Introduction toWindows Workflow Foundation

Introduction toWindows Workflow Foundation Matt WinklerTechnical Evangelist, Windows Workflow Foundationhttp://blogs.msdn.com/mwinklemwinkle@microsoft.com

AgendaAgenda

What is Windows Workflow Foundation?Architecture & Core conceptsBuilding WorkflowsBuilding ActivitiesRuntime ServicesWorkflow Communication

Windows Workflow FoundationWindows Workflow Foundation

Single workflow technology for WindowsAvailable to all customers of WindowsAvailable for use across a broad range of scenarios

Redefining workflowExtensible framework & API to build workflow centric productsOne technology for human and system workflow

Take workflow mainstreamBring declarative workflow to any .NET developerFundamental part of the Office 2007Strong workflow partner & solution ecosystem

Windows Workflow Foundation is the programming model, engine and tools for quickly building workflow enabled applications on Windows.

PackagingPackaging

Third foundational .NET Framework 3.0Windows Communication Foundation (“Indigo”)Windows Presentation Foundation (“Avalon”)Windows Workflow Foundation (“WinOE/WinWS”)Cardspace (“Infocard”)

Support for Windows XP & Windows Server 2003Licensed as part of Windows Released!

What is a workflow?What is a workflow?

A set of activities that coordinate people

and / or software...EscalateToManagerExample activities…. CheckInventory

Like a flowchart….

…organized into some form of workflow.

Or a state diagram…. or based on rules.

Windows Workflow FoundationWindows Workflow Foundation

Key Concepts

Host Process

WindowsWorkflow Foundation

Runtime Engine

A Workflow

An Activity

Runtime Services

Base Activity Library

Custom Activity Library

Visual Designer

Visual Designer: Graphical and code-based construction

Workflows are a set of ActivitiesWorkflows run within a Host Process: any application or serverDevelopers can build their own Custom Activity Libraries

Components

Base Activity Library: Out-of-box activities and base for custom activities

Runtime Engine: Workflow execution and state management

Runtime Services: Hosting flexibility and communication

Building a WorkflowBuilding a Workflow

What are Activities?What are Activities?

An activity is a step in a workflowHas properties and events that are programmable within your workflow codeHas methods (e.g. Execute) that are only invoked by the workflow runtime

Think of Forms & ControlsActivity == ControlsWorkflows == Forms

Activities fall under two broad categoriesBasic – steps that “do work”Composite – manage a set of child activities

Base Activity LibraryBase Activity Library

Base Activities get you started…Designed for modeling control flow & communications

IfElse, Delay, While, State, etc.InvokeWebService, InvokeMethod, etc.

Custom activities can derive from the Base ActivitiesBase Activities have been built using the same framework that’s available to you as developers

Activities: An Extensible ApproachActivities: An Extensible Approach

OOB activities,workflow types,base typesGeneral-purposeActivity libraries define workflow constructs

Create/Extend/Compose activitiesApp-specificbuilding blocksFirst-class citizens

Base ActivityLibrary

Custom ActivityLibraries

Author new activity

Out-of-Box Activities

Extend activity

Compose activities

Vertical-specificactivities & workflowsBest-practice IP &Knowledge

Domain-SpecificWorkflow Packages

Compliance

RosettaNet

CRM

IT Mgmt

Why build custom activities?Why build custom activities?

Activity is unit of:ExecutionReuseComposition

Activities enable workflow modelingCustom activity examples

SendEmail, FileSystemEvent, PurchaseOrderCreated, AssignTask, etc.

Write custom activities forReusing workflow logicIntegrating with technologiesModeling advanced control flowsModeling various workflow styles

Simplicity

Flexibility

Code Code ActivityActivity

InvokeMethod InvokeMethod &&EventSinkEventSinkCustom Custom ActivitiesActivities

InvokeWebService InvokeWebService ActivityActivity

Workflow Execution LogicWorkflow Execution Logic

Example: A SendMail ActivityExample: A SendMail Activityusing System.Workflow.ComponentModel;public partial class SendMail : System.Workflow.ComponentModel.Activity{ public SendMail() { InitializeComponent(); } protected override Status Execute(ActivityExecutionContext context) { // my logic here to send the email

return Status.Closed; }}public partial class SendMail{ public string subject; public string Subject { get { return subject; }

set { this.subject = value; } } private void InitializeComponent() // designer generated { this.ID = "SendMail"; }}

Activity Component ModelActivity Component Model

Each activity has an associated set of componentsComponents are associated through attributes on the Activity Definition

Required

Optional (defaults provided)

// Companion classes

[Designer(typeof(MyDesigner))]

[CodeGenerator(typeof(MyCodeGen))]

[Validator(typeof(MyValidator))]

// Behaviors

[SupportsTransaction]

public class MyActivity: Activity {...}

ActivityActivity

Code Code GeneratorGenerator

DesignerDesigner

ValidatorValidator

SerializerSerializer

BehaviorsBehaviors

Activity Execution StatusActivity Execution Status

Returned by Execute() methodCan be determined by a parent activity or workflow

this.sendEmail1.Status

Tracked by a Tracking Runtime ServiceActivity.Status Enumeration

InitializedExecutingCompensatingCancellingClosedFaulting

Activity ExecutionActivity Execution

Activity Execution MethodsInitialize()Execute()Cancel()Compensate()HandleFault()

Transition Types

ActivityRuntime

InitializedInitialized

ExecutingExecuting

ClosedClosed

CanceledCanceled CompensatingCompensating

FaultedFaulted

Advanced Composite Activity ExecutionAdvanced Composite Activity Execution

Activities may need long-running execution environments as a part of their executionThis opens up interesting possibilities of modeling advanced control flowsLoops, Continuations, Dynamic Activities etc.

Sequence Activity – Execute()Sequence Activity – Execute()protected override Status Execute(ActivityExecutionContext context)protected override Status Execute(ActivityExecutionContext context){{

Activity Activity childAchildActivity = this.ExecutableActivities[0];ctivity = this.ExecutableActivities[0];EventHandler<ActivityEventHandler<ActivityExecutionExecutionStatusChangeEventArgs> OnClosed = null;StatusChangeEventArgs> OnClosed = null;OnClosed = delegateOnClosed = delegate{{

childAchildActivity.Closed -= OnClosed;ctivity.Closed -= OnClosed;if(this.if(this.ExecutionExecutionStatus == Status == ActivityExecutionActivityExecutionStatus.Canceling)Status.Canceling) context.CloseActivity();context.CloseActivity();else if (else if (ExecutionExecutionStatus == Status == ActivityExecutionActivityExecutionStatus.Executing)Status.Executing){{ this.index++;this.index++; if (this.ExecutableActivities.Count > this.index)if (this.ExecutableActivities.Count > this.index) {{

childAchildActivityctivity = this.ExecutableActivities[this.index];= this.ExecutableActivities[this.index];

childAcchildActivity.Closed += OnClosed;tivity.Closed += OnClosed; context.ExecuteActivity(childActivity );context.ExecuteActivity(childActivity );

}} elseelse context.CloseActivity();context.CloseActivity();}}

};};childActivitychildActivity.Closed.Closed += OnClosed; += OnClosed;context.ExecuteActivity(childActivity);context.ExecuteActivity(childActivity);return return ActivityExecutionActivityExecutionStatus.Executing;Status.Executing;

}}

ForEach Activity Execution ContextsForEach Activity Execution Contexts

Template Activity

Context Owner Activities

Children Contexts of ForEach activity

Context 1

Context 2

Context 3

Default Workflow Context

Building a Basic ActivityBuilding a Basic Activity

Activity SummaryActivity Summary

An Activity is a key concept of Windows Workflow FoundationWF allows you to write custom activities to model your application control flow explicitlyActivities are the fundamental unit of:

Execution, Reuse, & Composition

Two broad types of activities:Basic & Composite

Activity Designer simplifies the development of custom activities – especially compositesSystem.Workflow.ComponentModel provides the framework to build custom activitiesCall to action: Write Activities!

Benefits of State Machine WorkflowsBenefits of State Machine Workflows

FlexibilityAbility to handle multiple business exceptionsAbility to handle multiple paths leading to the same goal

VisibilityAbility to view the past, present and future of a business process

ControlAbility of the business end user to control the flow of the process at run time

State Machine Workflow ConceptsState Machine Workflow Concepts

The basic elements of a state machine workflow

StatesEventsActionsTransitions

A state machine workflow is composed of a set of statesIn a given state a set of events can be receivedBased on the event received an action is performed at the end of which a state transition may or may not be made

Activities in a State Machine WorkflowActivities in a State Machine Workflow

State Machine WorkflowRoot activity that is the container for a state machine

StateRepresents the state of the state machine

EventDrivenUsed to handle an event in a given state

SetStateUsed to transition from one state to another

StateInitializationUsed for default action on entering a state

StateFinalizationUse for default action on leaving a state

Event Driven

State Machine Workflow

Event Driven

State Initialization

StateState

Set State

State

State Finalization

Order Processing ExampleOrder Processing Example

On Order CreatedOn Order Processed

OrderCreated Order

Processed

OrderShipped

On Order Shipped

On Order Completed

On Order Completed

Waiting toCreate Order

On Order Completed

On Order Shipped

OrderCompleted

Querying a State Machine WorkflowQuerying a State Machine Workflow

Crucial in creating effective Business Applications

Need to answer the question “Where is the process currently at?”

StateMachineWorkflowInstance class to query and interact with an instance of a state machine workflowUsed to answer questions like:

What is the current state of the workflow?What transitions are possible from the current state?Enumerate all the states in the workflow?

A State Machine WorkflowA State Machine Workflow

Runtime ServicesRuntime Services

The workflow runtime is lightweightDepends on a set of services

Only Threading is requiredOften you also want Transactions and Persistence

Add services programmatically or using a config file What ships in System.Workflow.Runtime.Hosting?

Abstract service definitionsConcrete service implementations

DefaultWorkflowSchedulerService (asynchronous)ManualWorkflowSchedulerService (synchronous; for ASP.NET scenarios)DefaultWorkflowTransactionServiceSqlWorkflowPersistenceService

Runtime ServicesRuntime ServicesHost Application

App Domain

SQL

Out of Box Services are provided that support SQL Server 2000 & 2005

Common resource services for managing threading, timers and creating transactions

PersistenceService stores and retrieves instance state.TrackingService manages profiles and stores tracked information.

Runtime

Services

PersistenceService

TrackingService

SchedulerService

TransactionService

Out-of-Box ServicesOut-of-Box ServicesManualWorkflowSchedulerService

Synchronous threading service used for in-line execution; used by ASP module for web services

DefaultWorkflowSchedulerService

Used for asynchronous execution of workflows; uses default .Net thread pool

DefaultWorkflowTransactionService

Creates .NET transactions

SharedConnectionWorkflowCommitWorkBatchService

Sql services share connection to SqlServer

SqlWorkflowPersistenceService

Stores workflow instance state information in SqlServer/MSDE

SqlTrackingService Stores tracking information in SqlServer/MSDE

Workflow State ManagementWorkflow State Management

Many workflows are long runningA workflow instance is idle when it has no runnable workPersistence services determine whether to unload the WF when idleLoading/unloading is not a concern of the workflow developer or the application developer

Persistence points are checkpointsTransactionsEnable crash recoveryPersistence occurs at:

Closure of a transactionClosure of any activity marked [PersistOnClose]Closure of the workflow

Enabling Workflow PersistenceEnabling Workflow PersistencePersistence Support for Workflow Instances

Create the SQL database with the SqlWorkflowStatePersistence schemaCreate a Workflow RuntimeDefine Connection StringRegister StatePersistenceService with RuntimeStart the WorkflowLoading and Unloading uses StatePersistenceService

private void RunWorkflow(){ WorkflowRuntime wr = new WorkflowRuntime(); string connectionstring = "Initial Catalog=Persistence;Data Source=localhost;Integrated Security=SSPI;";

wr.AddService(new SqlWorkflowStatePersistenceService(connectionstring));

wr.CreateWorkflow(typeof(SimpleWorkflow)).Start();}

TrackingTracking

Track all state changes and data within the workflowEmit tracking info from codeDynamic changesProfile

XML file that specifies what to trackIncludes and excludes, state changes, data context, typesObject model to create

TrackingInformation Tracking

Service

Host Application

StoreActivities

WorkflowInstance Query

WriteProfile

Enabling Workflow TrackingEnabling Workflow Tracking

Tracking Support for Workflow InstancesDefine tracking profilesCreate workflow runtimeDefine connection stringRegister one or more TrackingService’s with the WorkflowRuntimeStart the workflowQuery tracking database – instance and activity information

private void RunWorkflow(){ WorkflowRuntime wr = new WorkflowRuntime(); string connectionstring = "Initial Catalog=Tracking;Data Source=localhost;Integrated Security=SSPI;";

//Out of the Box Tracking Service wr.AddService(new SqlTrackingService(connectionstring)); wr.CreateWorkflow(typeof(SimpleWorkflow)).Start();}

Workflow Authoring ToolsWorkflow Authoring Tools

Line of Business Manager / End usersWizards

Business AnalystVisio Like

Script Developers or VARsScript Like

Code Developers or ISVsWindows Workflow Foundation Designer

Commonality between Tools:Support a common object model for describing Workflow informationThe object model needs to be exchangeable between tools

Rehosting Workflow DesignerRehosting Workflow Designer

SummarySummaryA single workflow technology for Windows

Platform level workflow framework for use within Microsoft products & ISV applicationsWill be used by BizTalk Server, Office 2007, MBS & other Microsoft client/server productsAvailable to all Windows customers

Microsoft is redefining workflowUnified technology for System & Human workflowMultiple styles: sequential, rules-based, state machineSupports dynamic interaction

Microsoft is taking workflow mainstreamConsistent and familiar programming model for reaching mainstream application developerAvailable to millions of end-users through Office 2007Extensible platform for ISVs

Community SiteSubscribe to the RSS feed for news & updatesFind, download, & register ActivitiesFind blogs, screencasts, whitepapers, and other resourcesDownload samples, tools, and runtime service componentshttp://wf.netfx3.com

MSDN® Workflow PageDownload 12 Hands-on Labshttp://msdn.microsoft.com/workflow

ForumsAsk questions in the forumsGo to the community site

Windows Workflow Foundation ResourcesWindows Workflow Foundation Resources