Renew slots when MOVED occured during request to Cluster

* It's suggested by http://redis.io/topics/cluster-spec
** antirez/redis-rb-cluster implementation does it, too
* Since Redis 3.0-beta 7 introduces CLUSTER SLOTS, it becomes easier
* FIXME: It's fully synchronized, so it hurts performance (somewhat poor implementation)
** We can try Reader / Writer strategy to make lock waiting make shorter

src/main/java/redis/clients/jedis/JedisClusterCommand.java

@@ -72,13 +72,15 @@ public abstract class JedisClusterCommand<T> {
 	} catch (JedisRedirectionException jre) {
 	    if (jre instanceof JedisAskDataException) {
 		asking = true;
-	    } else if (jre instanceof JedisMovedDataException) {
-		// TODO : In antirez's redis-rb-cluster implementation, 
-		// it rebuilds cluster's slot and node cache
-	    }
-
-	    this.connectionHandler.assignSlotToNode(jre.getSlot(),
-		    jre.getTargetNode());
+            this.connectionHandler.assignSlotToNode(jre.getSlot(),
+                    jre.getTargetNode());
+        } else if (jre instanceof JedisMovedDataException) {
+            // it rebuilds cluster's slot cache
+            // recommended by Redis cluster specification
+            this.connectionHandler.renewSlotCache();
+        } else {
+            throw new JedisClusterException(jre);
+        }
 
 	    releaseConnection(connection, false);
 	    connection = null;

src/main/java/redis/clients/jedis/JedisClusterConnectionHandler.java

@@ -1,27 +1,26 @@
 package redis.clients.jedis;
 
-import java.util.*;
-
 import redis.clients.jedis.exceptions.JedisConnectionException;
-import redis.clients.util.ClusterNodeInformation;
-import redis.clients.util.ClusterNodeInformationParser;
+
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+
+import static redis.clients.jedis.JedisClusterInfoCache.getNodeKey;
 
 public abstract class JedisClusterConnectionHandler {
-    public static ClusterNodeInformationParser nodeInfoParser = new ClusterNodeInformationParser();
-
-    protected Map<String, JedisPool> nodes = new HashMap<String, JedisPool>();
-    protected Map<Integer, JedisPool> slots = new HashMap<Integer, JedisPool>();
+    protected JedisClusterInfoCache cache = new JedisClusterInfoCache();
 
     abstract Jedis getConnection();
 
-    protected void returnConnection(Jedis connection) {
-	nodes.get(getNodeKey(connection.getClient()))
-		.returnResource(connection);
+    public void returnConnection(Jedis connection) {
+        cache.getNode(getNodeKey(connection.getClient()))
+                .returnResource(connection);
     }
 
     public void returnBrokenConnection(Jedis connection) {
-	nodes.get(getNodeKey(connection.getClient())).returnBrokenResource(
-		connection);
+        cache.getNode(getNodeKey(connection.getClient()))
+                .returnBrokenResource(connection);
     }
 
     abstract Jedis getConnectionFromSlot(int slot);
@@ -31,7 +30,11 @@ public abstract class JedisClusterConnectionHandler {
     }
 
     public Map<String, JedisPool> getNodes() {
-	return nodes;
+	return cache.getNodes();
+    }
+
+    public void assignSlotToNode(int slot, HostAndPort targetNode) {
+        cache.assignSlotToNode(slot, targetNode);
     }
 
     private void initializeSlotsCache(Set<HostAndPort> startNodes) {
@@ -39,89 +42,43 @@ public abstract class JedisClusterConnectionHandler {
 	    JedisPool jp = new JedisPool(hostAndPort.getHost(),
 		    hostAndPort.getPort());
 
-	    this.nodes.clear();
-	    this.slots.clear();
-
 	    Jedis jedis = null;
 	    try {
 		jedis = jp.getResource();
-		discoverClusterNodesAndSlots(jedis);
+        cache.discoverClusterNodesAndSlots(jedis);
 		break;
 	    } catch (JedisConnectionException e) {
-		if (jedis != null) {
-		    jp.returnBrokenResource(jedis);
-		    jedis = null;
-		}
-
 		// try next nodes
 	    } finally {
-		if (jedis != null) {
-		    jp.returnResource(jedis);
-		}
+            if (jedis != null) {
+                jedis.close();
+            }
 	    }
 	}
 
 	for (HostAndPort node : startNodes) {
-	    setNodeIfNotExist(node);
+	    cache.setNodeIfNotExist(node);
 	}
     }
 
-    private void discoverClusterNodesAndSlots(Jedis jedis) {
-	String localNodes = jedis.clusterNodes();
-	for (String nodeInfo : localNodes.split("\n")) {
-	    ClusterNodeInformation clusterNodeInfo = nodeInfoParser.parse(
-		    nodeInfo, new HostAndPort(jedis.getClient().getHost(),
-			    jedis.getClient().getPort()));
-
-	    HostAndPort targetNode = clusterNodeInfo.getNode();
-	    setNodeIfNotExist(targetNode);
-	    assignSlotsToNode(clusterNodeInfo.getAvailableSlots(), targetNode);
-	}
-    }
-
-    public void assignSlotToNode(int slot, HostAndPort targetNode) {
-	JedisPool targetPool = nodes.get(getNodeKey(targetNode));
-
-	if (targetPool == null) {
-	    setNodeIfNotExist(targetNode);
-	    targetPool = nodes.get(getNodeKey(targetNode));
-	}
-	slots.put(slot, targetPool);
-    }
-
-    public void assignSlotsToNode(List<Integer> targetSlots,
-	    HostAndPort targetNode) {
-	JedisPool targetPool = nodes.get(getNodeKey(targetNode));
-
-	if (targetPool == null) {
-	    setNodeIfNotExist(targetNode);
-	    targetPool = nodes.get(getNodeKey(targetNode));
-	}
-
-	for (Integer slot : targetSlots) {
-	    slots.put(slot, targetPool);
-	}
+    public void renewSlotCache() {
+        for (JedisPool jp : cache.getNodes().values()) {
+            Jedis jedis = null;
+            try {
+                jedis = jp.getResource();
+                cache.discoverClusterSlots(jedis);
+                break;
+            } finally {
+                if (jedis != null) {
+                    jedis.close();
+                }
+            }
+        }
     }
 
     protected JedisPool getRandomConnection() {
-	Object[] nodeArray = nodes.values().toArray();
+	Object[] nodeArray = cache.getNodes().values().toArray();
 	return (JedisPool) (nodeArray[new Random().nextInt(nodeArray.length)]);
     }
 
-    protected String getNodeKey(HostAndPort hnp) {
-	return hnp.getHost() + ":" + hnp.getPort();
-    }
-
-    protected String getNodeKey(Client client) {
-	return client.getHost() + ":" + client.getPort();
-    }
-
-    private void setNodeIfNotExist(HostAndPort node) {
-	String nodeKey = getNodeKey(node);
-	if (nodes.containsKey(nodeKey))
-	    return;
-
-	JedisPool nodePool = new JedisPool(node.getHost(), node.getPort());
-	nodes.put(nodeKey, nodePool);
-    }
 }

src/main/java/redis/clients/jedis/JedisClusterInfoCache.java

@@ -0,0 +1,127 @@
+package redis.clients.jedis;
+
+import redis.clients.util.ClusterNodeInformation;
+import redis.clients.util.ClusterNodeInformationParser;
+import redis.clients.util.SafeEncoder;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class JedisClusterInfoCache {
+    public static final ClusterNodeInformationParser nodeInfoParser = new ClusterNodeInformationParser();
+
+    private Map<String, JedisPool> nodes = new HashMap<String, JedisPool>();
+    private Map<Integer, JedisPool> slots = new HashMap<Integer, JedisPool>();
+
+    public synchronized void discoverClusterNodesAndSlots(Jedis jedis) {
+        this.nodes.clear();
+        this.slots.clear();
+
+        String localNodes = jedis.clusterNodes();
+        for (String nodeInfo : localNodes.split("\n")) {
+            ClusterNodeInformation clusterNodeInfo = nodeInfoParser.parse(
+                    nodeInfo, new HostAndPort(jedis.getClient().getHost(),
+                            jedis.getClient().getPort()));
+
+            HostAndPort targetNode = clusterNodeInfo.getNode();
+            setNodeIfNotExist(targetNode);
+            assignSlotsToNode(clusterNodeInfo.getAvailableSlots(), targetNode);
+        }
+    }
+
+    public synchronized void discoverClusterSlots(Jedis jedis) {
+        this.slots.clear();
+
+        List<Object> slots = jedis.clusterSlots();
+
+        for (Object slotInfoObj : slots) {
+            List<Object> slotInfo = (List<Object>) slotInfoObj;
+
+            if (slotInfo.size() <= 2) {
+                continue;
+            }
+
+            // assigned slots
+            List<Integer> slotNums = new ArrayList<Integer>();
+            for (int slot = ((Long) slotInfo.get(0)).intValue() ;
+                 slot <= ((Long) slotInfo.get(1)).intValue() ;
+                 slot++) {
+                slotNums.add(slot);
+            }
+
+            // hostInfos
+            List<Object> hostInfos = (List<Object>) slotInfo.get(2);
+            if (hostInfos.size() <= 0) {
+                continue;
+            }
+
+            // at this time, we just use master, discard slave information
+            HostAndPort targetNode = new HostAndPort(
+                    SafeEncoder.encode((byte[]) hostInfos.get(0)),
+                    ((Long) hostInfos.get(1)).intValue());
+
+            setNodeIfNotExist(targetNode);
+            assignSlotsToNode(slotNums, targetNode);
+        }
+    }
+
+    public synchronized void setNodeIfNotExist(HostAndPort node) {
+        String nodeKey = getNodeKey(node);
+        if (nodes.containsKey(nodeKey))
+            return;
+
+        JedisPool nodePool = new JedisPool(node.getHost(), node.getPort());
+        nodes.put(nodeKey, nodePool);
+    }
+
+    public synchronized void assignSlotToNode(int slot, HostAndPort targetNode) {
+        JedisPool targetPool = nodes.get(getNodeKey(targetNode));
+
+        if (targetPool == null) {
+            setNodeIfNotExist(targetNode);
+            targetPool = nodes.get(getNodeKey(targetNode));
+        }
+        slots.put(slot, targetPool);
+    }
+
+    public synchronized void assignSlotsToNode(List<Integer> targetSlots,
+                                  HostAndPort targetNode) {
+        JedisPool targetPool = nodes.get(getNodeKey(targetNode));
+
+        if (targetPool == null) {
+            setNodeIfNotExist(targetNode);
+            targetPool = nodes.get(getNodeKey(targetNode));
+        }
+
+        for (Integer slot : targetSlots) {
+            slots.put(slot, targetPool);
+        }
+    }
+
+    public synchronized JedisPool getNode(String nodeKey) {
+        return nodes.get(nodeKey);
+    }
+
+    public synchronized JedisPool getSlotPool(int slot) {
+        return slots.get(slot);
+    }
+
+    public synchronized Map<String, JedisPool> getNodes() {
+        return new HashMap<String, JedisPool>(nodes);
+    }
+
+    public static String getNodeKey(HostAndPort hnp) {
+        return hnp.getHost() + ":" + hnp.getPort();
+    }
+
+    public static String getNodeKey(Client client) {
+        return client.getHost() + ":" + client.getPort();
+    }
+
+    public static String getNodeKey(Jedis jedis) {
+        return getNodeKey(jedis.getClient());
+    }
+
+}

src/main/java/redis/clients/jedis/JedisSlotBasedConnectionHandler.java

@@ -46,14 +46,9 @@ public class JedisSlotBasedConnectionHandler extends
 	throw new JedisConnectionException("no reachable node in cluster");
     }
 
-    @Override
-    public void assignSlotToNode(int slot, HostAndPort targetNode) {
-	super.assignSlotToNode(slot, targetNode);
-    }
-
     @Override
     public Jedis getConnectionFromSlot(int slot) {
-	JedisPool connectionPool = slots.get(slot);
+	JedisPool connectionPool = cache.getSlotPool(slot);
 	if (connectionPool != null) {
 	    // It can't guaranteed to get valid connection because of node assignment
 	    return connectionPool.getResource();
@@ -64,7 +59,7 @@ public class JedisSlotBasedConnectionHandler extends
     
     private List<JedisPool> getShuffledNodesPool() {
 	List<JedisPool> pools = new ArrayList<JedisPool>();
-	pools.addAll(nodes.values());
+	pools.addAll(cache.getNodes().values());
 	Collections.shuffle(pools);
 	return pools;
     }