Register with FQDN in URL

cmd/client/main.go

@@ -174,7 +174,7 @@ func loop(c Coordinator, client *http.Client) error {
 		level.Error(c.logger).Log("msg", "Error parsing url:", "err", err)
 		return errors.Wrap(err, "error parsing url")
 	}
-	u, err := url.Parse("poll")
+	u, err := url.Parse("poll/" + *myFqdn)
 	if err != nil {
 		level.Error(c.logger).Log("msg", "Error parsing url:", "err", err)
 		return errors.Wrap(err, "error parsing url poll")

cmd/proxy/coordinator.go

@@ -25,9 +25,9 @@ import (
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/google/uuid"
+	"github.com/prometheus-community/pushprox/util"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
-	"github.com/prometheus-community/pushprox/util"
 )
 
 var (
@@ -73,6 +73,8 @@ func NewCoordinator(logger log.Logger) (*Coordinator, error) {
 }
 
 // Generate a unique ID
+// It is important this ID is cryptographically unique to ensure clients can't
+// be mixed up.
 func (c *Coordinator) genID() (string, error) {
 	id, err := uuid.NewRandom()
 	return id.String(), err
@@ -114,6 +116,8 @@ func (c *Coordinator) DoScrape(ctx context.Context, r *http.Request) (*http.Resp
 		return nil, err
 	}
 	level.Info(c.logger).Log("msg", "DoScrape", "scrape_id", id, "url", r.URL.String())
+	// It is important this id is cryptographically generated as it is relied
+	// upon to match the request and the response.
 	r.Header.Add("Id", id)
 	select {
 	case <-ctx.Done():

cmd/proxy/main.go

@@ -99,6 +99,7 @@ func newHTTPHandler(logger log.Logger, coordinator *Coordinator, mux *http.Serve
 	handlers := map[string]http.HandlerFunc{
 		"/push":    h.handlePush,
 		"/poll":    h.handlePoll,
+		"/poll/":   h.handlePollWithPath,
 		"/clients": h.handleListClients,
 		"/metrics": promhttp.Handler().ServeHTTP,
 	}
@@ -144,7 +145,17 @@ func (h *httpHandler) handlePush(w http.ResponseWriter, r *http.Request) {
 // handlePoll handles clients registering and asking for scrapes.
 func (h *httpHandler) handlePoll(w http.ResponseWriter, r *http.Request) {
 	fqdn, _ := ioutil.ReadAll(r.Body)
-	request, err := h.coordinator.WaitForScrapeInstruction(strings.TrimSpace(string(fqdn)))
+	h.pollWithFQDN(string(fqdn), w)
+}
+
+// handlePoll handles clients registering and asking for scrapes.
+func (h *httpHandler) handlePollWithPath(w http.ResponseWriter, r *http.Request) {
+	fqdn := r.URL.Path[len("/poll/"):]
+	h.pollWithFQDN(fqdn, w)
+}
+
+func (h *httpHandler) pollWithFQDN(fqdn string, w http.ResponseWriter) {
+	request, err := h.coordinator.WaitForScrapeInstruction(strings.TrimSpace(fqdn))
 	if err != nil {
 		level.Info(h.logger).Log("msg", "Error WaitForScrapeInstruction:", "err", err)
 		http.Error(w, fmt.Sprintf("Error WaitForScrapeInstruction: %s", err.Error()), 408)