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kratos/middleware/circuitbreaker/circuitbreaker.go

54 lines
1.4 KiB

package circuitbreaker
import (
"context"
"github.com/go-kratos/aegis/circuitbreaker"
"github.com/go-kratos/aegis/circuitbreaker/sre"
"github.com/go-kratos/kratos/v2/errors"
"github.com/go-kratos/kratos/v2/middleware"
)
// Option is circuit breaker option.
type Option func(*options)
// WithBreaker set circuit breaker implentation
func WithBreaker(breaker circuitbreaker.CircuitBreaker) Option {
return func(o *options) {
o.breaker = breaker
}
}
type options struct {
breaker circuitbreaker.CircuitBreaker
}
// Client circuitbreaker middleware will return errBreakerTriggered when the circuit
// breaker is triggered and the request is rejected directly.
func Client(opts ...Option) middleware.Middleware {
options := &options{
breaker: sre.NewBreaker(),
}
for _, o := range opts {
o(options)
}
return func(handler middleware.Handler) middleware.Handler {
return func(ctx context.Context, req interface{}) (interface{}, error) {
if err := options.breaker.Allow(); err != nil {
// rejected
// NOTE: when client reject requets locally,
// continue add counter let the drop ratio higher.
options.breaker.MarkFailed()
return nil, errors.New(503, "CIRCUITBREAKER", "request failed due to circuit breaker triggered")
}
// allowed
reply, err := handler(ctx, req)
if err != nil {
options.breaker.MarkFailed()
} else {
options.breaker.MarkSuccess()
}
return reply, err
}
}
}