terminal.txt

ugh ~/tmp/hystr cat example.go
package main

import (
        "errors"
        "log"

        "github.com/afex/hystrix-go/hystrix"
)

func main() {
        log.SetFlags(0)

        const (
                commandName   = "my-endpoint"
                errorPercent  = 5
                maxConcurrent = 1000
        )
        hystrix.ConfigureCommand(commandName, hystrix.CommandConfig{
                ErrorPercentThreshold: errorPercent,
                MaxConcurrentRequests: maxConcurrent,
        })
        var (
                primeWith  = hystrix.DefaultVolumeThreshold * 2
                shouldPass = func(n int) bool { return (float64(n) / float64(primeWith+n)) <= (float64(errorPercent-1) / 100.0) }
        )

        var myErr error
        run := func() error { return myErr }
        log.Printf("priming with %d successful requests", primeWith)

        for i := 0; i < primeWith; i++ {
                if err := hystrix.Do(commandName, run, nil); err != myErr {
                        log.Fatalf("initial request %d failed: %v", i+1, err)
                }
        }

        log.Printf("switching to errors...")
        myErr = errors.New("kaboom")
        log.Printf("now the next few requests should give us our error: %v", myErr)

        for i := 0; shouldPass(i); i++ {
                if err := hystrix.Do(commandName, run, nil); err != myErr {
                        log.Fatalf("post-error request %d failed: %v", i+1, err)
                }
                log.Printf("got expected error %d", i+1)
        }

        log.Printf("the circuit should have opened by now")

        for i := 0; i < 5; i++ {
                if err := hystrix.Do(commandName, run, nil); err != hystrix.ErrCircuitOpen {
                        log.Fatalf("got unexpected error at request %d: %v", i+1, err)
                }
                log.Printf("got expected error: %v", hystrix.ErrCircuitOpen)
        }

        log.Printf("everything works as expected")
}
ugh ~/tmp/hystr cd $GOPATH/src/github.com/afex/hystrix-go ; git checkout 5b79165 ; cd -
HEAD is now at 5b79165... use buffered client for statsd collector to reduce TotalDuration overhead
ugh ~/tmp/hystr rm -rf $GOPATH/pkg/darwin_amd64/github.com/afex/hystrix-go ; go run example.go
priming with 40 successful requests
switching to errors...
now the next few requests should give us our error: kaboom
got expected error 1
got expected error 2
the circuit should have opened by now
got unexpected error at request 1: kaboom
exit status 1
ugh ~/tmp/hystr cd $GOPATH/src/github.com/afex/hystrix-go ; git checkout be7b59e ; cd -
Previous HEAD position was 5b79165... use buffered client for statsd collector to reduce TotalDuration overhead
HEAD is now at be7b59e... Merge branch 'master' into loadtest
ugh ~/tmp/hystr rm -rf $GOPATH/pkg/darwin_amd64/github.com/afex/hystrix-go ; go run example.go
priming with 40 successful requests
switching to errors...
now the next few requests should give us our error: kaboom
got expected error 1
got expected error 2
the circuit should have opened by now
hystrix-go: opening circuit my-endpoint
got expected error: hystrix: circuit open
got expected error: hystrix: circuit open
got expected error: hystrix: circuit open
got expected error: hystrix: circuit open
got expected error: hystrix: circuit open
everything works as expected
ugh ~/tmp/hystr