V2 (#61)

* [Go 1.21] Replace 'any' / 'interface{}' implementation with Generics (#54)

* gobreaker/v2: added generics implementation in v2 module

* gobreaker/v2/example: added v2 example

* gobreaker/README: updated README.md

* fixup! gobreaker/v2: added generics implementation in v2 module

---------

Co-authored-by: Yoshiyuki Mineo <[email protected]>

* Do refactoring

* Update README.md for v2

* Update README.md for v2

* Update README.md for v2

---------

Co-authored-by: Mario Salgado <[email protected]>

README.md

@@ -9,17 +9,18 @@ Installation
 ------------
 
 ```
-go get github.com/sony/gobreaker
+go get github.com/sony/gobreaker/v2
 ```
 
 Usage
 -----
 
 The struct `CircuitBreaker` is a state machine to prevent sending requests that are likely to fail.
 The function `NewCircuitBreaker` creates a new `CircuitBreaker`.
+The type parameter `T` specifies the return type of requests.
 
 ```go
-func NewCircuitBreaker(st Settings) *CircuitBreaker
+func NewCircuitBreaker[T any](st Settings) *CircuitBreaker[T]
 ```
 
 You can configure `CircuitBreaker` by the struct `Settings`:
@@ -81,7 +82,7 @@ on the change of the state or at the closed-state intervals.
 `CircuitBreaker` can wrap any function to send a request:
 
 ```go
-func (cb *CircuitBreaker) Execute(req func() (interface{}, error)) (interface{}, error)
+func (cb *CircuitBreaker[T]) Execute(req func() (T, error)) (T, error)
 ```
 
 The method `Execute` runs the given request if `CircuitBreaker` accepts it.
@@ -94,17 +95,17 @@ Example
 -------
 
 ```go
-var cb *breaker.CircuitBreaker
+var cb *gobreaker.CircuitBreaker[[]byte]
 
 func Get(url string) ([]byte, error) {
-	body, err := cb.Execute(func() (interface{}, error) {
+	body, err := cb.Execute(func() ([]byte, error) {
 		resp, err := http.Get(url)
 		if err != nil {
 			return nil, err
 		}
 
 		defer resp.Body.Close()
-		body, err := ioutil.ReadAll(resp.Body)
+		body, err := io.ReadAll(resp.Body)
 		if err != nil {
 			return nil, err
 		}
@@ -115,11 +116,11 @@ func Get(url string) ([]byte, error) {
 		return nil, err
 	}
 
-	return body.([]byte), nil
+	return body, nil
 }
 ```
 
-See [example](https://github.com/sony/gobreaker/blob/master/example) for details.
+See [example](https://github.com/sony/gobreaker/blob/master/v2/example) for details.
 
 License
 -------

v2/example/http_breaker.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+
+	"github.com/sony/gobreaker/v2"
+)
+
+var cb *gobreaker.CircuitBreaker[[]byte]
+
+func init() {
+	var st gobreaker.Settings
+	st.Name = "HTTP GET"
+	st.ReadyToTrip = func(counts gobreaker.Counts) bool {
+		failureRatio := float64(counts.TotalFailures) / float64(counts.Requests)
+		return counts.Requests >= 3 && failureRatio >= 0.6
+	}
+
+	cb = gobreaker.NewCircuitBreaker[[]byte](st)
+}
+
+// Get wraps http.Get in CircuitBreaker.
+func Get(url string) ([]byte, error) {
+	body, err := cb.Execute(func() ([]byte, error) {
+		resp, err := http.Get(url)
+		if err != nil {
+			return nil, err
+		}
+
+		defer resp.Body.Close()
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+
+		return body, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return body, nil
+}
+
+func main() {
+	body, err := Get("http://www.google.com/robots.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println(string(body))
+}

v2/go.mod

@@ -0,0 +1,11 @@
+module github.com/sony/gobreaker/v2
+
+go 1.21
+
+require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

v2/go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=