static ActorAssignment GetAssignment(Actor actor, bool prepareTestData = true)
{
ActorAssignment actorEntity = null;
try
{
// Create the CloudTable object that represents the "topology" table.
CloudTable table = Environment.GetTable("topology");
// $TEST: prepare test data so that the code can be executed in Azure Emulator
if (prepareTestData)
{
Environment.PrepareTestData(actor);
}
// Create a retrieve operation that takes a customer entity.
TableOperation retrieveOperation = TableOperation.Retrieve <ActorAssignment>(ActorAssignment.Key, actor.Id.ToString());
// Execute the retrieve operation.
TableResult retrievedResult = table.Execute(retrieveOperation);
// Get Assignment
if (retrievedResult.Result != null)
{
actorEntity = (ActorAssignment)retrievedResult.Result;
}
}
catch (Exception e)
{
Trace.TraceInformation("Failed to get assignment:" + e.Message);
RoundLogger.Current.Log(e.StackTrace);
}
return(actorEntity);
}
// The thread procedure performs the independent task
static void ThreadProc(Object stateInfo)
{
ActorAssignment assignment = null;
Actor actor = (Actor)stateInfo;
Trace.TraceInformation("Deployment {0} Actor {1} is Initialized.", actor.DeploymentId, actor.Id);
while (true)
{
RoundLogger.Current.SetSceneId(actor);
if (actor.State == ActorState.NewBorn)
{
// Needs to contact central to get new assignment
// if there is an assignment then
assignment = GetAssignment(actor);
if (assignment != null && !string.IsNullOrWhiteSpace(assignment.Name))
{
actor.State = ActorState.Working;
RoundLogger.Current.Log("Get Assignment and switch State to Working.");
}
else
{
RoundLogger.Current.Log("Waiting for assignment.");
// Let's check assignment 10 seconds later
Thread.Sleep(10000);
}
}
else if (actor.State == ActorState.Working)
{
RoundLogger.Current.Log("Working on the assignment");
try
{
// $TODO: need to fetch package for new assignment
(new ActorExecution(actor, assignment)).Run();
}
catch (Exception e)
{
actor.State = ActorState.Error;
actor.ErrorMessage = e.Message;
actor.ErrorStack = e.StackTrace;
RoundLogger.Current.Log("Failed to execute topology:" + e.Message);
RoundLogger.Current.Log(e.StackTrace);
}
}
else if (actor.State == ActorState.Error)
{
RoundLogger.Current.Log("The Actor is shutdown due to Error State.");
break;
}
actor.HeartBeat = DateTime.UtcNow;
}
}
public ActorExecution(Actor actor, ActorAssignment assignment)
{
this.actor = actor;
this.assignment = assignment;
}
/// <summary>
/// - Send Heartbeat to Central
/// - Service Up/Down
/// - Actor State
/// - Kill Error Actor and Keep Actor Number;
/// </summary>
internal void Run()
{
do
{
Thread.Sleep(15000);
Trace.TraceInformation("Service Maintain {0}", RoleEnvironment.DeploymentId);
CloudTable table = Environment.GetTable("topology");
lock (LockObject)
{
IList <Guid> errorActors = new List <Guid>();
// Remove Actor which in Error State, and fork a new one
foreach (Guid id in this.actors.Keys)
{
// NOTE: we still give Actor in Error State the last chance to report its state.
if (this.actors[id].State == ActorState.Error)
{
// Cannot modify this.actors in foreach
errorActors.Add(id);
}
try
{
if (this.actors[id].State == ActorState.Working)
{
var ass = GetAssignment(this.actors[id], false);
if (ass != null)
{
if (string.Equals("Kill", ass.Operation, StringComparison.OrdinalIgnoreCase))
{
// I didn't lock this Actor considering there is no state transition from Working to non Error.
this.actors[id].State = ActorState.Error;
}
}
}
ActorAssignment assignment = new ActorAssignment(id)
{
HeartBeat = this.actors[id].HeartBeat, State = this.actors[id].State.ToString(), ErrorMessage = this.actors[id].ErrorMessage, ErrorStack = this.actors[id].ErrorStack
};
TableOperation mergeOperation = TableOperation.InsertOrMerge(assignment);
TableResult retrievedResult = table.Execute(mergeOperation);
Trace.TraceInformation("Actor {0} updated HeartBeat", id);
}
catch (Exception e)
{
Trace.TraceInformation("Actor {0} failed to update HeartBeat due to {1}", id, e.Message);
}
}
foreach (Guid id in errorActors)
{
this.actors.Remove(id);
this.ForkNewActor();
}
}
}while (true);
}