bypass on no hosts found

Author: meiji163

cmd/freno/main.go

@@ -11,6 +11,8 @@ import (
 	"github.com/github/freno/pkg/http"
 	"github.com/github/freno/pkg/throttle"
 	"github.com/outbrain/golib/log"
+	"os"
+	"strconv"
 )
 
 // AppVersion has to be filled by ldflags:
@@ -120,6 +122,12 @@ func httpServe() error {
 	throttler := throttle.NewThrottler()
 	log.Infof("Starting consensus service")
 	log.Infof("- forced leadership: %+v", group.ForceLeadership)
+
+	bypassEnabled, err := strconv.ParseBool(os.Getenv("FRENO_BYPASS_ENABLED"))
+	if err != nil {
+		bypassEnabled = false
+	}
+	throttler.BypassOnNoHostsFound = bypassEnabled
 	consensusServiceProvider, err := group.NewConsensusServiceProvider(throttler)
 	if err != nil {
 		return err

pkg/throttle/throttler.go

@@ -78,6 +78,8 @@ type Throttler struct {
 
 	nonLowPriorityAppRequestsThrottled *cache.Cache
 	httpClient                         *http.Client
+
+	BypassOnNoHostsFound bool
 }
 
 func NewThrottler() *Throttler {
@@ -331,6 +333,10 @@ func (throttler *Throttler) refreshMySQLInventory() error {
 					}
 				}
 				if len(totalHosts) == 0 {
+					if throttler.bypassOnNoHostsFound {
+						log.Debugf("No hosts for pool: %+v, but bypass is enabled", poolName)
+						return nil
+					}
 					return log.Errorf("Unable to get any HAproxy hosts for pool: %+v", poolName)
 				}