public void TestWriteIsAborted_AfterWriteWithBallotGreaterThanCurrent()
{
using (CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().First()))
{
using (CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().Second()))
{
using (var testSetup = CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().Third()))
{
var ballotGenerator = testSetup.BallotGenerator;
var localNode = testSetup.LocalNode;
var roundBasedRegister = testSetup.RoundBasedRegister;
var ballot0 = ballotGenerator.New(localNode.SocketIdentity);
var lease = new Lease(localNode.SocketIdentity, ownerEndpoint, DateTime.UtcNow);
var txResult = roundBasedRegister.Write(ballot0, lease);
Assert.AreEqual(TxOutcome.Commit, txResult.TxOutcome);
var ballot1 = new Ballot(ballot0.Timestamp - TimeSpan.FromSeconds(10), ballot0.MessageNumber, localNode.SocketIdentity);
Assert.IsTrue(ballot0 > ballot1);
txResult = roundBasedRegister.Write(ballot1, lease);
Assert.AreEqual(TxOutcome.Abort, txResult.TxOutcome);
}
}
}
}
public void TestReadCommitsWithNonEmptyLease_IfWriteCommittedLeaseWithBallotLessThanCurrent()
{
using (CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().First()))
{
using (CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().Second()))
{
using (var testSetup = CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().Third()))
{
var ballotGenerator = testSetup.BallotGenerator;
var localNode = testSetup.LocalNode;
var roundBasedRegister = testSetup.RoundBasedRegister;
var ballot0 = ballotGenerator.New(localNode.SocketIdentity);
var lease = new Lease(localNode.SocketIdentity, ownerEndpoint, DateTime.UtcNow);
var txResult = roundBasedRegister.Write(ballot0, lease);
Assert.AreEqual(TxOutcome.Commit, txResult.TxOutcome);
var ballot1 = ballotGenerator.New(localNode.SocketIdentity);
Assert.IsTrue(ballot0 < ballot1);
txResult = roundBasedRegister.Read(ballot1);
Assert.AreEqual(TxOutcome.Commit, txResult.TxOutcome);
Assert.AreEqual(lease.ExpiresAt, txResult.Lease.ExpiresAt);
Assert.AreEqual(lease.OwnerEndpoint.MulticastUri, txResult.Lease.OwnerEndpoint.MulticastUri);
Assert.AreEqual(lease.OwnerEndpoint.UnicastUri, txResult.Lease.OwnerEndpoint.UnicastUri);
Assert.IsTrue(Unsafe.Equals(lease.OwnerIdentity, txResult.Lease.OwnerIdentity));
}
}
}
}
private void LogLeaseProlonged(Lease lastReadLease)
{
if (lastReadLease != null)
{
if (IsLeaseOwner(lastReadLease))
{
logger.Debug($"[{DateTime.UtcNow.ToString("HH:mm:ss fff")}] " +
"PROLONG === process " +
$"{localNode.Uri.AbsoluteUri} " +
"wants to prolong it's lease " +
$"{lastReadLease.ExpiresAt.ToString("HH:mm:ss fff")}");
}
else
{
logger.Debug($"[{DateTime.UtcNow.ToString("HH:mm:ss fff")}] " +
"RENEW === process " +
$"{localNode.Uri.AbsoluteUri} " +
"wants to renew lease " +
$"{lastReadLease.ExpiresAt.ToString("HH:mm:ss fff")}");
}
}
}
private void ReadOrRenewLease()
{
var now = DateTime.UtcNow;
var lease = AсquireOrLearnLease(ballotGenerator.New(localNode.SocketIdentity), now);
if (ProcessBecameLeader(lease, lastKnownLease) || ProcessLostLeadership(lease, lastKnownLease))
{
var renewPeriod = CalcLeaseRenewPeriod(ProcessBecameLeader(lease, lastKnownLease));
leaseTimer.Change(renewPeriod, renewPeriod);
}
lastKnownLease = lease;
}
private bool LeaseIsNotSafelyExpired(Lease lease, DateTime now)
{
return lease != null
&& lease.ExpiresAt < now
&& lease.ExpiresAt + config.ClockDrift > now;
}
private static bool LeaseNullOrExpired(Lease lease, DateTime now)
{
return lease == null || lease.ExpiresAt < now;
}
private bool IsLeaseOwner(Lease lease)
{
return lease != null && Unsafe.Equals(lease.OwnerIdentity, localNode.SocketIdentity);
}
private Lease AсquireOrLearnLease(Ballot ballot, DateTime now)
{
var read = register.Read(ballot);
if (read.TxOutcome == TxOutcome.Commit)
{
var lease = read.Lease;
if (LeaseIsNotSafelyExpired(lease, now))
{
LogStartSleep();
Sleep(config.ClockDrift);
LogAwake();
// TODO: Add recursion exit condition
return AсquireOrLearnLease(ballotGenerator.New(localNode.SocketIdentity), DateTime.UtcNow);
}
if (LeaseNullOrExpired(lease, now) || IsLeaseOwner(lease))
{
LogLeaseProlonged(lease);
var ownerEndpoint = new OwnerEndpoint {UnicastUri = rendezvousConfig.UnicastUri, MulticastUri = rendezvousConfig.MulticastUri};
lease = new Lease(localNode.SocketIdentity, ownerEndpoint, now + config.MaxLeaseTimeSpan);
}
var write = register.Write(ballot, lease);
if (write.TxOutcome == TxOutcome.Commit)
{
return lease;
}
}
return null;
}
private bool ProcessBecameLeader(Lease nextLease, Lease previousLease)
{
return ((previousLease == null || !Unsafe.Equals(previousLease.OwnerIdentity, localNode.SocketIdentity))
&& nextLease != null && Unsafe.Equals(nextLease.OwnerIdentity, localNode.SocketIdentity));
}
private bool ProcessLostLeadership(Lease nextLease, Lease previousLease)
{
return (previousLease != null && Unsafe.Equals(previousLease.OwnerIdentity, localNode.SocketIdentity)
&& nextLease != null && !Unsafe.Equals(nextLease.OwnerIdentity, localNode.SocketIdentity));
}
public void TestReadIsAborted_AfterWriteWithBallotEqualToCurrent()
{
using (CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().First()))
{
using (CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().Second()))
{
using (var testSetup = CreateRoundBasedRegister(GetSynodMembers(), GetSynodMembers().Third()))
{
var ballotGenerator = testSetup.BallotGenerator;
var localNode = testSetup.LocalNode;
var roundBasedRegister = testSetup.RoundBasedRegister;
var ballot0 = ballotGenerator.New(localNode.SocketIdentity);
var lease = new Lease(localNode.SocketIdentity, ownerEndpoint, DateTime.UtcNow);
var txResult = roundBasedRegister.Write(ballot0, lease);
Assert.AreEqual(TxOutcome.Commit, txResult.TxOutcome);
txResult = roundBasedRegister.Read(ballot0);
Assert.AreEqual(TxOutcome.Abort, txResult.TxOutcome);
}
}
}
}
