Blazing Fast Feedback Loops in the Java Universe
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The document discusses strategies for enhancing feedback loops in Java development, specifically emphasizing the importance of timely communication among team members and proactive issue resolution. It highlights the use of various tools and practices to ensure code quality, streamline testing, and improve documentation, while recommending approaches to tackle common project challenges. The overarching goal is continuous improvement and learning, with an emphasis on the belief that feedback, rather than failure, is an opportunity for growth.
Blazing Fast Feedback Loops in the Java Universe
- 1. Michał Kordas Blazing Fast Feedback Loops in the Java Universe
- 2. FEEDBACK DO A THING CHECK HOW IT WENT DO NOT BUILD ON ASSUMPTIONS
- 5. CONTEXT • Small team • All use IntelliJ IDEA • ~30 repositories • Java, Groovy, Scala • Maven, Groovy • Jenkins • GitHub
- 6. WHAT YOU DO WHEN…? • broken environment • not meaningful exception • struggling with technology • struggling with project • style-related comment during code review
- 7. EVERY TIME WHEN FEEDBACK COMES TOO LATE TRY TO MAKE IT FASTER
- 8. BROKEN ANYTHING? ADD A HELL LOT OF HEALTH CHECK BUILDS
- 9. NOT MEANINGFUL EXCEPTION? FAIL FAST CATCH EXCEPTION OR THROWABLE ADD CONTEXT AND RETHROW OR YOU’LL DIE
- 10. STRUGGLING WITH TECHNOLOGY? ASK ON STACKOVERFLOW (AND ANSWER BY YOURSELF)
- 11. STRUGGLING WITH PROJECT? ADD TO KNOWLEDGE BASE README.md wiki
- 12. STYLE ISSUES DURING CODE REVIEW? ADD TASK TO AUTOMATE NEXT TIME
- 17. MONITORING DEPENDENCY UPDATES MAVEN GRADLE HOW? • tool that invokes the above commands in all repositories • report for developers is created periodically
- 18. COMMIT MESSAGES "git log origin/master..HEAD".execute().text
- 19. BUILD STATUS
- 20. JENKINS CI BUILD MONITOR PLUGIN https://github.com/jan-molak/jenkins-build-monitor-plugin
- 22. GITGUARD Chrome extension blocking GitHub merge button based on specified Jenkins jobs https://chrome.google.com/webstore/detail/ gitguard/dlbacfedgdjanlkofjckclmgmijbhakl
- 23. NO RED MASTER PLEASE! • Run all tests on branches • Use GitHub Status API • Merge master before running tests
- 24. ENFORCE UP-TO-DATE • Enforce branch to be up-to-date before merge
- 26. UNIT TESTS Fast (hundreds per second, run in parallel) Isolated (single unit tested) Repeatable (always the same result) Self verifying (either pass or fail) Timely (written early) FIRST BLAZINGLY FAST AND ULTIMATELY RELIABLE TESTS mvn test gradlew test SHIFT+F10
- 29. GRADLE PERFORMANCE TIPS mavenCentral() jcenter() USE DAEMON UPDATE TO LATEST GRADLE gradlew wrapper –gradle-version 3.1 gradlew build --profile USE JCENTER PROFILE GRADLE BUILD SCANS COMPILE INCREMENTALLY compileJava.options.incremental = true
- 30. CODE STYLE / STATIC ANALYSIS • Checkstyle, PMD, FindBugs, CodeNarc • Agree on common rules for all projects • Shared configurations • Gradle plugin • Maven plugin • Maven parent POM (tricky)
- 31. INTERNAL QUALITY PLUGIN • Integrates all agreed tools with all reasonable rules enabled • Customized for project/company needs • Zero configuration by default • Unified console output with clickable links gradlew checkstyleMain pmdMain findbugsMain codenarcMain checkstyleTest pmdTest findbugsTest codenarcTest gradlew quality
- 32. BLACKLISTS • Use blacklists instead of whitelists to get new rules PMD FindBugs CodeNarc
- 33. EARLY STATIC ANALYSIS FEEDBACK • CheckStyle-IDEA • FindBugs-IDEA • SonarLint
- 34. GATHER VIOLATIONS FROM ALL TOOLS AND MODULES gradlew quality --continue mvn -fae mvn --fail-at-end
- 35. GRADLE BASE PLUGIN • Applies ‘java’, ‘groovy’ and ‘maven’ plugins • Always shows full stacktraces, even if --stacktrace is forgotten • Adds provided configuration (missing in Gradle) • Configures repositories with dependencies • Adds tuned compiler configuration for Java and Groovy • Displays detailed information about all warnings (-Xlint:all option) • Fails build on any unsuppressed warning (-Werror option) • Adds configuration to run tests in parallel • Enables rich test logging with summary • (Tests run: 3, Failures: 2, Skipped: 1) and full stacktraces • Configures wrapper task with latest Gradle • Applies taskTree plugin • Applies com.github.ben-manes.versions plugin • Prints Gradle and JVM versions in the output
- 36. SANITY BUILD MATRIX Periodically run on master series of builds using different configurations that developers may use • various Java and Maven versions • various build parameters like -DskipTests • various JVM params like locale • compilation with fresh repository
- 37. MUTATION TESTING • Mutations are made to the code • If tests fail then the mutant is • If tests pass then the mutant • Percentage of mutants killed is indicator of your tests quality • Can be really killed lived slow!
- 38. FAST MUTATION TESTING scmMutationCoverage GitHub status Report
- 39. NON-REQUIRED CHECKS https://help.github.com/articles/about-required-status-checks/
- 40. NONDEX • Tool for detecting wrong assumptions about Java APIs • assuming specific order of HashMap iteration • Run tests with changed implementations of standard classes to return shuffled results • Same happens when upgrading Java
- 41. APIS ANAYZED BY NONDEX
- 42. PLAY WITH COMMITTING .IDEA FILES
- 44. GET STATUS ON PULL REQUESTS QUICKLY
- 46. CODE REVIEW • Do timely • Assign people • Internal team review • External review • Address comments
- 47. OPEN PULL REQUESTS DASHBOARD https://github.com/pulls
- 48. CONTRIBUTING FILE create CONTRIBUTING.md in repository root be notified
- 50. RETROSPECTIVES
- 51. RETROSPECTIVES IF IT IS NOT FUN, YOU'RE DOING IT WRONG
- 54. SUMMARY • We want feedback to • continuously improve • deliver more value • reduce risk • learn • Feedback has • many types • many sources
- 55. THERE IS NO FAILURE. ONLY FEEDBACK. Robert Allen