Merge branch 'master' into task-stuff

client/src/main/java/com/metamx/druid/client/cache/Cache.java

@@ -19,8 +19,11 @@
 
 package com.metamx.druid.client.cache;
 
+import com.google.common.base.Charsets;
 import com.google.common.base.Preconditions;
+import com.google.common.primitives.Ints;
 
+import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Map;
 
@@ -48,6 +51,14 @@ public interface Cache
       this.key = key;
     }
 
+    public byte[] toByteArray() {
+      final byte[] nsBytes = this.namespace.getBytes(Charsets.UTF_8);
+      return ByteBuffer.allocate(Ints.BYTES + nsBytes.length + this.key.length)
+          .putInt(nsBytes.length)
+          .put(nsBytes)
+          .put(this.key).array();
+    }
+
     @Override
     public boolean equals(Object o)
     {

client/src/main/java/com/metamx/druid/client/cache/MemcachedCache.java

@@ -20,9 +20,10 @@
 package com.metamx.druid.client.cache;
 
 import com.google.common.base.Function;
+import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
 import com.google.common.collect.Maps;
-import net.iharder.base64.Base64;
+import com.google.common.primitives.Ints;
 import net.spy.memcached.AddrUtil;
 import net.spy.memcached.ConnectionFactoryBuilder;
 import net.spy.memcached.DefaultHashAlgorithm;
@@ -31,9 +32,12 @@ import net.spy.memcached.MemcachedClient;
 import net.spy.memcached.MemcachedClientIF;
 import net.spy.memcached.internal.BulkFuture;
 import net.spy.memcached.transcoders.SerializingTranscoder;
+import org.apache.commons.codec.digest.DigestUtils;
 
 import javax.annotation.Nullable;
 import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
@@ -62,6 +66,7 @@ public class MemcachedCache implements Cache
                                         .build(),
           AddrUtil.getAddresses(config.getHosts())
         ),
+        config.getMemcachedPrefix(),
         config.getTimeout(),
         config.getExpiration()
       );
@@ -72,6 +77,7 @@ public class MemcachedCache implements Cache
 
   private final int timeout;
   private final int expiration;
+  private final String memcachedPrefix;
 
   private final MemcachedClientIF client;
 
@@ -79,10 +85,15 @@ public class MemcachedCache implements Cache
   private final AtomicLong missCount = new AtomicLong(0);
   private final AtomicLong timeoutCount = new AtomicLong(0);
 
-  MemcachedCache(MemcachedClientIF client, int timeout, int expiration) {
+  MemcachedCache(MemcachedClientIF client, String memcachedPrefix, int timeout, int expiration) {
+    Preconditions.checkArgument(memcachedPrefix.length() <= MAX_PREFIX_LENGTH,
+                                "memcachedPrefix length [%d] exceeds maximum length [%d]",
+                                memcachedPrefix.length(),
+                                MAX_PREFIX_LENGTH);
     this.timeout = timeout;
     this.expiration = expiration;
     this.client = client;
+    this.memcachedPrefix = memcachedPrefix;
   }
 
   @Override
@@ -101,7 +112,7 @@ public class MemcachedCache implements Cache
   @Override
   public byte[] get(NamedKey key)
   {
-    Future<Object> future = client.asyncGet(computeKeyString(key));
+    Future<Object> future = client.asyncGet(computeKeyHash(memcachedPrefix, key));
     try {
       byte[] bytes = (byte[]) future.get(timeout, TimeUnit.MILLISECONDS);
       if(bytes != null) {
@@ -110,7 +121,7 @@ public class MemcachedCache implements Cache
       else {
         missCount.incrementAndGet();
       }
-      return bytes;
+      return bytes == null ? null : deserializeValue(key, bytes);
     }
     catch(TimeoutException e) {
       timeoutCount.incrementAndGet();
@@ -129,7 +140,30 @@ public class MemcachedCache implements Cache
   @Override
   public void put(NamedKey key, byte[] value)
   {
-    client.set(computeKeyString(key), expiration, value);
+    client.set(computeKeyHash(memcachedPrefix, key), expiration, serializeValue(key, value));
+  }
+
+  private static byte[] serializeValue(NamedKey key, byte[] value) {
+    byte[] keyBytes = key.toByteArray();
+    return ByteBuffer.allocate(Ints.BYTES + keyBytes.length + value.length)
+                     .putInt(keyBytes.length)
+                     .put(keyBytes)
+                     .put(value)
+                     .array();
+  }
+
+  private static byte[] deserializeValue(NamedKey key, byte[] bytes) {
+    ByteBuffer buf = ByteBuffer.wrap(bytes);
+
+    final int keyLength = buf.getInt();
+    byte[] keyBytes = new byte[keyLength];
+    buf.get(keyBytes);
+    byte[] value = new byte[buf.remaining()];
+    buf.get(value);
+
+    Preconditions.checkState(Arrays.equals(keyBytes, key.toByteArray()),
+                             "Keys do not match, possible hash collision?");
+    return value;
   }
 
   @Override
@@ -144,7 +178,7 @@ public class MemcachedCache implements Cache
               @Nullable NamedKey input
           )
           {
-            return computeKeyString(input);
+            return computeKeyHash(memcachedPrefix, input);
           }
         }
     );
@@ -163,9 +197,11 @@ public class MemcachedCache implements Cache
 
       Map<NamedKey, byte[]> results = Maps.newHashMap();
       for(Map.Entry<String, Object> entry : some.entrySet()) {
+        final NamedKey key = keyLookup.get(entry.getKey());
+        final byte[] value = (byte[]) entry.getValue();
         results.put(
-            keyLookup.get(entry.getKey()),
-            (byte[])entry.getValue()
+            key,
+            value == null ? null : deserializeValue(key, value)
         );
       }
 
@@ -186,7 +222,15 @@ public class MemcachedCache implements Cache
     // no resources to cleanup
   }
 
-  private static String computeKeyString(NamedKey key) {
-    return key.namespace + ":" + Base64.encodeBytes(key.key, Base64.DONT_BREAK_LINES);
+  public static final int MAX_PREFIX_LENGTH =
+        MemcachedClientIF.MAX_KEY_LENGTH
+        - 40 // length of namespace hash
+        - 40 // length of key hash
+        - 2  // length of separators
+        ;
+
+  private static String computeKeyHash(String memcachedPrefix, NamedKey key) {
+    // hash keys to keep things under 250 characters for memcached
+    return memcachedPrefix + ":" + DigestUtils.sha1Hex(key.namespace) + ":" + DigestUtils.sha1Hex(key.key);
   }
 }

client/src/main/java/com/metamx/druid/client/cache/MemcachedCacheConfig.java

@@ -18,4 +18,7 @@ public abstract class MemcachedCacheConfig
 
   @Config("${prefix}.maxObjectSize")
   public abstract int getMaxObjectSize();
+
+  @Config("${prefix}.memcachedPrefix")
+  public abstract String getMemcachedPrefix();
 }

client/src/test/java/com/metamx/druid/client/cache/MapCacheTest.java

@@ -26,7 +26,7 @@ import org.junit.Test;
 
 /**
  */
-public class MapCacheBrokerTest
+public class MapCacheTest
 {
   private static final byte[] HI = "hi".getBytes();
   private static final byte[] HO = "ho".getBytes();

client/src/test/java/com/metamx/druid/client/cache/MemcachedCacheBenchmark.java

@@ -17,7 +17,7 @@ import java.util.Map;
 import java.util.Random;
 import java.util.concurrent.TimeUnit;
 
-public class MemcachedCacheBrokerBenchmark extends SimpleBenchmark
+public class MemcachedCacheBenchmark extends SimpleBenchmark
 {
   private static final String BASE_KEY = "test_2012-11-26T00:00:00.000Z_2012-11-27T00:00:00.000Z_2012-11-27T04:11:25.979Z_";
   public static final String NAMESPACE = "default";
@@ -56,6 +56,7 @@ public class MemcachedCacheBrokerBenchmark extends SimpleBenchmark
 
     cache = new MemcachedCache(
         client,
+        "druid-memcached-benchmark",
         30000, // 30 seconds
         3600 // 1 hour
     );
@@ -113,6 +114,6 @@ public class MemcachedCacheBrokerBenchmark extends SimpleBenchmark
   }
 
   public static void main(String[] args) throws Exception {
-    Runner.main(MemcachedCacheBrokerBenchmark.class, args);
+    Runner.main(MemcachedCacheBenchmark.class, args);
   }
 }

client/src/test/java/com/metamx/druid/client/cache/MemcachedCacheTest.java

@@ -50,7 +50,7 @@ import java.util.concurrent.TimeoutException;
 
 /**
  */
-public class MemcachedCacheBrokerTest
+public class MemcachedCacheTest
 {
   private static final byte[] HI = "hi".getBytes();
   private static final byte[] HO = "ho".getBytes();
@@ -60,7 +60,7 @@ public class MemcachedCacheBrokerTest
   public void setUp() throws Exception
   {
     MemcachedClientIF client = new MockMemcachedClient();
-    cache = new MemcachedCache(client, 500, 3600);
+    cache = new MemcachedCache(client, "druid-memcached-test", 500, 3600);
   }
 
   @Test