1 Building you build process with Windows Workflow Foundation Abid Quereshi.

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Building you build process with Windows Workflow Foundation

Abid Quereshi

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Agenda

Existing build technologies

Promise of Workflow Foundation

Demonstration – reusing Nant scripts

Demonstration - Custom Task

Authoring Modes

Serialization and Deserialization

Designer Re-Hosting

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Cruise Control

MS Build

Nant/Ant

Visual Build

Automated Build Studio

DB Change management tools (DB Ghost, Embarcadero)

Make files, batch files, any other


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Motivation for new way of building software


ObjectivesVisual Configuration (script free)

Real-time distributed feedback

Parallel Task processing

Cheap

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Promise of Windows Workflow Foundation

Design by markup

Access to high level programming language- Threading, tracing, events

End user configuration

Possibilities that WF provides

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Co-ordinate work performed by people and software

Long-running and stateful

Based on extensible models

Transparent and dynamic throughout their life cycle

The Four Workflow Tenants:

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Build technologies

New software development technologies and platforms

Configuration

Motive for a Dynamic Build process

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ScenarioCheckout

Start

Compile in Release configuration

Compile in Debug configuration

Deploy

Stop

ConfigMode = Release?

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Reuse of existing scripts and build technologies

Example of a code only workflow

Build script encapsulation demo

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Authoring Modes


Code Only

Markup (XAML) + Compiled Code Beside

Full Visual Studio Support

Some Visual Studio Support + Prayer

Markup + Assembly binding

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Custom Activities

Workflow Customization

Part of Workflow tenants (Based on extensible models)

Reusable components

Possibility of Software Build DSL

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Domain Specific Language


Limited form of computer language designed for a specific class of problems.

Library(Framework) + Configuration (Process, algorithm or how to perform a process)

Most Frameworks in a particular platform address technical concerns

DSL’s address business concerns (Higher level level of abstraction)

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DSL’s typically come with a code generation tool

• Constraint syntax• Accessible to non-developers

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• May require a Parser• Schemas help to validate instructions• Algorithm Syntax - what is being said – is limited

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Algorithm Syntax - what is being said – is limited

How it is being said may take two forms• Internal DSL - syntax of instruction is a subset of host

general purpose language code• External DSL – often a configuration file

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Custom Workflow


SequentialWorkflowActivity

SequenceActivity

CompositeActivity

Activity

DependencyObject<abstract>

MyCustomWorkflow

MyCustomActivity

System.Workflow.ComponentModel

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Activity Class


Methods to override:

• Execute• Cancel• Initialize

These are called by the WF runtime – not manually

Activity


Execute(ActivityExecutionContext):ActivityExecutionContext Cancel(ActivityExecutionContext):ActivityExecutionContext Initialize(IServiceProvider)

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Activity Class State

Workflow State

Compensating

Closed FaultingCanceling

Executing

Initialized

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Dependency Object & Dependency Properties

Workflow State


• Activity data storage mechanism• Allows activities to project their properties onto their

children• Essential provision for WF tenent (Long-running and

stateful)

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Dependency Object

Workflow State

• Hash table

• Essential provision for WF tenant (Long-running and stateful)

• Add a public static instance of Dependency Property to manage that property for all instances of the activity

• Implement .NET Property that accesses an activities Dependency Property

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Dependency Properties

Workflow State

Must derive from DependencyObject

Register property then define property

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Workflow State

public static DependencyProperty MyDepPropProperty = DependencyProperty.Register( “MyDepProp",

typeof(String), typeof(MyClass));

Property name

Property Type

Owner Type

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Workflow State

public String CompilationMode{ get { return (String)(base.GetValue(MyClass. MyDepPropProperty)); } set { base.SetValue(MyClass.MyDepPropProperty, value); }}

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Parameter Passing

Workflow State

Dictionary<String, Object> Args = new Dictionary<string, object>();

Args.Add("RepositorySource", "C:\\Projects\\BuildManager\\Repository");

Args.Add("CompilationMode", "Release");

Args.Add("Application", "C:\\Projects\\BuildManager\\Checkout\\BuildMeWinApp\\BuildMeWinApp.sln");

Args.Add("Target", "C:\\Projects\\BuildManager\\BuildTarget");

WorkflowInstance instance = workflowRuntime.CreateWorkflow(typeof(BuildTasks.Builder), Args);

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Custom Workflow

Domain specific activities

Domain specific workflow

Example of Code+Markup workflow

Build custom workflow demo

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Markup

Authoring Modes

<SequentialWorkflowActivity x:Class="MarkupBuild.Build" x:Name="Build"

xmlns:ns0="clr-namespace:BuildTasks;Assembly=BuildTasks, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/workflow">

<ns0:Checkout BuildFile="{x:Null}" x:Name="checkout1" RepositorySource="{x:Null}" />

<ns0:Compile BuildFile="{x:Null}" x:Name="compile1" CompilationMode="{x:Null}" Application="{x:Null}" />

<ns0:Deploy BuildFile="{x:Null}" x:Name="deploy1" CompilationMode="{x:Null}" Target="{x:Null}" />

</SequentialWorkflowActivity>

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XOML

Authoring Modes

Extensible Orchestration Markup Language (XOML) files, a special case of XAML file types, which specify the workflow logic within an application.

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Binding

Authoring Modes

<SequentialWorkflowActivity x:Class="MarkupBuild.Build" x:Name="Build"

xmlns:ns0="clr-namespace:BuildTasks;Assembly=BuildTasks, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/workflow">

<ns0:Checkout x:Name="checkout1" RepositorySource="{ActivityBind Build,Path=RepositorySource}" />

<ns0:Compile x:Name="compile1" CompilationMode="{ActivityBind Build,Path=CompilationMode}" Application="{ActivityBind Build,Path=Application}" />

<ns0:Deploy x:Name="deploy1" Target="{ActivityBind Build,Path=Target}" CompilationMode="{ActivityBind Build,Path=CompilationMode}" />

</SequentialWorkflowActivity>

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Authoring Modes

Binding

gives a dependency property an ActivityBind object to evaluate when asked for its value

ActivityBind can point to other fields, properties, or methods of activities inside a workflow.

One activity could bind its input properties to a previous activity's outputs.

Binding makes the data flow a part of the workflow model.

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Markup-only workflows

Authoring Modes

Allows for declarative programming

Facilitates the highest degree of encapsulation

Facilitates usage of code-generation tool

Requires mechanism to serialize and deserialize WF

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Serialization

Serialization

Serialization

Create a XAML workflow markup file from an in-memory workflow model

Deserialization

Reads markup and creates in-memory object containing definition of workflow model

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Serialization

Serialization

private static void SerializeToMarkup(Activity workflow, String fileName)

{

try

{

using (XmlWriter xmlWriter = XmlWriter.Create(fileName))

{

WorkflowMarkupSerializer mrkupSerializer = new WorkflowMarkupSerializer();

mrkupSerializer.Serialize(xmlWriter, workflow);

}

}

catch (Exception e)

{

Console.WriteLine("Exception during serialization: {0}" e.Message);

}

}

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Serialization

Deserializer needs knowledge of the types referenced in the markup

ServiceContainer, TypeProvider, DesignSerializationManager

Deserialization

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Serialization

Activity workflow = null;

ServiceContainer container = new ServiceContainer();

Add a TypeProvider to resolve BuildTask references

TypeProvider provider = new TypeProvider(container);

provider.AddAssembly(typeof(SharedWorkflows.MarkupOnlyBaseWorkflow).Assembly);

container.AddService(typeof(ITypeProvider), provider);

Add ServiceContainer with the TypeProvider to serialization manager

DesignerSerializationManager dsm = new DesignerSerializationManager(container);

XmlReader xmlReader = XmlReader.Create(fileName)

WorkflowMarkupSerializer markupSerializer = new WorkflowMarkupSerializer();

workflow = markupSerializer.Deserialize(dsm, xmlReader) as Activity;

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Designer Re-Hosting

Code generation tool

Configurable by end user

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Introduction

Designer Re-hosting

The logic of a build process is often simple enough for to allow drag and drop process design by non-developers

WF allows for re-hosting the workflow designer in a windows application (outside of the Visual Studio environment)

Powerful proposition

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Designer Classes

System.ComponentModel.Design.DesignSurface

General-purpose design canvas

System.Workflow.ComponentModel.Design.

WorkflowDesignerLoader

Serialization/Deserialization

Loading of services used by the designer

System.Workflow.ComponentModel.Design.WorkflowView

Implements visual representation of your workflow model

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Designer Classes

IDesignerHost

Persisted Workflow Models

(.xoml files)

Design Surface

MyDesignerLoader: WorkflowDesignerLoader

Load services and populate visual treeIRootDesigner

WorkflowView

BeginLoad method

GetServices method

GetDesigner method

GetView method

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Property Attributes

Designer Re-hosting

Description

Category

Browsable

DesignerSerializationVisibility

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Designer Re-hosting

Abstract

Must be implemented in a derived class

Responsible for loading workflow from peristable tore .xoml and populating tree of visual objects in the designer and Vise-Versa

WorkflowDesignerLoader

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Designer Re-hosting

Services

IMenuCommandService

ITypeProvider

IToolboxService

IPropertyValueUIService

IEventBindingService

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Designer Re-hosting

Demo

Simple workflow

Workflow with conditional branch

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Conclusion

Revisiting Objectives

Visual Configuration (script free)



Cheap

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Conclusion


Limitation is due to fact that WF Markup is a subset of XAML – the markup parser is not extensible


Parallel task activity is not multithreaded

This can be implemented but it’s not out-of-the box functionality

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Conclusion

References

• Pro WF Windows Workflow in .NET 3.0, Apress, Bruce Bukovics

• Professional Windows Workflow Foundation, Wrox, Todd Kitta

• Introduction to Domain Specific Languages, Martin Fowler, http://www.infoq.com/presentations/domain-specific-languages

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1 Building you build process with Windows Workflow Foundation Abid Quereshi.

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