モジュールの深さについて / depth of module

http://nakawatch.hatenablog.com/entry/module-depth

1. Ϟδϡʔϧͷਂ͞ʹ͍ͭͯ CAEC MeetUP #4
2. Me • தඌ ྋ (@nakabonne) • தԝେֶ঎ֶ෦3೥ • AWAϚΠΫϩαʔϏε • Go, Envoy, etc…
3. My tasks https://www.redhat.com/cms/managed-files/service-mesh-1680.png
4. My tasks https://github.com/DataDog/dd-py-tracing-workshop
5. Agenda • ྑ͍Ϟδϡʔϧͱ͸ • deep moduleͱ͸
6. ྑ͍Ϟδϡʔϧͱ͸
7. খ͍͞Ϟδϡʔϧʁ
8. –The Unix Philosophy “Small is beautiful”
9. ԿނϞδϡʔϧΛ࡞Δͷ͔
10. ؔ࿈ੑͷߴ͍ཁૉ͕ू·Δ →࣮૷ͷෳࡶ͞ΛԼ͛Δ
11. Open a file in Java FileInputStream fileStream = new FileInputStream(fileName); BufferedInputStream bufferedStream = new BufferedInputStream(fileStream); ObjectInputStream objectStream = new ObjectInputStream(bufferedStream);
12. Open a file in Java FileInputStream fileStream = new FileInputStream(fileName); BufferedInputStream bufferedStream = new BufferedInputStream(fileStream); ObjectInputStream objectStream = new ObjectInputStream(bufferedStream); ॳาతͳI/O
13. Open a file in Java FileInputStream fileStream = new FileInputStream(fileName); BufferedInputStream bufferedStream = new BufferedInputStream(fileStream); ObjectInputStream objectStream = new ObjectInputStream(bufferedStream); όοϑΝϦϯά
14. Open a file in Java FileInputStream fileStream = new FileInputStream(fileName); BufferedInputStream bufferedStream = new BufferedInputStream(fileStream); ObjectInputStream objectStream = new ObjectInputStream(bufferedStream); read/write
15. ࣮૷ͷෳࡶ͕͞࿙ΕͯΔ…
16. • খ͍͞ͱ͍͏͜ͱ͸ɺ࣋ͬͯΔ৘ใྔ͕গͳ͍ • ࣋ͬͯΔ৘ใྔ͕গͳ͍ͱɺ࣮૷ͷෳࡶ͕͞࿙ Ε΍͍͢ • ࣮૷ͷෳࡶ͕͞࿙Ε͍ͯΔͱɺ࣮૷มߋ͕पΓ ʹӨڹΛ༩͑΍͘͢ͳΔ
17. খ͞͞Λҙࣝ͗͢͠Δ
18. খ͞͞Λҙࣝ͗͢͠Δ
19. ߴڽूʁૄ݁߹ʁ
20. ߴڽूʁૄ݁߹ʁ
21. ߴڽूʁૄ݁߹ʁ ྑ͍ΠϯλʔϑΣʔε͕ඞཁ
22. ྑ͍ΠϯλʔϑΣʔεͱ͸
23. Bad interface
24. Bad interface
25. Bad interface
26. ͔͠͠ιϑτ΢ΣΞ͸มߋ͞ΕΔ →͜ͷໃ६ͷதͰ΋่Εͳ͍͜ͱ͕ٻΊΒΕΔ
27. Good interface ෆมʢ௥ՃҎ֎ͷมߋΛڐ͞ͳ͍ʣ
28. And
29. ࢖͍΍͋͘͢Δ΂͖
30. –Rich Hickey “Easy is relative”
31. Կ͕ศར͔͸ϢʔβʔʹΑΔ
32. Use case Edge case General case
33. Use case Edge case General case
34. Ұൠతͳέʔεʹߜͬͯ ࢖͍΍͢͞Λ௥ٻ͢Δ
35. ෳࡶԽͷཧ༝ FileInputStream fileStream = new FileInputStream(fileName); BufferedInputStream bufferedStream = new BufferedInputStream(fileStream); ObjectInputStream objectStream = new ObjectInputStream(bufferedStream); όοϑΝϦϯά͠ͳ͍ͱ͍͏ ΤοδέʔεΛڐ༰͍ͯ͠Δ
36. Good module ؔ࿈ੑͷߴ͍ͨ͘͞ΜͷཁૉΛӅ࣋ͪ͠ɺ ҰൠతͳέʔεͰ࢖͍΍͘͢ෆมͳΠϯλʔ ϑΣʔεʹΑͬͯڧྗͳػೳΛఏڙ͢Δ
37. ߟ͑Δ͜ͱଟ͗͢ʂ
38. ຊ୊
39. deep module
40. A Philosophy of Software Design • ஶऀ͸ελϯϑΥʔυେֶ John Ousterhoutڭत • ઐ໳͸෼ࢄγεςϜ΍OS ͳͲଟذʹ౉Δ
41. deep module γϯϓϧͳΠϯλʔϑΣʔεͰ ڧྗͳػೳΛఏڙ͢Δ
42. deep vs shallow modules
43. deep vs shallow modules
44. ΠϯλʔϑΣʔεͷෳࡶ͞͸ίετͰ ػೳͷڧྗ͞͸རӹ
45. ࢹ఺ • ػೳ͸ڧྗ͚ͩͲɺͦΕҎ্ʹΠϯλʔ ϑΣʔε͕ෳࡶʹͳͬͯͳ͍͔ʁ • ΠϯλʔϑΣʔε͸؆୯͚ͩͲɺػೳ ͸ශऑͰ͸ͳ͍͔ʁ
46. ྫɿUnix ϑΝΠϧI/O • open() • read() • write() • close() • lseek() ←ෆม
47. Χʔωϧ ϢʔβΞϓϦέʔγϣϯΛ҆ఆͯ͠ ಈ࡞ͤ͞ΔͨΊʹઃܭ͞Ε͍ͯΔ →ࢀߟʹͳΔ
48. ·ͱΊ
49. ·ͱΊ • ྑ͍Ϟδϡʔϧͱ͸ʮؔ࿈ੑͷߴ͍ͨ͘͞ΜͷཁૉΛӅ࣋ͪ͠ɺҰൠత ͳέʔεͰ࢖͍΍͘͢ෆมͳΠϯλʔϑΣʔεʹΑͬͯڧྗͳػೳΛఏ ڙ͢Δ΋ͷʯ • ࣮ݱ͢ΔͨΊʹʮϞδϡʔϧͷਂ͞ʯΛҙࣝ͢Δ • ͋͘·ͰҰͭͷߟ͑ํͰ͋ΔͨΊɺ൓࿦΢ΣϧΧϜ
50. ͋Γ͕ͱ͏͍͟͝·ͨ͠