Enterprise Library for .NET Framework 2.0:Core Architecture

Enterprise Library for .NET Framework 2.0

Major new release of Enterprise Library

Designed for Microsoft® .NET Framework 2.0

• Leverages key new capabilities provided by the platform

• Certain features from Enterprise Library v1.x have been deprecated in favor of the platform

Scenarios and features largely unchanged

• Public application programming interfaces (APIs) not identical, but changes are minor

• …but many improvements are hiding under the covers!

Key Changes from Enterprise Library 1.x

Configuration now built on System.Configuration

• Configuration Application Block no longer exists

• Easier to use blocks with or without configuration files

Instrumentation configurable and disabled by default

Much improved Logging Application Block

• Flexibility and performance

Simpler and more powerful Data Access Application Block

• Use with OLE-DB, Open Database Connectivity (ODBC) or any managed provider

Most of the Security Application Block has been removed

• Deprecated in favor of .NET Membership and Profile features

CachingCaching

SecuritySecurity

Data Data AccessAccess LoggingLogging

ExceptionExceptionHandlingHandling

Enterprise Library for .NET Framework 2.0

Plug-inConfigConfig

Helpers Helpers & Design& Design

Instrumen-Instrumen-tationtation

ObjectObjectBuilderBuilder

CryptographyCryptography

Core

Block DependencyOptional ProviderDependency

CachingCaching

SecuritySecurity

Data Data AccessAccess LoggingLogging

ExceptionExceptionHandlingHandling

Enterprise Library for .NET Framework 2.0

Plug-inConfigConfig

Helpers Helpers & Design& Design

Instrumen-Instrumen-tationtation

ObjectObjectBuilderBuilder

CryptographyCryptography

Core

Block DependencyOptional ProviderDependency

Core Architecture

Configuration runtime

Configuration design and tooling

Instrumentation

Factories and object builder

Configuration in Enterprise Library

All Enterprise Library blocks are configurable

• Controls how the blocks work in your application

• Specifies which plug-ins you are using

Previous versions of Enterprise Library included a Configuration Application Block

• Supported reading/writing complex configuration objects from pluggable storage

• Used by all Enterprise Library blocks, and can be used by customer code

In Enterprise Library for .NET Framework 2.0, the requirements are the same but the solution is different

System.Configuration in .NET 2.0

Much more powerful than the Microsoft® .NET Framework 1.x classes

• Supports reading and writing rich graphs of objects

• Automatic serialization and deserialization between configuration classes and XML using ConfigurationSection and ConfigurationElement

Some Enterprise Library 1.x features are not directly supported

• Storing configuration somewhere other than XML Files

• Monitoring external changes to configuration

Configuration Runtime

Enterprise Library for .NET Framework 2.0 uses System.Configuration, but provides additional helper classes to provide more functionality

• All blocks provide ConfigurationSections which are stored in app.config / web.config by default

• All System.Configuration features such as encryption and using external files are supported

Configuration Runtime helper classes are in the Common assembly

• Used by all Enterprise Library application blocks

• Can be used by your apps, but you generally won’t need to

Configuration Sources

Application BlocksApplication Blocksor Custom Codeor Custom Code

IConfigurationSourceIConfigurationSource

SystemConfigurationSystemConfigurationSourceSource

FileConfigurationFileConfigurationSourceSource

SqlConfigurationSqlConfigurationSourceSource

app.config/ web.config

foo.config

app.config/ web.config

DefaultConfigurationSource

= …

System.ConfigurationSystem.Configuration

File WatcherFile Watcher

Configuration Sources

Abstract interface that supports loading/saving configuration and monitoring for changes

Two implementations included in the core

• SystemConfigurationSource defers to System.Configuration to read from default configuration file (plus adds file watchers)

• FileConfigurationSource defers to System.Configuration but reads from arbitrary files

SqlConfigurationSource included as a sample

• Requires that sections derive from SerializableConfigurationSection

Choosing a Configuration Source

Several ways of choosing a configuration source when using Enterprise Library

If you access blocks using static façades or factories (Examples: DatabaseFactory, Logger), you will always use the application’s default ConfigurationSource:

• If you define a ConfigurationSources section in your default.config file, you can specify which type of source should be used

• If you don’t have this section, SystemConfigurationSource is used

If you use the instance factories (Examples:DatabaseProviderFactory, LogWriterFactory) you can specify a configuration source of your choosing

• Instantiated directly or using ConfigurationSourceFactory

Configuration Source Examples

// Use default source specified in the app.config / web.config file

Database db1 = DatabaseFactory.CreateDatabase(“Sales”);

// Use the specified source – you don’t need an app.config / web.config file

FileConfigurationSource fileSource = new FileConfigurationSource(“tom.config”);

DatabaseProviderFactory factory = new DatabaseProviderFactory(fileSource);

Database db2 = factory.Create(“Sales”);

<enterpriseLibrary.ConfigurationSource selectedSource="fileSource"> <sources> <add name="fileSource" type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.FileConfigurationSource, Microsoft.Practices.EnterpriseLibrary.Common" filePath="test.config"/>

<add name="systemSource" type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.SystemConfigurationSource, Microsoft.Practices.EnterpriseLibrary.Common"/>

</sources> </enterpriseLibrary.ConfigurationSource>

Change Notifications

IConfigurationSource supports monitoring configuration data for changes

• AddSectionHandler(string sectionName, ConfigurationChangedEventHandler handler)

• RemoveSectionHandler(string sectionName, ConfigurationChangedEventHandler handler)

Any code can register for changes and respond accordingly

In Enterprise Library, only the Logging Application Block currently registers to receive change notification events

Configuration Design and Tooling

Configuration tool eliminates the need to edit the blocks’ XML configuration files

• Quickly add default configuration for a block

• Strongly-typed properties and providers

• Validate configuration before you save

No major changes to configuration tool user experience from previous versions of Enterprise Library

Configuration design-time subsystem can be used in your own applications and blocks to provide a similar experience for your users

Configuration Design-Time

Improved API

• Simple base configuration design manager

• Better node registration and command registration

• 3 to 4 simple classes to register your custom provider

• No more OnSited

One configuration design manager per section

Dependent configuration design managers

Easy to interop with any .NET configuration

Instrumentation

All Enterprise Library blocks include instrumentation to assist in development, testing and operations

• Event Log events

• Performance Counters

• Microsoft® Windows® Management Instrumentation (WMI) events

All instrumentation is disabled by default, but each type can be individually enabled using the configuration tool

Instrumentation code contained in common assembly can be reused in your apps

Enabling Instrumentation

Run the installer classes to create the instrumentation artifacts:

• Run installservices.bat (using an admin account), or

• Run installutil.exe over each Enterprise Library assembly (using an admin account), or

• Create your own installers/MSI that do this

Configure instrumentation for your app using the tool

Instrumentation Architecture

Event-driven architecture

InstrumentationInstrumentationProviderProviderClass(es)Class(es)

InstrumentationInstrumentationListenerListenerClass(es)Class(es)

InstrumentationInstrumentationConfigurationConfiguration

SettingsSettings

WMIWMI

PerfPerfCountersCounters

EventEventLogLog

EventEvent

ObjectBuilderObjectBuilder

Wires upWires up

Application or BlockApplication or Blockcallscalls

Instrumentation Attributes

Instrumentation is wired up using attributes:

• [InstrumentationListener]

Defined on a type within the block or application

Specifies which listener will deal with instrumentation events

• [InstrumentationProvider]

Defined on an event within the block or application

Specifies the name of the event being fired

• [InstrumentationConsumer]

Defined on a method within the instrumentation listener

The method contains the instrumentation logic, and the name must match the one used in an [InstrumentationProvider] declaration

Instrumentation Example

public class public class Database : Database : IInstrumentationEventProviderIInstrumentationEventProvider { { DbConnection OpenConnection() { DbConnection OpenConnection() { // Do stuff// Do stuff instrumentationProvider.FireConnectionOpenedEvent();instrumentationProvider.FireConnectionOpenedEvent(); }} public object GetInstrumentationEventProvider() {public object GetInstrumentationEventProvider() { return instrumentationProvider; }return instrumentationProvider; }}}

[InstrumentationListener([InstrumentationListener( typeof(DataInsttypeof(DataInstrumentationListener), rumentationListener), typeof(DataInstrumentationListenerBinder)typeof(DataInstrumentationListenerBinder))])] public class public class DataInstrumentationProviderDataInstrumentationProvider { {

[InstrumentationProvider("ConnectionOpene[InstrumentationProvider("ConnectionOpened")]d")] public event public event EEventHandler<EventArgs> ventHandler<EventArgs> connectionOpened;connectionOpened;

public void FireConnectionOpenedEvent() public void FireConnectionOpenedEvent() {{ connectionOpened(this, new connectionOpened(this, new EventArgs());EventArgs());}}

internal class internal class DataInstrumentationListenerDataInstrumentationListener : : InstrumentationListenerInstrumentationListener { {

public public DataInstrumentationListener(string DataInstrumentationListener(string instanceName, bool perfCountersEnabled,instanceName, bool perfCountersEnabled,bool eventLogEnabled, bool wmiEnabled) :bool eventLogEnabled, bool wmiEnabled) : base(perf…, event…, wmi…) {}base(perf…, event…, wmi…) {}

[InstrumentationConsumer( “ConnectionOpe[InstrumentationConsumer( “ConnectionOpened")]ned")]public void ConnectionOpened(object public void ConnectionOpened(object sender, EventArgs e) {sender, EventArgs e) {if (PerformanceCountersEnabled)if (PerformanceCountersEnabled) connectionOpenedCounter.Increment();connectionOpenedCounter.Increment();}}

Instrumentation Installation Attributes

Running installutil over an instrumented class should install all required event log sources, WMI schemas and performance counters

Enterprise Library provides a ReflectionInstaller which uses reflection to find these, with the help of some attributes

[HasInstallableResources]

• Indicates that there is instrumentation to install

[PerformanceCountersDefinition]

• Defines the counters used by the block or app

[EventLogDefinition]

• Defines the event log sources used by the block or app

Factories and Object Builder

Objects inside application blocks need to be constructed and configured

There are different ways you can construct objects depending on what you want to do

• Use a default configuration source

• Use a custom configuration source

• Don’t use any configuration at all

• Inject instrumentation

Although each block is different, all rely on similar types of factories for construction

Object Builder

New subsystem shared between EntLib and Composite UI Application Block

Responsible for building objects inside the application blocks

• Invoking the necessary custom factory using data from configuration

• Configuring instrumentation for the blocks

Can be leveraged from your own apps, but understanding ObjectBuilder is not required to use Enterprise Library

CoreCoreApplication BlockApplication Block

Factories

Static FactoryStatic Factoryor façadeor façade

Instance Instance Provider FactoryProvider Factory

Enterprise LibraryEnterprise Library FactoryFactory

CustomCustom FactoryFactory

Block ObjectsBlock Objects

Object BuilderObject Builder

StrategiesStrategies

UserUserCodeCode

ConfigurationConfigurationSourceSource

Using Static Facades and Factories

Easiest way to use the blocks

Configuration is retrieved from the default configuration source

Instrumentation is wired up (but may be disabled)

Results in a call to an instance factory behind the scenes

Examples:

• Dim db As Database = DatabaseFactory.CreateDatabase(“Sales”)

• Logger.Write(“My message”, “My Category”)

Using Instance Provider Factories

You get slightly more control on how objects are created

You can choose your own configuration source

Instrumentation is wired up (but may be disabled)

Examples:

• Dim factory As New DatabaseProviderFactory(configSource)Dim db As Database = factory.Create(“Sales”)

• Dim factory As New LogWriterFactory(configSource)Dim writer As LogWriter = factory.Create()

Creating Objects Directly

New up the object and any dependent objects yourself

Configuration sources are not used

Object Builder is not involved

Instrumentation will not be automatically wired up (but you can add it yourself)

Example:

• Dim db As SqlDatabase = New SqlDatabase("server=(local)\SQLEXPRESS;database=EntLibQuickStarts;Integrated Security=true")

Resources

Download Enterprise Library and related resources from:

• http://msdn.microsoft.com/practices

Join the Enterprise Library Community at:

• http://practices.gotdotnet.com/projects/entlib

Read blogs from the Enterprise Library team at:

• http://msdn.microsoft.com/practices/Comm/EntLibBlogs/