Software Architecture Recovery: The 5 Questions You Always Asked Yourself About,

Software Architecture Recovery: The 5 Questions You Always Asked Yourself About,

1. 1. The 5 questions you always asked yourself about Software Architecture Recovery Mircea Lungu Faculty of Informatics, University of Lugano October 2008
2. 2. 5 Questions about SAR Software Architecture Recovery - Mircea Lungu, 2008
3. 3. 5 Questions about SAR • What is it? Software Architecture Recovery - Mircea Lungu, 2008
4. 4. 5 Questions about SAR • What is it? • Why is it important? Software Architecture Recovery - Mircea Lungu, 2008
5. 5. 5 Questions about SAR • What is it? • Why is it important? • How does it work? Software Architecture Recovery - Mircea Lungu, 2008
6. 6. 5 Questions about SAR • What is it? • Why is it important? • How does it work? • Who does it? Software Architecture Recovery - Mircea Lungu, 2008
7. 7. 5 Questions about SAR • What is it? • Why is it important? • How does it work? • Who does it? • Where is it headed? Software Architecture Recovery - Mircea Lungu, 2008
8. 8. What? • Architecture Recovery • Architecture • Viewpoints
9. 9. Architecture recovery ... Software Architecture Recovery - Mircea Lungu, 2008
10. 10. Architecture recovery ... or Architecture Reconstruction, Software Architecture Recovery - Mircea Lungu, 2008
11. 11. Architecture recovery ... or Architecture Reconstruction, or Reverse Architecting Software Architecture Recovery - Mircea Lungu, 2008
12. 12. Architecture recovery ... or Architecture Reconstruction, or Reverse Architecting [...] an archaeological activity where the analysts must unveil all the historical design decisions by looking at the existing implementation and documentation of the system. [ Riva’00 ] Software Architecture Recovery - Mircea Lungu, 2008
13. 13. Architecture recovery ... Software Architecture Recovery - Mircea Lungu, 2008
14. 14. Architecture recovery ... ... the flavor of reverse engineering that concerns all activities for making existing of software architectures explicit. [Krikhaar’97] Software Architecture Recovery - Mircea Lungu, 2008
15. 15. Architecture recovery ... ... the flavor of reverse engineering that ... the techniques and concerns all activities for processes used to uncover making existing of software a system’s architecture architectures explicit. from available information. [Jazayeri’00] [Krikhaar’97] Software Architecture Recovery - Mircea Lungu, 2008
16. 16. Architecture... Software Architecture Recovery - Mircea Lungu, 2008
17. 17. Architecture... [...] the structure or structures of the system, which comprise software elements, the externally visible properties of those elements, and the relationships among them. [Bass et al.’03] Software Architecture Recovery - Mircea Lungu, 2008
18. 18. Architecture... [...] the structure or structures of the system, which comprise software elements, the externally [...] the fundamental visible properties of those organization of a system, elements, and the embodied in its components, relationships among them. their relationships to each other and the environment, and the [Bass et al.’03] principles governing its design and evolution. [ANSI/IEEE Std. 1471-2000] Software Architecture Recovery - Mircea Lungu, 2008
19. 19. Architecture... For many others visit www.sei.cmu.edu/architecture/ definitions.html [...] the structure or structures of the system, which comprise software elements, the externally [...] the fundamental visible properties of those organization of a system, elements, and the embodied in its components, relationships among them. their relationships to each other and the environment, and the [Bass et al.’03] principles governing its design and evolution. [ANSI/IEEE Std. 1471-2000] Software Architecture Recovery - Mircea Lungu, 2008
20. 20. What is the difference between architecture and design? Software Architecture Recovery - Mircea Lungu, 2008
21. 21. Architectural Styles • Recurring architectural solutions • Examples • Pipes and filters • Blackboard • Peer-to-peer • ... a Software Architecture Recovery - Mircea Lungu, 2008
22. 22. Architectural Styles • Recurring architectural solutions • Examples • Pipes and filters • Blackboard • Peer-to-peer • ... a Software Architecture Recovery - Mircea Lungu, 2008
23. 23. Architectural Styles • Recurring architectural solutions • Examples • Pipes and filters • Blackboard SAR is not preoccupied with • Peer-to-peer recovering the architectural • ... style of the system. a Software Architecture Recovery - Mircea Lungu, 2008
24. 24. Viewpoints • Viewpoints catalogues • Kruchten’95 • Hofmeister’99 • Ad-hoc viewpoints • Smolander’01 • Conway’s law Software Architecture Recovery - Mircea Lungu, 2008
25. 25. Viewpoints • Viewpoints catalogues • Kruchten’95 • Hofmeister’99 • Ad-hoc viewpoints • Smolander’01 Most of the SAR processes focus on • Conway’s law recovering component-and- connector viewpoints. Software Architecture Recovery - Mircea Lungu, 2008
26. 26. What is the relation between architecture recovery and reverse engineering? Software Architecture Recovery - Mircea Lungu, 2008
27. 27. Why? • Reasons • Benefits • Goals • Challenges
28. 28. Architecture erosion [...] the documentation about the internal architecture becomes rapidly obsolete. To make changes, developers need a clear understanding of the underlying architecture of the products. C. Riva, Software Architecture Group, Nokia Research Software Architecture Recovery - Mircea Lungu, 2008
29. 29. Architecture Evolution One frequently accompanying property of evolution is an increasing brittleness of the system -- that is, an increasing resistance to change, or at least to changing gracefully. [Perry & Wolf ’92] Software Architecture Recovery - Mircea Lungu, 2008
30. 30. Architecture Evolution One frequently accompanying property of evolution is an • Architectural drift increasing brittleness of the system -- that is, an • Architectural erosion increasing resistance to change, or at least to • Architectural upgrade changing gracefully. [Perry & Wolf ’92] Software Architecture Recovery - Mircea Lungu, 2008
31. 31. Conceptual vs. As-is architecture Software systems must evolve or become obsolete [...] [Lehmann’80] Software Architecture Recovery - Mircea Lungu, 2008
32. 32. Conceptual vs. As-is architecture Software systems must Change In Environment evolve or become obsolete [...] Change In Code Environment Code [Lehmann’80] Change In Code Architecture Change In Architecture As-Is Architecture Software Architecture Recovery - Mircea Lungu, 2008
33. 33. Conceptual vs. As-is architecture Software systems must Change In Environment evolve or become obsolete [...] Change In Code Environment Code [Lehmann’80] Change In Code Change In Architecture Architecture There is a need for As-Is Architecture enforcing the architecture of a system Software Architecture Recovery - Mircea Lungu, 2008
34. 34. Conceptual vs. As-is architecture Software systems must evolve or become Architectural Change In Firewall Environment obsolete [...] Change In Code Environment Code [Lehmann’80] Change In Code Change In Architecture Architecture There is a need for enforcing the architecture of a system Software Architecture Recovery - Mircea Lungu, 2008
35. 35. Consultant’s POV [...] Frequently we are asked to analyze • Missing architectural a systemʼs software specifications architecture and are • Support the given only its code • Re-documentation and the (limited) time • Reengineering of a designer. [Kazman et al.’99] Software Architecture Recovery - Mircea Lungu, 2008
36. 36. Benefits • Stepping stone towards reengineering • Supports detecting components for reuse Software Architecture Recovery - Mircea Lungu, 2008
37. 37. Challenges • What process can support uncovering the software architecture within a system? • How much can you automate in this process? • What are the limits of architecture recovery? (e.g., Recovering all design decisions). Software Architecture Recovery - Mircea Lungu, 2008
38. 38. How? • Generic approach • Processes • Bottom-up • Top-down • Integrated
39. 39. Phases of Reconstruction Knowledge Information Data Extraction Organization Exploration [Tilley et al.’96] Software Architecture Recovery - Mircea Lungu, 2008
40. 40. The Meta- Phases of Reconstruction Architecture of Architecture Recovery Tools Knowledge Information Data Extraction Organization Exploration [Tilley et al.’96] Software Architecture Recovery - Mircea Lungu, 2008
41. 41. Data Extraction Software Architecture Recovery - Mircea Lungu, 2008
42. 42. Data Extraction • Source Code (static analysis) Software Architecture Recovery - Mircea Lungu, 2008
43. 43. Data Extraction • Source Code (static analysis) • Historical Information Software Architecture Recovery - Mircea Lungu, 2008
44. 44. Data Extraction • Source Code (static analysis) • Historical Information • Human Expertise Software Architecture Recovery - Mircea Lungu, 2008
45. 45. Data Extraction • Source Code (static analysis) • Historical Information • Human Expertise • Runtime Behavior (dynamic analysis) Software Architecture Recovery - Mircea Lungu, 2008
46. 46. Data Extraction • Source Code (static analysis) • Historical Information • Human Expertise • Runtime Behavior (dynamic analysis) • Physical Organization Software Architecture Recovery - Mircea Lungu, 2008
47. 47. Data Extraction • Source Code (static analysis) • Historical Information • Human Expertise • Runtime Behavior (dynamic analysis) • Physical Organization • Social Organization Software Architecture Recovery - Mircea Lungu, 2008
48. 48. [Pollet et al.’07] Software Architecture Recovery - Mircea Lungu, 2008
49. 49. Facts extracted from code [Guo et al.’99] Software Architecture Recovery - Mircea Lungu, 2008
50. 50. Knowledge Abstraction • Get rid of useless information • Aggregation • Directory • Packages • Clustering • Filtering [Lungu et al.’05] Software Architecture Recovery - Mircea Lungu, 2008
51. 51. p n -u w om do d ri p- tt yb Bo To H Processes Software Architecture Recovery - Mircea Lungu, 2008
52. 52. p n -u w om do d ri p- tt yb Bo To H Processes [Pollet et al.’07] Software Architecture Recovery - Mircea Lungu, 2008
53. 53. • Start with low-level fact 1. Bottom-up extraction Approaches • Aggregate the information to higher abstraction levels either manually or automatically Software Architecture Recovery - Mircea Lungu, 2008
54. 54. Tools 4 bottom-up • Arch • ArchView • ArcVis • ARMIN • BUNCH • DALI • Gupro • Intensive • Rigi • Softwarenaut Software Architecture Recovery - Mircea Lungu, 2008
55. 55. Arch • Developed at Siemens Research • Mavericks - individual procedures in the wrong modules • Heuristic modularization advice [Schwanke’91] Software Architecture Recovery - Mircea Lungu, 2008
56. 56. Archview [Pinzger’05] Software Architecture Recovery - Mircea Lungu, 2008
57. 57. Archview [Pinzger’05] Software Architecture Recovery - Mircea Lungu, 2008
58. 58. Dali Rigi, IAPR (Interactive Architecture Pattern Recognition) [12], RMTool [14], and Perl for analysis and manipulation. Lightweight Source Model Extraction PostgreSQL (based (LSME), Imagix, make, and Perl on POSTGRES) for for extraction of source model model storage, information for C and C++, Software Architecture Recovery - Mircea Lungu, 2008
59. 59. Advertising break! Software Architecture Recovery - Mircea Lungu, 2008
60. 60. Advertising break! • Aggregation: based on directory structure, clustering, package structure Software Architecture Recovery - Mircea Lungu, 2008
61. 61. Advertising break! • Aggregation: based on directory structure, clustering, package structure • Filtering: based on evolutionary information, metrics Software Architecture Recovery - Mircea Lungu, 2008
62. 62. Advertising break! • Aggregation: based on directory structure, clustering, package structure • Filtering: based on evolutionary information, metrics • Visualization: polymetric Software Architecture Recovery - Mircea Lungu, 2008
63. 63. Softwarenaut Software Architecture Recovery - Mircea Lungu, 2008
64. 64. Softwarenaut Software Architecture Recovery - Mircea Lungu, 2008
65. 65. Softwarenaut Software Architecture Recovery - Mircea Lungu, 2008
66. 66. Softwarenaut Software Architecture Recovery - Mircea Lungu, 2008
67. 67. • Start with previous high- 2. Top-down level knowledge about the application domain approaches • Formulate hypotheses and verify them against the source code Software Architecture Recovery - Mircea Lungu, 2008
68. 68. Tools 4 top-down • RMTool • Pulse • W4 Software Architecture Recovery - Mircea Lungu, 2008
69. 69. Reflexion Models Marco... Software Architecture Recovery - Mircea Lungu, 2008
70. 70. Pulse • Fraunhofer Institute for ESE • Architecture- and Domain-Oriented Re-engineering • Product Line Software Engineering Software Architecture Recovery - Mircea Lungu, 2008
71. 71. Pulse Software Architecture Recovery - Mircea Lungu, 2008
72. 72. Pulse Software Architecture Recovery - Mircea Lungu, 2008
73. 73. Pulse Software Architecture Recovery - Mircea Lungu, 2008
74. 74. Pulse Software Architecture Recovery - Mircea Lungu, 2008
75. 75. W4 By distilling pearls of wisdom stored deep inside source control systems, we can assist developers to understand the state of their project and plan confidently for its future [Hassan & Holt’04] Software Architecture Recovery - Mircea Lungu, 2008
76. 76. W4 By distilling pearls of wisdom stored deep inside source control systems, we can assist developers to understand the state of their project and plan • Which,Who,Why,When confidently for its future [Hassan & Holt’04] Software Architecture Recovery - Mircea Lungu, 2008
77. 77. • Combine top-down with 3. Hybrid bottom-up Approaches • Abstract low-level information • Refine high-level information Software Architecture Recovery - Mircea Lungu, 2008
78. 78. Tools 4 hybrid • Albortz • ARM • Bauhaus • Cacophony • DiscoTect • ManSART • PBS/SBS • Symphony / Nimeta Software Architecture Recovery - Mircea Lungu, 2008
79. 79. ManSART • Mitre Corporation • Used to provide architecture level consulting in multiple military systems Software Architecture Recovery - Mircea Lungu, 2008
80. 80. ManSART [Harris et al.’ 95] Software Architecture Recovery - Mircea Lungu, 2008
81. 81. Discotect • Examine runtime behavior • Big problem: abstraction gap • State machines to map between implementation- level events and architectural operations [Yan et al.’04] Software Architecture Recovery - Mircea Lungu, 2008
82. 82. Who? • SEI at Carnegie Mellon • Hasso-Plattner Institute • Nokia Research Center
83. 83. Case Study #1 • Author: CMU Software Engineering Institute • Subject: VANISH, 50KLOC • Tools: Dali, ARMIN • Goals • generate several architectural views • determine if strict layering is in place • Assumptions: little documentation, no developers available Software Architecture Recovery - Mircea Lungu, 2008
84. 84. #1: Results Software Architecture Recovery - Mircea Lungu, 2008
85. 85. #1: Results Software Architecture Recovery - Mircea Lungu, 2008
86. 86. #1: Results Software Architecture Recovery - Mircea Lungu, 2008
87. 87. #1: Results Software Architecture Recovery - Mircea Lungu, 2008
88. 88. #1: Results Software Architecture Recovery - Mircea Lungu, 2008
89. 89. Case Study #2 • Author: Hasso-Plattner Institute • Subject: Apache, 100KLOC C code • Participants: 60 4th semester students • 32 topics assigned • Sources • documentation (well written, little info about the conceptual architecture) • “Writing Apache modules with Perl” • Results: overview analysis, detailed state diagrams, memory management • Time:: half a semester for getting accustomed with the domain and half for analyzing the implementation Software Architecture Recovery - Mircea Lungu, 2008
90. 90. #2: Results www.fmc-modeling.org/category/projects/apache/amp/Apache_Modeling_ Project.html - Software Architecture Recovery - Mircea Lungu, 2008
91. 91. #2: Results www.fmc-modeling.org/category/projects/apache/amp/Apache_Modeling_ Project.html - Software Architecture Recovery - Mircea Lungu, 2008
92. 92. #2: Results www.fmc-modeling.org/category/projects/apache/amp/Apache_Modeling_ Project.html - Software Architecture Recovery - Mircea Lungu, 2008
93. 93. #2: Results www.fmc-modeling.org/category/projects/apache/amp/Apache_Modeling_ Project.html - Software Architecture Recovery - Mircea Lungu, 2008
94. 94. #2: Results www.fmc-modeling.org/category/projects/apache/amp/Apache_Modeling_ Project.html - Software Architecture Recovery - Mircea Lungu, 2008
95. 95. Case Study #3 • Author: Nokia Research • System: Embedded Software Written in C • Existing Reference Architecture • Scripts that extract information about messages Software Architecture Recovery - Mircea Lungu, 2008
96. 96. #3: Results Software Architecture Recovery - Mircea Lungu, 2008
97. 97. #3: Results Software Architecture Recovery - Mircea Lungu, 2008
98. 98. #3: Results Software Architecture Recovery - Mircea Lungu, 2008
99. 99. #3: Results Software Architecture Recovery - Mircea Lungu, 2008
100. 100. Others • “Linux as a Case Study, it’s Extracted Architecture”, Bowman et al. • “Static evaluation of Software Architectures”, Knodel et al. Software Architecture Recovery - Mircea Lungu, 2008
101. 101. Where? • Future of SAR • Further Reading
102. 102. The Future of SAR Software Architecture Recovery - Mircea Lungu, 2008
103. 103. The Future of SAR • Integrating with forward engineering (continuous supervision, architectural firewalls, etc.) Software Architecture Recovery - Mircea Lungu, 2008
104. 104. The Future of SAR • Integrating with forward engineering (continuous supervision, architectural firewalls, etc.) • Collaborative architecture recovery Software Architecture Recovery - Mircea Lungu, 2008
105. 105. The Future of SAR • Integrating with forward engineering (continuous supervision, architectural firewalls, etc.) • Collaborative architecture recovery • Product family architecture Software Architecture Recovery - Mircea Lungu, 2008
106. 106. The Future of SAR • Integrating with forward engineering (continuous supervision, architectural firewalls, etc.) • Collaborative architecture recovery • Product family architecture • Ecosystem architecture Software Architecture Recovery - Mircea Lungu, 2008
107. 107. Further Reading • Annotated Bibliography www.inf.unisi.ch/phd/lungu/recovery • Essays on Architecture http://www.sei.cmu.edu/architecture/essays.html • PhD Theses: Pinzger’05, Krikhaar’99 • Survey Articles: Pollet’07 Software Architecture Recovery - Mircea Lungu, 2008
108. 108. THE END Software Architecture Recovery - Mircea Lungu, 2008