func Example_stringer() {
err0 := errors.New("err0")
err1 := errors.Wrap(err0, "err1")
err2 := func() error { return errors.Wrap(err1, "err2") }()
err3 := func() error { return errors.Wrap(err2, "err3") }()
fmt.Println(err3) // fmt.Println(err3.Error())
fmt.Println(err3.(fmt.Stringer).String()) // print json string
}
func Example_wraped() {
err0 := errors.New("err0")
err1 := errors.Wrap(err0, "err1")
err2 := func() error { return errors.Wrap(err1, "err2") }()
err3 := func() error { return errors.Wrap(err2, "err3") }()
fmt.Println(err3)
for j, x := range err3.(errors.Error).Caller() {
if j == 0 {
// Closure path is different between Go1.4 and Go1.5
ver := runtime.Version()
if strings.HasPrefix(ver, "go1.3") || strings.HasPrefix(ver, "go1.4") {
if x.FuncName == "github.com/chai2010/errors_test.func" {
x.FuncName = "github.com/chai2010/errors_test.Example_wraped.func"
}
}
}
fmt.Printf("caller:%d: %s\n", j, x.FuncName)
}
for i, err := range err3.(errors.Error).Wraped() {
fmt.Printf("wraped:%d: %v\n", i, err)
for j, x := range err.(errors.Error).Caller() {
fmt.Printf(" caller:%d: %s\n", j, x.FuncName)
}
}
// Output:
// err3 -> {err2 -> {err1 -> {err0}}}
// caller:0: github.com/chai2010/errors_test.Example_wraped.func
// caller:1: github.com/chai2010/errors_test.Example_wraped
// caller:2: testing.runExample
// caller:3: testing.RunExamples
// caller:4: testing.(*M).Run
// caller:5: main.main
// wraped:0: err2 -> {err1 -> {err0}}
// caller:0: github.com/chai2010/errors_test.Example_wraped.func
// caller:1: github.com/chai2010/errors_test.Example_wraped
// caller:2: testing.runExample
// caller:3: testing.RunExamples
// caller:4: testing.(*M).Run
// caller:5: main.main
// wraped:1: err1 -> {err0}
// caller:0: github.com/chai2010/errors_test.Example_wraped
// caller:1: testing.runExample
// caller:2: testing.RunExamples
// caller:3: testing.(*M).Run
// caller:4: main.main
// wraped:2: err0
// caller:0: github.com/chai2010/errors_test.Example_wraped
// caller:1: testing.runExample
// caller:2: testing.RunExamples
// caller:3: testing.(*M).Run
// caller:4: main.main
}
func Example_caller() {
err := errors.New("error message")
fmt.Println(err)
for i, x := range err.(errors.Error).Caller() {
fmt.Printf("caller:%d: %s\n", i, x.FuncName)
}
// Output:
// error message
// caller:0: github.com/chai2010/errors_test.Example_caller
// caller:1: testing.runExample
// caller:2: testing.RunExamples
// caller:3: testing.(*M).Run
// caller:4: main.main
}
func Example() {
err0 := errors.New("err0")
err1 := errors.Wrap(err0, "err1")
err2 := func() error { return errors.Wrap(err1, "err2") }()
err3 := func() error { return errors.Wrap(err2, "err3") }()
fmt.Println(err0)
fmt.Println(err1)
fmt.Println(err2)
fmt.Println(err3)
// Output:
// err0
// err1 -> {err0}
// err2 -> {err1 -> {err0}}
// err3 -> {err2 -> {err1 -> {err0}}}
}
func Example_wraped() {
err0 := errors.New("err0")
err1 := errors.Wrap(err0, "err1")
err2 := func() error { return errors.Wrap(err1, "err2") }()
err3 := func() error { return errors.Wrap(err2, "err3") }()
fmt.Println(err3)
for j, x := range err3.(errors.Error).Caller() {
fmt.Printf("caller:%d: %s\n", j, x.FuncName)
}
for i, err := range err3.(errors.Error).Wraped() {
fmt.Printf("wraped:%d: %v\n", i, err)
for j, x := range err.(errors.Error).Caller() {
fmt.Printf(" caller:%d: %s\n", j, x.FuncName)
}
}
// Output:
// err3 -> {err2 -> {err1 -> {err0}}}
// caller:0: github.com/chai2010/errors_test.Example_wraped.func2
// caller:1: github.com/chai2010/errors_test.Example_wraped
// caller:2: testing.runExample
// caller:3: testing.RunExamples
// caller:4: testing.(*M).Run
// caller:5: main.main
// wraped:0: err2 -> {err1 -> {err0}}
// caller:0: github.com/chai2010/errors_test.Example_wraped.func1
// caller:1: github.com/chai2010/errors_test.Example_wraped
// caller:2: testing.runExample
// caller:3: testing.RunExamples
// caller:4: testing.(*M).Run
// caller:5: main.main
// wraped:1: err1 -> {err0}
// caller:0: github.com/chai2010/errors_test.Example_wraped
// caller:1: testing.runExample
// caller:2: testing.RunExamples
// caller:3: testing.(*M).Run
// caller:4: main.main
// wraped:2: err0
// caller:0: github.com/chai2010/errors_test.Example_wraped
// caller:1: testing.runExample
// caller:2: testing.RunExamples
// caller:3: testing.(*M).Run
// caller:4: main.main
}
func Example_json() {
err0 := errors.New("err0")
err1 := errors.Wrap(err0, "err1")
err2 := func() error { return errors.Wrap(err1, "err2") }()
err3 := func() error { return errors.Wrap(err2, "err3") }()
err3JsonData, err := json.Marshal(err3)
if err != nil {
log.Fatal(err)
}
errx := errors.MustFromJson(string(err3JsonData))
if !reflect.DeepEqual(errx, err3) {
log.Fatal("errors_test.Example_json:", errx, "!=", err3)
}
fmt.Println("done")
// Output:
// done
}