tryagain

README

Tryagain

Simple golang module using retry pattern.

Features

• Max retries
• Max time in ms
• Time between retries in ms
• Linear backoff
• Exponential backoff
• Random backoff

Installation

go get github.com/mcoup/tryagain

Usage

Simple try:

url := "https://127.0.0.1"

err := tryagain.Try().
    MaxTries(3).
    MaxTime(400).    // ms
    TimeBetween(50). // ms
    LinearBackoff().
    Do(func() error {
        _, err := http.Get(url)
        if err != nil {
            return err
        }
        return nil
    })

if err != nil {
    fmt.Println(err)
}

// Get https://127.0.0.1: dial tcp 127.0.0.1:443: connect: connection refused
// Get https://127.0.0.1: dial tcp 127.0.0.1:443: connect: connection refused
// Get https://127.0.0.1: dial tcp 127.0.0.1:443: connect: connection refused
// max retries reached

Or reuse:

r := tryagain.
    Try().
    MaxTries(3).
    MaxTime(400).
    TimeBetween(50)

// first
err = r.Do(func() error {
    return fmt.Errorf("an err")
})
if err != nil {
    fmt.Println(err)
}

// second
err = r.Do(func() error {
    return fmt.Errorf("an err")
})
if err != nil {
    fmt.Println(err)
}

Backoff strategies:

// linear
r := tryagain.Try().
    MaxTries(3).
    MaxTime(400).
    TimeBetween(50).
    LinearBackoff()

// exponential
r := tryagain.Try().
    MaxTries(3).
    MaxTime(400).
    TimeBetween(50).
    ExponentialBackoff()

// random
r := tryagain.Try().
    MaxTries(3).
    MaxTime(400).
    TimeBetween(50).
    RandomBackoff()

Contributing

PRs are always welcome.

Why

Quite a few go modules implement some retry mechanism but so far I have not found one that is as straightforward as I would like it to be.

Some references:

• github.com/Rican7/retry
• github.com/avast/retry-go
• github.com/matryer/try

Documentation

Index

• type Errors
  • func (errs Errors) Error() string
• type Retry
  • func Try() *Retry
  • func (r *Retry) Do(f retryableFunc) Errors
  • func (r *Retry) ExponentialBackoff() *Retry
  • func (r *Retry) LinearBackoff() *Retry
  • func (r *Retry) MaxTime(ms int) *Retry
  • func (r *Retry) MaxTries(count int) *Retry
  • func (r *Retry) RandomBackoff() *Retry
  • func (r *Retry) TimeBetween(ms int) *Retry

Types

type Errors

type Errors []error

Errors represents all errors during execution.

func (Errors) Error

func (errs Errors) Error() string

type Retry

type Retry struct {
	// contains filtered or unexported fields
}

Retry represents the retry settings.

func Try

func Try() *Retry

Try creates a new retry of something.

func (*Retry) Do

func (r *Retry) Do(f retryableFunc) Errors

Do executes the function given the retry settings.

func (*Retry) ExponentialBackoff

func (r *Retry) ExponentialBackoff() *Retry

ExponentialBackoff will back off exponentially.

func (*Retry) LinearBackoff

func (r *Retry) LinearBackoff() *Retry

LinearBackoff will back off linearly.

func (*Retry) MaxTime

func (r *Retry) MaxTime(ms int) *Retry

MaxTime sets the max time in miliseconds.

func (*Retry) MaxTries

func (r *Retry) MaxTries(count int) *Retry

MaxTries sets the maximum number of tries.

func (*Retry) RandomBackoff

func (r *Retry) RandomBackoff() *Retry

RandomBackoff will randomly multiply TimeBetween 1 to 10 times.

func (*Retry) TimeBetween

func (r *Retry) TimeBetween(ms int) *Retry

TimeBetween sets the time between tries in miliseconds.