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proxy_round_tripper.go
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/
proxy_round_tripper.go
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package round_tripper
import (
"io/ioutil"
"net"
"net/http"
"code.cloudfoundry.org/gorouter/proxy/handler"
"code.cloudfoundry.org/gorouter/route"
)
type AfterRoundTrip func(rsp *http.Response, endpoint *route.Endpoint, err error)
func NewProxyRoundTripper(backend bool, transport http.RoundTripper, endpointIterator route.EndpointIterator,
handler *handler.RequestHandler, afterRoundTrip AfterRoundTrip) http.RoundTripper {
if backend {
return &BackendRoundTripper{
transport: transport,
iter: endpointIterator,
handler: handler,
after: afterRoundTrip,
}
} else {
return &RouteServiceRoundTripper{
transport: transport,
handler: handler,
after: afterRoundTrip,
}
}
}
type BackendRoundTripper struct {
iter route.EndpointIterator
transport http.RoundTripper
after AfterRoundTrip
handler *handler.RequestHandler
}
func (rt *BackendRoundTripper) RoundTrip(request *http.Request) (*http.Response, error) {
var err error
var res *http.Response
var endpoint *route.Endpoint
if request.Body != nil {
closer := request.Body
request.Body = ioutil.NopCloser(request.Body)
defer func() {
closer.Close()
}()
}
for retry := 0; retry < handler.MaxRetries; retry++ {
endpoint, err = rt.selectEndpoint(request)
if err != nil {
return nil, err
}
rt.setupRequest(request, endpoint)
res, err = rt.transport.RoundTrip(request)
if err == nil || !retryableError(err) {
break
}
rt.reportError(err)
}
if rt.after != nil {
rt.after(res, endpoint, err)
}
return res, err
}
func (rt *BackendRoundTripper) selectEndpoint(request *http.Request) (*route.Endpoint, error) {
endpoint := rt.iter.Next()
if endpoint == nil {
err := handler.NoEndpointsAvailable
rt.handler.HandleBadGateway(err, request)
return nil, err
}
return endpoint, nil
}
func (rt *BackendRoundTripper) setupRequest(request *http.Request, endpoint *route.Endpoint) {
rt.handler.Logger().Debug("backend")
request.URL.Host = endpoint.CanonicalAddr()
request.Header.Set("X-CF-ApplicationID", endpoint.ApplicationId)
handler.SetRequestXCfInstanceId(request, endpoint)
}
func (rt *BackendRoundTripper) reportError(err error) {
rt.iter.EndpointFailed()
rt.handler.Logger().Error("backend-endpoint-failed", err)
}
type RouteServiceRoundTripper struct {
transport http.RoundTripper
after AfterRoundTrip
handler *handler.RequestHandler
}
func (rt *RouteServiceRoundTripper) RoundTrip(request *http.Request) (*http.Response, error) {
var err error
var res *http.Response
for retry := 0; retry < handler.MaxRetries; retry++ {
res, err = rt.transport.RoundTrip(request)
if err == nil || !retryableError(err) {
break
}
rt.reportError(err)
}
if rt.after != nil {
endpoint := newRouteServiceEndpoint()
rt.after(res, endpoint, err)
}
return res, err
}
func (rs *RouteServiceRoundTripper) reportError(err error) {
rs.handler.Logger().Error("route-service-failed", err)
}
func retryableError(err error) bool {
ne, netErr := err.(*net.OpError)
if netErr && ne.Op == "dial" {
return true
}
return false
}
func newRouteServiceEndpoint() *route.Endpoint {
return &route.Endpoint{
Tags: map[string]string{},
}
}