 George Chrysanthakopoulos Software Architect Microsoft Corporation

Coordination and Concurrency runtime (CCR) Decentralized Software Services (DSS) Visual Programming Language Visual Configuration and Deployment Visual Studio templates Samples and tutorials Infrastructure services

Event processing for security systems Mail sorting system ASP.NET page handling, IO coordination

Dispatcher Port Dispatcher Queues Threads Arbiter Handler Arbiter is attached to port Arbiter is activated on queue Dispatcher schedules items from its queues round-robin to run in its threads Post places a message on the port Arbiter checks whether it can consume the message Creates work item from message and handler Creates work item from message and handler Enqueue work item Thread calls handler with message as arg Scheduler picks next work item to execute

Handler Dispatcher Port Dispatcher Queues Threads Arbiter Handler There can be many of everything

Single-Port Primitives Code-Scheduling (non port-specific) Multi-Port Primitives

var dispatcher = new Dispatcher(0,”default”); var queue = new DispatcherQueue(dispatcher); var port = new Port (); port.Post("Hello, World!"); Arbiter.Activate(queue, port.Receive(message => Console.WriteLine(message) ) ); Port: Building block for sending and receiving messages Post: Queues a message Task: Delegate that handles the message (message is consumed) Receive coordination primitive Dispatcher uses fixed number of threads, schedules from queues in round-robin Port on which to receive the message

void Start() { var queue = new DispatcherQueue(); var port = new Port (); port.Post("Hello"); port.Post(“World”); Arbiter.Activate(queue, new IterativeTask(() => Hello(port) ) ); } IEnumerator Hello(Port port) { for(var i=0; i<5; i++) { yield return port.Receive(); var message = (string)port; Console.WriteLine(message); } Schedule iterative task Lambda captures arguments for iterator Yield execution until receive is satisfied Item retrieved after yield Loops around asynchronous operations are easy

IEnumerator CcrReadFileAsync(string file) { var result = new Port (); using (var fs = new FileStream(file,…,FileOptions.Asynchronous)) { var buf = new byte[fs.Length]; fs.BeginRead(buf, 0, buf.Length, result.Post, null); yield return result.Receive(); var ar = (IAsyncResult)resultPort.Test(); try { fs.EndRead(ar); ProcessData(buf); } catch { // handle exception } } Instead of passing a delegate, stream will post AR to port Retrieve AR result from port Complete operation

static IEnumerator CopyStream(Stream source, Stream dest) { var buffer = new byte[4096]; int read = 0; do { PortSet readResult = StreamAdapter.Read( source, buffer, 0, buffer.Length); yield return readResult.Choice(); var exception = (Exception)readResult; if (exception != null) yield break; read = (int)readResult; var writeResult = StreamAdapter.Write(buffer,0,read); yield return writeResult.Choice(); } while (…) } CCR Adapter for Stream class Yield to result outcomes Retrieve success outcome (bytes read) Proceed to asynchronous write

Microsoft Open Specification Promise

<DriveState true … … T13:07: :00 Flexible UI Service Orchestration

[DataContract] class State { [DataMember] public List {get; set;} } [DataContract] class Record { [DataMember] public string Name {get; set;} [DataMember] public int Age{get; set;} } // operation class Query : Query {} // operation port class OperationsPort : PortSet {}

[Contract(Contract.Identifier)] class RecordKeeperService : DsspServiceBase { [Partner(“PeopleLookup”, Policy = PartnerCreationPolicy.UseExistingOrCreate, Optional = false)] peopleLookup.OperationsPort _peopleLookupPort = peopleLookup.OperationsPort(); [ServicePort(“/recordkeeper”,AllowMultipleInstances = true] OperationsPort _mainPort; protected override void Start() { base.Start(); } Declarative, dynamic composition, annotations picked up by visual editor Attach handlers to operation port, publish instance URI in service directory

[ServiceHandler(ServiceHandlerBehavior.Concurrent)] public IEnumerator QueryHandler(Query queryOp) { var response = FindItem(queryOp.Body); queryOp.ResponsePort.Post(response); yield break; } [ServiceHandler(ServiceHandlerBehavior.Exclusive)] public IEnumerator UpdateHandler(Update updateOp) { QueryAge queryAgeOp; yield return _peopleLookupPort.Query(out queryAgeOp); int age = (int) queryAgeOp.ResponsePort; UpdateRecord(age, updateOp.Body.Name); updateOp.ResponsePort.Post(new UpdateResponse()); } CCR Interleave is iterator-aware, guaranteeing atomicity across asynchronous steps

Create causality at root of execution graph Failure occurs on one of the side branches Deal with error as message at origin of execution

Available DSS services Request Notification Response Service instance

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