Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Loading in …3
1 of 49

Steer and/or sink the supertanker by Andrew Rendell



Download to read offline

Andrew Rendell's (Principal Consultant from Valtech) presentation on: "Steer and or sink the supertanker"!
This presentation was held at the SPA conference on the 14th June 2011.

A case study into the pros and cons of over three years experience of continuous source code analysis followed by an interactive session using the real tool on real source code.
Andrew discusses what continuous inspection is and why directing software development can feel like trying to steer a super tanker.

Related Books

Free with a 30 day trial from Scribd

See all

Steer and/or sink the supertanker by Andrew Rendell

  1. 1. Continuous source code analysis to help steer the super tanker and / or hit the iceberg ANDREW RENDELL, PRINCIPAL CONSULTANT Image found on: ttp:// .
  2. 2. INTRODUCTION What is Continuous Inspection? Directing software development can feel like trying to steer a super tanker. – This practice might help you succeed, or... – You might still hit the iceberg. – You might even hit the iceberg because of this practice!
  3. 3. INTRODUCTION Agile techniques focus on retrospection and reflection Gathering metrics on source code is nothing new Continuous Inspection has in theory been possible for many years but gaining momentum recently, possibly because of new, easy to use tools such as Maven and Sonar New focus on temporal aspect of data (4th dimension) and web based graphical analysis
  4. 4. CONTINUOUS INSPECTION OF EVOLVING SOFTWARE CAN... Give developers and architects an incredible insight into real software quality as it changes Get the feedback required to make a development team adaptive to real issues Allow the technical architect to apply lighter direction empowering the team and helping it become self-governing Allow clients, sponsors and managers to explore and investigate their codebase through visualisation tools
  5. 5. CONTINUOUS INSPECTION OF EVOLVING SOFTWARE CAN... Allow clients, sponsors and managers to explore and investigate their codebase through visualisation tools Facilitate an understanding of underlying trends of development quality and the consequences of actions on that code base Allow architects and developers to assimilate large swathes of code then drill down to specific areas in seconds rather than spending hours wading through generated data and code reviews
  6. 6. It might be possible to STEER THE SUPER TANKER* that is non-trivial software development * I know it’s not a super tanker but it is very cool Image found on: /
  7. 7. CONTINUOUS INSPECTION OF EVOLVING SOFTWARE CAN... Supply developers and architects with a surprising amount of misinformation Provide metrics which can be abused by developers and managers alike to prove pet theories or disprove unpopular ideas The act of looking at a metric often results in conscious or subconscious gaming of that metric for short term gain with no real benefit other than the temporarily improved remuneration or status
  8. 8. CONTINUOUS INSPECTION OF EVOLVING SOFTWARE CAN... Well meaning, intelligent individuals will become incredibly excited by the presentation of an attractive infographic whilst having zero understanding of what it is they are seeing Architects and developers become obsessed by a gradient on a graph or the exact hue of a pulsating ball and forget about working software.
  9. 9. The development team will STILL HIT THE ICEBERG of software entropy Image found
  10. 10. SESSION STRUCTURE Case studies – A number of experiences from various projects which highlight the positive and negative of Continuous Inspection HANDS ON TUTORIAL – Using an interactive tool (Sonar) to investigate a code base
  12. 12. FINDING THE TECHNICAL DEBT With a large legacy application, can these tools help us locate the areas of high debt? A large and relatively opaque code base. With high volatility (i.e. high number of pushes to repository). Geographically disparate team, knowledge spread across several time zones. Attempt to increase velocity and reduce development, test and deployment costs by reducing technical debt and increasing test coverage. With almost 100k lines of code, where do you start? STEER THE SUPER TANKER
  13. 13. FINDING THE TECHNICAL DEBT SEVERAL SOURCES OF DATA – Human knowledge, which component is important and troublesome? – Source control statistics, which files are amended the most? – Issue tracking, can we identify areas with most defects or changes? – Static source code analysis metrics augmented by test coverage STEER THE SUPER TANKER
  16. 16. FINDING THE TECHNICAL DEBT Not low hanging fruit, those are genuinely rotten Sonar report from previous screen created automatically every morning by CI Very little effort to check Means that technical leads receive visual feedback that corrective action are being taken STEER THE SUPER TANKER
  17. 17. GAMING THE METRIC As soon as you focus on a metric, its likely to be gamed with unexpected results. A large legacy code base with a team spread around the world. We know we have too much technical debt because: – Simple changes take too long – The teams spend almost all their time fire fighting in production – Complex changes never make it out of development HIT THE ICEBERG
  18. 18. GAMING THE METRIC This is a zero test system! Some modules are larger than others Some of the code is ‘too Some of the code complex’ has a ‘good’ level of complexity HIT THE ICEBERG
  19. 19. GAMING THE METRIC This system obviously would be better with tests Can say with some confidence that not having tests is one of the reasons for this system’s perceived poor quality This is a very easy metric to measure SOLUTION: – Lets increase test coverage – Lets motivate development teams across the world by making their end of year bonus dependent on achieving a certain level of unit test coverage HIT THE ICEBERG
  20. 20. GAMING THE METRIC Day before bonus day HIT THE ICEBERG
  21. 21. BLIP ON THE RADAR What happened here? Spikes in loc, coverage. When you continually measure, have to be ready to react to erroneous data now and again (inclusion of generated code in this case). HIT THE ICEBERG
  22. 22. EMPIRICAL EVIDENCE Metrics, even without a tool like Sonar, can provide valuable empirical evidence on the state of the system A multi-team project with between eight and fifteen developers at any one time Geographically co-located with strong cross team communications and management Before using Sonar metrics collected via shell scripts and excel STEER THE SUPER TANKER
  23. 23. EMPIRICAL EVIDENCE Anecdotally, team felt complexity was rising and velocity slowing. Culture of refactoring, rationalising and retiring code. – Was strategy working? Following graph showed unexpected level of problem. STEER THE SUPER TANKER
  24. 24. EMPIRICAL EVIDENCE Code has consistently average complexity per method. There is simply more code being written every release. Analysis of code found duplication at the functional rather than code level STEER THE SUPER TANKER
  25. 25. EMPIRICAL EVIDENCE Team’s ‘gut feeling’ was right in that there was a problem. Gathering the metrics provided empirical evidence of the issue. Complexity growth rate had been underestimated. Continually collecting these metrics might not have stopped team creating the situation. This evidence was enough to justify a significant (12 man weeks) investment in refactoring. STEER THE SUPER TANKER
  26. 26. A LIGHTER TOUCH Architects and technical leads often have a broad remit across several projects. Tools like Sonar can support the architect’s ability to pragmatically monitor large code bases without intrusive working practices. STEER THE SUPER TANKER
  27. 27. A LIGHTER TOUCH Small (2 man) team tasked with phased approached to correction: – Capture existing behaviour through automated tests (current coverage high but not high enough). – Implement a replacement system for several duplicated modules in an existing system. No budget for manual testing – automated tests must be fit for purpose. Very limited budget for technical governance and project management. Key metrics monitored several times a week through Sonar. Augmented by code review and design walk though. STEER THE SUPER TANKER
  28. 28. A LIGHTER TOUCH Start of exercise, 75.8k loc in main system Objective: Reduce duplication (and therefore loc), improve quality STEER THE SUPER TANKER
  29. 29. A LIGHTER TOUCH Progress continually monitored End of exercise, main system 65k loc Average complexity / method reduced Functionality extracted into new module 4.3k loc – 5k redundant code removed STEER THE SUPER TANKER
  30. 30. A LIGHTER TOUCH Metrics as we saw them evolve Total complexity increases slightly – artefact of way of Rules working compliance increases Something worrying happening to complexity / method STEER THE SUPER TANKER
  31. 31. FALSE POSITIVE Tools and tool users are fallible. They can supply false positives that create noise for the project and waste resources investigating. Metrics collected continuously using sonar. Technical Architect: – Inspected metrics several times a week. – Observed standup and burndown. – Reviewed automated acceptance tests. – Collaborated in design exercises on whiteboard – Delegated technical implementation to team HIT THE ICEBERG
  32. 32. FALSE POSITIVE Development suspended for a week when complexity per method metric went red and correction not executed. Detailed code review initiated. HIT THE ICEBERG
  33. 33. FALSE POSITIVE Original module, complexity / method okay, coverage good New module, complexity / method worse, coverage low HIT THE ICEBERG
  34. 34. FALSE POSITIVE Drilled down using sonar to identify where higher than expected complexity was originating from. Code then inspected. False alarm: – Sonar complexity algorithm rated JAX-RS method signatures as high, nothing in dev team control. – Other methods were part of automated test controls which were verbose in order to demonstrate purpose. HIT THE ICEBERG
  35. 35. FALSE POSITIVE Cluster of complex packages Test utility Test utility JAX-RS resources HIT THE ICEBERG
  36. 36. CASTING A WIDE NET Powerful visualisation tools coupled with an array of integrated metrics can allow large code basis to be monitored. A large, highly volatile, code base. Geographically disparate team, spread across several timezones. How can technical authorities police such a code base without velocity crushing (and probably ineffective) prescriptive processes or a code review team almost as big as the development team? STEER THE SUPER TANKER
  37. 37. CASTING A WIDE NET A warning to investigate further Something bad happens to coverage in one module Duplication starts to rise STEER THE SUPER TANKER
  38. 38. CASTING A WIDE NET One package in module is being worked on Complexity / LOC and method rising duplicatio rapidly n increasing Flagged up whilst development is ongoing, not later in process STEER THE SUPER TANKER
  39. 39. CASTING A WIDE NET New module appears, unusually high avg complexity / method STEER THE SUPER TANKER
  40. 40. CASTING A WIDE NET Complexity / method average drops (as code size increases, bad code still there) Duplication rises STEER THE SUPER TANKER
  41. 41. HOW WE DO CONTINUOUS INSPECTION Build system established in Sprint Zero – Jenkins CI – Sonar Rules (PMD, Checkstyle) configured to use those defined for use on this site STEER THE SUPER TANKER
  42. 42. HOW WE USE CONTINOUS INSPECTION Daily sonar build (4am) triggered by Jenkins Runs unit and integration tests Dashboard printed out and reviewed by team at end of stand-up Anything ‘unusual’ discussed and actions taken to investigate / correct Includes violations, coverage, complexity, any unexpected change Continuous inspection, continuous improvement STEER THE SUPER TANKER
  43. 43. CONCLUSIONS NEGATIVE EXPERIENCES CAN BE CATEGORISED AS: – Being distracted then satisfied by the superficial – Using the metrics in isolation to decide whether something is good or bad, high or low quality, true or false Everybody loves an infographic, be aware they are often misunderstood and even knowingly abused Continuous Inspection is a great tool for anybody involved with the project willing to invest a little time understanding and questioning what they see STEER THE SUPER TANKER
  44. 44. CONCLUSIONS Can Continuous Inspection enable developers to steer the super tanker? – Or will they still hit the iceberg, – Or even hit the iceberg because of the feedback from inspection? Continuous Inspection is a valuable tool that if used with care can make a difference Must recognise that it rarely delivers the full story, just an indication Be wary of wider dissemination of attractive data STEER THE SUPER TANKER
  45. 45. YOUR TURN! / Image found
  46. 46. STRUCTURE OF NEXT SECTION Point everybody at useful resources (metric definitions etc) Get everybody accessing the Sonar server Five minute tour of the relevant features In small groups or as individuals use the tool to draw some positive and negative conclusions about the code base COLLATE OUR CONCLUSIONS AND DISCUSS: – Do we feel the conclusions have merit? – Are they superficial or of real impact on quality? – How could we correct, control or even prevent in future? – What negative implications (e.g. gaming) could this have? STEER THE SUPER TANKER
  48. 48. COLLATE RULES – Three minutes maximum each per point (we can come back to you) – Please let the speaker describe their point in full before we discuss and analyse – Presenter will try and keep analysis of any one point to a sensible length, shout if he forgets! STEER THE SUPER TANKER
  49. 49.