“Behind the Scenes” of the Enterprise Development Reference Architecture (EDRA) Jonathan Wanagel Microsoft patterns & practices

“Behind the Scenes” of the Enterprise Development Reference Architecture (EDRA)

Jonathan Wanagel

Microsoft patterns & practices

http://www.microsoft.com/practices

http://www.microsoft.com/practices

2

Agenda

About This Talk

What is p&p and EDRA

Application Architecture Challenges

Building an Architecture

Creating an Architectural Framework

Summary

Questions

About This Talk

Things to Expect

• Polls

• Storytelling

• Questions

• Intermission

4

Agenda

About This Talk





Summary

Questions

Microsoft patterns & practices

Guidance on Enterprise Business Applications

Available for download from Microsoft’s website

Learning the most significant challenges from customers

Analyzing the patterns and/or best practices for solving those challenges

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Enterprise Development Reference Architecture (EDRA)

EDRA incorporates numerous best practices for solving enterprise business system challenges

Utilizes various p&p guidance to apply the best practices

Includes a reusable implementation of the architecture

Includes complete conceptual architecture documentation

Includes Global Bank sample application demonstrating real-world uses cases using the framework

EDRA Key Benefits

Extensible architecture for cross cutting concerns

Support for secure infrastructure deployments

Support for integration

Improved developer productivity

Easier adjustment to significant system requirement changes

Reference Architecture ChallengesIntegration CapableMultiple transportException handlingApplication hostingExtensible architectureServices BasedStateless ComponentsSecure deploymentTransport choiceDeveloper ProductivityDeveloper PortabilityConcern SeparationLive Configuration UpdatesRequirements Change Adaptability (deployment, transport, etc)

Consistent Development ExperienceConsistent Usage of Best PracticesApplication Architectural GovernanceTransaction ManagementAuthenticationAuthorizationValidationRemote DebuggingCompensating TransactionTimeout ManagementInstrumentationLoggingDuplicate Requests (Idempotency)Business Eventing

Agenda

About This Talk





Summary

Questions

Challenge: Integration Capable

Challenge Summary:

An organization can have all the integration infrastructure in the world, such as various networks, EAI middleware, integration server products, messaging systems, etc. However, if an applications architecture is closed and offers no way of interfacing with any of the integration infrastructure, then you have an application that you cannot integrate with.

How can you ensure your application architecture is integration capable so it is possible to be integrated with other systems?

Poll

Stories


More Challenge Details

• A new application may not start with integration requirements

• Sometime after deployment, integration requirements come up because of needs from other applications

• Want to avoid screen scraping or data oriented integration


Solution Best Practices

• Build your application with a cleanly separated business API

• Expose the business API with an external invocation mechanism

• Include an interception mechanism to allow adding hooks for raising “business events”

Questions

Challenge: Exception Management

Challenge Summary:

All applications will have errors occur during operation, both expected and unexpected types of errors.

When errors occur, how should they get handled by the application?

Poll

Stories



• Do all errors get reported to the caller or user?

• What about error information containing information that is a security risk such as “Connection string X failed”?

• What about reporting errors to the system administrator?

• What about the error propagation within the system?



• Categorize errors as “business” errors versus “technical” errors

• Always propagate errors to the system boundary (unless explicitly handled)

• Use normal try/catch/throw, not error return codes

• Business logic code throws “business” errors such as a business rule violation, with a message that is safe and user appropriate

• At the system boundary, if error is a “technical” error then:

Log the error for a system administrator including unique log id

Replace error message with generic message to ensure unsafe information is not leaked

Include log id in generic message for correlation

Questions

Challenge: Secure Deployment

Challenge Summary:

A very common infrastructure setup for security is creating a perimeter network (DMZ) that “outsiders” access, separated with a firewall from the secure network. Additionally, there might be another firewall inside the secure network separating your database servers.

How do you design your application architecture so it can be deployed to a secure infrastructure setup?

Poll

Stories



• Are the “outsiders” users or systems (i.e. UI or programmatic access)?

• How do you split your application architecture for the different zones?



• Build your application with a cleanly separated business API

• Split your business tier into an “interface” and “implementation”

• Handle boundary verification responsibilities (validation, authentication, etc) in the interface

• Deploy your interface in the DMZ and implementation in the secure network

Questions

Challenge: Multiple Transports

Challenge Summary:

Sometimes an application needs to be used by multiple external systems, but they do not all support a single communication mechanism.

How do you design your application architecture so it can support multiple communication mechanisms?

Poll

Stories



• The organization hasn’t implemented an integration server, or one or more systems are an “exception” to using it

• This application instance alone cannot justify bringing in an integration server, and expanding scope isn’t realistic

• Transitioning communication mechanisms and need to support old and new simultaneously, or plan to transition in the future



• Create a separation between the communication transport and the rest of the architecture

• Normalize the request input and request output mechanisms of the architecture and have the transports adapt to them

Questions

Challenge: Concern Separation

Challenge Summary:

Your organization or development team contains a mix of more skilled developers or architects experienced in dealing with technical issues, and less skilled developers experienced in coding business logic and rules.

How can you factor your application architecture so the coding for the technical issues is separated from the coding of the business logic?

Poll

Stories



• Ratio of highly skilled developers to less skilled developers can be very low

• Coding things such as instrumentation, logging, authentication, database connections, transactions, and authorization tend to be different types of thinking then business logic

• When business logic and technical code are intermingled, it makes it harder to follow the code when focusing specifically on the business logic or vice versa



• Encapsulate the business logic into specific components called “business actions”

• Try to move as much technical code as possible into separate components from business logic

• For each business action, call the necessary technical components before and/or after the business action

• The components with the technical code can be further sub-divided based on concern type

Questions

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Agenda

About This Talk





Summary

Questions

DatabaseServer

DatabaseServer

ApplicationServer

ApplicationServer

Building An Architecture

ASPX pagesASPX pages

SQL Server DatabaseSQL Server Database

Web BrowserWeb Browser

ApplicationServer

ApplicationServer Business

Tier

BusinessTier

DatabaseServer

DatabaseServer




Business LogicBusiness Logic

Business APIBusiness API

ApplicationServer


Tier

BusinessTier

DatabaseServer

DatabaseServer





Interception MechanismInterception Mechanism

ASMX pagesASMX pages

Integration Infrastructure /External Applications

Integration Infrastructure /External Applications

Business Events


ApplicationServer


Tier

BusinessTier

DatabaseServer

DatabaseServer





Interception MechanismInterception Mechanism


Integration Infrastructure /Other Applications



Exception ManagementException Management

Business Events

ApplicationServer(Secure)


ServiceImplementation


ApplicationServer(DMZ)


ServiceInterface

ServiceInterface

DatabaseServer

DatabaseServer







FirewallFirewall

FirewallFirewall

FirewallFirewall



Interception MechanismInterception MechanismException ManagementException Management

Boundary LogicBoundary Logic

Business E

vents







ServiceInterface

ServiceInterface

DatabaseServer

DatabaseServer




ASMXASMX



FirewallFirewall

FirewallFirewall

FirewallFirewall

Business APIBusiness APIInProcInProc MSMQMSMQ

InternalApplication

InternalApplication

Business E

vents

Boundary LogicBoundary Logic


Interception MechanismInterception MechanismException ManagementException Management




ServiceImplementationBusiness

Logic

BusinessLogic



ServiceInterface

ServiceInterface

DatabaseServer

DatabaseServer




ASMXASMX



FirewallFirewall

FirewallFirewall

FirewallFirewall

Business APIBusiness APIInProcInProc MSMQMSMQ

InternalApplication

InternalApplicationB

usiness Events

ConcernsConcerns

ConcernsConcerns

Biz ActionsBiz Actions

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Agenda

About This Talk





Summary

Questions


Creating an architectural framework is taking an architecture and making it reusable

Some challenge best practices can help with reusability

An architectural framework is itself a best practice for solving many challenges

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Challenge: Consistent Usage of Best Practices

Challenge Summary:

Various architectural best practices may be known by different people, but the applications being built by the organization inconsistently apply them.

How can you ensure that best practices are used as new applications are being developed by various development teams across the organization?

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Challenge: Consistent Usage of Best Practices


• Organizations often make efforts to try and improve the quality of architectures across the company

• Setting up meetings or trainings to share “best practices” across projects or teams

• Creating documentation or training to show best practices that can be used

Why a Framework Helps

• Usage of best practices on an application can become an “implicit” activity requiring no training or communication

• Adding best practices to development can also be “implicit”

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Challenge: Developer Productivity

Challenge Summary:

The various business units in your organization always have more IT needs then what gets fulfilled because they cannot afford or justify the costs.

How can you improve the productivity of the development teams to try and fulfill more business needs cost effectively?

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Challenge: Developer Productivity


• More training

• Improved development processes

• More developer specialization


• Reduced time spent on establishing and building the architecture

• Reuse of architecture reduces overall development

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Challenge: Application Architectural Governance

Challenge Summary:

Many organizations have a person or group responsible for setting rules or policies affecting the architectures of applications.

How can you enforce rules or policies that affect application architecture or development?

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Challenge: Application Architectural Governance


• How to communicate rules and policies

• Enforcement through reviews and general policing

• What to do when application slips through the cracks

• How to keep existing applications compliant with rules and policies


• Rules and policies can be enforced through updates to framework

• Existing applications can be upgraded to newest framework to ensure compliance

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Challenge: Developer Portability

Challenge Summary:

Organizations often need to transfer developers from working on one application to another. This can mean significant ramp up time for the developer to understand the application well enough to work on it effectively.

How can you reduce the ramp up time necessary for a developer to switch from working on one application to another?

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Challenge: Developer Portability


• Sometimes moving developers occurs in “swaps” that take a long time because you then have ramp up dependencies

• Understanding an application architecture can be time consuming

• Understanding the business logic versus architecture logic


• A framework creates more consistencies in architecture requiring less ramp up time

• Better separation of concerns allows focusing more strictly on business logic

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Challenge: Requirement Change Adaptability

Challenge Summary:

Changes in the requirements for an application can usually be reasonably handled if they affect business rules or business functionality. But requirement changes that impact the architecture can be extremely difficult to deal with.

How can you reduce the difficulty of dealing with requirement changes impacting an applications architecture?

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Challenge: Requirement Change Adaptability


• Difficult to predict the requirement changes

• Cost of adding flexibility


• Reusability for different scenarios offers flexibility

• Flexibility cost is significantly less

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Agenda

About This Talk





Summary

Questions

To Download

To download the EDRA source code, documentation, candidate features for future releases, and the EDRI:

• Go to the EDRA community workspace at http://workspaces.gotdotnet.com/shadowfx

• Sign in (you will first need to join the workspace)

• Go to the “Releases” section

For a knowledge base on EDRA including frequently asked questions, known issues, etc:

• Go to the Wiki site at http://channel9.msdn.com/wiki/default.aspx/Channel9.EDRAWiki

http://w/

http://w/

http://channel9.msdn.com/wiki/default.aspx/Channel9.EDRAWiki

Summary

Application architecture requires understanding and choosing your challenges

Architectural frameworks can help solve challenges

EDRA is an application architectural framework that attempts to incorporate several best practices

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Agenda

About This Talk





Summary

Questions

Questions?

Documents

“Behind the Scenes” of the Enterprise Development Reference Architecture (EDRA) Jonathan Wanagel Microsoft patterns & practices