Documentation
¶
Overview ¶
Package nopanic provides a utility to wrap function to prevent any panics from escaping. If a panic occurs in the callback, the value of the panic will be converted to an error, and returned normally.
This packages has the opinion that you should not panic with arbitrary values. The argument to panic should either be a string, or a value that implements the error interface.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Unwrap ¶
Unwrap will panic if err is an instance of PanicError, otherwise it will return the error unmodified.
Example ¶
package main
import (
"fmt"
"bitbucket.org/rj/goey/internal/nopanic"
)
func main() {
defer func() {
if r := recover(); r != nil {
fmt.Println("Recovered...")
fmt.Println(r)
}
}()
// Wrap the callback to prevent the escape of any panics.
err := nopanic.Unwrap(nopanic.Wrap(func() error {
// Bad things sometimes happen to good people...
panic("No luck!")
}))
// Check for errors.
if err != nil {
// Otherwise, continue with normal error handling.
fmt.Println("Normal error...")
fmt.Println(err)
}
// Output (not reproducible because of stack trace):
// Recovered...
// No luck!
//
// goroutine 1 [running]:
// runtime/debug.Stack(0x0, 0x0, 0xc04202b9c8)
// C:/Go/src/runtime/debug/stack.go:24 +0x80
// bitbucket.org/rj/goey/internal/nopanic.New(0x5190c0, 0xc04200cf30, 0xc04200cf30, 0xc04202ba78, 0x40ef6c, 0xc04200cf30)
// bitbucket.org/rj/goey/internal/nopanic/_test/_obj_test/nopanic.go:35 +0x33
// bitbucket.org/rj/goey/internal/nopanic.Wrap.func1(0xc04202bb58)
// bitbucket.org/rj/goey/internal/nopanic/_test/_obj_test/nopanic.go:45 +0x71
// panic(0x5190c0, 0xc04200cf30)
// C:/Go/src/runtime/panic.go:489 +0x2dd
// ... several frame omitted ...
// main.main()
// bitbucket.org/rj/goey/internal/nopanic/_test/_testmain.go:98 +0x201
}
Output:
func Wrap ¶
Wrap ensures that no panics escape. Action will be called, and if it returns normally, its return value will be returned. However, if action panics, the panic will be converted to an error, and will be returned.
Example ¶
package main
import (
"errors"
"fmt"
"bitbucket.org/rj/goey/internal/nopanic"
)
func main() {
myerr := errors.New("No luck!")
// Wrap the callback to prevent the escape of any panics.
err := nopanic.Wrap(func() error {
return myerr
})
// Check for errors.
if err != nil {
// Print the
fmt.Println(err)
}
}
Output: No luck!
Example (Panic) ¶
package main
import (
"fmt"
"bitbucket.org/rj/goey/internal/nopanic"
)
func main() {
defer func() {
if r := recover(); r != nil {
fmt.Println("Recovered...")
fmt.Println(r)
}
}()
// Wrap the callback to prevent the escape of any panics.
err := nopanic.Wrap(func() error {
// Bad things sometimes happen to good people...
panic("No luck!")
})
// Check for errors.
if err != nil {
// If this is a PanicError, we rethrow.
if value, ok := err.(nopanic.PanicError); ok {
panic(value.Value())
}
// Otherwise, continue with normal error handling.
fmt.Println("Normal error...")
fmt.Println(err)
}
}
Output: Recovered... No luck!
Types ¶
type PanicError ¶
type PanicError struct {
// contains filtered or unexported fields
}
PanicError represents a panic that occurred.
func New ¶
func New(value interface{}) PanicError
New wraps the value returned by recover into a PanicError.
func (PanicError) Error ¶
func (pe PanicError) Error() string
Error returns a description of the error.
func (PanicError) Stack ¶
func (pe PanicError) Stack() string
Stack returns a formatted stack trace of the goroutine that originally paniced.
func (PanicError) Value ¶
func (pe PanicError) Value() interface{}
Value returns the value returned by recover after a panic.
Source Files