Documentation
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Overview ¶
Package retryutils defines common retry and jitter logic.
Package retryutils defines common retry and jitter logic.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func PermanentRetryError ¶
PermanentRetryError returns a new instance of a permanent retry error.
Types ¶
type Driver ¶
type Driver interface {
// Duration calculates the step-specific delay for a given attempt. Excludes
// base duration and jitter, which are applied by the outer retry instance.
Duration(attempt int64) time.Duration
// Check verifies the correctness of any driver-internal parameters.
Check() error
}
driver is the underlying retry driver. determines the difference in behavior between linear/exponential retries.
NOTE: drivers must be stateless. If a stateful driver needs to be implemented in the future, this interface will need to be extended to support safe use of Retry.Clone.
func NewExponentialDriver ¶
NewExponentialDriver creates a new exponential retry driver with the supplied base step value. Resulting retries double their base backoff on each increment.
func NewLinearDriver ¶
NewLinearDriver creates a linear retry driver with the supplied step value. Resulting retries have increase their backoff by a fixed step amount on each increment, with the first retry having a base step amount of zero.
type Jitter ¶
Jitter is a function which applies random jitter to a duration. Used to randomize backoff values. Must be safe for concurrent usage.
func NewFullJitter ¶
func NewFullJitter() Jitter
NewFullJitter builds a new jitter on the range [0,d). Most use-cases are better served by a jitter with a meaningful minimum value, but if the *only* purpose of the jitter is to spread out retries to the greatest extent possible (e.g. when retrying a CompareAndSwap operation), a full jitter may be appropriate.
func NewHalfJitter ¶
func NewHalfJitter() Jitter
NewHalfJitter returns a new jitter on the range [d/2,d). This is a large range and most suitable for jittering things like backoff operations where breaking cycles quickly is a priority.
func NewJitter ¶
func NewJitter() Jitter
NewJitter builds a new default jitter (currently jitters on the range [d/2,d), but this is subject to change).
func NewSeventhJitter ¶
func NewSeventhJitter() Jitter
NewSeventhJitter builds a new jitter on the range [6d/7,d). Prefer smaller jitters such as this when jittering periodic operations (e.g. cert rotation checks) since large jitters result in significantly increased load.
func NewShardedFullJitter ¶
func NewShardedFullJitter() Jitter
NewShardedFullJitter is equivalent to NewFullJitter except that it performs better under high concurrency at the cost of having a larger footprint in memory.
func NewShardedHalfJitter ¶
func NewShardedHalfJitter() Jitter
NewShardedHalfJitter is equivalent to NewHalfJitter except that it performs better under high concurrency at the cost of having a larger footprint in memory.
func NewShardedSeventhJitter ¶
func NewShardedSeventhJitter() Jitter
NewShardedSeventhJitter is equivalent to NewSeventhJitter except that it performs better under high concurrency at the cost of having a larger footprint in memory.
type Linear ¶
type Linear struct {
// LinearConfig is a linear retry config
LinearConfig
// contains filtered or unexported fields
}
Linear is used to calculate retry period that follows the following logic: On the first error there is no delay on the next error, delay is FastLinear on all other errors, delay is SlowLinear
func NewConstant ¶
NewConstant returns a new linear retry with constant interval.
func NewLinear ¶
func NewLinear(cfg LinearConfig) (*Linear, error)
NewLinear returns a new instance of linear retry
func (*Linear) After ¶
After returns channel that fires with timeout defined in Duration method, as a special case if Duration is 0 returns a closed channel
func (*Linear) ResetToDelay ¶
func (r *Linear) ResetToDelay()
ResetToDelay resets retry period and increments the number of attempts.
type LinearConfig ¶
type LinearConfig struct {
// First is a first element of the progression,
// could be 0
First time.Duration
// Step is a step of the progression, can't be 0
Step time.Duration
// Max is a maximum value of the progression,
// can't be 0
Max time.Duration
// Jitter is an optional jitter function to be applied
// to the delay. Note that supplying a jitter means that
// successive calls to Duration may return different results.
Jitter Jitter `json:"-"`
// AutoReset, if greater than zero, causes the linear retry to automatically
// reset after Max * AutoReset has elapsed since the last call to Incr.
AutoReset int64
// Clock to override clock in tests
Clock clockwork.Clock
}
LinearConfig sets up retry configuration using arithmetic progression
func (*LinearConfig) CheckAndSetDefaults ¶
func (c *LinearConfig) CheckAndSetDefaults() error
CheckAndSetDefaults checks and sets defaults
type Retry ¶
type Retry interface {
// Reset resets retry state
Reset()
// Inc increments retry attempt
Inc()
// Duration returns retry duration,
// could be 0
Duration() time.Duration
// After returns time.Time channel
// that fires after Duration delay,
// could fire right away if Duration is 0
After() <-chan time.Time
// Clone creates a copy of this retry in a
// reset state.
Clone() Retry
}
Retry is an interface that provides retry logic
type RetryV2 ¶
type RetryV2 struct {
// RetryV2Config is a linear retry config
RetryV2Config
// contains filtered or unexported fields
}
RetryV2 is used to moderate the rate of retries by applying successively increasing delays. The nature of the progression is determined by the 'Driver', which generates the portion of the delay corresponding to the attempt number (e.g. Exponential(1s) might generate the sequence 0s, 1s, 2s, 4s, 8s, etc). This progression is can be modified through the use of a custom base/start value, jitters, etc.
func NewRetryV2 ¶
func NewRetryV2(cfg RetryV2Config) (*RetryV2, error)
NewRetryV2 returns a new retry instance.
type RetryV2Config ¶
type RetryV2Config struct {
// First is a first element of the progression,
// could be 0
First time.Duration
// Driver generates the underlying progression of delays. Cannot be nil.
Driver Driver
// Max is a maximum value of the progression,
// can't be 0
Max time.Duration
// Jitter is an optional jitter function to be applied
// to the delay. Note that supplying a jitter means that
// successive calls to Duration may return different results.
Jitter Jitter `json:"-"`
// AutoReset, if greater than zero, causes the linear retry to automatically
// reset after Max * AutoReset has elapsed since the last call to Incr.
AutoReset int64
// Clock to override clock in tests
Clock clockwork.Clock
}
RetryV2Config sets up retry configuration using arithmetic progression
func (*RetryV2Config) CheckAndSetDefaults ¶
func (c *RetryV2Config) CheckAndSetDefaults() error
CheckAndSetDefaults checks and sets defaults
Source Files