cumulative counters implemented.

cmd/converge/prometheus.go

@@ -12,6 +12,22 @@ import (
 const NAMESPACE = "converge"
 
 var (
+	// remember previous values of agent guids and clients so that we can increment
+	// the cumulative counters.
+	lastAgentGuids  map[string]bool = make(map[string]bool)
+	lastClientGuids map[string]bool = make(map[string]bool)
+
+	cumulativeAgentCount = promauto.NewCounter(prometheus.CounterOpts{
+		Namespace: NAMESPACE,
+		Name:      "agent_count_total",
+		Help:      "Total number of agents connected over time",
+	})
+	cumulativeClientCount = promauto.NewCounter(prometheus.CounterOpts{
+		Namespace: NAMESPACE,
+		Name:      "client_count_total",
+		Help:      "Total number of clients connected over time",
+	})
+
 	agentCount = promauto.NewGauge(prometheus.GaugeOpts{
 		Namespace: NAMESPACE,
 		Name:      "agent_count",
@@ -88,14 +104,29 @@ func updateMetrics(state *models.State) {
 	// become 0.
 
 	log.Printf("Got notification %v", *state)
+
+	agentGuids := make(map[string]bool)
+	clientGuids := make(map[string]bool)
+
 	agentCount.Set(float64(len(state.Agents)))
 	agentInfo.Reset()
 	for _, agent := range state.Agents {
+		if !lastAgentGuids[agent.Guid] {
+			cumulativeAgentCount.Inc()
+		}
+		agentGuids[agent.Guid] = true
 		agentActive(agent)
 	}
+	lastAgentGuids = agentGuids
+
 	clientCount.Set(float64(len(state.Clients)))
 	clientInfo.Reset()
 	for _, client := range state.Clients {
+		if !lastClientGuids[client.Guid] {
+			cumulativeClientCount.Inc()
+		}
+		clientGuids[client.Guid] = true
 		clientActive(client)
 	}
+	lastClientGuids = clientGuids
 }

pkg/models/state.go

@@ -1,6 +1,9 @@
 package models
 
 type State struct {
+	CumulativeAgentCount  int
+	CumulativeClientCount int
+
 	Agents  []Agent
 	Clients []Client
 	Ascii   string