/
main.go
86 lines (74 loc) · 1.99 KB
/
main.go
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/*
Copyright (c) 2022 - Present. Blend Labs, Inc. All rights reserved
Use of this source code is governed by a MIT license that can be found in the LICENSE file.
*/
package main
import (
"context"
"encoding/json"
"flag"
"fmt"
"math/rand"
"net/http"
"net/http/httptest"
"time"
"github.com/blend/go-sdk/breaker"
"github.com/blend/go-sdk/ex"
"github.com/blend/go-sdk/r2"
"github.com/blend/go-sdk/webutil"
)
// Result is a json thingy.
type Result struct {
ID int `json:"id"`
Name string `json:"name"`
}
func createUpstreamCaller(opts ...r2.Option) breaker.Actioner {
return breaker.ActionerFunc(func(ctx context.Context, args interface{}) (interface{}, error) {
res, err := r2.New(args.(string), opts...).Do()
if err != nil {
return nil, err
}
defer res.Body.Close()
if res.StatusCode >= 300 {
return nil, fmt.Errorf("non 200 status code returned from remote")
}
var result Result
json.NewDecoder(res.Body).Decode(&result)
return result, nil
})
}
var (
flagNumCalls = flag.Int("num-calls", 1024, "The number of calls")
)
func init() {
flag.Parse()
}
func main() {
mockServer := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
if rand.Float64() > 0.5 {
http.Error(rw, "should fail", http.StatusInternalServerError)
return
}
webutil.WriteJSON(rw, http.StatusOK, Result{1, "Foo"})
}))
defer mockServer.Close()
b := breaker.New(
breaker.OptOpenExpiryInterval(5 * time.Second),
)
cb := b.Intercept(createUpstreamCaller())
var err error
var res interface{}
for x := 0; x < *flagNumCalls; x++ {
if res, err = cb.Action(context.Background(), mockServer.URL); err != nil {
fmt.Printf("(%v) circuit breaker error: %v\n", b.EvaluateState(context.Background()), err)
if ex.Is(err, breaker.ErrOpenState) {
time.Sleep(5 * time.Second)
} else {
time.Sleep(100 * time.Millisecond)
}
} else {
fmt.Printf("(%v) result: %v\n", b.EvaluateState(context.Background()), res)
time.Sleep(100 * time.Millisecond)
}
}
}