Tracing CORBA applications using interceptors

1. Tracing CORBA applications using interceptors

Zoltán Mann
Supervisor: Dr. Károly Kondorosi
Budapest University of Technology
and Economics
Department of Control Engineering and
Information Technology
Zoltán Mann: Tracing CORBA applications
1/22

2. Contents

1. Motivation
2. Tracing in general
3. Interceptors
4. Tracing using interceptors
5. Conclusion
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3. Motivation

1. Technical development:
• Distributed, heterogeneous environment
• Object-oriented integration CORBA
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4. Motivation

2. Applications:
• e-Business
• Embedded systems
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5. Motivation

3. Growing competition:
• Functional and reliability requirements
• Time-to-market pressure
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6. Contents

1. Motivation
2. Tracing in general
3. Interceptors
4. Tracing using interceptors
5. Conclusion
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7. Tracing vs. debugging

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8. Aims of tracing (use cases)

1. Checking correct behaviour
2. Locating bugs
3. Better understanding of how the system works
4. Monitoring crucial applications
5. Automatic documentation extraction
6. Performance analysis, identifying bottlenecks
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9. Current tracing mechanisms

Current solutions are bound to particular programming
languages.
Problems with distributed systems:
• Heterogeneity
• Collecting information from different namespaces
• Synchronization, lack of global clock etc.
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10. Current tracing mechanisms

State of the art in distributed systems:
+ Central tracer
– Manual instrumentation
– Extra programming work
– Prone to errors
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11. Contents

1. Motivation
2. Tracing in general
3. Interceptors
4. Tracing using interceptors
5. Conclusion
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12. CORBA interceptor

• An object implementing the interceptor
interface
• extending the functionality of the ORB
• using callback methods
• without actually modifying the ORB
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13. Callback methods

Client
Client
Client
Request
Interceptor
Proxy
Server
Skeleton
Server
Request
Interceptor
Servant
methodX()
send_request()
receive_request()
methodX()
send_reply()
receive_reply()
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14. Definitions & implementations

Definitions & implementations
First definition: CORBA 2.3
Incompatible implementations
September 1998: OMG RFP
December 1999: Joint Submission
March 2000: CORBA 3.0 Working Draft
• The used implementation: TAO 1.1 and
1.1.9 beta
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15. Other possible solutions

Smart proxies
Servant managers
Pluggable protocols
ORB event handlers
…
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16. Contents

1. Motivation
2. Tracing in general
3. Interceptors
4. Tracing using interceptors
5. Conclusion
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17. Tracing using interceptors

Client
Server
Tracer
send_request()
receive_request()
send_reply()
receive_reply()
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18. The resulting architecture

Automatic instrumentation
One single line of initialization code per name
space
With the standard registration mechanism of
interceptors, even that could be avoided
Until then: a slight modification of the ORB
Open system
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19. Overhead

In interactive mode: ~ 500 %
communication overhead
In local mode: ~ 15 %
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20. Contents

1. Motivation
2. Tracing in general
3. Interceptors
4. Tracing using interceptors
5. Conclusion
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21. Results

A tracing architecture satisfying the
previously defined requirements
A tool for documenting and interactive
tracing of CORBA applications
The solution works in a distributed and
heterogeneous environment
Prototype of a future product
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22. Future plans

• Improving interoperability
• Extending the architecture for other
middleware systems, such as DCOM
• Improving user interface, with the
inclusion of possible users
• Making the tracer persistent
• …
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23. Tracing CORBA applications using interceptors

Zoltán Mann
Supervisor: Dr. Károly Kondorosi
Budapest University of Technology
and Economics
Department of Control Engineering and
Information Technology
Zoltán Mann: Tracing CORBA applications
23/22