C10: Getting Rejected on the Bus How OpenEdge ® Developers Deal with Failure Chris James Senior Consultant.

C10: Getting Rejected on the Bus

How OpenEdge® Developers Deal with Failure

Chris JamesSenior Consultant

© 2008 Progress Software Corporation2

“It is possible to fail in many ways… while to succeed is possible in only one way”

Aristotle – Greek philosopher

© 2008 Progress Software Corporation3

OpenEdge and Sonic™ ESB

You can align business and IT goals using Sonic and OpenEdge in your SOA

You can create robust and flexible business applications

You can handle failures in your infrastructure, applications, or data

© 2008 Progress Software Corporation4

Agenda

Sonic ESB Endpoints Faults and rejected messages Quality of Service (QOS) and Message Time

To Live (TTL) Application architecture and AppServer™

operating modes Fault processing options AppServer Down!!!!

Dealing with rejection on the bus

© 2008 Progress Software Corporation5

Terminology

Service• Your OpenEdge based application exposed to

Sonic ESB through the Sonic Adapter Process

• A Sonic ESB process that uses an itineary to execute 1 or more operations on 1 or more services

Container• A Sonic managed executable process that

hosts processes and services

© 2008 Progress Software Corporation6

Sonic ESB Endpoints

Destination where ESB services and processes send and receive messages

Can be associated with a Queue or Topic 4 defined Endpoint types for Services

• Entry (required for services)

• Exit (usually ReplyTo)

• Fault

• RME

© 2008 Progress Software Corporation7

OpenEdge ESB Adapter Architecture

Database

AppServerAdapter

Entry Endpoint

Exit Endpoint

Fault Endpoint

Rejected Endpoint

© 2008 Progress Software Corporation8

Faults and Rejected Messages

Rejected Messages• Invalid message types

• Invalid data

• Adapter exceptions

• Failure to send result

Fault Messages• Infrastructure issues

• Applications errors (RETURN ERROR)

Service has Fault and Rejected Message endpoints

© 2008 Progress Software Corporation9

Anatomy of a Rejected Message

<SOAP-ENV:Body>

<xq:rejectedMessageInfo xmlns:xq=“…">

<rejectedCode>OPENEDGE_INVOCATION_ERROR</rejectedCode>

<rejectedLocation container="dev_OpenEdgeTest"

host="pcdcleary" process="CheckCustomer"

serviceApplication="dev.OpenEdge" step="Find Customer"

topLevelProcess="CheckCustomer"/>

<rejectedDetails>

{Error message and stack trace}

</rejectedDetails>

© 2008 Progress Software Corporation10

Anatomy of a Fault Message

<exception xmlns=“…">

<message>Fault String: SessionPool : NoAvailableSessions[Could not connect to the AppServer: General Error: Connection refused: connect. (7203)]</message>

<class>com.progress.open4gl.dynamicapi.SessionPool.NoAvailableSessionsException</class>

<detail>

<faultDetails container="dev_OpenEdgeTest" host="pcdcleary" process="CheckCustomer" serviceApplication="dev.OpenEdge" step="Find Customer" topLevelProcess="CheckCustomer" />

</detail>

< message>

Fault String: SessionPool : NoAvailableSessions[Could not connect to the AppServer: General Error: Connection refused: connect. (7203)]

</message>

<class>

com.progress.open4gl.dynamicapi.SessionPool.NoAvailableSessionsException

</class>

<faultDetails container="dev_OpenEdgeTest" host="pcnbcdjxp" process="CheckCustomer" serviceApplication="dev.OpenEdge" step="Find Customer" topLevelProcess="CheckCustomer" />

© 2008 Progress Software Corporation11

Quality of Service

Best Effort• Default

• Messages may be lost or redelivered

At Least Once• No lost messages

• May be redelivered

Exactly Once• Most reliable

• No lost or redelivered messages

© 2008 Progress Software Corporation12

Message Time To Live

Specifies a timeout on a process Messages that timeout sent to RME Default is 0 (no timeout)

© 2008 Progress Software Corporation13

Configuring Properties

Service• Fault and Rejected Message endpoints

• Can be overridden by process

Endpoint• Entry endpoint specifies QOS

• Process sets minimum QOS

Process• Time to Live

© 2008 Progress Software Corporation14

Application Architecture and Operating Modes

Sonic container and OpenEdge AppServer treated as single unit• Sonic provides networking

• Fewer faults due to AppServer availability

• ESB Service and OpenEdge AppService same

Session-free operating mode recommended• Each operation does complete unit of work

• No state saved on AppServer

• Persistent procedures defeat this architecture

© 2008 Progress Software Corporation15

Session-managed and Persistent Procedure Issues

Requires three calls for a single operation Saves state on AppServer even with Session-

free AppServer still bound due to fault or rejected

message Limits scalability Enable Intra-Container messaging to mitigate

issues

© 2008 Progress Software Corporation16

Fault Processing Options

Settable per operation Fault Only (Default)

• Original message lost

Fault and Original message• Original message can be remediated and

resubmitted

Rejected and Original message• Same as above, but rejected format

Continue process with Fault

© 2008 Progress Software Corporation17

Fault Processing Options

© 2008 Progress Software Corporation18

Booking a Vacation

Client Flight Booking

Coordinator Service

Hotel Booking Car Booking

© 2008 Progress Software Corporation19

Book Hotel Room Process

© 2008 Progress Software Corporation20

Checking Availability

Yes, there are rooms available• Process/transaction continues

No, there are not rooms available• Entire transaction fails

I don’t know if rooms are available• AppServer down

• No available agents

© 2008 Progress Software Corporation21

Fix problem and resubmit

© 2008 Progress Software Corporation22

AppServer Down Demo!!!

© 2008 Progress Software Corporation23

Agenda

Sonic ESB Endpoints Faults and rejected messages Quality of Service (QOS) and Message Time

To Live (TTL) Application architecture and AppServer

operating modes Fault processing options AppServer Down!!!!

Dealing with rejection on the bus

© 2008 Progress Software Corporation24

In Summary

You can align business and IT goals using Sonic and OpenEdge

You can create robust and flexible business applications

You can handle failures in your infrastructure, applications, or data

© 2008 Progress Software Corporation25

For More Information, go to…

PSDN• Introducing Native Invocation with the Open

Edge Adapter for Sonic ESB• Progress Sonic ESB Developers Guide - Re

submit Sample Progress eLearning Community:

• OpenEdge Development with Sonic ESB• Designing ESB Processes• Orchestrating Services with Sonic BPEL Ser

ver

© 2008 Progress Software Corporation26

Relevant PTW Sessions

C4: Common Applications for Sonic ESB

C8: Getting the Most Out of Sonic Workbench

© 2008 Progress Software Corporation27

Questions?

© 2008 Progress Software Corporation28

Thank You

© 2008 Progress Software Corporation29