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labelerrͱ
 suberrΛ࡞ͬͨ࿩ @nametake

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ࣗݾ঺հ

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Shogo Nameki @nametake Go, Vim

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Error handling

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Έͳ͞Μ

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GoͷError handling ޷͖Ͱ͔͢ʁ

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΋ͪΖΜ ޷͖Ͱ͢ΑͶʁ

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ࢲ΋޷͖Ͱ͢

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޷͖ͳΜͰ͕͢……

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StackTraceͱ͔ ErrorͷݪҼͱ͔ ແͯ͘ࠔΔ

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ͦΜͳ͋ͳͨʹʂ

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pkg/errors

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Stack Trace͕ Errorʹͭ͘ʂ

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errors.CauseͰ ݪҼΛऔΓग़ͤΔʂ

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͜Ε͑͋͞Ε͹ ࠔͬͨ͜ͱ͸ ى͜Βͳ͍ʂʂʂ

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Θ͚Ͱ΋ͳ͔ͬͨ

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ྫ͑͹

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WebΞϓϦͰͷ Error Handling

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4xx 5xx

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4xx͸Ϣʔβʔͷ ૢ࡞ʹΑͬͯ͸ ൃੜ͢Δ

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4xxͱ5xx͸ ҧ͏΋ͷͱͯ͠ औΓѻ͍͍ͨ

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Go͸಺෦తʹ͸ Ͳͬͪ΋Error (e.g. NotFound)

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ൃੜݯͰ͸ 4xxͱ͔5xxͱ͔͸ ҙࣝ͠ͳ͍

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errors.CauseͰ͸ ۠ผͰ͖ͳ͍

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΄͔ʹ΋

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No content

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No content

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ͲΜͳઃܭͰ΋

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ϏδωεϩδοΫ (DomainϩδοΫ)

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Domain Error

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Errorͷதͷ Domain ErrorΛ औΓग़͍ͨ͠ (e.g. middleware)

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ઌʹผͷError͕ ൃੜ͍ͯͨ͠৔߹ errors.Cause͸ ࢖͑ͳ͍

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ͦͷ݁Ռ

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if err := f(); err != nil { return errors.Wrap( ErrDomain, err.Error(), ) }

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if err := f(); err != nil { return errors.Wrap( ErrDomain, err.Error(), ) }

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if err := f(); err != nil { return errors.Wrap( ErrDomain, err.Error(), ) }

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if err := f(); err != nil { return errors.Wrap( ErrDomain, err.Error(), ) }

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Stack Trace΋ ফ͑Δ͠ඇৗʹअѱ

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Ͳ͏ʹ͔͍ͨ͠

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࡞ͬͨ

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github.com/nametake/labelerr github.com/nametake/suberr

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github.com/ nametake/labelerr

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Wrap(err error, label string) error Label(err error) string

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Wrap(err error, label string) error Label(err error) string

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Wrap(err error, label string) error Label(err error) string

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Wrap(err error, label string) error Label(err error) string

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Wrap(err error, label string) error Label(err error) string

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Wrap(err error, label string) error Label(err error) string

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err)) third: second: warning: first: cause

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err)) warning

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err)) warning

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = labelerr.Wrap(err, "warning") err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(labelerr.Label(err)) fmt.Println(errors.Cause(err)) cause

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cause first wrap LABEL ERROR second wrap

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cause first wrap LABEL ERROR second wrap

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github.com/ nametake/suberr

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Add(main error, sub error) error SubCause(err error) error

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Add(main error, sub error) error SubCause(err error) error

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Add(main error, sub error) error SubCause(err error) error

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Add(main error, sub error) error SubCause(err error) error

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Add(main error, sub error) error SubCause(err error) error

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Add(main error, sub error) error SubCause(err error) error

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err)) third: second: sub: first: cause

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err)) sub

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err)) sub

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err))

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err := errors.New("cause") err = errors.Wrap(err, "first") err = suberr.Add(err, errors.New("sub")) err = errors.Wrap(err, "second") err = errors.Wrap(err, "third") fmt.Println(err) fmt.Println(suberr.SubCause(err)) fmt.Println(errors.Cause(err)) cause

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cause first wrap second wrap third wrap

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cause first wrap second wrap third wrap SUB ERROR

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಺෦Ͱpkg/errorsΛ ࢖͍ͬͯΔͷͰ Stack Trace΋࢒Δ

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Ҿ਺΋ฦΓ஋΋ Primitiveͳܕ͔͠ ࢖͍ͬͯͳ͍

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FB଴ͬͯ·͢ʂ