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-rw-r--r--same/src/main/java/com/orbekk/paxos/MasterProposer.java4
-rw-r--r--same/src/main/java/com/orbekk/same/Client.java17
-rw-r--r--same/src/test/java/com/orbekk/same/FunctionalTest.java28
3 files changed, 42 insertions, 7 deletions
diff --git a/same/src/main/java/com/orbekk/paxos/MasterProposer.java b/same/src/main/java/com/orbekk/paxos/MasterProposer.java
index 8469cf4..094a749 100644
--- a/same/src/main/java/com/orbekk/paxos/MasterProposer.java
+++ b/same/src/main/java/com/orbekk/paxos/MasterProposer.java
@@ -91,9 +91,9 @@ public class MasterProposer extends Thread {
}
Integer proposeRetry(int proposalNumber, Runnable retryAction) {
- assert proposalNumber >= 0;
+ assert proposalNumber > 0;
int nextProposal = proposalNumber;
- int result = -1;
+ int result = nextProposal - 1;
while (!Thread.interrupted() && result != nextProposal) {
result = internalPropose(nextProposal);
diff --git a/same/src/main/java/com/orbekk/same/Client.java b/same/src/main/java/com/orbekk/same/Client.java
index 18fecd2..ceacd12 100644
--- a/same/src/main/java/com/orbekk/same/Client.java
+++ b/same/src/main/java/com/orbekk/same/Client.java
@@ -123,7 +123,7 @@ public class Client implements DiscoveryListener {
}
@Override
- public void masterTakeover(String masterUrl, String networkName,
+ public synchronized void masterTakeover(String masterUrl, String networkName,
int masterId) throws Exception {
if (masterId <= Client.this.masterId) {
logger.warn("{}:{} tried to take over, but current master is " +
@@ -135,6 +135,7 @@ public class Client implements DiscoveryListener {
new Object[]{masterUrl, networkName, masterId});
abortMasterElection();
Client.this.masterUrl = masterUrl;
+ Client.this.masterId = masterId;
connectionState = ConnectionState.STABLE;
}
@@ -147,7 +148,7 @@ public class Client implements DiscoveryListener {
}
logger.warn("Master down.");
connectionState = ConnectionState.UNSTABLE;
- tryBecomeMaster();
+ tryBecomeMaster(masterId);
}
};
@@ -266,7 +267,7 @@ public class Client implements DiscoveryListener {
return paxosUrls;
}
- private void tryBecomeMaster() {
+ private void tryBecomeMaster(int failedMasterId) {
List<String> paxosUrls = getPaxosUrls();
MasterProposer proposer = new MasterProposer(getUrl(), paxosUrls,
connections);
@@ -283,7 +284,12 @@ public class Client implements DiscoveryListener {
}
};
synchronized (this) {
- currentMasterProposal = proposer.startProposalTask(1, sleeperTask);
+ if (failedMasterId < masterId) {
+ logger.info("Master election aborted. Master already chosen.");
+ return;
+ }
+ currentMasterProposal = proposer.startProposalTask(masterId + 1,
+ sleeperTask);
}
Integer result = null;
try {
@@ -310,11 +316,12 @@ public class Client implements DiscoveryListener {
public void startMasterElection() {
List<String> participants = state.getList(".participants");
+ final int masterId = getMasterIdEstimate();
broadcaster.broadcast(participants, new ServiceOperation() {
@Override public void run(String url) {
ClientService client = connections.getClient(url);
try {
- client.masterDown(getMasterIdEstimate());
+ client.masterDown(masterId);
} catch (Exception e) {
logger.info("{}.masterDown() did not respond (ignored): " +
url, e);
diff --git a/same/src/test/java/com/orbekk/same/FunctionalTest.java b/same/src/test/java/com/orbekk/same/FunctionalTest.java
index 0da38a6..ea920c4 100644
--- a/same/src/test/java/com/orbekk/same/FunctionalTest.java
+++ b/same/src/test/java/com/orbekk/same/FunctionalTest.java
@@ -127,4 +127,32 @@ public class FunctionalTest {
assertThat(client1.masterUrl, is(newMasterUrl));
assertThat(client2.masterUrl, is(newMasterUrl));
}
+
+ @Test public void onlyOneNewMaster() {
+ String newMasterUrl = "http://newMaster/MasterService.json";
+ final Master newMaster = Master.create(connections,
+ broadcaster, newMasterUrl, "TestMaster");
+ connections.masterMap.put(newMasterUrl, newMaster.getService());
+ joinClients();
+ MasterController controller = new MasterController() {
+ boolean firstMaster = true;
+ @Override
+ public synchronized void enableMaster(State lastKnownState,
+ int masterId) {
+ assertThat(firstMaster, is(true));
+ newMaster.resumeFrom(lastKnownState, masterId);
+ firstMaster = false;
+ }
+ @Override
+ public void disableMaster() {
+ }
+ };
+ client1.setMasterController(controller);
+ client2.setMasterController(controller);
+ client3.setMasterController(controller);
+ client1.startMasterElection();
+ newMaster.performWork();
+ assertThat(client1.masterUrl, is(newMasterUrl));
+ assertThat(client2.masterUrl, is(newMasterUrl));
+ }
}