Method forwardCP

ais/proxy.go:1727–1790

============================ supporting methods and misc ============================ forward control plane request to the current primary proxy return: forf (forwarded or failed) where forf = true means exactly that: forwarded or failed

(w http.ResponseWriter, r *http.Request, msg *apc.ActionMsg,
	s string, origBody ...[]byte)

// forward control plane request to the current primary proxy
// return: forf (forwarded or failed) where forf = true means exactly that: forwarded or failed
func (p *proxy) forwardCP(w http.ResponseWriter, r *http.Request, msg *apc.ActionMsg,
	s string, origBody ...[]byte) (forf bool) {
	var (
		body []byte
		smap = p.owner.smap.get()
	)
	if !smap.isValid() {
		errmsg := fmt.Sprintf("%s must be starting up: cannot execute", p.si)
		if msg != nil {
			p.writeErrStatusf(w, r, http.StatusServiceUnavailable, "%s %s: %s", errmsg, msg.Action, s)
		} else {
			p.writeErrStatusf(w, r, http.StatusServiceUnavailable, "%s %q", errmsg, s)
		}
		return true
	}
	if p.inPrimaryTransition.Load() {
		p.writeErrStatusf(w, r, http.StatusServiceUnavailable,
			"%s is in transition, cannot process the request", p.si)
		return true
	}
	if smap.isPrimary(p.si) {
		return
	}
	// We must **not** send any request body when doing HEAD request.
	// Otherwise, the request can be rejected and terminated.
	if r.Method != http.MethodHead {
		if len(origBody) > 0 && len(origBody[0]) > 0 {
			body = origBody[0]
		} else if msg != nil {
			body = cos.MustMarshal(msg)
		}
	}
	primary := &p.rproxy.primary
	primary.Lock()
	if primary.url != smap.Primary.PubNet.URL {
		primary.url = smap.Primary.PubNet.URL
		uparsed, err := url.Parse(smap.Primary.PubNet.URL)
		cos.AssertNoErr(err)
		cfg := cmn.GCO.Get()
		primary.rp = httputil.NewSingleHostReverseProxy(uparsed)
		primary.rp.Transport = cmn.NewTransport(cmn.TransportArgs{
			UseHTTPS:   cfg.Net.HTTP.UseHTTPS,
			SkipVerify: cfg.Net.HTTP.SkipVerify,
		})
		primary.rp.ErrorHandler = p.rpErrHandler
	}
	primary.Unlock()
	if len(body) > 0 {
		debug.AssertFunc(func() bool {
			l, _ := io.Copy(io.Discard, r.Body)
			return l == 0
		})

		r.Body = io.NopCloser(bytes.NewBuffer(body))
		r.ContentLength = int64(len(body)) // Directly setting `Content-Length` header.
	}
	if msg != nil {
		glog.Infof("%s: forwarding \"%s:%s\" to the primary %s", p, msg.Action, s, smap.Primary.StringEx())