Merge pull request #3 from avast/retry_if

retryIf

Author: JaSei

README.md

@@ -22,7 +22,7 @@ http get with retry:
     url := "http://example.com"
     var body []byte
 
-    err := retry.Retry(
+    err := retry.Do(
     	func() error {
     		resp, err := http.Get(url)
     		if err != nil {
@@ -61,29 +61,23 @@ slightly similar as this package, don't have 'simple' `Retry` method
 * [matryer/try](https://github.com/matryer/try) - very popular package,
 nonintuitive interface (for me)
 
-## Usage
 
-#### func  Retry
+### BREAKING CHANGES
 
-```go
-func Retry(retryableFunction Retryable) error
-```
-Retry - simple retry
+0.3.0 -> 1.0.0
 
-#### func  RetryCustom
+* `retry.Retry` function are changed to `retry.Do` function
 
-```go
-func RetryCustom(retryableFunction Retryable, onRetryFunction OnRetry, opts RetryOpts) error
-```
-RetryCustom - the most customizable retry is possible set OnRetry function
-callback which are called each retry
+* `retry.RetryCustom` (OnRetry) and `retry.RetryCustomWithOpts` functions are
+now implement via functions produces Options (aka `retry.OnRetryFunction`)
+
+## Usage
 
-#### func  RetryWithOpts
+#### func  Do
 
 ```go
-func RetryWithOpts(retryableFunction Retryable, opts RetryOpts) error
+func Do(retryableFunc RetryableFunc, opts ...Option) error
 ```
-RetryWithOpts - customizable retry via RetryOpts
 
 #### type Error
 
@@ -111,57 +105,96 @@ implementation of the `errwrap.Wrapper` interface in package
 [errwrap](https://github.com/hashicorp/errwrap) so that `retry.Error` can be
 used with that library.
 
-#### type OnRetry
+#### type OnRetryFunc
 
 ```go
-type OnRetry func(n uint, err error)
+type OnRetryFunc func(n uint, err error)
 ```
 
-Function signature of OnRetry function n = count of tries
+Function signature of OnRetry function n = count of attempts
 
-#### type RetryOpts
+#### type Option
 
 ```go
-type RetryOpts struct {
-}
+type Option func(*config)
 ```
 
-Struct for configure retry tries - count of tries delay - waiting time units -
-waiting time unit (for tests purpose)
+Option represents an option for retry.
 
-#### func  NewRetryOpts
+#### func  Attempts
 
 ```go
-func NewRetryOpts() RetryOpts
+func Attempts(attempts uint) Option
 ```
-Create new RetryOpts struct with default values default tries are 10 default
-delay are 1e5 default units are microsecond
+Attempts set count of retry default is 10
 
-#### func (RetryOpts) Delay
+#### func  Delay
 
 ```go
-func (opts RetryOpts) Delay(delay time.Duration) RetryOpts
+func Delay(delay time.Duration) Option
 ```
-Delay setter
+Delay set delay between retry default are 1e5 units
 
-#### func (RetryOpts) Tries
+#### func  OnRetry
 
 ```go
-func (opts RetryOpts) Tries(tries uint) RetryOpts
+func OnRetry(onRetry OnRetryFunc) Option
 ```
-Tries setter
+OnRetry function callback are called each retry
 
-#### func (RetryOpts) Units
+log each retry example:
+
+    retry.Do(
+    	func() error {
+    		return errors.New("some error")
+    	},
+    	retry.OnRetry(func(n unit, err error) {
+    		log.Printf("#%d: %s\n", n, err)
+    	}),
+    )
+
+#### func  RetryIf
 
 ```go
-func (opts RetryOpts) Units(timeUnit time.Duration) RetryOpts
+func RetryIf(retryIf RetryIfFunc) Option
 ```
-Units setter
+RetryIf controls whether a retry should be attempted after an error (assuming
+there are any retry attempts remaining)
+
+skip retry if special error example:
+
+    retry.Do(
+    	func() error {
+    		return errors.New("special error")
+    	},
+    	retry.RetryIf(func(err error) bool {
+    		if err.Error() == "special error" {
+    			return false
+    		}
+    		return true
+    	})
+    )
+
+#### func  Units
+
+```go
+func Units(units time.Duration) Option
+```
+Units set unit of delay (probably only for tests purpose) default are
+microsecond
+
+#### type RetryIfFunc
+
+```go
+type RetryIfFunc func(error) bool
+```
+
+Function signature of retry if function
 
-#### type Retryable
+#### type RetryableFunc
 
 ```go
-type Retryable func() error
+type RetryableFunc func() error
 ```
 
 Function signature of retryable function

VERSION

@@ -1 +1 @@
-0.3.0
+1.0.0

examples/http_get_test.go

@@ -13,7 +13,7 @@ func TestGet(t *testing.T) {
 	url := "http://example.com"
 	var body []byte
 
-	err := retry.Retry(
+	err := retry.Do(
 		func() error {
 			resp, err := http.Get(url)
 

options.go

@@ -0,0 +1,87 @@
+package retry
+
+import (
+	"time"
+)
+
+// Function signature of retry if function
+type RetryIfFunc func(error) bool
+
+// Function signature of OnRetry function
+// n = count of attempts
+type OnRetryFunc func(n uint, err error)
+
+type config struct {
+	attempts uint
+	delay    time.Duration
+	units    time.Duration
+	onRetry  OnRetryFunc
+	retryIf  RetryIfFunc
+}
+
+// Option represents an option for retry.
+type Option func(*config)
+
+// Attempts set count of retry
+// default is 10
+func Attempts(attempts uint) Option {
+	return func(c *config) {
+		c.attempts = attempts
+	}
+}
+
+// Delay set delay between retry
+// default are 1e5 units
+func Delay(delay time.Duration) Option {
+	return func(c *config) {
+		c.delay = delay
+	}
+}
+
+// Units set unit of delay (probably only for tests purpose)
+// default are microsecond
+func Units(units time.Duration) Option {
+	return func(c *config) {
+		c.units = units
+	}
+}
+
+// OnRetry function callback are called each retry
+//
+// log each retry example:
+//
+//	retry.Do(
+//		func() error {
+//			return errors.New("some error")
+//		},
+//		retry.OnRetry(func(n unit, err error) {
+//			log.Printf("#%d: %s\n", n, err)
+//		}),
+//	)
+func OnRetry(onRetry OnRetryFunc) Option {
+	return func(c *config) {
+		c.onRetry = onRetry
+	}
+}
+
+// RetryIf controls whether a retry should be attempted after an error
+// (assuming there are any retry attempts remaining)
+//
+// skip retry if special error example:
+//
+//	retry.Do(
+//		func() error {
+//			return errors.New("special error")
+//		},
+//		retry.RetryIf(func(err error) bool {
+//			if err.Error() == "special error" {
+//				return false
+//			}
+//			return true
+//		})
+//	)
+func RetryIf(retryIf RetryIfFunc) Option {
+	return func(c *config) {
+		c.retryIf = retryIf
+	}
+}

retry.go

@@ -10,7 +10,7 @@ http get with retry:
 	url := "http://example.com"
 	var body []byte
 
-	err := retry.Retry(
+	err := retry.Do(
 		func() error {
 			resp, err := http.Get(url)
 			if err != nil {
@@ -43,6 +43,15 @@ SEE ALSO
 
 * [matryer/try](https://github.com/matryer/try) - very popular package, nonintuitive interface (for me)
 
+BREAKING CHANGES
+
+0.3.0 -> 1.0.0
+
+* `retry.Retry` function are changed to `retry.Do` function
+
+* `retry.RetryCustom` (OnRetry) and `retry.RetryCustomWithOpts` functions are now implement via functions produces Options (aka `retry.OnRetry`)
+
+
 */
 package retry
 
@@ -53,39 +62,39 @@ import (
 )
 
 // Function signature of retryable function
-type Retryable func() error
+type RetryableFunc func() error
 
-// Function signature of OnRetry function
-// n = count of tries
-type OnRetry func(n uint, err error)
-
-// Retry - simple retry
-func Retry(retryableFunction Retryable) error {
-	return RetryWithOpts(retryableFunction, NewRetryOpts())
-}
+func Do(retryableFunc RetryableFunc, opts ...Option) error {
+	var n uint
 
-// RetryWithOpts - customizable retry via RetryOpts
-func RetryWithOpts(retryableFunction Retryable, opts RetryOpts) error {
-	return RetryCustom(retryableFunction, func(n uint, err error) {}, opts)
-}
+	//default
+	config := &config{
+		attempts: 10,
+		delay:    1e5,
+		onRetry:  func(n uint, err error) {},
+		retryIf:  func(err error) bool { return true },
+	}
 
-// RetryCustom - the most customizable retry
-// is possible set OnRetry function callback
-// which are called each retry
-func RetryCustom(retryableFunction Retryable, onRetryFunction OnRetry, opts RetryOpts) error {
-	var n uint
+	//apply opts
+	for _, opt := range opts {
+		opt(config)
+	}
 
-	errorLog := make(Error, opts.tries)
+	errorLog := make(Error, config.attempts)
 
-	for n < opts.tries {
-		err := retryableFunction()
+	for n < config.attempts {
+		err := retryableFunc()
 
 		if err != nil {
-			onRetryFunction(n, err)
+			config.onRetry(n, err)
 			errorLog[n] = err
 
-			delayTime := opts.delay * (1 << (n - 1))
-			time.Sleep((time.Duration)(delayTime) * opts.units)
+			if !config.retryIf(err) {
+				break
+			}
+
+			delayTime := config.delay * (1 << (n - 1))
+			time.Sleep((time.Duration)(delayTime) * config.units)
 		} else {
 			return nil
 		}
@@ -102,12 +111,24 @@ type Error []error
 // Error method return string representation of Error
 // It is an implementation of error interface
 func (e Error) Error() string {
-	logWithNumber := make([]string, len(e))
+	logWithNumber := make([]string, lenWithoutNil(e))
 	for i, l := range e {
-		logWithNumber[i] = fmt.Sprintf("#%d: %s", i+1, l.Error())
+		if l != nil {
+			logWithNumber[i] = fmt.Sprintf("#%d: %s", i+1, l.Error())
+		}
+	}
+
+	return fmt.Sprintf("All attempts fail:\n%s", strings.Join(logWithNumber, "\n"))
+}
+
+func lenWithoutNil(e Error) (count int) {
+	for _, v := range e {
+		if v != nil {
+			count++
+		}
 	}
 
-	return fmt.Sprintf("All retries fail:\n%s", strings.Join(logWithNumber, "\n"))
+	return
 }
 
 // WrappedErrors returns the list of errors that this Error is wrapping.