scratch imageでのtime.Location()

2024/12/11開催のSendai.goの登壇資料です

1. scratch imageでのtime.Location() 
 2024/12/11 Sendai.go
2. ©Showcase Gig 自己紹介
 • 照井寛也 • 株式会社Showcase Gig ◦ エンジニアリングオフィス • Sendai.go オーガナイザー • X : @10_ru_1
3. ©Showcase Gig scratchを使ったmulti stage build 
 FROM golang:1.23.4 AS build-env ENV WORKDIR_PATH /go/src/github.com/showcase-gig/go-awesome-project WORKDIR ${WORKDIR_PATH} COPY go.mod . COPY go.sum . ADD . ${WORKDIR_PATH} RUN CGO_ENABLED=0 go build -buildvcs=false -o /bin/go-awesome-project ./cmd/go-awesome-project FROM scratch COPY --from=build-env /bin/go-awesome-project /bin/go-awesome-project EXPOSE 80 ENTRYPOINT [ "/bin/go-awesome-project" ]
4. ©Showcase Gig • 最小のimageファイル ◦ scratchはゼロベースのimage • Goのバイナリだけで動作 ◦ CGO_ENABLED=0 • セキュリティ向上 ◦ binaryファイルだけが動作 multi stage buildの メリット

5. ©Showcase Gig scratch上で実行してみる 👀
 func main() { l, err := time.LoadLocation("Asia/Tokyo") if err != nil { log.Fatal(err) return } birthday := time.Date(1996, 10, 19, 0, 0, 0, 0, l) fmt.Println(birthday) }
6. ©Showcase Gig 💥 panic: unknown time zone Asia/Tokyo
7. ©Showcase Gig 🥺
8. ©Showcase Gig • local環境では動いていた。。 ◦ localではalpineベースで動かしてい た ◦ airやdlvなどを入れるため • でもdeployすると動かない ◦ scratch imageでdeploy用のdocker 用意してた しかもlocalでは 
 動いちゃって 
 気づかないことも 

9. ©Showcase Gig Go Standard Library 
 https://pkg.go.dev/time#LoadLocation
10. ©Showcase Gig Go Standard Library 
 https://pkg.go.dev/time#LoadLocation
11. ©Showcase Gig 1. ZONEINFOの環境変数を見にく a. なし 2. platfromZoneSourcesを見にいく a. 🤔 zoneinfo.go 
 https://cs.opensource.google/go/go/+/refs/tags/go1. 23.4:src/time/zoneinfo.go;l=666-699
12. ©Showcase Gig zoneinfo_unix.go 
 https://cs.opensource.google/go/go/+/refs/tags/go1. 23.4:src/time/zoneinfo.go;l=666-699 https://cs.opensource.google/go/go/+/refs/tags/go1.23.4:src/ti me/zoneinfo_unix.go;l=21-26
13. ©Showcase Gig scratchは基本0ベースなのでzoneinfoがない 

14. ©Showcase Gig 💥 panic: unknown time zone Asia/Tokyo
15. ©Showcase Gig //go:buildで区別している • zoneinfo_unix.go ◦ //go:build unix && !ios && !android • zoneinfo_goroot.go ◦ //go:build !ios && !android • zoneinfo_ios.go ◦ //go:build ios …… ちなみにzoneinfo_***.goは他にもある 

16. ©Showcase Gig (話を戻して)scratchを使ったmulti stage build 
 FROM golang:1.23.4 AS build-env ENV WORKDIR_PATH /go/src/github.com/showcase-gig/go-awesome-project WORKDIR ${WORKDIR_PATH} COPY go.mod . COPY go.sum . ADD . ${WORKDIR_PATH} RUN CGO_ENABLED=0 go build -buildvcs=false -o /bin/go-awesome-project ./cmd/go-awesome-project FROM scratch COPY --from=build-env /bin/go-awesome-project /bin/go-awesome-project EXPOSE 80 ENTRYPOINT [ "/bin/go-awesome-project" ]
17. ©Showcase Gig zoneinfoをcopyしてあげる 
 FROM golang:1.23.4 AS build-env ENV WORKDIR_PATH /go/src/github.com/showcase-gig/go-awesome-project WORKDIR ${WORKDIR_PATH} COPY go.mod . COPY go.sum . ADD . ${WORKDIR_PATH} RUN CGO_ENABLED=0 go build -buildvcs=false -o /bin/go-awesome-project ./cmd/go-awesome-project FROM scratch COPY --from=build-env /bin/go-awesome-project /bin/go-awesome-project COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo EXPOSE 80 ENTRYPOINT [ "/bin/go-awesome-project" ]
18. ©Showcase Gig もしくはalpineを使う 
 FROM golang:1.23 AS build-env ENV WORKDIR_PATH /go/src/github.com/showcase-gig/go-awesome-project WORKDIR ${WORKDIR_PATH} COPY go.mod . COPY go.sum . ADD . ${WORKDIR_PATH} RUN CGO_ENABLED=0 go build -buildvcs=false -o /bin/go-awesome-project ./cmd/go-awesome-project FROM golang:1.23.4-alpine COPY --from=build-env /bin/go-awesome-project /bin/go-awesome-project EXPOSE 80 ENTRYPOINT [ "/bin/go-awesome-project" ]
19. ©Showcase Gig 開発組織や環境に応じてどちらを使うか選択する 

20. ©Showcase Gig Thank you 👋