Add params serving

cmd/server/main.go

@@ -47,6 +47,8 @@ func init() {
 	promRegistry.MustRegister(metrics.TotalErrors)
 	promRegistry.MustRegister(metrics.TotalBlocksServedConter)
 	promRegistry.MustRegister(metrics.SendTransactionsCounter)
+	promRegistry.MustRegister(metrics.TotalSaplingParamsCounter)
+	promRegistry.MustRegister(metrics.TotalSproutParamsCounter)
 }
 
 // TODO stream logging
@@ -255,6 +257,10 @@ func main() {
 		log.Fatal(http.ListenAndServe(":2234", nil))
 	}()
 
+	// Start the download params handler
+	log.Infof("Starting params handler")
+	go common.ParamsDownloadHandler(metrics)
+
 	log.Infof("Starting gRPC server on %s", opts.bindAddr)
 
 	err = server.Serve(listener)

common/downloadhandler.go

@@ -0,0 +1,41 @@
+package common
+
+import (
+	"net/http"
+	"strings"
+)
+
+var (
+	metrics *PrometheusMetrics
+)
+
+// Handle http(s) downloads for zcash params
+func paramsHandler(w http.ResponseWriter, req *http.Request) {
+	if strings.HasSuffix(req.URL.Path, "sapling-output.params") {
+		metrics.TotalSaplingParamsCounter.Inc()
+		http.Redirect(w, req, "https://z.cash/downloads/sapling-output.params", 301)
+		return
+	}
+
+	if strings.HasSuffix(req.URL.Path, "sapling-spend.params") {
+		http.Redirect(w, req, "https://z.cash/downloads/sapling-spend.params", 301)
+		return
+	}
+
+	if strings.HasSuffix(req.URL.Path, "sprout-groth16.params") {
+		metrics.TotalSproutParamsCounter.Inc()
+		http.Redirect(w, req, "https://z.cash/downloads/sprout-groth16.params", 301)
+		return
+	}
+
+	http.Error(w, "Not Found", 404)
+}
+
+// ParamsDownloadHandler Listens on port 8090 for download requests for params
+func ParamsDownloadHandler(prommetrics *PrometheusMetrics) {
+	metrics = prommetrics
+	http.HandleFunc("/params/", paramsHandler)
+
+	println("Handling at params")
+	http.ListenAndServe(":8090", nil)
+}

common/prometheusmetrics.go

@@ -8,6 +8,8 @@ type PrometheusMetrics struct {
 	TotalBlocksServedConter   prometheus.Counter
 	SendTransactionsCounter   prometheus.Counter
 	TotalErrors               prometheus.Counter
+	TotalSaplingParamsCounter prometheus.Counter
+	TotalSproutParamsCounter  prometheus.Counter
 }
 
 func GetPrometheusMetrics() *PrometheusMetrics {
@@ -32,5 +34,15 @@ func GetPrometheusMetrics() *PrometheusMetrics {
 		Help: "Total number of errors seen by lightwalletd",
 	})
 
+	m.TotalSaplingParamsCounter = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "params_sapling_total",
+		Help: "Total number of params downloads for sapling params",
+	})
+
+	m.TotalSproutParamsCounter = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "params_sprout_total",
+		Help: "Total number of params downloasd for sprout params",
+	})
+
 	return m
 }