Sep 5, 2014 - for Component-Based Systems. Short talk ... Reusable design patterns. ⢠Systems are ... Coordination. ⢠Data transfer. 6. A b1 r1 p1 f1 f b. C p3 f3 r3 b3. B f2 b2 ... 17. Architectures in BIP. 8. A = (c,PA,γ) b1 f1 b2 f2 free taken b12 f12 b12 f12 .... (Embedded systems, web services, enterprise integration, etc.).
Architectures: Design Patterns for Component-Based Systems Short talk @ TGC, 5th of September, 2014 Simon Bliudze
École polytechnique fédérale de Lausanne Joint work with: Paul Attie, Eduard Baranov, Marius Bozga, Mohamad Jaber and Joseph Sifakis
Reusable design patterns •
Systems are not built from scratch
•
Maximal re-use of building blocks
(off-the-shelf components)
•
Maximal re-use of solutions
(libraries, design patterns, etc.)
•
Express coordination constraints in declarative manner
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Applications •
Concurrency:
(a)synchronous, time-triggered, token-ring,
mutual exclusion
•
Protocols:
communication protocols, data access control, encryption, authentication
•
Robustness:
fault detection & recovery, resource management
•
etc.
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Theory of architectures •
How to model?
•
How to specify?
•
How to combine?
•
How to implement efficiently?
Architectures enforce characteristic properties. The crucial question is whether these are preserved by composition? S.Bliudze @ TGC, Rome, 5th of September, 2014
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How to model?
Component-based design Component design by refinement Component design by refinement Component design by refinement Component design by refinement
•
Three Threelayers: layers:
Three layers: Three layers: Three layers 1 Component
Component Component 1 Component behaviour • Component behaviour behaviour behaviour behaviour Coordination 2 2Coordination 2 Coordination • Coordination 2 Coordination Data transfer 3 33Data transfer Data transfer 3 Data transfer 1 1
•
Data transfer
A.x = max (B.y, C.z)
f f11 f1 A p A Ap11 p 1 b1 rr1 b1 b1 1 r1
p p33 p3ff33 f3 b b33 b3 C C C r r33 r3
b b22 b2
B B B
f f22 f2
SC 2011 — S. Bliudze, J. Sifakis, “Synthesizing Glue Operators...” — Z¨ urich, June 30th , 2011 — 9 / 29 th 2011 SC 2011 — S. Bliudze, J. Sifakis, “Synthesizing Glue Operators...” — Z¨ uJune rich, 30 June th , 30 SC 2011 — S. Bliudze, J. Sifakis, “Synthesizing Glue Operators...” — Z¨ urich, 2011, — 9 /—299 / 29
SC 2011 — S. Bliudze, J. Sifakis, “Synthesizing Glue Operators...” — Z¨ urich, June 30th , 2011 — 8 / 29
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Example in BIP
b1
f1
b2
sleep
f1
f2 sleep
b1 work
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f2
b2 work
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Example in BIP
b1
f1
b12
sleep
f1
f12
b2 sleep
free
b1 work
S.Bliudze @ TGC, Rome, 5th of September, 2014
f12
b12 taken
f2
f2
b2 work
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Example in BIP
b1
f1
b12
sleep
f1
f12
b2 sleep
free
b1 work
S.Bliudze @ TGC, Rome, 5th of September, 2014
f12
b12 taken
f2
f2
b2 work
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Example in BIP
b1
f1
b12
f12
b2
f2
free
f12
b12 taken
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Example in BIP
b1
f1
b12
f12
b2
f2
free
f12
b12 taken
12
= {;, b1 b12 , b2 b12 , f1 f12 , f2 f12 }
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Architectures in BIP A = (C, PA , ) Set of coordinating behaviours
Interaction model Interface (ports)
The interface includes all ports
of the coordinator components [ PC ✓ PA C2C
S.Bliudze @ TGC, Rome, 5th of September, 2014
b1
f1
b12
f12
b2
f2
free
f12
b12 taken
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How to combine?
Constraints intuition
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Constraints intuition
Bad 1
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Constraints intuition
Bad 1
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Constraints intuition
Bad 1 Bad 2
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Constraints intuition
Bad 1 Bad 2
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Constraints intuition
Good
Bad 1 Bad 2
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Limits of white magic
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Limits of white magic
1 d Ba
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Limits of white magic
1 d Ba
S.Bliudze @ TGC, Rome, 5th of September, 2014
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Limits of white magic
1 d Ba
S.Bliudze @ TGC, Rome, 5th of September, 2014
Bad
2
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Limits of white magic
1 d Ba
S.Bliudze @ TGC, Rome, 5th of September, 2014
Bad
2
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Limits of white magic
1 d Ba
S.Bliudze @ TGC, Rome, 5th of September, 2014
Bad
2
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How to implement efficiently?
a a
c
b
c b
d
d
Architecture-based External: component behaviour is not modified
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Task 1:!
Task 2:!
while (true) {
free(S1); take(S2); do-a; free(S1); take(S2); do-b; }
while (true) { take(S1); free(S2); do-c; take(S1); free(S2); do-d; }
Architecture-agnostic Internal: the coordination primitives mix-up with the functional behaviour of the components S.Bliudze @ TGC, Rome, 5th of September, 2014
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Two sides of the same design
•
Architecture-based
•
Architecture-agnostic
•
External
•
Internal
•
Declarative
•
Imperative
•
Highly abstract
•
Detailed
•
Relies on an execution engine
•
Relies on low-level primitives
•
Easy to understand, analyse and manipulate
•
Efficient
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Two sides of the same design
•
Architecture-based
•
Architecture-agnostic
•
External
•
Internal
•
Declarative
•
Imperative
•
Highly abstract
•
Relies on an execution engine
•
Relies on low-level primitives
•
Easy to understand, analyse and manipulate
•
Efficient
Detailed Internalisation
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•
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Conclusion •
Architectures solve coordination problems by enforcing characteristic properties.
•
First steps toward the study of a rigorous concept of architecture and its effective use for achieving correctness by construction in a system design flow. •
A notion of architecture in BIP
•
Safety-preserving architecture composition operator •
•
[SEFM 2014] A General Framework for Architecture Composability
Architecture internalisation using Top/Bottom component model •
[CBSE 2014] Architecture internalisation in BIP
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Future work •
•
Modelling •
Study and classification of real-life architectures in various domains
(Embedded systems, web services, enterprise integration, etc.)
•
Versatility of the model
•
Dynamic architectures
Specification •
•
Development of a simple powerful language for specifying architectures and their characteristic properties
Efficiency & distribution •
Optimisation of internalised architectures
•
Implementation based on message-passing mechanisms (e.g. AKKA)
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Thank you for your attention
