/
arbiter.go
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/
arbiter.go
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/*
* Copyright 2018-2022, CS Systemes d'Information, http://csgroup.eu
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package retry
import (
"time"
"github.com/CS-SI/SafeScale/v21/lib/utils/fail"
"github.com/CS-SI/SafeScale/v21/lib/utils/retry/enums/verdict"
"github.com/CS-SI/SafeScale/v21/lib/utils/temporal"
)
// Arbiter sleeps or selects any amount of time for each attempt.
type Arbiter func(Try) (verdict.Enum, fail.Error)
// DefaultArbiter allows 10 retries, with a maximum duration of 30 seconds
var DefaultArbiter = PrevailDone(Max(10), Timeout(temporal.BigDelay()))
// CommonArbiter allows between 5 and 10 retries
var CommonArbiter = PrevailDone(Min(5), Max(10))
// ArbiterAggregator this type helps easy replacement of PrevailDone
type ArbiterAggregator func(arbiters ...Arbiter) Arbiter
// PrevailRetry aggregates verdicts from Arbiters for a try:
// - Returns Abort and the error as soon as an arbiter decides for an Abort.
// - If at least one arbiter returns Retry without any Abort from others, returns Retry with nil error.
// - Otherwise returns Done with nil error.
func PrevailRetry(arbiters ...Arbiter) Arbiter {
return func(t Try) (verdict.Enum, fail.Error) {
final := verdict.Done
for _, a := range arbiters {
v, err := a(t)
switch v {
case verdict.Retry:
final = verdict.Retry
case verdict.Abort:
return verdict.Abort, err
case verdict.Undecided:
continue
}
}
return final, nil
}
}
// PrevailDone aggregates verdicts from Arbiters for a try:
// - Returns Abort and the error as soon as an Abort is decided.
// - If at least one arbiter return Done without any Abort, returns Done with nil error.
// - Otherwise returns Retry with nil error.
func PrevailDone(arbiters ...Arbiter) Arbiter {
return func(t Try) (verdict.Enum, fail.Error) {
final := verdict.Retry
for _, a := range arbiters {
v, err := a(t)
switch v {
case verdict.Done:
final = verdict.Done
case verdict.Abort:
return verdict.Abort, err
case verdict.Undecided:
continue
}
}
return final, nil
}
}
// Unsuccessful returns Retry when the try produced an error; returns Done otherwise
func Unsuccessful() Arbiter {
return func(t Try) (verdict.Enum, fail.Error) {
if t.Err != nil {
switch cerr := t.Err.(type) {
case *ErrStopRetry:
return verdict.Abort, cerr
case *fail.ErrRuntimePanic:
return verdict.Abort, cerr
default:
return verdict.Retry, fail.ConvertError(t.Err)
}
}
return verdict.Done, nil
}
}
func OrArbiter(arbiters ...Arbiter) Arbiter {
return func(t Try) (verdict.Enum, fail.Error) {
final := verdict.Retry
var lastErr fail.Error
for _, a := range arbiters {
v, err := a(t)
switch v {
case verdict.Done:
return verdict.Done, nil
case verdict.Abort:
final = verdict.Abort
lastErr = err
case verdict.Undecided:
continue
}
}
return final, lastErr
}
}
// Successful returns Retry when the try produced no error; returns Done otherwise
func Successful() Arbiter {
return func(t Try) (verdict.Enum, fail.Error) {
if t.Err != nil {
return verdict.Done, fail.ConvertError(t.Err)
}
return verdict.Retry, nil
}
}
// Timeout returns Abort after a duration of time passes since the first try, while the try returns an error; returns Done if no error occurred during the last try
func Timeout(limit time.Duration) Arbiter {
return func(t Try) (verdict.Enum, fail.Error) {
if t.Err != nil {
switch cerr := t.Err.(type) {
case *ErrStopRetry:
return verdict.Abort, cerr
case *fail.ErrRuntimePanic:
return verdict.Abort, cerr
default:
if time.Since(t.Start) >= limit {
return verdict.Abort, TimeoutError(t.Err, limit, time.Since(t.Start))
}
return verdict.Undecided, fail.ConvertError(t.Err)
}
}
if time.Since(t.Start) >= limit {
return verdict.Abort, TimeoutError(t.Err, limit, time.Since(t.Start))
}
return verdict.Undecided, nil
}
}
// Max errors after a limited number of tries, while the last try returned an error
func Max(limit uint) Arbiter {
if limit == 0 {
panic("invalid Max configuration")
}
return func(t Try) (verdict.Enum, fail.Error) {
if t.Err != nil {
switch cerr := t.Err.(type) {
case *ErrStopRetry:
return verdict.Abort, cerr
case *fail.ErrRuntimePanic:
return verdict.Abort, cerr
default:
if t.Count > limit { // last try is also good
return verdict.Abort, LimitError(t.Err, limit)
}
return verdict.Retry, fail.ConvertError(t.Err)
}
}
return verdict.Undecided, nil
}
}
// Min errors after a limited number of tries, while the last try returned an error
func Min(limit uint) Arbiter {
if limit == 0 {
panic("invalid Min configuration")
}
return func(t Try) (verdict.Enum, fail.Error) {
if t.Err != nil {
switch cerr := t.Err.(type) {
case *ErrStopRetry:
return verdict.Abort, cerr
case *fail.ErrRuntimePanic:
return verdict.Abort, cerr
default:
if t.Count < limit { // last try is also good
return verdict.Retry, fail.ConvertError(t.Err)
}
return verdict.Undecided, fail.ConvertError(t.Err)
}
}
return verdict.Undecided, nil
}
}