// This probably shouldn't be called ServeHTTP anymore
func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request, addrs []string) {
pr := &ProxyRequest{
ResponseWriter: rw,
Request: req,
Backends: addrs,
}
for _, f := range p.OnRequest {
cont := f(pr)
if !cont {
return
}
}
pr.StartTime = time.Now()
res, err := p.doRequest(pr)
pr.Response = res
pr.ProxyError = err
pr.FinishTime = time.Now()
if err != nil {
log.Errorf("ERROR: HTTP proxy error - %v", err)
// We want to ensure that we have a non-nil response even on error for
// the OnResponse callbacks. If the Callback chain completes, this will
// be written to the client.
res = &http.Response{
Header: make(map[string][]string),
StatusCode: http.StatusBadGateway,
Status: http.StatusText(http.StatusBadGateway),
// this ensures Body isn't nil
Body: ioutil.NopCloser(bytes.NewReader(nil)),
}
pr.Response = res
}
for _, h := range hopHeaders {
res.Header.Del(h)
}
copyHeader(rw.Header(), res.Header)
for _, f := range p.OnResponse {
cont := f(pr)
if !cont {
return
}
}
// calls all completed with true, write the Response back to the client.
defer res.Body.Close()
rw.WriteHeader(res.StatusCode)
_, err = p.copyResponse(rw, res.Body)
if err != nil {
log.Warnf("WARN: id=%s transfer error: %s", req.Header.Get("X-Request-Id"), err)
}
}
func (b *Backend) check() {
if b.CheckAddr == "" {
return
}
up := true
if c, e := net.DialTimeout("tcp", b.CheckAddr, b.dialTimeout); e == nil {
c.(*net.TCPConn).SetLinger(0)
c.Close()
} else {
log.Warnf("WARN: Backend check for %s failed with error:", e)
up = false
}
b.Lock()
defer b.Unlock()
if up {
log.Debugf("DEBUG: Check OK for %s/%s", b.Name, b.CheckAddr)
b.fallCount = 0
b.riseCount++
b.checkOK++
if b.riseCount >= b.rise {
if !b.up {
log.Warnf("WARN: Marking backend %s Up", b.Name)
}
b.up = true
}
} else {
log.Debugf("DEBUG: Check failed for %s/%s", b.Name, b.CheckAddr)
b.riseCount = 0
b.fallCount++
b.checkFail++
if b.fallCount >= b.fall {
if b.up {
log.Warnf("WARN: Marking backend %s Down", b.Name)
}
b.up = false
}
}
}
// Return a *Service for this VirtualHost
func (v *VirtualHost) Service() *Service {
v.Lock()
defer v.Unlock()
if len(v.services) == 0 {
log.Warnf("WARN: No Services registered for VirtualHost %s", v.Name)
return nil
}
// start cycling through the services in case one has no backends available
for i := 1; i <= len(v.services); i++ {
idx := (v.last + i) % len(v.services)
if v.services[idx].Available() > 0 {
v.last = idx
return v.services[idx]
}
}
// even if all backends are down, return a service so that the request can
// be processed normally (we may have a custom 502 error page for this)
return v.services[v.last]
}
// Replace the service's configuration, or update its list of backends.
// Replacing a configuration will shutdown the existing service, and start a
// new one, which will cause the listening socket to be temporarily
// unavailable.
func (s *ServiceRegistry) UpdateService(newCfg client.ServiceConfig) error {
s.Lock()
defer s.Unlock()
log.Debug("DEBUG: Updating Service:", newCfg.Name)
service, ok := s.svcs[newCfg.Name]
if !ok {
log.Debug("DEBUG: Service not found:", newCfg.Name)
return ErrNoService
}
currentCfg := service.Config()
newCfg = currentCfg.Merge(newCfg)
if err := service.UpdateConfig(newCfg); err != nil {
return err
}
// Lots of looping here (including fetching the Config, but the cardinality
// of Backends shouldn't be very large, and the default RoundRobin balancing
// is much simpler with a slice.
// we're going to update just the backends for this config
// get a map of what's already running
currentBackends := make(map[string]client.BackendConfig)
for _, backendCfg := range currentCfg.Backends {
currentBackends[backendCfg.Name] = backendCfg
}
// Keep existing backends when they have equivalent config.
// Update changed backends, and add new ones.
for _, newBackend := range newCfg.Backends {
current, ok := currentBackends[newBackend.Name]
if ok && current.Equal(newBackend) {
log.Debugf("DEBUG: Backend %s/%s unchanged", service.Name, current.Name)
// no change for this one
delete(currentBackends, current.Name)
continue
}
// we need to remove and re-add this backend
log.Warnf("WARN: Updating Backend %s/%s", service.Name, newBackend.Name)
service.remove(newBackend.Name)
service.add(NewBackend(newBackend))
delete(currentBackends, newBackend.Name)
}
// remove any left over backends
for name := range currentBackends {
log.Debugf("DEBUG: Removing Backend %s/%s", service.Name, name)
service.remove(name)
}
if currentCfg.Equal(newCfg) {
log.Debugf("DEBUG: Service Unchanged %s", service.Name)
return nil
}
// replace error pages if there's any change
if !reflect.DeepEqual(service.errPagesCfg, newCfg.ErrorPages) {
log.Debugf("DEBUG: Updating ErrorPages")
service.errPagesCfg = newCfg.ErrorPages
service.errorPages.Update(newCfg.ErrorPages)
}
s.updateVHosts(service, filterEmpty(newCfg.VirtualHosts))
return nil
}