dev-8: appserver ™ mode case studies simon epps solutions engineer

DEV-8: AppServer™ Mode Case Studies

Simon EppsSolutions Engineer

© 2008 Progress Software Corporation2

Agenda

AppServer Fundamentals• AppServer Environment

Distributed Computing Design Considerations AppServer Operating Modes Case Studies


AppServer Environment

The Components

Bro

ker

Agents

Business

Logic

AppServer

Data

Nam

eSer

ver

Clients



NameServer

AppServer2

App1

Client1

AppServer1

App1

AppServer3

App1

Nam

eSer

ver



Inside the AppServer Agent

Agent Startup

Agent Shutdown

Client Connect

Client Disconnect

Begin Request

End Request

Sess

ion

Con

nect

ion

Req

uest

Three levels of execution context

Differ in when they are set and how long they last

Operating modes handle context differently


Agenda

AppServer Fundamentals Distributed Computing Design Considerations

• Authentication and Authorization• User Context Management• Application State Management• Performance and Scalability

AppServer Operating Modes Case Studies


Authentication and Authorization

Get the user login Lookup the user-id in authentication system Validate a “shared-secret” Check that the user account is valid Create login context info container

• Identify using unique token• Seal to prevent tampering

Authentication Process



Lookup the login context info Lookup user’s access-control data Check access-controls on access to

application resources

Authorization Process


AuthenticationClient/Server Environment

Lookup User Account

Authenticate User

Retrieve Acct Info

Create Login Context

User Accts

Access Control

ClientC

olle

ct L

ogin

C

rede

ntia

ls

User Input

Audit Log


AuthorizationClient/Server Environment

Authorization Manager

Data

Client

User Input

Business

Logic

Access Control

Audit Log


AuthenticationN-Tier Environment

Application Server

User Input

Lookup User Account

Authenticate User

Retrieve Acct Info

Create Login Context

Collect Login

Credentials

Client

Request Authentication

Retain Token Access Control

Audit Log

User Accts


AuthorizationN-Tier Environment

Application Server

User Input

Client

Service Request

Authorization Manager

Business

Logic

Audit LogAccess Control

User Accts


User Context Management

Client/Server

User Authentication Process

Client

User Input

DEFINE VAR user_name as char.

DEFINE VAR user_id as char.

DEFINE VAR user_lang as char.

Business

Logic

User Accts



N-Tier

User Context

Application Server

User Input

Client

Service Request


Authentication Request

User Context Object

Business Logic

User Accts

Audit Log


Application State Management

Client/Server

Inventory Data

Client

DEF VAR tot as dec init 0.DEF QUERY qInv FOR Inventory.OPEN QUERY qInv FOR EACH Inventory.GET FIRST qInv.DO WHILE AVAILABLE(qInv): tot = tot + qInv.amount. GET NEXT qInv.END.



N-Tier

Application ServerClient

Procedure initQry()

Procedure getAmt()

tot = 0.

RUN initQry() on hAS.

Repeat while more:

RUN getAmt() on hAS.

tot = tot + amt.

End.

Inventory Data

Define QUERY qInv

For Inventory.


Performance and Scalability

Client/Server

Data

Client

User Business

Logic

User

User

User



N-Tier

Data

Client

Client

Client

Client

Application Resources

Application ServerClient

Client


Agenda

AppServer Fundamentals Distributed Computing Design Considerations AppServer Operating Modes

• State-reset• State-aware• Stateless• State-free

Case Studies


State-Reset/State-aware Operating Modes

Connection Process

ABL

AppServer

Data

Client2

Client1

Client3

Client4X

Nam

eSer

ver

Agent

Agent

Agent

Bro

ker


State-Reset/State-aware Operating Modes


Agent Startup

Agent Shutdown

Client Connect

Client Disconnect

Begin Request

End Request

Startup Procedure

Shutdown Procedure

Connect Procedure

Disconnect Procedure

Sess

ion

Con

nect

ion

Req

uestClient bound to Agent for

CONNECTION Context


Stateless Operating Mode

Connection Process

Bro

ker

Agents

ABL

AppServer

Data

Client2

Client1

Client3

Client4

Nam

eSer

ver


Stateless Operating Mode


Agent Startup

Agent Shutdown

Client Connect

Client Disconnect

Begin Request

End Request

Startup Procedure

Shutdown Procedure

Connect Procedure

Disconnect Procedure

Sess

ion

Con

nect

ion

Req

uestClient bound to Agent

for REQUEST Context

Activate Procedure

Deactivate Procedure

SERVER-CONNECTION-ID SERVER-CONNECTION-CONTEXT


State-Free Operating Mode

Connection Process

Client1

Nam

eSer

ver

AppServer1

App1

AppServer2

App1

AppServer3

App1

Data


State-free Operating Mode


Agent Startup

Agent Shutdown

Client Connect

Client Disconnect

Begin Request

End Request

Startup Procedure

Shutdown Procedure

Sess

ion

Con

nect

ion

Req

uestClient bound to Agent

for REQUEST Context

Activate Procedure

Deactivate Procedure


Agenda

AppServer Fundamentals Distributed Computing Design Considerations AppServer Operating Modes Case Studies

• Authentication and Authorization• User Context Management• Application State Management• Performance and Scalability



State-reset/State-aware

AppServer

User Input

Client

CONNECT Procedure

CONNECT Request

Login Context Object

Business Logic

User Accts

Audit Log




Service Request

User Input



Stateless

User Context

AppServer

User Input

Client

Service Request



User Accts

Audit Log

SERVER-CONNECTION-ID Login Context Object

Business Logic

User Input



State-free

User Context

AppServer

User Input

Client

Service Request



User Accts

Audit Log


Business Logic

SERVER-CONNECTION-ID is NOT available

User Input




Application Server

User Input

Client

Service Request



Business Logic

User Accts

Audit Log

DEF VAR user_name ...

DEF VAR user_lang ...

Set Session User-Id Once at Login

User Input



Stateless

User Context

AppServer

User Input

Client

Service Request



User Accts

Audit Log

User Context Object

Business Logic

Set Session User-Id prior to each request

SERVER-CONNECTION-ID

User Input



State-free

User Context

AppServer

User Input

Client

Service Request



User Accts

Audit Log

User Context Object

Business Logic

SERVER-CONNECTION-ID is NOT available Set Session User-Id

prior to each request

User Input




Application Server

User Input

Client

Service Request



Business Logic

User Accts

Audit Log

DEF VAR tot ...

DEF QUERY qInv ...

User Input



Stateless

Application Context

AppServer

User Input

Client

Service Request



User Accts

Audit Log

Application Context

Business Logic

SERVER CONNECTION

CONTEXT

SERVER-CONNECTION-ID

User Input



State-free

Application Context

AppServer

User Input

Client

Service Request



User Accts

Audit Log

Application Context

Business Logic SERVER

CONNECTION CONTEXT is

NOT availableSERVER-CONNECTION-ID is NOT available

User Input



State-aware/State-reset

ABL

AppServer

Data

Client2

Client1

Clientn

Agent1

Agent2

Agentn

Client3 Agent3

Bro

ker



Stateless

Bro

ker ABL

AppServer

Data

Client2

Client1

Client3

Client4

Agent1

Agent2

Agent3

Clientn

Agentm



State-free

Clientn

Nam

eSer

ver

AppServer1

App1

AppServer2

App1

AppServerm

App1

Data


Getting Started

Scalability is not a requirement• Small number of users• Application is somewhat static

Requires complex application state• Requires large critical sections• Makes extensive use of remote persistent

procedures Requires fastest possible response time

Consider State-reset or State-aware mode if your application…


Getting Started

Need to support large number of users Manages small amounts of application state Critical sections are small Makes minimal use of remote persistent

procedures Makes short-lived remote procedure calls

Consider Stateless mode if your application…


Getting Started

Requires maximum scalability Can be distributed across multiple systems

• Any request can execute on different systems Can make use of concurrent processing of

remote procedures

Consider State-free mode if your application…


Getting Started

Organize your application into multiple services

Different services can use different operating modes

Consider multiple operating modes


In Summary

Different operating modes are available to suit different application requirements

Choice of modes often requires tradeoff between scalability and complexity

Choose the mode or modes most appropriate for both short and long term goals


For More Information, go to…

PSDN• Designing Common Business Services for the AppServer,

by Anthony Swindells• Understanding the AppServer, Inside-Out• A Stateful Application in a Stateless World

Documentation:• OpenEdge® Application Server: Developing AppServer

Applications• OpenEdge Application Server: Administration• OpenEdge Development: ABL Handbook, by John Sadd


Questions?


Thank You

dev-8: appserver ™ mode case studies simon epps solutions engineer

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