`Wrap(err)` in production

Presented on "Go(Un)Conference（Goあんこ）LT大会 4kg"
https://gounconference.connpass.com/event/99487/

- https://github.com/srvc/fail
- https://github.com/srvc/wraperr
- https://github.com/izumin5210/grapi

Transcript

1. Go(Un)Conference 4kg - @izumin5210 `Wra p ( e r r )` i n pro du ction
2. izumin5210 ‣ Wantedly People ‣ Web Engineer (serverside & frontend) ‣ Gopher & Rubyist
3. `Wrap(err)`
   ͯ͠·͔͢ʁ ࠓ೔
   AWrap(err)A
   ͨ͠ਓʙʁ
   
4. ෮श
   ͳΜͰ
   AWrap(err)A
   ͢Δͷʁ AWrap(err)A
   ͠ͳ͍ͱ͍͚ͳ͍ཧ༝෼͔Δਓʙʁ
   
5. func TestErrors_noWrapStdError(t *testing.T) { err := err1() if err != nil { printError(t, err) } } func err1() error { return stderr() } func stderr() error { return stderrors.New("error!") }
6. func TestErrors_noWrapStdError(t *testing.T) { err := err1() if err != nil { printError(t, err) } } func err1() error { return stderr() } func stderr() error { return stderrors.New("error!") } === RUN TestErrors_noWrapStdError --- PASS: TestErrors_noWrapStdError (0.00s) main.go:16: *** %#v ****************************************** main.go:17: &errors.errorString{s:"error!"} main.go:18: *** %+v ****************************************** main.go:19: error! main.go:20: *** stacktrace *********************************** main.go:20: /go/src/sandbox/main.go:16: main.TestErrors_noWrap main.go:20: /usr/local/go/src/testing/testing.go:777: testing. main.go:20: /usr/local/go/src/runtime/asm_amd64p32.s:968: runt PASS
7. func TestErrors_noWrapStdError(t *testing.T) { err := err1() if err != nil { printError(t, err) } } func err1() error { return stderr() } func stderr() error { return stderrors.New("error!") } === RUN TestErrors_noWrapStdError --- PASS: TestErrors_noWrapStdError (0.00s) main.go:16: *** %#v ****************************************** main.go:17: &errors.errorString{s:"error!"} main.go:18: *** %+v ****************************************** main.go:19: error! main.go:20: *** stacktrace *********************************** main.go:20: /go/src/sandbox/main.go:16: main.TestErrors_noWrap main.go:20: /usr/local/go/src/testing/testing.go:777: testing. main.go:20: /usr/local/go/src/runtime/asm_amd64p32.s:968: runt PASS
8. func TestErrors_noWrapStdError(t *testing.T) { err := err1() if err != nil { printError(t, err) } } func err1() error { return stderr() } func stderr() error { return stderrors.New("error!") } === RUN TestErrors_noWrapStdError --- PASS: TestErrors_noWrapStdError (0.00s) main.go:16: *** %#v ****************************************** main.go:17: &errors.errorString{s:"error!"} main.go:18: *** %+v ****************************************** main.go:19: error! main.go:20: *** stacktrace *********************************** main.go:20: /go/src/sandbox/main.go:16: main.TestErrors_noWrap main.go:20: /usr/local/go/src/testing/testing.go:777: testing. main.go:20: /usr/local/go/src/runtime/asm_amd64p32.s:968: runt PASS ΤϥʔΛฦͨؔ͠਺ͷ಺ଆͷελοΫτϨʔε͕ͱΕͳ͍
9. func TestErrors_Wrap(t *testing.T) { err := err2() if err != nil { printError(t, err) } } func err2() error { err := stderr() return pkgerrors.Wrap(err, "wrapped") } func pkgerr() error { return pkgerrors.New("error!") }
10. func TestErrors_Wrap(t *testing.T) { err := err2() if err != nil { printError(t, err) } } func err2() error { err := stderr() return pkgerrors.Wrap(err, "wrapped") } func pkgerr() error { return pkgerrors.New("error!") } === RUN TestErrors_Wrap --- PASS: TestErrors_Wrap (0.00s) main.go:47: *** %#v **************************************** main.go:48: wrapped: error! main.go:49: *** %+v **************************************** main.go:50: error! wrapped main.err2 /go/src/sandbox/main.go:30 main.TestErrors_Wrap /go/src/sandbox/main.go:21 testing.tRunner /usr/local/go/src/testing/testing.go:777 runtime.goexit /usr/local/go/src/runtime/asm_amd64p32.s:968 main.go:51: *** stacktrace ********************************* main.go:51: /go/src/sandbox/main.go:24: main.TestErrors_Wrap main.go:51: /usr/local/go/src/testing/testing.go:777: testin main.go:51: /usr/local/go/src/runtime/asm_amd64p32.s:968: ru PASS
11. func TestErrors_Wrap(t *testing.T) { err := err2() if err != nil { printError(t, err) } } func err2() error { err := stderr() return pkgerrors.Wrap(err, "wrapped") } func pkgerr() error { return pkgerrors.New("error!") } === RUN TestErrors_Wrap --- PASS: TestErrors_Wrap (0.00s) main.go:47: *** %#v **************************************** main.go:48: wrapped: error! main.go:49: *** %+v **************************************** main.go:50: error! wrapped main.err2 /go/src/sandbox/main.go:30 main.TestErrors_Wrap /go/src/sandbox/main.go:21 testing.tRunner /usr/local/go/src/testing/testing.go:777 runtime.goexit /usr/local/go/src/runtime/asm_amd64p32.s:968 main.go:51: *** stacktrace ********************************* main.go:51: /go/src/sandbox/main.go:24: main.TestErrors_Wrap main.go:51: /usr/local/go/src/testing/testing.go:777: testin main.go:51: /usr/local/go/src/runtime/asm_amd64p32.s:968: ru PASS
12. func TestErrors_Wrap(t *testing.T) { err := err2() if err != nil { printError(t, err) } } func err2() error { err := stderr() return pkgerrors.Wrap(err, "wrapped") } func pkgerr() error { return pkgerrors.New("error!") } === RUN TestErrors_Wrap --- PASS: TestErrors_Wrap (0.00s) main.go:47: *** %#v **************************************** main.go:48: wrapped: error! main.go:49: *** %+v **************************************** main.go:50: error! wrapped main.err2 /go/src/sandbox/main.go:30 main.TestErrors_Wrap /go/src/sandbox/main.go:21 testing.tRunner /usr/local/go/src/testing/testing.go:777 runtime.goexit /usr/local/go/src/runtime/asm_amd64p32.s:968 main.go:51: *** stacktrace ********************************* main.go:51: /go/src/sandbox/main.go:24: main.TestErrors_Wrap main.go:51: /usr/local/go/src/testing/testing.go:777: testin main.go:51: /usr/local/go/src/runtime/asm_amd64p32.s:968: ru PASS ࠷ॳʹ
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13. func main() { err := auth() if err != nil { fmt.Fprintln(os.Stderr, errors.Wrap(err, "failed to authorization")) } } func auth() error { _, err := getUser() if err != nil { return errors.Wrap(err, "failed to get user") } return nil } func getUser() (*User, error) { return nil, errors.New("not found error") }
14. func main() { err := auth() if err != nil { fmt.Fprintln(os.Stderr, errors.Wrap(err, "failed to authorization")) } } func auth() error { _, err := getUser() if err != nil { return errors.Wrap(err, "failed to get user") } return nil } func getUser() (*User, error) { return nil, errors.New("not found error") } failed to authorization: failed to get user: not found error
15. func main() { err := auth() if err != nil { fmt.Fprintln(os.Stderr, errors.Wrap(err, "failed to authorization")) } } func auth() error { _, err := getUser() if err != nil { return errors.Wrap(err, "failed to get user") } return nil } func getUser() (*User, error) { return nil, errors.New("not found error") } failed to authorization: failed to get user: not found error Τϥʔϝοηʔδ΋ͲΜͲΜ
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21. Go(Un)Conference 4kg - @izumin5210 `Wra p ( e r r )` i n p rod uct ion
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25. func (r *repo) GetUser(ctx context.Context, id uint64) (*User, user, err := r.db.GetContext(ctx, &user, "...", id) if err == sql.ErrNoRows { return nil, fail.Wrap( err, fail.WithCode(appx.NotFound), fail.WithIgnorable(), ) } if err != nil { return nil, fail.Wrap(err, fail.WithCode(appx.Internal)) } // snip. } ‣ AGBJM8JUI*HOPSBCMF A
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