Asynchronous paxos client using the protobuf interface.

4 files changed, 114 insertions, 51 deletions

diff --git a/same/src/main/java/com/orbekk/paxos/MasterProposer.java b/same/src/main/java/com/orbekk/paxos/MasterProposer.java
index 094a749..9b74532 100644
--- a/same/src/main/java/com/orbekk/paxos/MasterProposer.java
+++ b/same/src/main/java/com/orbekk/paxos/MasterProposer.java
@@ -5,76 +5,119 @@ import static com.orbekk.same.StackTraceUtil.throwableToString;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Future;
 import java.util.concurrent.FutureTask;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.google.protobuf.RpcCallback;
+import com.orbekk.protobuf.Rpc;
 import com.orbekk.same.ConnectionManager;
+import com.orbekk.same.Services;
+import com.orbekk.same.Services.ClientState;
+import com.orbekk.same.Services.PaxosRequest;
+import com.orbekk.same.Services.PaxosResponse;
 
 public class MasterProposer extends Thread {
-    private Logger logger = LoggerFactory.getLogger(getClass());
-    private String myUrl;
-    private List<String> paxosUrls = new ArrayList<String>();
-    private ConnectionManager connections;
+    private final Logger logger = LoggerFactory.getLogger(getClass());
+    private final ClientState client;
+    private final List<String> paxosLocations;
+    private final ConnectionManager connections;
     
-    public MasterProposer(String clientUrl, List<String> paxosUrls,
+    public MasterProposer(ClientState client, List<String> paxosLocations,
             ConnectionManager connections) {
-        this.myUrl = clientUrl;
-        this.paxosUrls = paxosUrls;
+        this.client = client;
+        this.paxosLocations = paxosLocations;
         this.connections = connections;
     }
-
-    private int internalPropose(int proposalNumber) {
-        int bestPromise = -proposalNumber;
-        int promises = 0;
-        for (String url : paxosUrls) {
-            PaxosService paxos = connections.getPaxos(url);
-            int result = 0;
-            try {
-                result = paxos.propose(myUrl, proposalNumber);
-            } catch (Exception e) {
-                logger.warn("Exception from {}: {}", url,
-                        throwableToString(e));
+    
+    private class ResponseHandler implements RpcCallback<PaxosResponse> {
+        final int proposalNumber;
+        final int numRequests;
+        AtomicInteger bestPromise = new AtomicInteger();
+        AtomicInteger numPromises = new AtomicInteger(0);
+        AtomicInteger numResponses = new AtomicInteger(0);
+        AtomicInteger result = new AtomicInteger();
+        CountDownLatch done = new CountDownLatch(1);
+        
+        public ResponseHandler(int proposalNumber, int numRequests) {
+            this.proposalNumber = proposalNumber;
+            this.numRequests = numRequests;
+            bestPromise.set(-proposalNumber);
+        }
+        
+        @Override public void run(PaxosResponse response) {
+            numResponses.incrementAndGet();
+            if (response != null) {
+                int result = response.getResult();
+                if (result == proposalNumber) {
+                    numPromises.incrementAndGet();
+                }
+                while (true) {
+                    int oldVal = bestPromise.get();
+                    int update = Math.min(oldVal, result);
+                    if (bestPromise.compareAndSet(oldVal, update)) {
+                        break;
+                    }
+                }
             }
-            if (result == proposalNumber) {
-                promises += 1;
+            checkDone();
+        }
+        
+        private void checkDone() {
+            if (done.getCount() > 0) {
+                if (numPromises.get() >= numRequests / 2) {
+                    result.set(proposalNumber);
+                    done.countDown();
+                } else if (numResponses.get() >= numRequests) {
+                    result.set(bestPromise.get());
+                    done.countDown();
+                }
             }
-            bestPromise = Math.min(bestPromise, result);
         }
-        if (promises > paxosUrls.size() / 2) {
-            return proposalNumber;
-        } else {
-            return bestPromise;
+        
+        public int getResult() throws InterruptedException {
+            done.await();
+            return result.get();
         }
     }
 
-    private int internalAcceptRequest(int proposalNumber) {
-        int bestAccepted = -proposalNumber;
-        int accepts = 0;
-        for (String url : paxosUrls) {
-            PaxosService paxos = connections.getPaxos(url);
-            int result = 0;
-            try {
-                result = paxos.acceptRequest(myUrl, proposalNumber);
-            } catch (Exception e) {
-                logger.warn("Exception from {}: {}", url,
-                        throwableToString(e));
-            }
-            if (result == proposalNumber) {
-                accepts += 1;
-            }
-            bestAccepted = Math.min(bestAccepted, result);
+    private int internalPropose(int proposalNumber)
+            throws InterruptedException {
+        ResponseHandler handler = new ResponseHandler(proposalNumber,
+                paxosLocations.size());
+        for (String location : paxosLocations) {
+            Rpc rpc = new Rpc();
+            Services.Paxos paxos = connections.getPaxos0(location);
+            PaxosRequest request = PaxosRequest.newBuilder()
+                    .setClient(client)
+                    .setProposalNumber(proposalNumber)
+                    .build();
+            paxos.propose(rpc, request, handler);
         }
-        if (accepts > paxosUrls.size() / 2) {
-            return proposalNumber;
-        } else {
-            return bestAccepted;
+        return handler.getResult();
+    }
+
+    private int internalAcceptRequest(int proposalNumber)
+            throws InterruptedException {
+        ResponseHandler handler = new ResponseHandler(proposalNumber,
+                paxosLocations.size());
+        for (String location : paxosLocations) {
+            Rpc rpc = new Rpc();
+            Services.Paxos paxos = connections.getPaxos0(location);
+            PaxosRequest request = PaxosRequest.newBuilder()
+                    .setClient(client)
+                    .setProposalNumber(proposalNumber)
+                    .build();
+            paxos.acceptRequest(rpc, request, handler);
         }
+        return handler.getResult();
     }
 
-    boolean propose(int proposalNumber) {
+    boolean propose(int proposalNumber) throws InterruptedException {
         int result = internalPropose(proposalNumber);
         if (result == proposalNumber) {
             result = internalAcceptRequest(proposalNumber);
@@ -86,16 +129,17 @@ public class MasterProposer extends Thread {
         }
     }
 
-    boolean proposeRetry(int proposalNumber) {
+    boolean proposeRetry(int proposalNumber) throws InterruptedException {
         return proposeRetry(proposalNumber, null) != null;
     }
     
-    Integer proposeRetry(int proposalNumber, Runnable retryAction) {
+    Integer proposeRetry(int proposalNumber, Runnable retryAction)
+            throws InterruptedException {
         assert proposalNumber > 0;
         int nextProposal = proposalNumber;
         int result = nextProposal - 1;
 
-        while (!Thread.interrupted() && result != nextProposal) {
+        while (!Thread.currentThread().isInterrupted() && result != nextProposal) {
             result = internalPropose(nextProposal);
             if (result == nextProposal) {
                 result = internalAcceptRequest(nextProposal);
@@ -109,7 +153,7 @@ public class MasterProposer extends Thread {
             }
         }
         if (Thread.interrupted()) {
-            return null;
+            throw new InterruptedException();
         }
 
         return result;
diff --git a/same/src/main/java/com/orbekk/same/ConnectionManager.java b/same/src/main/java/com/orbekk/same/ConnectionManager.java
index f1ca65f..e4c7832 100644
--- a/same/src/main/java/com/orbekk/same/ConnectionManager.java
+++ b/same/src/main/java/com/orbekk/same/ConnectionManager.java
@@ -15,4 +15,5 @@ public interface ConnectionManager {
     Services.Master getMaster0(String location);
     Services.Client getClient0(String location);
     Services.Directory getDirectory(String location);
+    Services.Paxos getPaxos0(String location);
 }
diff --git a/same/src/main/java/com/orbekk/same/ConnectionManagerImpl.java b/same/src/main/java/com/orbekk/same/ConnectionManagerImpl.java
index 34536a0..1bf697f 100644
--- a/same/src/main/java/com/orbekk/same/ConnectionManagerImpl.java
+++ b/same/src/main/java/com/orbekk/same/ConnectionManagerImpl.java
@@ -145,4 +145,14 @@ public class ConnectionManagerImpl implements ConnectionManager {
             return null;
         }
     }
+    
+    @Override
+    public Services.Paxos getPaxos0(String location) {
+        RpcChannel channel = getChannel(location);
+        if (channel != null) {
+            return Services.Paxos.newStub(channel);
+        } else {
+            return null;
+        }
+    }
 }
diff --git a/same/src/main/java/com/orbekk/same/TestConnectionManager.java b/same/src/main/java/com/orbekk/same/TestConnectionManager.java
index 2305311..b93e49b 100644
--- a/same/src/main/java/com/orbekk/same/TestConnectionManager.java
+++ b/same/src/main/java/com/orbekk/same/TestConnectionManager.java
@@ -6,6 +6,7 @@ import java.util.HashMap;
 import com.orbekk.paxos.PaxosService;
 import com.orbekk.same.Services.Directory;
 import com.orbekk.same.Services.Master;
+import com.orbekk.same.Services.Paxos;
 
 /**
  * This class is used in test.
@@ -23,6 +24,8 @@ public class TestConnectionManager implements ConnectionManager {
             new HashMap<String, Services.Master>();
     public Map<String, Services.Client> clientMap0 =
             new HashMap<String, Services.Client>();
+    public Map<String, Services.Paxos> paxosMap0 =
+            new HashMap<String, Services.Paxos>();
 
     public TestConnectionManager() {
     }
@@ -56,4 +59,9 @@ public class TestConnectionManager implements ConnectionManager {
     public Services.Client getClient0(String location) {
         return clientMap0.get(location);
     }
+    
+    @Override
+    public Services.Paxos getPaxos0(String location) {
+        return paxosMap0.get(location);
+    }
 }