traefik/pkg/middlewares/emptybackendhandler/empty_backend_handler.go
mpl 838a8e18d3
healthcheck: add support at the load-balancers of services level
Co-authored-by: Dmitry Sharshakov <d3dx12.xx@gmail.com>
Co-authored-by: Julien Salleyron <julien.salleyron@gmail.com>
Co-authored-by: Jean-Baptiste Doumenjou <925513+jbdoumenjou@users.noreply.github.com>
Co-authored-by: Romain <rtribotte@users.noreply.github.com>
Co-authored-by: Tom Moulard <tom.moulard@traefik.io>
2021-06-25 21:08:11 +02:00

34 lines
1.1 KiB
Go

package emptybackendhandler
import (
"net/http"
"github.com/traefik/traefik/v2/pkg/healthcheck"
)
// EmptyBackend is a middleware that checks whether the current Backend
// has at least one active Server in respect to the healthchecks and if this
// is not the case, it will stop the middleware chain and respond with 503.
type emptyBackend struct {
healthcheck.BalancerStatusHandler
}
// New creates a new EmptyBackend middleware.
func New(lb healthcheck.BalancerStatusHandler) http.Handler {
return &emptyBackend{BalancerStatusHandler: lb}
}
// ServeHTTP responds with 503 when there is no active Server and otherwise
// invokes the next handler in the middleware chain.
func (e *emptyBackend) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
if len(e.BalancerStatusHandler.Servers()) != 0 {
e.BalancerStatusHandler.ServeHTTP(rw, req)
return
}
rw.WriteHeader(http.StatusServiceUnavailable)
if _, err := rw.Write([]byte(http.StatusText(http.StatusServiceUnavailable))); err != nil {
http.Error(rw, err.Error(), http.StatusInternalServerError)
return
}
}