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package s3api
import (
"errors"
"fmt"
"github.com/gorilla/mux"
"github.com/seaweedfs/seaweedfs/weed/filer"
"github.com/seaweedfs/seaweedfs/weed/glog"
"github.com/seaweedfs/seaweedfs/weed/pb"
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"github.com/seaweedfs/seaweedfs/weed/pb/s3_pb"
"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
"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, 0, option.Filer, option.GrpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
content, err := filer.ReadInsideFiler(client, s3_constants.CircuitBreakerConfigDir, s3_constants.CircuitBreakerConfigFile)
if errors.Is(err, filer_pb.ErrNotFound) {
return nil
}
if err != nil {
return fmt.Errorf("read S3 circuit breaker config: %w", err)
}
return cb.LoadS3ApiConfigurationFromBytes(content)
})
if err != nil {
}
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: %w", 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
}
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