104 lines
2.4 KiB
Go
104 lines
2.4 KiB
Go
package mirror
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"net/http"
|
|
"sync"
|
|
|
|
"github.com/containous/traefik/v2/pkg/safe"
|
|
)
|
|
|
|
// Mirroring is an http.Handler that can mirror requests.
|
|
type Mirroring struct {
|
|
handler http.Handler
|
|
mirrorHandlers []*mirrorHandler
|
|
rw http.ResponseWriter
|
|
routinePool *safe.Pool
|
|
|
|
lock sync.RWMutex
|
|
total uint64
|
|
}
|
|
|
|
// New returns a new instance of *Mirroring.
|
|
func New(handler http.Handler, pool *safe.Pool) *Mirroring {
|
|
return &Mirroring{
|
|
routinePool: pool,
|
|
handler: handler,
|
|
rw: blackholeResponseWriter{},
|
|
}
|
|
}
|
|
|
|
func (m *Mirroring) inc() uint64 {
|
|
m.lock.Lock()
|
|
defer m.lock.Unlock()
|
|
m.total++
|
|
return m.total
|
|
}
|
|
|
|
type mirrorHandler struct {
|
|
http.Handler
|
|
percent int
|
|
|
|
lock sync.RWMutex
|
|
count uint64
|
|
}
|
|
|
|
func (m *Mirroring) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
|
|
m.handler.ServeHTTP(rw, req)
|
|
|
|
select {
|
|
case <-req.Context().Done():
|
|
// No mirroring if request has been canceled during main handler ServeHTTP
|
|
return
|
|
default:
|
|
}
|
|
|
|
m.routinePool.GoCtx(func(_ context.Context) {
|
|
total := m.inc()
|
|
for _, handler := range m.mirrorHandlers {
|
|
handler.lock.Lock()
|
|
if handler.count*100 < total*uint64(handler.percent) {
|
|
handler.count++
|
|
handler.lock.Unlock()
|
|
// When a request served by m.handler is successful, req.Context will be cancelled,
|
|
// which would trigger a cancellation of the ongoing mirrored requests.
|
|
// Therefore, we give a new, non-cancellable context to each of the mirrored calls,
|
|
// so they can terminate by themselves.
|
|
handler.ServeHTTP(m.rw, req.WithContext(contextStopPropagation{req.Context()}))
|
|
} else {
|
|
handler.lock.Unlock()
|
|
}
|
|
}
|
|
})
|
|
}
|
|
|
|
// AddMirror adds an httpHandler to mirror to.
|
|
func (m *Mirroring) AddMirror(handler http.Handler, percent int) error {
|
|
if percent < 0 || percent >= 100 {
|
|
return errors.New("percent must be between 0 and 100")
|
|
}
|
|
m.mirrorHandlers = append(m.mirrorHandlers, &mirrorHandler{Handler: handler, percent: percent})
|
|
return nil
|
|
}
|
|
|
|
type blackholeResponseWriter struct{}
|
|
|
|
func (b blackholeResponseWriter) Header() http.Header {
|
|
return http.Header{}
|
|
}
|
|
|
|
func (b blackholeResponseWriter) Write(bytes []byte) (int, error) {
|
|
return len(bytes), nil
|
|
}
|
|
|
|
func (b blackholeResponseWriter) WriteHeader(statusCode int) {
|
|
}
|
|
|
|
type contextStopPropagation struct {
|
|
context.Context
|
|
}
|
|
|
|
func (c contextStopPropagation) Done() <-chan struct{} {
|
|
return make(chan struct{})
|
|
}
|