From 6f40fe71353084c6c1ec8482e1c938fd4a4706f6 Mon Sep 17 00:00:00 2001
From: Ben Wilson <ben@z.cash>
Date: Wed, 4 Dec 2019 12:45:02 -0500
Subject: [PATCH] Added initial chaintip collections

---
 collector.go |  8 ++++++++
 main.go      | 28 ++++++++++++++++++++++++++++
 rpc.go       | 11 +++++++++++
 3 files changed, 47 insertions(+)

diff --git a/collector.go b/collector.go
index 9fae20f..56e66b8 100644
--- a/collector.go
+++ b/collector.go
@@ -52,6 +52,13 @@ var (
 			Help: "Bytes received from peer node."},
 		[]string{"addr", "addrlocal", "inbound", "banscore", "subver"},
 	)
+	zcashdChainTips = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "zcash_chainips_at_height",
+			Help: "Information about all known tips in the block tree.",
+		},
+		[]string{"hash", "branchlen", "status"},
+	)
 )
 
 // ZCASH_PEERS = Gauge("zcash_peers", "Number of peers")
@@ -90,4 +97,5 @@ func init() {
 	prometheus.MustRegister(zcashdPeerConnTime)
 	prometheus.MustRegister(zcashdPeerBytesSent)
 	prometheus.MustRegister(zcashdPeerBytesRecv)
+	prometheus.MustRegister(zcashdChainTips)
 }
diff --git a/main.go b/main.go
index 07d1b0f..9bb1ed3 100644
--- a/main.go
+++ b/main.go
@@ -56,6 +56,7 @@ func main() {
 	go getMemPoolInfo()
 	go getWalletInfo()
 	go getPeerInfo()
+	go getChainTips()
 	log.Infoln("Listening on", *listenAddress)
 	if err := http.ListenAndServe(*listenAddress, nil); err != nil {
 		log.Fatal(err)
@@ -205,3 +206,30 @@ func getPeerInfo() {
 	}
 
 }
+
+func getChainTips() {
+	basicAuth := base64.StdEncoding.EncodeToString([]byte(*rpcUser + ":" + *rpcPassword))
+	rpcClient := jsonrpc.NewClientWithOpts("http://"+*rpcHost+":"+*rpcPort,
+		&jsonrpc.RPCClientOpts{
+			CustomHeaders: map[string]string{
+				"Authorization": "Basic " + basicAuth,
+			}})
+	var chaintips *GetChainTips
+
+	for {
+		if err := rpcClient.CallFor(&chaintips, "getchaintips"); err != nil {
+			log.Warnln("Error calling getchaintips", err)
+		} else {
+			for _, ct := range *chaintips {
+				log.Infoln("Got chaintip: ", ct.Hash)
+				zcashdChainTips.WithLabelValues(
+					ct.Hash,
+					strconv.Itoa(ct.Branchlen),
+					ct.Status,
+				).Set(float64(ct.Height))
+			}
+		}
+		time.Sleep(time.Duration(30) * time.Second)
+	}
+
+}
diff --git a/rpc.go b/rpc.go
index 746012d..4269cbe 100644
--- a/rpc.go
+++ b/rpc.go
@@ -51,3 +51,14 @@ type PeerInfo struct {
 	SyncedHeaders  int     `json:"synced_headers"`
 	SyncedBlocks   int     `json:"synced_blocks"`
 }
+
+// GetChainTips Return information about all known tips in the block tree
+// https://zcash-rpc.github.io/getchaintips.html
+type GetChainTips []ChainTip
+
+type ChainTip struct {
+	Height    int    `json:"height"`
+	Hash      string `json:"hash"`
+	Branchlen int    `json:"branchlen"`
+	Status    string `json:"status"`
+}