async Task <List <Siblings> > ReplicateGetAsync(string key)
{
IList <string> replicaNodes = _ring.PreferenceList(key, N);
replicaNodes.Remove(_name);
var replicaValues = new List <Siblings>();
List <Task <Siblings> > pendingGets = replicaNodes.Select(r => _remote.GetReplicaAsync(r, key)).ToList();
await Task.WhenAll(pendingGets);
foreach (var pendingGet in pendingGets)
{
try
{
Siblings siblings = await pendingGet;
replicaValues.Add(siblings);
}
catch (Exception e)
{
Log.Error("Error replicating get -- ignored", e);
}
}
return(replicaValues);
}
public void Add(Siblings siblings)
{
foreach (VersionedObject sibling in siblings)
{
Add(sibling);
}
}
public async Task PutReplicaAsync(string node, string key, Siblings siblings)
{
var requestUri = GetReplicaRequestUri(node, key);
using (var client = new HttpClient())
{
var req = new HttpRequestMessage(HttpMethod.Put, requestUri);
req.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(JsonMediaType));
// TODO: Serialize JSON to stream, not string
//MemoryStream stream = new MemoryStream();
//StreamReader streamWriter = new StreamReader(stream);
//using (JsonWriter jsonWriter = new JsonTextWriter(streamWriter))
//{
// JsonSerializer serializer = new JsonSerializer();
// serializer.Serialize(jsonWriter, value);
//}
//req.Content = new StreamContent();
string json = JsonConvert.SerializeObject(siblings);
req.Content = new StringContent(json, Encoding.UTF8, JsonMediaType);
HttpResponseMessage response = await client.SendAsync(req);
response.EnsureSuccessStatusCode();
}
}
public static Siblings Merge(this DvvKernel kernel, IList <Siblings> siblingsList)
{
Ensure.That(siblingsList, "siblingsList").IsNotNull();
Siblings merged = siblingsList.Aggregate(kernel.Sync);
return(merged);
}
public VersionVector Join(Siblings s1)
{
Ensure.That(s1, "s1").IsNotNull();
var ids = s1.Ids().Select(i => new CausalEvent(i, s1.MaxDot(i)));
return(new VersionVector(ids));
}
async Task ReplicatePutAsync(string key, Siblings siblings)
{
IList <string> replicaNodes = _ring.PreferenceList(key, N);
replicaNodes.Remove(_name);
List <Task> pendingPuts = replicaNodes.Select(r => _remote.PutReplicaAsync(r, key, siblings)).ToList();
await Task.WhenAll(pendingPuts);
}
/// <summary>
/// Remove obsolete versions.
/// </summary>
public Siblings Discard(Siblings s, VersionVector context)
{
Ensure.That(s, "s").IsNotNull();
Ensure.That(context, "context").IsNotNull();
// discard all siblings that are obsolete because they are included
// in the context.
IEnumerable <VersionedObject> concurrent = s.Where(sibling => !sibling.Clock.HappensBefore(context));
return(new Siblings(concurrent));
}
internal Siblings GetReplicaAsync(string key)
{
Ensure.That(key, "key").IsNotNullOrWhiteSpace();
Log.DebugFormat("get-replica k={0}", key);
BigInteger hash = _ring.Hash(key);
Siblings siblings = _data[hash];
return(siblings);
}
public Siblings Sync(Siblings s1, Siblings s2)
{
Ensure.That(s1, "s1").IsNotNull();
Ensure.That(s2, "s2").IsNotNull();
IEnumerable <VersionedObject> r1 = s1.Where(sibling1 => !s2.Any(sibling1.HappensBefore));
IEnumerable <VersionedObject> r2 = s2.Where(sibling2 => !s1.Any(sibling2.HappensBefore));
IEnumerable <VersionedObject> union = r1.Union(r2).ToList();
return(new Siblings(union));
}
internal void PutReplicaAsync(string key, Siblings coordinatorSiblings)
{
Ensure.That(key, "key").IsNotNullOrWhiteSpace();
Log.DebugFormat("put-replica k={0}", key);
BigInteger hash = _ring.Hash(key);
Siblings siblings = _data.GetValueOrDefault(hash) ?? new Siblings();
siblings = _kernel.Sync(siblings, coordinatorSiblings);
_data[hash] = siblings;
}
/// <summary>
/// Generates a new clock.
/// </summary>
public DottedVersionVector Event(VersionVector context, Siblings s, string i)
{
Ensure.That(s, "s").IsNotNull();
Ensure.That(context, "context").IsNotNull();
Ensure.That(i, "i").IsNotNullOrEmpty();
long maxDot = s.MaxDot(i);
long maxCausalHistory = context[i];
long maxCounter = Math.Max(maxDot, maxCausalHistory);
var dot = new CausalEvent(i, maxCounter + 1);
return(new DottedVersionVector(dot, context));
}
internal async Task PutAsync(string key, JToken value, VersionVector context = null)
{
Ensure.That(key, "key").IsNotNullOrWhiteSpace();
context = context ?? new VersionVector();
string coordinatingNode = _ring.Node(key);
if (_ring.PreferenceList(key, N).Contains(_name))
{
Log.DebugFormat("put k={0}", key);
BigInteger hash = _ring.Hash(key);
Siblings siblings = _data.GetValueOrDefault(hash);
if (siblings != null)
{
// discard obsolete versions
siblings = _kernel.Discard(siblings, context);
}
else
{
siblings = new Siblings();
}
DottedVersionVector dvv = _kernel.Event(context, siblings, _name);
var versionedObject = new VersionedObject(value, dvv);
siblings.Add(versionedObject);
_data[hash] = siblings;
await ReplicatePutAsync(key, siblings);
}
else
{
Log.DebugFormat("forward to coordinating node {0}", coordinatingNode);
await _remote.PutAsync(coordinatingNode, key, value, context);
}
}
