Here is a presentation that covers modern software architecture styles and patterns such as microservices, CQRS and event sourcing.

1. MODERN SOFTWARE ARCHITECTURE
styles and patterns

2. – Roy Fielding
“an architectural style is a co-ordinated set of
architectural constraints that restricts the roles/
features of architectural elements and the allowed
relationships among those elements within any
architecture that conforms to that style”
R.T.Fielding “Architectural styles and the design of network-based software architectures. PhD thesis, University of California, 2000.

3. POSA - before and after

4. Layered
Pipe-and-Filter
Broker
Client-Server
Peer-to-Peer
Blackboard

5. $ cat limerick.txt
There was a young lady of Niger
Who smiled as she rode on a tiger.
They returned from the ride
With the lady inside
And a smile on the face of the tiger.

6. $ cat limerick.txt | tr -cs "[:alpha:]" "n" | awk '{print
length(), $0}' | sort | uniq
1 a
2 as
2 of
2 on
3 And
3 Who
3 she
3 the
3 was
4 They
4 With
4 face
4 from
4 lady
4 ride
4 rode
5 Niger
5 There
5 smile
5 tiger
5 young
6 inside
6 smiled
8 returned

7. List<String> lines
= Files.readAllLines(Paths.get("./limerick.txt"), Charset.defaultCharset());
Map<Integer, List<String>> wordGroups
= lines.stream()
.map(line -> line.replaceAll("W", "n").split("n"))
.flatMap(Arrays::stream)
.sorted()
.distinct()
.collect(Collectors.groupingBy(String::length));
wordGroups.forEach( (count, words) -> {
words.forEach(word -> System.out.printf("%d %s %n", count, word));
});
1 a
2 as
2 of
2 on
3 And
3 Who
3 she
3 the
3 was
4 They
4 With
4 face
4 from
4 lady
4 ride
4 rode
5 Niger
5 There
5 smile
5 tiger
5 young
6 inside
6 smiled
8 returned

8. What architectural style is
this?

9. Real-world pipes-and-filters
sediment
pre-
carbon
ultra-filter
post-
carbon
Filtered
water

10. Pipe-and-filter: Benefits
+ Flexibility by filter exchange
+ Flexibility by recombination
+ Reuse of filter components
+ Rapid prototyping of pipelines
Frank Buschmann, Regine Meunier, Hans Rohnert, Peter Sommerlad, and Michael Stal. 1996. Pattern-Oriented Software Architecture: A System of Patterns. John Wiley & Sons, Inc., NY, USA.

11. Pipe-and-filter: Liabilities
- Sharing state information is expensive or
inflexible
- Efficiency gain by parallel processing is
often an illusion
- Data transformation overhead
- Difficult to handle errors
Frank Buschmann, Regine Meunier, Hans Rohnert, Peter Sommerlad, and Michael Stal. 1996. Pattern-Oriented Software Architecture: A System of Patterns. John Wiley & Sons, Inc., NY, USA.

12. What is the
architecture style
followed by
World Wide Web
(WWW)?

15. SOA (Service Oriented
Architecture)
Lambda Style
Microservices
REST (Representational State Transfer)
Map-Reduce
CQRS (Command-Query Responsibility
Segregation )
Software Containers
Event Sourcing

16. List<String> lines
= Files.readAllLines(Paths.get("./limerick.txt"), Charset.defaultCharset());
Map<Integer, List<String>> wordGroups
= lines.parallelStream()
.map(line -> line.replaceAll("W", "n").split("n"))
.flatMap(Arrays::stream)
.sorted()
.distinct()
.collect(Collectors.groupingBy(String::length));
wordGroups.forEach( (count, words) -> {
words.forEach(word -> System.out.printf("%d %s %n", count, word));
});
1 a
2 as
2 of
2 on
3 And
3 Who
3 she
3 the
3 was
4 They
4 With
4 face
4 from
4 lady
4 ride
4 rode
5 Niger
5 There
5 smile
5 tiger
5 young
6 inside
6 smiled
8 returned

17. Java: Fork-join framework

18. Map-Reduce pattern
Input
Sara
Booch
Thayer
Merlin
Sara
Ralph
Merlin
Tim
Sara
Christian
Ralph
Cormen
…
Computer Cluster
map
map
map
Sara, 1
Ralph, 1
Merlin, 1
Tim, 1
Sara, 1
Booch, 1
Thayer, 1
Merlin, 1
Sara, 1
Christian, 1
Ralph, 1
Cormen, 1
reduce
reduce
Sara, 3
Booch, 1
Thayer,1
Merlin, 2
Ralph, 2
Tim, 1
Christian, 1
Cormen, 1
…
OutputSara, 1
Sara, 1
Sara, 1
Booch, 1
Thayer, 1
Merlin, 1
Merlin, 1
Ralph, 1
Ralph, 1
Tim, 1
Christian, 1
Cormen, 1

19. Lambda style
Batch layer
Serving layerSpeed layer

20. Lambda style
source: https://spark-summit.org/2014/wp-content/uploads/2014/07/Lambda-Architecture-Jim-Scott..pdf

21. code-on-
demand
client-server
cache
statelesslayered
system
uniform
interface
REST
constraints
(in www)

22. Event Sourcing pattern
source: https://msdn.microsoft.com/en-us/library/dn589792.aspx

23. Command Query Responsibility
Segregation (CQRS) pattern
source: https://msdn.microsoft.com/en-us/library/jj591573.da82141c6f9950d64c1263fa4da825ec(l=en-us).png

24. Microservices = “fine
grained SOA” or “SOA 2.0”

25. Microservices is an
architectural style

26. Complex application =
composed of tiny services

27. Communicate over REST API
HTTPGET
HTTPPUT
HTTP POST
HTTPDELETE

28. Underlying philosophy
“do one thing and do it well”

29. Monolithic

30. Microservices

31. Conway’s law
“Any organization that designs a
system… will inevitably produce
a design whose structure is a
copy of the organization's
communication structure”

32. Conway’s law
Team 1
Team 2Team 3
Team 4

33. Conway’s law
Team 1 Team 2
Team 3
Team 4

34. Monolithic to microservices

35. Monolithic to microservices

36. Service = manageable by
“two pizza” team

37. Service = a team can DURS
(Deploy, Update, Replace, Scale)
Microservices = Damn U R Sexy

38. Amazon case study
2-tier
architecture
SOA Microservices

40. email sgganesh@gmail.com
website www.designsmells.com
twitter @GSamarthyam
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