Websight Visualizing the Execution of Web Services

IBM TJ Watson Research Center

Workshop on Testing, Analysis and Verification of Web ServicesJuly 11, 2004 Boston, MA

WebsightVisualizing the Execution of Web Services

Wim De Pauw, Bob Hoch, Sophia Krasikov, Michelle Lei, John Morar, Raju Pavuluri, Amit Phalgune, Ed Pring, Senthil Velayudham

Contact: [email protected]

mailto:[email protected]

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IBM T.J. Watson Research Center

Websight - Visualizing the Execution of Web Services IBM TJ Watson Research © 2004 IBM Corporation

Outline

Motivation

Debugging Web Services

Profiling and understanding Web Services

Dealing with complexity

Technology

Conclusions

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What are Web Services?

"A WSDL described interface that defines a collection of network accessible operations"

Modular Composed Described Published Found Bound Invoked

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Evolution of Web Services

Internal Enterprise Application Integration

External Integration

Dynamic adaptation in e-business

=> Lingua Franca for (loosely coupled) distributed systems

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Web Services: the Challenge

Do you know how your Web Services are interacting ?

Ever tried to read their trace logs?

Ever tried to collate ten trace logs?

Where are the bottlenecks?

Is your workflow correct?

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Websight: Problem Determination for Web Services

Debugging and understanding

Analysis at application level

Understand message flow of Web Services in complex applications

Total processing time vs. business logic time

Experimental research tool

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BPEL Engine

PartnerWorld

SAP-F

Compatibility

Exclusivity

Check warranty

period

Check Model &

Serial number

--

------

---

--------

Web Services wrapperValidation Functions

BP

Mod

elfo

r SP

V

Java to Web Services

Sample Target: eServicePac

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Lifecycle

Business requirementsCountry= Utopia Order entry scenario

e-ServicePac type 1 - tied order 2 – discrete order (h/w specified)

3 – discrete order(no h/w specified)

Warranty and maintenance option 1,3 A 1,2,3,4 A A

Installation 1,3 1,2,3,4

Maintenance B 1,2,5 B B

Example 1,2,3

Example 3 3

Design

ImplementDeploy

OperationMaintenance

Problem Determination

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Websight demo

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Debugging Web Services

Syntax errors

Semantic errors

“Resource unavailable” errors

Business logic errors

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Syntax Errors

Often relate to representing “unusual values”

Example: ambiguous type conversions XML – Java– In subsequent versions of a SOAP engine:

java.util.GregorianCalendar xsd:datejava.util.GregorianCalendar xsd:dateTime

Example: encoding of null String vs. empty String

Example: problem with “out of range” values

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Find Syntax Errors by Inspecting the Content

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Semantic Errors: Discordant Meanings

Even if the syntax is correct, service providers and consumers may associate different meanings to certain expressions

Examples:

–Empty field means: “wildcard” or “missing information”?

–Timestamp (omitting or ignoring time zones)

2004-07-11T10:49:24.938000-04:00

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Semantic Errors: Unexpected Modes of Execution

Example:

–Client node sends (unexpectedly!) two identical messages for every transaction.

–Functional Testing did not reveal this problem

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Semantic Error: Unexpected Modes of Execution

Unexpected Flow Order:

Architect did not expect “stackingChecker” before “compatibilityChecker” because workflow engine was in parallel instead of serial mode.

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“Resource Unavailable” Errors

Find out if/where a node is down

Effect / cause may be in different places

Examples:

–Database server down, workflow engine continues

–Server throws an HTTP error, fed into SOAP parser

We use reactive approach

Proactive approach: synthetic heartbeat

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Business logic error

Example:

– For this operation we didn’t need to call StackingChecker service

– Unit testing did not expose this problem – since the existing test data generated the correct result

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Profiling is Understanding

Where is time spent?

Network vs. business logic?

Chatty communication?

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Profiling: Sorting Statistics

Table view helps find outliers by sorting Network Duration in table view for several transactions

Selecting the outliers in table highlights corresponding messages in other views

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Understanding Web Services Configurations Example: Two concurrent Transactions using two workflow engines

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Understanding Web Services Configurations

From Design Document SCM Traced Topology SCM

Supply Chain Management from WS-I

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Dealing with complexity

High traffic, high number of nodes, complex interactions

Pattern extraction

Selective tracing

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Fifty Concurrent Transactions

Dealing with complexity: Pattern Extraction

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Selective Tracing for Heavy Loads

Tracing everything during heavy load is undesirable: too much perturbation, too much data

Start with “marked” transaction (carrying correlator)

Tracing will be turned on when this transaction is handled

Reduces amount of data to be traced

Easier to understand 1 typical transaction than 10000

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Technology: based on Eclipse and Hyades

Hyades:

Integrated test, trace and monitoring environment– Open source basic infrastructure– Tool interoperability across testing/profiling process– www.eclipse.org/hyades

Components– Information model (EMF)– Communication framework (Remote Agent Controller)– Data collection

http://www.eclipse.org/hyades

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Typical architecture for existing testing/profiling tools

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Hyades provides a common infrastructure

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Deployment

1) Collect runtimeinformation

2) Present to user

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Websight Runtime (experimental setup)

Websight Interface

AxisParser

WebsphereParser

Websight Runtime

Non-SOAPprotocols

Apache SOAPParser

Websight Trace FileVisualizer

WebsphereRuntimeCorrelationLogging Selective

Tracing

Remote Agent Controller

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Correlating Distributed Events

Problem : correlating messages

Goal : trace end-to-end message flow across system

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Correlating Distributed Events

Correlator technology:– ARM correlator technology

Web Services correlator– Websight SOAP header carries correlator

– Propagation through business logic handled by middleware

AttachCorrelator

ReceiveCorrelator

ReceiveCorrelator

AttachCorrelator

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Summary

Debugging Web Services requires new methodologies and tools

Complexity at the application level

Opportunities for work flow

IBM TJ Watson Research Center

Workshop on Testing, Analysis and Verification of Web ServicesJuly 11, 2004 Boston, MA

Contact:[email protected]

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Backup foils

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New Order Transaction

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Existing Order Transaction

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Two Concurrent Transactions using Two Workflow Engines

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Navigation between Views

…highlights corresponding items in the other views

Selecting an item in one view…

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Supply Chain Management: Maximal Transaction(understanding the complex flow)

Websight Visualizing the Execution of Web Services

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