GolangCI を使ってコードの品質を保ちながら快適な Golang 生活を送る話 #gounco / GolangCI

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GolangCI Λ࢖ͬͯ ίʔυͷ඼࣭Λอͪͳ͕Β շదͳ Golang ੜ׆ΛૹΔ࿩ 19/01/31 Go(Un)ConferenceʢGo͋Μ͜ʣLTେձ 5kg Dai Kurosawa / @ponde_m

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Introduce

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Έͳ͞ΜɺLint ࢖ͬͯ·͔͢

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ઌ೔ͷ golang.tokyo #21 Ͱ΋͜Μͳ͓࿩͕͋Γ·ͨ͠

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՝୊ͷϑΟʔυόοΫ From: 34ਓͷGoͷ՝୊ΛϨϏϡʔͯ͠ײͨ͜͡ͱ  (https://docs.google.com/presentation/d/1TAwxT9mRmiEjQOZurz-TbXc8SQf0mlEJDS8tL49Q-M4)

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՝୊ͷϑΟʔυόοΫ From: 34ਓͷGoͷ՝୊ΛϨϏϡʔͯ͠ײͨ͜͡ͱ  (https://docs.google.com/presentation/d/1TAwxT9mRmiEjQOZurz-TbXc8SQf0mlEJDS8tL49Q-M4)

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πʔϧ࢖͍͖ͬͯ·͠ΐ͏ʂ

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ࠓ೔͸͍ͭ͜ͷ࿩Ͱ͢

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GolangCI ? ʕ ◔ϖ◔ʔ

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GolangCI ͱ͸ • GitHub ͷ Pull Request ͷ໰୊Λݕ஌ͯ͠ίϝϯτͯ͘͠ΕΔ Golang ༻ ͷ CI αʔϏε • ͍ΖΜͳ Linter Λ࣮ߦͯ͘͠ΕΔ • OSS ͳΒແྉͰ࢖͑Δ • Private Repo ͸1Ϣʔβ $20/mo • GolangCI ࣗମ΋ OSS ͳͷͰιʔε͕શ෦ެ։͞Ε͍ͯΔ • https://github.com/golangci Image From: https://golangci.com/

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࣮ߦͯ͘͠ΕΔ Linter • શ 31 छྨ (19/01/31 ݱ࣌఺ ͷυΩϡϝϯτ্) • ΊͬͪΌ͋Δ • ࣮ࡍ͸ Linter ͕ merge ͞ΕͨΓͯ͠ΔͷͰਖ਼֬ͳछྨ਺ ͱͯ͠͸΋ͬͱগͳ͔ͬͨΓ͢Δ • جຊͷ gofmt, goimports, govet ͔Β  errorcheck ͳͲҰൠతʹ࢖ΘΕͯͦ͏ͳ΋ͷ͸໢ཏ͞Ε ͯΔ͸ͣ

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࣮ߦΠϝʔδ

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࢖͍ํ • https://golangci.com/ ʹߦͬͯ GitHub ೝূͯ͠ϦϙδτϦબ୒ ͢Δ͚ͩ • 30 ඵͰऴΘΔͷͰΈΜͳ΍Ζ͏ʂ

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ద༻͢Δ Linter ͷΧελϚΠζ • .golangci.yml ʹ৭ʑॻ͍ͯ͋͛Δ • σϑΥϧτͩͱແޮʹͳ͍ͬͯΔ Linter ͕݁ߏଟ͍ͷͰ஫ҙ • https://github.com/golangci/golangci- lint#enabled-by-default-linters

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Ͱ΋ Linter ͸ CI ͚ͩͰ͸ͳ͘ ϩʔΧϧͰ΋ಈ͔͍ͨ͠ (push ͠ͳ͍ͱ݁ՌݟΕͳ͍ͷ͸ͩΔ͍)

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GolangCI-Lint

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Golang-CI Lint • ϩʔΧϧͰ GolangCI Ͱಈ͘ Lint Λ࣮ߦͰ͖Δ • CircleCI ͳͲͷ CI αʔϏεʹ૊ΈࠐΉ • VSCode ͳͲͷΤσΟλͱ౷߹Ͱ͖Δ • ࣅͨΑ͏ͳ Linter ʹ gometalinter ͕ଘࡏ͢Δ͕ͦΕΑΓ΋ߴ଎ʹಈ࡞ ͢Δͷ͕ಛ௃ • ଞʹ΋৭ʑվળ͞Ε͍ͯΔ (ޙड़) • Istio ΍ kustomize Ͱ࢖ΘΕ͍ͯͨΓ͢Δ

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gometalinter ͱͷൺֱ From: https://github.com/golangci/golangci-lint#golangci-lint-vs-gometalinter

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gometalinter ͱͷൺֱ • 2 ~ 7ഒ͘Β͍଎͍ • 26%͘Β͍ϝϞϦফඅ͕গͳ͍ • ฏߦॲཧ਺ͪΌΜͱ੍ޚͰ͖Δ • ग़ྗϑΥʔϚοτΛΧελϚΠζͰ͖Δ • আ֎ϦετͳͲΛ࢖ͬͯҰൠతͳޡݕ஌ʹରԠ • Git ͷεςʔδϯά, τϥοΩϯά͞Εͯͳ͍ϑΝΠϧͷΈʹ࣮ߦ,  ಛఆͷϦϏδϣϯҎ߱ͷίϛοτʹର࣮ͯ͠ߦΈ͍ͨͳઃఆ͕Ͱ͖ΔͷͰେن໛ͳίʔυ ϕʔεʹ΋ಋೖ͕Ͱ͖Δ • Linter ͷݸผͷΠϯετʔϧ͕ෆཁͰ GolangCI-Lint ͚ͩΠϯετʔϧ͢Ε͹Α͍ • YAML Ͱઃఆ͕Ͱ͖Δ From: https://github.com/golangci/golangci-lint#golangci-lint-vs-gometalinter

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gometalinter ͱͷൺֱ From: https://github.com/golangci/golangci-lint#comparison-with-gometalinter

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ΊͬͪΌൺֱͯ͠Δ

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Φεεϝͷ࢖͍ํ (?) • ೴ࢮͰ enable-all • શ෦ͷ Linter ͕ಈ͘

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ͱݴ͍͍ͨͱ͜Ζ͚ͩͲ ྲྀੴʹͭΒ͍

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ͭΒ͍ྫ • gochecknoinits • init ؔ਺͕͋ΔͱౖΒΕΔ From: https://github.com/leighmcculloch/gochecknoinits

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Lint ͸ద੾ʹ࢖͏ • ݫ͗͢͠Δ Lint ͸ෛ୲ʹͳΔ • ಛʹ CI ͷϫʔΫϑϩʔʹ૊Έࠐ·Ε͍ͯΔ৔߹ ͸ڧ੍ྗ͕͋ΔͷͰ஫ҙ͢Δ • νʔϜ։ൃͷ৔߹ͳͲ͸ແཧͳ͘औΓ૊ΊΔΑ͏ɺ খ͘͞গͣͭ͠ಋೖͯ͘͠ • ద੾ͳબ୒ɺΧελϚΠζΛ͠Α͏

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Ͳͷ Linter Λ࢖͏໰୊

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@ponde_m ͷීஈ • ΘΓͱ೴ࢮͯ͠Δ • ແޮʹ͍ͯ͠Δ Linter • gochecknoglobals • άϩʔόϧείʔϓͷม਺͕͋ͬͨΒౖΒΕΔ • gochecknoinits • init ؔ਺͕͋ͬͨΒౖΒΕΔ

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͜ͷ··ͩͱ ͋·ΓࢀߟʹͳΒͳ͍ͷͰ

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࢖͍ͬͯΔ Linter Λ ެ։͍ͯ͠Δձࣾ͞Μͷ঺հ

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ϝϧΧϦ͞Μ From: Microservices implementation guide in Go at Mercari Inc  (https://speakerdeck.com/ygnmhdtt/microservices-implementation-guide-in-go-at-mercari-inc?slide=27)

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αΠϘ΢ζ͞Μ From: Neco ϓϩδΣΫτͷεΩϧνΣοΫγʔτ  (https://gist.github.com/ymmt2005/bd92296166e52d1beba9df8ac516a9db)

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͔͜͜Β͸ ࠓग़͖ͯͨ Linter + ͓͢͢Ί Linter ͷ ঺հίʔφʔ

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gofmt • ίʔυ੔ܗ • جຊ

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gofmt -s • -s ΦϓγϣϯΛ͚ͭΔͱίʔυΛγϯϓϧʹͯ͘͠ΕΔ

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goimports • gofmt + import ͷमਖ਼Λͯ͘͠ΕΔ • جຊ

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golint • Effective Go ΍ CodeReviewComments ʹج͍ͮ ͯίʔσΟϯάελΠϧΛࢦఠͯ͘͠ΕΔ From: Effective Go  (https://golang.org/doc/effective_go.html)  From: CodeReviewComments  (https://github.com/golang/go/wiki/CodeReviewComments)

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govet • ίϯύΠϥ͕ݕग़ͯ͘͠Εͳ͍ΤϥʔΛࢦఠͯ͘͠ΕΔ

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errcheck • error ͷϋϯυϦϯάͯ͠ͳ͍ͱౖΒΕΔ

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staticcheck • αʔυύʔςΟ੡͚ͩͲ৭ʑͳ໰୊Λݕ஌ͯ͘͠ΕΔ • govet ͬΆ͍΍ͭ • νΣοΫͯ͘͠ΕΔ΋ͷ͸ຊ౰ʹ৭ʑ͋ΔͷͰυΩϡϝϯτࢀর • https://staticcheck.io/docs/checks

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misspell • ίϝϯτ಺ͷεϖϧϛεΛݟ͚ͭͯ͘ΕΔ

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interfacer • ͜͜ͷҾ਺ΠϯλϑΣʔεʹͰ͖ΔΑΈ͍ͨͳͷΛڭ͑ͯ͘ΕΔ

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prealloc • ࣄલʹׂΓ౰ͯՄೳͳεϥΠεΛݟ͚ͭͯ͘ΕΔ

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lll • 1ߦ௕͗͢໰୊Λڭ͑ͯ͘ΕΔ

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·ͱΊ

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·ͱΊ • GolangCI-Lint ͸୯ମͰ·ͱΊͯ Linter Λ࣮ߦ Ͱ͖ΔΠέͯΔπʔϧ • Linter ͸ద੾ʹઃఆ͢Δ • ಋೖ͸খ͘͞গͣͭ͠ • ݸਓɺνʔϜʹ߹ΘͤͨΧελϚΠζΛ

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͓͠·͍ ʕ ◔ϖ◔ʔ