mirror of
https://github.com/Luzifer/go_helpers.git
synced 2024-12-24 13:01:21 +00:00
Add special error to terminate retries immediately
Signed-off-by: Knut Ahlers <knut@ahlers.me>
This commit is contained in:
parent
9dec41b9ea
commit
8991a9232b
3 changed files with 65 additions and 14 deletions
|
@ -1,20 +1,23 @@
|
|||
// Package backoff contains a configurable retry-functionality using
|
||||
// either exponential or constant backoff
|
||||
package backoff
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"time"
|
||||
)
|
||||
|
||||
const (
|
||||
// Default value to use for number of iterations: infinite
|
||||
// DefaultMaxIterations contains the default value to use for number of iterations: infinite
|
||||
DefaultMaxIterations uint64 = 0
|
||||
// Default value to use for maximum iteration time
|
||||
// DefaultMaxIterationTime contains the default value to use for maximum iteration time
|
||||
DefaultMaxIterationTime = 60 * time.Second
|
||||
// Default value to use for maximum execution time: infinite
|
||||
// DefaultMaxTotalTime contains the default value to use for maximum execution time: infinite
|
||||
DefaultMaxTotalTime time.Duration = 0
|
||||
// Default value to use for initial iteration time
|
||||
// DefaultMinIterationTime contains the default value to use for initial iteration time
|
||||
DefaultMinIterationTime = 100 * time.Millisecond
|
||||
// Default multiplier to apply to iteration time after each iteration
|
||||
// DefaultMultipler contains the default multiplier to apply to iteration time after each iteration
|
||||
DefaultMultipler float64 = 1.5
|
||||
)
|
||||
|
||||
|
@ -41,6 +44,12 @@ func NewBackoff() *Backoff {
|
|||
// Retry executes the function and waits for it to end successul or for the
|
||||
// given limites to be reached. The returned error uses Go1.13 wrapping of
|
||||
// errors and can be unwrapped into the error of the function itself.
|
||||
//
|
||||
// To break free from the Retry function ignoring the remaining retries
|
||||
// return an ErrCannotRetry containing the original error. At this
|
||||
// point the ErrCannotRetry will NOT be returned but unwrapped. So
|
||||
// returning NewErrCannotRetry(errors.New("foo")) will give you the
|
||||
// errors.New("foo") as a return value from Retry.
|
||||
func (b Backoff) Retry(f Retryable) error {
|
||||
var (
|
||||
iterations uint64
|
||||
|
@ -55,13 +64,18 @@ func (b Backoff) Retry(f Retryable) error {
|
|||
return nil
|
||||
}
|
||||
|
||||
var ecr ErrCannotRetry
|
||||
if errors.As(err, &ecr) {
|
||||
return ecr.Unwrap()
|
||||
}
|
||||
|
||||
iterations++
|
||||
if b.MaxIterations > 0 && iterations == b.MaxIterations {
|
||||
return fmt.Errorf("Maximum iterations reached: %w", err)
|
||||
return fmt.Errorf("maximum iterations reached: %w", err)
|
||||
}
|
||||
|
||||
if b.MaxTotalTime > 0 && time.Since(start) >= b.MaxTotalTime {
|
||||
return fmt.Errorf("Maximum execution time reached: %w", err)
|
||||
return fmt.Errorf("maximum execution time reached: %w", err)
|
||||
}
|
||||
|
||||
time.Sleep(sleepTime)
|
||||
|
|
|
@ -4,9 +4,22 @@ import (
|
|||
"errors"
|
||||
"testing"
|
||||
"time"
|
||||
|
||||
"github.com/stretchr/testify/assert"
|
||||
)
|
||||
|
||||
var testError = errors.New("Test-Error")
|
||||
var errTestError = errors.New("Test-Error")
|
||||
|
||||
func TestBreakFree(t *testing.T) {
|
||||
var seen int
|
||||
err := NewBackoff().WithMaxIterations(5).Retry(func() error {
|
||||
seen++
|
||||
return NewErrCannotRetry(errTestError)
|
||||
})
|
||||
assert.Error(t, err)
|
||||
assert.Equal(t, 1, seen)
|
||||
assert.Equal(t, errTestError, err)
|
||||
}
|
||||
|
||||
func TestMaxExecutionTime(t *testing.T) {
|
||||
b := NewBackoff()
|
||||
|
@ -17,9 +30,9 @@ func TestMaxExecutionTime(t *testing.T) {
|
|||
b.MinIterationTime = 100 * time.Millisecond
|
||||
b.Multiplier = 1.5
|
||||
|
||||
var start = time.Now()
|
||||
start := time.Now()
|
||||
|
||||
err := b.Retry(func() error { return testError })
|
||||
err := b.Retry(func() error { return errTestError })
|
||||
|
||||
// After 6 iterations the time of 2078.125ms and after 7 iterations
|
||||
// the time of 3217.1875ms should be reached and therefore no further
|
||||
|
@ -41,7 +54,7 @@ func TestMaxIterations(t *testing.T) {
|
|||
|
||||
err := b.Retry(func() error {
|
||||
counter++
|
||||
return testError
|
||||
return errTestError
|
||||
})
|
||||
|
||||
if counter != 5 {
|
||||
|
@ -58,7 +71,6 @@ func TestSuccessfulExecution(t *testing.T) {
|
|||
b.MaxIterations = 5
|
||||
|
||||
err := b.Retry(func() error { return nil })
|
||||
|
||||
if err != nil {
|
||||
t.Errorf("An error was thrown: %s", err)
|
||||
}
|
||||
|
@ -68,9 +80,9 @@ func TestWrappedError(t *testing.T) {
|
|||
b := NewBackoff()
|
||||
b.MaxIterations = 5
|
||||
|
||||
err := b.Retry(func() error { return testError })
|
||||
err := b.Retry(func() error { return errTestError })
|
||||
|
||||
if errors.Unwrap(err) != testError {
|
||||
if errors.Unwrap(err) != errTestError {
|
||||
t.Errorf("Error unwrapping did not yield test error: %v", err)
|
||||
}
|
||||
}
|
||||
|
|
25
backoff/error.go
Normal file
25
backoff/error.go
Normal file
|
@ -0,0 +1,25 @@
|
|||
package backoff
|
||||
|
||||
import "fmt"
|
||||
|
||||
type (
|
||||
// ErrCannotRetry wraps the original error and signals the backoff
|
||||
// should be stopped now as a retry i.e. would be harmful or would
|
||||
// make no sense
|
||||
ErrCannotRetry struct{ inner error }
|
||||
)
|
||||
|
||||
// NewErrCannotRetry wraps the given error into an ErrCannotRetry and
|
||||
// should be used to break from a Retry() function when the retry
|
||||
// should stop immediately
|
||||
func NewErrCannotRetry(err error) error {
|
||||
return ErrCannotRetry{err}
|
||||
}
|
||||
|
||||
func (e ErrCannotRetry) Error() string {
|
||||
return fmt.Sprintf("retry cancelled by error: %s", e.inner.Error())
|
||||
}
|
||||
|
||||
func (e ErrCannotRetry) Unwrap() error {
|
||||
return e.inner
|
||||
}
|
Loading…
Reference in a new issue