1 files changed, 183 insertions, 0 deletions
diff --git a/weed/s3api/s3api_circuit_breaker.go b/weed/s3api/s3api_circuit_breaker.go
new file mode 100644
index 000000000..111b404c7
--- /dev/null
+++ b/weed/s3api/s3api_circuit_breaker.go
@@ -0,0 +1,183 @@
+package s3api
+
+import (
+	"fmt"
+	"github.com/chrislusf/seaweedfs/weed/filer"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/pb/s3_pb"
+	"github.com/chrislusf/seaweedfs/weed/s3api/s3_constants"
+	"github.com/chrislusf/seaweedfs/weed/s3api/s3err"
+	"github.com/gorilla/mux"
+	"net/http"
+	"sync"
+	"sync/atomic"
+)
+
+type CircuitBreaker struct {
+	sync.RWMutex
+	Enabled     bool
+	counters    map[string]*int64
+	limitations map[string]int64
+}
+
+func NewCircuitBreaker(option *S3ApiServerOption) *CircuitBreaker {
+	cb := &CircuitBreaker{
+		counters:    make(map[string]*int64),
+		limitations: make(map[string]int64),
+	}
+
+	err := pb.WithFilerClient(false, option.Filer, option.GrpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
+		content, err := filer.ReadInsideFiler(client, s3_constants.CircuitBreakerConfigDir, s3_constants.CircuitBreakerConfigFile)
+		if err != nil {
+			return fmt.Errorf("read S3 circuit breaker config: %v", err)
+		}
+		return cb.LoadS3ApiConfigurationFromBytes(content)
+	})
+
+	if err != nil {
+		glog.Warningf("fail to load config: %v", err)
+	}
+
+	return cb
+}
+
+func (cb *CircuitBreaker) LoadS3ApiConfigurationFromBytes(content []byte) error {
+	cbCfg := &s3_pb.S3CircuitBreakerConfig{}
+	if err := filer.ParseS3ConfigurationFromBytes(content, cbCfg); err != nil {
+		glog.Warningf("unmarshal error: %v", err)
+		return fmt.Errorf("unmarshal error: %v", err)
+	}
+	if err := cb.loadCircuitBreakerConfig(cbCfg); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (cb *CircuitBreaker) loadCircuitBreakerConfig(cfg *s3_pb.S3CircuitBreakerConfig) error {
+
+	//global
+	globalEnabled := false
+	globalOptions := cfg.Global
+	limitations := make(map[string]int64)
+	if globalOptions != nil && globalOptions.Enabled && len(globalOptions.Actions) > 0 {
+		globalEnabled = globalOptions.Enabled
+		for action, limit := range globalOptions.Actions {
+			limitations[action] = limit
+		}
+	}
+	cb.Enabled = globalEnabled
+
+	//buckets
+	for bucket, cbOptions := range cfg.Buckets {
+		if cbOptions.Enabled {
+			for action, limit := range cbOptions.Actions {
+				limitations[s3_constants.Concat(bucket, action)] = limit
+			}
+		}
+	}
+
+	cb.limitations = limitations
+	return nil
+}
+
+func (cb *CircuitBreaker) Limit(f func(w http.ResponseWriter, r *http.Request), action string) (http.HandlerFunc, Action) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if !cb.Enabled {
+			f(w, r)
+			return
+		}
+
+		vars := mux.Vars(r)
+		bucket := vars["bucket"]
+
+		rollback, errCode := cb.limit(r, bucket, action)
+		defer func() {
+			for _, rf := range rollback {
+				rf()
+			}
+		}()
+
+		if errCode == s3err.ErrNone {
+			f(w, r)
+			return
+		}
+		s3err.WriteErrorResponse(w, r, errCode)
+	}, Action(action)
+}
+
+func (cb *CircuitBreaker) limit(r *http.Request, bucket string, action string) (rollback []func(), errCode s3err.ErrorCode) {
+
+	//bucket simultaneous request count
+	bucketCountRollBack, errCode := cb.loadCounterAndCompare(s3_constants.Concat(bucket, action, s3_constants.LimitTypeCount), 1, s3err.ErrTooManyRequest)
+	if bucketCountRollBack != nil {
+		rollback = append(rollback, bucketCountRollBack)
+	}
+	if errCode != s3err.ErrNone {
+		return
+	}
+
+	//bucket simultaneous request content bytes
+	bucketContentLengthRollBack, errCode := cb.loadCounterAndCompare(s3_constants.Concat(bucket, action, s3_constants.LimitTypeBytes), r.ContentLength, s3err.ErrRequestBytesExceed)
+	if bucketContentLengthRollBack != nil {
+		rollback = append(rollback, bucketContentLengthRollBack)
+	}
+	if errCode != s3err.ErrNone {
+		return
+	}
+
+	//global simultaneous request count
+	globalCountRollBack, errCode := cb.loadCounterAndCompare(s3_constants.Concat(action, s3_constants.LimitTypeCount), 1, s3err.ErrTooManyRequest)
+	if globalCountRollBack != nil {
+		rollback = append(rollback, globalCountRollBack)
+	}
+	if errCode != s3err.ErrNone {
+		return
+	}
+
+	//global simultaneous request content bytes
+	globalContentLengthRollBack, errCode := cb.loadCounterAndCompare(s3_constants.Concat(action, s3_constants.LimitTypeBytes), r.ContentLength, s3err.ErrRequestBytesExceed)
+	if globalContentLengthRollBack != nil {
+		rollback = append(rollback, globalContentLengthRollBack)
+	}
+	if errCode != s3err.ErrNone {
+		return
+	}
+	return
+}
+
+func (cb *CircuitBreaker) loadCounterAndCompare(key string, inc int64, errCode s3err.ErrorCode) (f func(), e s3err.ErrorCode) {
+	e = s3err.ErrNone
+	if max, ok := cb.limitations[key]; ok {
+		cb.RLock()
+		counter, exists := cb.counters[key]
+		cb.RUnlock()
+
+		if !exists {
+			cb.Lock()
+			counter, exists = cb.counters[key]
+			if !exists {
+				var newCounter int64
+				counter = &newCounter
+				cb.counters[key] = counter
+			}
+			cb.Unlock()
+		}
+		current := atomic.LoadInt64(counter)
+		if current+inc > max {
+			e = errCode
+			return
+		} else {
+			current := atomic.AddInt64(counter, inc)
+			f = func() {
+				atomic.AddInt64(counter, -inc)
+			}
+			if current > max {
+				e = errCode
+				return
+			}
+		}
+	}
+	return
+}