public void ShouldBeAbleToGetLastTimestampOfLatestHeartbeat()
{
// The first response should be DateTime.Never
var requesterId = Guid.NewGuid();
var response = _raftNode.Request(requesterId, () => new GetLastUpdatedTimestamp());
Assert.NotNull(response);
Assert.IsType <DateTime>(response.ResponseMessage);
var lastUpdated = (DateTime)response.ResponseMessage;
Assert.True(lastUpdated.Equals(default(DateTime)));
Assert.True(lastUpdated.Equals(DateTime.MinValue));
var currentTime = DateTime.UtcNow;
var appendEntries = new Request <AppendEntries>(requesterId,
new AppendEntries(0, Guid.NewGuid(), 0, 0, new object[0], 0));
_raftNode.Tell(appendEntries);
var secondResponse = _raftNode.Request(requesterId, () => new GetLastUpdatedTimestamp());
Assert.NotNull(secondResponse);
Assert.IsType <DateTime>(secondResponse.ResponseMessage);
// The last updated timestamp should be relatively similar to the current time
var timestamp = (DateTime)secondResponse.ResponseMessage;
var timeDifference = timestamp - currentTime;
Assert.True(timeDifference.TotalMilliseconds >= 0 && timeDifference <= TimeSpan.FromSeconds(5));
}
public void ShouldAcceptAppendEntriesOnFirstRequest()
{
var numberOfOtherActors = 3;
var otherActors = Enumerable.Range(0, numberOfOtherActors).Select(_ => Guid.NewGuid());
var outbox = new ConcurrentBag <object>();
var eventLog = new ConcurrentBag <object>();
var startingTerm = 0;
var leaderId = Guid.NewGuid();
var nodeId = Guid.NewGuid();
_raftNode = new RaftNode(nodeId, outbox.Add, eventLog.Add, () => otherActors, startingTerm);
_raftNode.Tell(new Initialize());
var term = 42;
var response = _raftNode.Request(nodeId,
() => new AppendEntries(term, leaderId, 0, 0, new object[] { "Hello, World" }, 1));
// The response must be valid
Assert.NotEqual(Response <AppendEntries> .Empty, response);
Assert.IsType <AppendEntriesResult>(response.ResponseMessage);
// The first entry must be successful since there are no prior entries
var firstResult = (AppendEntriesResult)response.ResponseMessage;
Assert.True(firstResult.Success);
Assert.Equal(term, firstResult.Term);
}
public void ShouldResetElectionTimerWhenVoteIsGrantedToCandidate()
{
// Route all the network output to the collection object
var nodeId = Guid.NewGuid();
var outbox = new ConcurrentBag <object>();
var eventLog = new ConcurrentBag <object>();
_raftNode = new RaftNode(nodeId, outbox.Add, eventLog.Add, () => new Guid[0]);
// The first response should be DateTime.Never
var requesterId = Guid.NewGuid();
var response = _raftNode.Request(requesterId, () => new GetLastUpdatedTimestamp());
Assert.NotNull(response);
Assert.IsType <DateTime>(response.ResponseMessage);
var lastUpdated = (DateTime)response.ResponseMessage;
Assert.True(lastUpdated.Equals(default(DateTime)));
Assert.True(lastUpdated.Equals(DateTime.MinValue));
var currentTime = DateTime.UtcNow;
var candidateId = Guid.NewGuid();
var requestVote = new Request <RequestVote>(requesterId, new RequestVote(42, candidateId, 0, 0));
_raftNode.Tell(requestVote);
var secondResponse = _raftNode.Request(requesterId, () => new GetLastUpdatedTimestamp());
Assert.NotNull(secondResponse);
Assert.IsType <DateTime>(secondResponse.ResponseMessage);
// The last updated timestamp should be relatively similar to the current time
var timestamp = (DateTime)secondResponse.ResponseMessage;
var timeDifference = timestamp - currentTime;
Assert.True(timeDifference.TotalMilliseconds >= 0 && timeDifference <= TimeSpan.FromSeconds(5));
}
public void MustVoteForCandidateIfCandidateTermIsHigherThanCurrentTerm()
{
var currentTerm = 42;
_raftNode = new RaftNode(Guid.NewGuid(), delegate { }, delegate { }, () => new Guid[0], currentTerm);
var response = _raftNode.Request(Guid.NewGuid(), () => new RequestVote(43, Guid.NewGuid(), 0, 0));
Assert.NotNull(response);
Assert.IsType <RequestVoteResult>(response.ResponseMessage);
var result = (RequestVoteResult)response.ResponseMessage;
Assert.Equal(currentTerm, result.Term);
Assert.True(result.VoteGranted);
}
public void MustRejectVoteIfVoteRequestIsInvalid()
{
// Reply false if term < currentTerm (§5.1)
var currentTerm = 42;
_raftNode = new RaftNode(Guid.NewGuid(), delegate { }, delegate { }, () => new Guid[0], currentTerm);
var response = _raftNode.Request(Guid.NewGuid(), () => new RequestVote(0, Guid.NewGuid(), 0, 0));
Assert.NotNull(response);
Assert.IsType <RequestVoteResult>(response.ResponseMessage);
var result = (RequestVoteResult)response.ResponseMessage;
Assert.Equal(currentTerm, result.Term);
Assert.False(result.VoteGranted);
}
public void ShouldSendRequestVoteToOtherActorsInTheClusterIfElectionTimerExpires()
{
var minMilliseconds = 150;
var maxMilliseconds = 300;
var nodeId = Guid.NewGuid();
var term = 42;
var numberOfActorsInCluster = 5;
var actorIds = Enumerable.Range(0, numberOfActorsInCluster)
.Select(_ => Guid.NewGuid()).ToArray();
var outbox = new ConcurrentBag <object>();
var eventLog = new ConcurrentBag <object>();
_raftNode = new RaftNode(nodeId, outbox.Add, eventLog.Add, () => actorIds, term);
// Set the request timeout to be from 150-300ms
var requesterId = Guid.NewGuid();
_raftNode.Request(requesterId, () => new SetElectionTimeoutRange(minMilliseconds, maxMilliseconds));
// Start the node
_raftNode.Tell(new Initialize());
// Let the timer expire
Thread.Sleep(1000);
var voteRequests = outbox.Where(msg => msg is Request <RequestVote> rv && rv.RequestMessage is RequestVote)
.Cast <Request <RequestVote> >().ToArray();
Assert.NotEmpty(voteRequests);
Assert.True(voteRequests.Count() == numberOfActorsInCluster);
for (var i = 0; i < numberOfActorsInCluster; i++)
{
var request = voteRequests[i];
var voteRequest = request.RequestMessage;
Assert.Equal(nodeId, voteRequest.CandidateId);
// Note: The new candidate must increment the current vote by one
Assert.Equal(term + 1, voteRequest.Term);
}
}
public void ShouldRejectAppendEntriesIfFollowerCannotFindAMatchForAnEntryInItsOwnLog()
{
/* When sending an AppendEntries RPC,
* the leader includes the term number and index of the entry
* that immediately precedes the new entry.
*
* If the follower cannot find a match for this entry in its own log,
* it rejects the request to append the new entry.
*/
var nodeId = Guid.NewGuid();
var numberOfOtherActors = 3;
var otherActors = Enumerable.Range(0, numberOfOtherActors).Select(_ => Guid.NewGuid());
var outbox = new ConcurrentBag <object>();
var eventLog = new ConcurrentBag <object>();
var startingTerm = 0;
_raftNode = new RaftNode(nodeId, outbox.Add, eventLog.Add, () => otherActors, startingTerm);
_raftNode.Tell(new Initialize());
Thread.Sleep(100);
var term = 42;
var leaderId = Guid.NewGuid();
var appendEntries = new AppendEntries(term, leaderId, 1, 41, new object[0], 0);
var requesterId = Guid.NewGuid();
var response = _raftNode.Request(requesterId, () => appendEntries);
Assert.Equal(requesterId, response.RequesterId);
Assert.Equal(nodeId, response.ResponderId);
// Reply false if log doesn’t contain an entry at prevLogIndex whose term matches prevLogTerm (§5.3)
Assert.IsType <AppendEntriesResult>(response.ResponseMessage);
var result = (AppendEntriesResult)response.ResponseMessage;
Assert.False(result.Success);
}
