GoのASTを用いて フィルター機能を作ろうとした話

1. ླ໦ ହే GoͷASTΛ༻͍ͯ ϑΟϧλʔػೳΛ࡞Ζ͏ͱͨ͠࿩ Go Connect #6 2025.04.24
2. ླ໦ ହే / Suzuki Taito / @ts__0625 • WebΤϯδχΞ (6೥໨ • όοΫΤϯυ • Goྺ͸໿Go೥ • ݩʑ͸σʔλΤϯδχΞͬΆ͍ (7೥ • ݱࡏ • WebΤϯδχΞ @גࣜձࣾHRBrain ࣗݾ঺հ
3. ࢓ࣄͰ͸Ϙπʹͳ͚ͬͨͲ ASTͷԠ༻ࣄྫͱͯ͠໘ന͍ (…ͱࢥ͏) ͳͥ͜ͷ࿩Λ͢Δʁ
4. ΞδΣϯμ GoͷASTΛ༻͍ͯϑΟϧλʔػೳΛ࡞Ζ͏ͱͨ͠࿩ എܠ ϑΟϧλʔػೳͱ͸ ASTΛ༻͍Δ͜ͱʹͳͬͨܦҢ ຊ୊ ϑΟϧλʔػೳͷ࡞Γํ ৼΓฦΓ ࣗݾ঺հ
5. എܠ
6. ΍Γ͍ͨ͜ͱ λ ϑΟϧλ ϝοηʔδ mailૹ৴ DB λ Ϣʔβʔຖͷ ϑΟϧλઃఆ ΤϯυϢʔβʔ ϝοηʔδ͕ྲྀΕͯ͘Δ
7. ΍Γ͍ͨ͜ͱ λ DB ΤϯυϢʔβʔ ౦ژ౎৽॓۠ɺ͔ͭɺ઄౪ࣄ݅ ·ͨ͸ ࡛ۄݝॴ୔ࢢɺ͔ͭɺߑਫɺ͔ͭɺʮচ্ਁਫʯؚ͕·ΕΔ
8. ࣮૷ͷ՝୊(೰) λ DB ΤϯυϢʔβʔ ౦ژ౎৽॓۠ɺ͔ͭɺ઄౪ࣄ݅ ·ͨ͸ ࡛ۄݝॴ୔ࢢɺ͔ͭɺߑਫɺ͔ͭɺʮচ্ਁਫʯؚ͕·ΕΔ ςΩετͷϑΟϧλʔઃఆͷύʔε Ͳ͏΍Δʁ ςΩετͷϑΟϧλʔઃఆͷจ๏ɻͲ͏͢Δʁ ύʔεͨ݁͠ՌͷASTͷධՁ Ͳ͏΍Δʁ
9. ;ͱʮGoͷASTʯΛࢥ͍ग़ͨ͠ ඪ४ϥΠϒϥϦ go/ast, go/parser GoݴޠͷιʔείʔυΛ੩తղੳ͢Δͱ͖ʹ࢖ΘΕΔ go/ast … AST ද͢ߏ଄ମͳͲ go/parser … ιʔείʔυ΍͔ࣜΒASTΛߏங͢Δύʔαʔ go/parser.ParseExpr ؔ਺ … Goݴޠͷࣜ(Expression)͚ͩͷASTΛฦ͢ ( a + fn(1) ) * d
10. GoͷASTΛ࢖͑͹… λ DB ΤϯυϢʔβʔ ςΩετͷϑΟϧλઃఆΛ GoͷࣜͰهड़͢Δ ςΩετͷϑΟϧλʔઃఆͷจ๏ Goݴޠͷࣜ ΦϨ͸ASTͷධՁॲཧΛ࣮૷͢Δ͚ͩʂ ςΩετͷϑΟϧλʔઃఆͷύʔε ParseExprؔ਺Λ༻͍Δ
11. ࣮૷ݮΒͤͯ ໘നͦ͏😀😀
12. ຊ୊
13. λ DB ΤϯυϢʔβʔ ςΩετͷϑΟϧλઃఆΛ GoͷࣜͰهड़͢Δ ຊ୊ʂ
14. ຊ୊ ίϨΛ Ͳ͏࡞͔ͬͨʁ ϑΟϧλʔઃఆ(Goͷࣜ) ↑࣍εϥΠυͰৄ͘͠
15. ϑΟϧλʔઃఆ(Goͷࣜ) ࣜͷධՁ݁Ռ͸ඞͣϒʔϧ஋ 3ͭͷؔ਺͕ఆٛͯ͋͠Δ contains(a string) bool : Πϕϯτͷ಺༰͕ a ΛؚΉʁ equalType(a string) bool : Πϕϯτͷछྨ͕ a Ͱ͋Δʁ equalLoc(a string) bool : Πϕϯτͷൃੜ৔ॴ͕ a Ͱ͋Δʁ &&ͱ||ͷԋࢉࢠͷΈ͕࢖༻Մೳ ྫ equalLoc(“౦ژ౎৽॓۠”) && equalType(“઄౪ࣄ݅”) || equalLoc(“࡛ۄݝॴ୔ࢢ”) && equalType(“ߑਫ”) && contains(“চ্ਁਫ”) ౦ژ౎৽॓۠ɺ͔ͭɺ઄౪ࣄ݅ ·ͨ͸ ࡛ۄݝॴ୔ࢢɺ͔ͭɺߑਫɺ͔ͭɺʮচ্ਁਫʯؚ͕·ΕΔ
16. Filter(ev Event, setting string) bool ॲཧͷྲྀΕ (1) setting(ϑΟϧλʔઃఆ)ͷASTΛ࡞Δ (2) ASTʹؚ·ΕΔશͯͷؔ਺ΛධՁ͢Δ (3) AST(ࣜશମ)ΛධՁ͢Δ
17. Filter(ev Event, setting string) bool (1) setting(ϑΟϧλʔઃఆ)ͷASTΛ࡞Δ ast/parser.ParseExpr ؔ਺ΛݺͿ͚ͩ equalLoc(“౦ژ౎৽॓۠”) && equalType(“઄౪ࣄ݅”) || equalLoc(“࡛ۄݝॴ୔ࢢ”) && equalType(“ߑਫ”) && contains(“চ্ਁਫ”) ্هͷࣜΛASTʹม׵͢Δͱ…΍ͬͯΈΔ https://go.dev/play/p/7llFDi3gdeI
18. Filter(ev Event, setting string) bool (1) setting(ϑΟϧλʔઃఆ)ͷASTΛ࡞Δ || && equalLoc “౦ژ౎৽॓۠” equalType “઄౪ࣄ݅” && && equalLoc “࡛ۄݝॴ୔ࢢ” equalType “ߑਫ” contains “চ্ਁਫ”
19. Filter(ev Event, setting string) bool (2) ASTʹؚ·ΕΔશͯͷؔ਺ΛධՁ͢Δ ؔ਺͚ͩධՁ (ਂ͞༏ઌ୳ࡧ͠ɺਂ͍ͱ͜Ζʹ͋Δؔ਺͔Β) || && equalLoc “౦ژ౎৽॓۠” equalType “઄౪ࣄ݅” && && equalLoc “࡛ۄݝॴ୔ࢢ” equalType “ߑਫ” contains “চ্ਁਫ”
20. Filter(ev Event, setting string) bool (2) ASTʹؚ·ΕΔશͯͷؔ਺ΛධՁ͢Δ ؔ਺͚ͩධՁ (ਂ͞༏ઌ୳ࡧ͠ɺਂ͍ͱ͜Ζʹ͋Δؔ਺͔Β) || && True False && && False True False
21. Filter(ev Event, setting string) bool (3) AST(ࣜશମ)ΛධՁ͢Δ ͜ͷྫͰ͸False || && True False && && False True False
22. Filter(ev Event, setting string) bool ASTͷਂ͞༏ઌ୳ࡧ walk.go Walkؔ਺ Inspectؔ਺
23. 😄Θʔ͍ Πέͦ͏
24. ࣾ಺ͷϨϏϡʔձͰ͓൸࿐໨ͯ͠Έͨ݁Ռ ςοΫϦʔυͳਓA ͋Μ·Γมͳ͜ͱ΍Βͳ͍ํ͕͍͍ͱࢥ͏ͳʂ ςοΫϦʔυͳਓB ύϑΥʔϚϯεѱͦ͏ PdMͳਓ ඇΤϯδχΞʹͱͬͯɺGoݴޠͷࣜ͸Ή͍ͣͬ͢ PdMͳਓ ͦ΋ͦ΋ෳࡶͳݕࡧ৚͍݅ΒΜ
25. 😭ܸ௜ 🪦ιʔείʔυຒ૴
26. ౔ʹຒΊͨιʔείʔυ͸ͪ͜Β https://github.com/suzuito/ fi lter-by-ast-go ࠓճͷઆ໌ͷͨΊʹఏࣔͨ͠ʮྫʯͱ͸࣮૷͕एׯҧͬͯ·͕͢ɺ ϕʔεͱͯ͠Δߟ͑ํ͸ಉ͡Ͱ͢ɻ ࠓճͷઆ໌ͷͨΊʹɺ5೥ͿΓʹಈ͔ͯ͠ΈͨΒɺͪΌΜͱಈ͍ͨ(͢͞Go)
27. ৼΓฦΓ
28. ͍·ࢥ͏ɺࣗ෼ͳΓͷධՁ 👌ϝϦοτ ґଘͳ͠ɿGoͷඪ४ϥΠϒϥϦͷΈͰ࣮૷ՄೳͳͨΊɻ ޓ׵ੑΛอͯΔɿGoͷࣜʹ͍ͭͯɺഁյతมߋͷϦεΫ͸௿͍ͨΊɻ ASTͷධՁͷΧελϚΠζੑྑ͠ɿධՁͷ࣮૷ΛࣗલͰॻ͘ʹͳΜͰ΋Ͱ͖Δ 👎σϝϦοτ ASTͷධՁ෦෼ͷ࣮૷͕ෳࡶ πϦʔΛ୳ࡧͨ͠ΓɺελοΫPush/PopɺGoͷશASTϊʔυ΁ͷରԠ ΧελϜؔ਺ΛݺͿॲཧɺ…
29. ͍·ࢥ͏ɺ͍·΍ΔͳΒ ඇΤϯδχΞͰ΋ѻ͑ΔϑΟϧλʔઃఆͱ͸ʁ ΛͪΌΜͱߟ͑Δ with PdMͱσβΠφʔ ධՁࣜ༻ͷϥΠϒϥϦΛ࢖͏ CEL https://cel.dev/ Open Policy Agent https://www.openpolicyagent.org/docs/latest/ Expr https://expr-lang.org/ ϥΠϒϥϦͷ໨త͔Β֎Εͨ࢖͍ํΛ͠ͳ͍
30. 🙇 Goਗ਼ௌ͋Γ͕ͱ͏Go͍͟·ͨ͠