures = CacheBuilder.newBuilder()
+                .expireAfterWrite(pendingFutureTimeoutMinutes, TimeUnit.MINUTES)
+                .removalListener(new TimeoutFuture())
+                .build();
+
+        pendingFutures.putAll(prevFutures.asMap());
+    }
+
+    /**
+     * Extracts properties from the component configuration context.
+     *
+     * @param context the component context
+     */
+    private void readComponentConfiguration(ComponentContext context) {
+        Dictionary<?, ?> properties = context.getProperties();
+
+        Integer newPendingFutureTimeoutMinutes =
+                Tools.getIntegerProperty(properties, "pendingFutureTimeoutMinutes");
+        if (newPendingFutureTimeoutMinutes == null) {
+            pendingFutureTimeoutMinutes = DEFAULT_PENDING_FUTURE_TIMEOUT_MINUTES;
+            log.info("Pending future timeout is not configured, " +
+                             "using current value of {}", pendingFutureTimeoutMinutes);
+        } else {
+            pendingFutureTimeoutMinutes = newPendingFutureTimeoutMinutes;
+            log.info("Configured. Pending future timeout is configured to {}",
+                     pendingFutureTimeoutMinutes);
+        }
+    }
+
+    @Override
+    public int getFlowRuleCount(NetworkId networkId) {
+
+        int sum = 0;
+        for (ConcurrentMap<FlowId, List<StoredFlowEntry>> ft :
+                flowEntries.get(networkId).values()) {
+            for (List<StoredFlowEntry> fes : ft.values()) {
+                sum += fes.size();
+            }
+        }
+        return sum;
+    }
+
+    @Override
+    public FlowEntry getFlowEntry(NetworkId networkId, FlowRule rule) {
+        return getFlowEntryInternal(networkId, rule.deviceId(), rule);
+    }
+
+    @Override
+    public Iterable<FlowEntry> getFlowEntries(NetworkId networkId, DeviceId deviceId) {
+        return FluentIterable.from(getFlowTable(networkId, deviceId).values())
+                .transformAndConcat(Collections::unmodifiableList);
+    }
+
+    @Override
+    public void storeFlowRule(NetworkId networkId, FlowRule rule) {
+        storeFlowRuleInternal(networkId, rule);
+    }
+
+    @Override
+    public void storeBatch(NetworkId networkId, FlowRuleBatchOperation batchOperation) {
+        List<FlowRuleBatchEntry> toAdd = new ArrayList<>();
+        List<FlowRuleBatchEntry> toRemove = new ArrayList<>();
+
+        for (FlowRuleBatchEntry entry : batchOperation.getOperations()) {
+            final FlowRule flowRule = entry.target();
+            if (entry.operator().equals(FlowRuleBatchEntry.FlowRuleOperation.ADD)) {
+                if (!getFlowEntries(networkId, flowRule.deviceId(),
+                                    flowRule.id()).contains(flowRule)) {
+                    storeFlowRule(networkId, flowRule);
+                    toAdd.add(entry);
+                }
+            } else if (entry.operator().equals(FlowRuleBatchEntry.FlowRuleOperation.REMOVE)) {
+                if (getFlowEntries(networkId, flowRule.deviceId(), flowRule.id()).contains(flowRule)) {
+                    deleteFlowRule(networkId, flowRule);
+                    toRemove.add(entry);
+                }
+            } else {
+                throw new UnsupportedOperationException("Unsupported operation type");
+            }
+        }
+
+        if (toAdd.isEmpty() && toRemove.isEmpty()) {
+            notifyDelegate(networkId, FlowRuleBatchEvent.completed(
+                    new FlowRuleBatchRequest(batchOperation.id(), Collections.emptySet()),
+                    new CompletedBatchOperation(true, Collections.emptySet(),
+                                                batchOperation.deviceId())));
+            return;
+        }
+
+        SettableFuture<CompletedBatchOperation> r = SettableFuture.create();
+        final int batchId = localBatchIdGen.incrementAndGet();
+
+        pendingFutures.put(batchId, r);
+
+        toAdd.addAll(toRemove);
+        notifyDelegate(networkId, FlowRuleBatchEvent.requested(
+                new FlowRuleBatchRequest(batchId, Sets.newHashSet(toAdd)), batchOperation.deviceId()));
+
+    }
+
+    @Override
+    public void batchOperationComplete(NetworkId networkId, FlowRuleBatchEvent event) {
+        final Long batchId = event.subject().batchId();
+        SettableFuture<CompletedBatchOperation> future
+                = pendingFutures.getIfPresent(batchId);
+        if (future != null) {
+            future.set(event.result());
+            pendingFutures.invalidate(batchId);
+        }
+        notifyDelegate(networkId, event);
+    }
+
+    @Override
+    public void deleteFlowRule(NetworkId networkId, FlowRule rule) {
+        List<StoredFlowEntry> entries = getFlowEntries(networkId, rule.deviceId(), rule.id());
+
+        synchronized (entries) {
+            for (StoredFlowEntry entry : entries) {
+                if (entry.equals(rule)) {
+                    synchronized (entry) {
+                        entry.setState(FlowEntry.FlowEntryState.PENDING_REMOVE);
+                    }
+                }
+            }
+        }
+    }
+
+    @Override
+    public FlowRuleEvent addOrUpdateFlowRule(NetworkId networkId, FlowEntry rule) {
+        // check if this new rule is an update to an existing entry
+        List<StoredFlowEntry> entries = getFlowEntries(networkId, rule.deviceId(), rule.id());
+        synchronized (entries) {
+            for (StoredFlowEntry stored : entries) {
+                if (stored.equals(rule)) {
+                    synchronized (stored) {
+                        //FIXME modification of "stored" flow entry outside of flow table
+                        stored.setBytes(rule.bytes());
+                        stored.setLife(rule.life());
+                        stored.setPackets(rule.packets());
+                        if (stored.state() == FlowEntry.FlowEntryState.PENDING_ADD) {
+                            stored.setState(FlowEntry.FlowEntryState.ADDED);
+                            // TODO: Do we need to change `rule` state?
+                            return new FlowRuleEvent(FlowRuleEvent.Type.RULE_ADDED, rule);
+                        }
+                        return new FlowRuleEvent(FlowRuleEvent.Type.RULE_UPDATED, rule);
+                    }
+                }
+            }
+        }
+
+        // should not reach here
+        // storeFlowRule was expected to be called
+        log.error("FlowRule was not found in store {} to update", rule);
+
+        return null;
+    }
+
+    @Override
+    public FlowRuleEvent removeFlowRule(NetworkId networkId, FlowEntry rule) {
+        // This is where one could mark a rule as removed and still keep it in the store.
+        final DeviceId did = rule.deviceId();
+
+        List<StoredFlowEntry> entries = getFlowEntries(networkId, did, rule.id());
+        synchronized (entries) {
+            if (entries.remove(rule)) {
+                return new FlowRuleEvent(RULE_REMOVED, rule);
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public FlowRuleEvent pendingFlowRule(NetworkId networkId, FlowEntry rule) {
+        List<StoredFlowEntry> entries = getFlowEntries(networkId, rule.deviceId(), rule.id());
+        synchronized (entries) {
+            for (StoredFlowEntry entry : entries) {
+                if (entry.equals(rule) &&
+                        entry.state() != FlowEntry.FlowEntryState.PENDING_ADD) {
+                    synchronized (entry) {
+                        entry.setState(FlowEntry.FlowEntryState.PENDING_ADD);
+                        return new FlowRuleEvent(FlowRuleEvent.Type.RULE_UPDATED, rule);
+                    }
+                }
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public void purgeFlowRule(NetworkId networkId, DeviceId deviceId) {
+        flowEntries.get(networkId).remove(deviceId);
+    }
+
+    @Override
+    public void purgeFlowRules(NetworkId networkId) {
+        flowEntries.get(networkId).clear();
+    }
+
+    @Override
+    public FlowRuleEvent
+    updateTableStatistics(NetworkId networkId, DeviceId deviceId, List<TableStatisticsEntry> tableStats) {
+        //TODO: Table operations are not supported yet
+        return null;
+    }
+
+    @Override
+    public Iterable<TableStatisticsEntry>
+    getTableStatistics(NetworkId networkId, DeviceId deviceId) {
+        //TODO: Table operations are not supported yet
+        return null;
+    }
+
+    /**
+     * Returns the flow table for specified device.
+     *
+     * @param networkId identifier of the virtual network
+     * @param deviceId identifier of the virtual device
+     * @return Map representing Flow Table of given device.
+     */
+    private ConcurrentMap<FlowId, List<StoredFlowEntry>>
+    getFlowTable(NetworkId networkId, DeviceId deviceId) {
+        return flowEntries
+                .computeIfAbsent(networkId, n -> new ConcurrentHashMap<>())
+                .computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
+    }
+
+    private List<StoredFlowEntry>
+    getFlowEntries(NetworkId networkId, DeviceId deviceId, FlowId flowId) {
+        final ConcurrentMap<FlowId, List<StoredFlowEntry>> flowTable
+                = getFlowTable(networkId, deviceId);
+
+        List<StoredFlowEntry> r = flowTable.get(flowId);
+        if (r == null) {
+            final List<StoredFlowEntry> concurrentlyAdded;
+            r = new CopyOnWriteArrayList<>();
+            concurrentlyAdded = flowTable.putIfAbsent(flowId, r);
+            if (concurrentlyAdded != null) {
+                return concurrentlyAdded;
+            }
+        }
+        return r;
+    }
+
+    private FlowEntry
+    getFlowEntryInternal(NetworkId networkId, DeviceId deviceId, FlowRule rule) {
+        List<StoredFlowEntry> fes = getFlowEntries(networkId, deviceId, rule.id());
+        for (StoredFlowEntry fe : fes) {
+            if (fe.equals(rule)) {
+                return fe;
+            }
+        }
+        return null;
+    }
+
+    private void storeFlowRuleInternal(NetworkId networkId, FlowRule rule) {
+        StoredFlowEntry f = new DefaultFlowEntry(rule);
+        final DeviceId did = f.deviceId();
+        final FlowId fid = f.id();
+        List<StoredFlowEntry> existing = getFlowEntries(networkId, did, fid);
+        synchronized (existing) {
+            for (StoredFlowEntry fe : existing) {
+                if (fe.equals(rule)) {
+                    // was already there? ignore
+                    return;
+                }
+            }
+            // new flow rule added
+            existing.add(f);
+        }
+    }
+
+    private static final class TimeoutFuture
+            implements RemovalListener<Integer, SettableFuture<CompletedBatchOperation>> {
+        @Override
+        public void onRemoval(RemovalNotification<Integer,
+                SettableFuture<CompletedBatchOperation>> notification) {
+            // wrapping in ExecutionException to support Future.get
+            if (notification.wasEvicted()) {
+                notification.getValue()
+                        .setException(new ExecutionException("Timed out",
+                                                             new TimeoutException()));
+            }
+        }
+    }
+}