Circuit Breaker for web middleware and rpc interceptor.
gin circuit breaker middleware
import "github.com/i2dou/sponge/pkg/shield/circuitbreaker"
// CircuitBreaker a circuit breaker middleware
func CircuitBreaker(opts ...CircuitBreakerOption) gin.HandlerFunc {
o := defaultCircuitBreakerOptions()
o.apply(opts...)
return func(c *gin.Context) {
breaker := o.group.Get(c.FullPath()).(circuitbreaker.CircuitBreaker)
if err := breaker.Allow(); err != nil {
// NOTE: when client reject request locally, keep adding counter let the drop ratio higher.
breaker.MarkFailed()
response.Output(c, http.StatusServiceUnavailable, err.Error())
c.Abort()
return
}
c.Next()
code := c.Writer.Status()
// NOTE: need to check internal and service unavailable error, e.g. http.StatusInternalServerError
_, isHit := o.validCodes[code]
if isHit {
breaker.MarkFailed()
} else {
breaker.MarkSuccess()
}
}
}
rpc server circuit breaker interceptor
import "github.com/i2dou/sponge/pkg/shield/circuitbreaker"
// UnaryServerCircuitBreaker server-side unary circuit breaker interceptor
func UnaryServerCircuitBreaker(opts ...CircuitBreakerOption) grpc.UnaryServerInterceptor {
o := defaultCircuitBreakerOptions()
o.apply(opts...)
return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
breaker := o.group.Get(info.FullMethod).(circuitbreaker.CircuitBreaker)
if err := breaker.Allow(); err != nil {
// NOTE: when client reject request locally, keep adding let the drop ratio higher.
breaker.MarkFailed()
return nil, errcode.StatusServiceUnavailable.ToRPCErr(err.Error())
}
reply, err := handler(ctx, req)
if err != nil {
// NOTE: need to check internal and service unavailable error
s, ok := status.FromError(err)
_, isHit := o.validCodes[s.Code()]
if ok && isHit {
breaker.MarkFailed()
} else {
breaker.MarkSuccess()
}
}
return reply, err
}
}