eliminated unused fields in State

Now preserving the lastState in prometheus.go in a State object instead
of in multiple values.

README.md

@@ -8,13 +8,13 @@ At least go version 1.21 so that it automatically downloads the correct version
 ```
 go install github.com/a-h/templ/cmd/templ@latest
 go install golang.org/x/pkgsite/cmd/pkgsite@latest
-
+go install honnef.co/go/tools/cmd/staticcheck@v0.5.0
 ```
 
 # Profiling
 
 ```
-go tool pprof -http:8081 http://localhost:8000/debug/pprof/profile?seconds=30
+go tool pprof -http 8081 http://localhost:8000/debug/pprof/profile?seconds=30
-go tool pprof -http:8081 http://localhost:8000/debug/pprof/heap
+go tool pprof -http 8081 http://localhost:8000/debug/pprof/heap
-go tool pprof -http:8081 http://localhost:8000/debug/pprof/goroutine
+go tool pprof -http 8081 http://localhost:8000/debug/pprof/goroutine
 ```

cmd/converge/prometheus.go

@@ -15,8 +15,7 @@ const NAMESPACE = "converge"
 var (
 	// remember previous values of agent guids and clients so that we can increment
 	// the cumulative counters.
-	lastAgents  map[string]models.Agent  = make(map[string]models.Agent)
+	lastState *models.State = &models.State{}
-	lastClients map[string]models.Client = make(map[string]models.Client)
 
 	cumulativeAgentCount = promauto.NewCounter(prometheus.CounterOpts{
 		Namespace: NAMESPACE,
@@ -100,7 +99,7 @@ var (
 	)
 )
 
-func agentLabels(agent models.Agent) prometheus.Labels {
+func agentLabels(agent *models.Agent) prometheus.Labels {
 	return prometheus.Labels{
 		"agent_guid":     agent.Guid,
 		"agent_address":  agent.RemoteAddr,
@@ -113,7 +112,7 @@ func agentLabels(agent models.Agent) prometheus.Labels {
 	}
 }
 
-func clientLabels(client models.Client) prometheus.Labels {
+func clientLabels(client *models.Client) prometheus.Labels {
 	return prometheus.Labels{
 		"client_guid":        client.Guid,
 		"client_address":     client.RemoteAddr,
@@ -129,9 +128,9 @@ func clientLabels(client models.Client) prometheus.Labels {
 	}
 }
 
-func agentActive(agent models.Agent) {
+func agentActive(agent *models.Agent) {
-	prevAgent, ok := lastAgents[agent.Guid]
+	prevAgent, ok := findAgent(lastState, agent.Guid)
-	if ok && prevAgent != agent {
+	if ok && *prevAgent != *agent {
 		removeAgentInfoMetrics(prevAgent)
 	}
 	agentInfo.With(agentLabels(agent)).Set(1)
@@ -143,9 +142,27 @@ func agentActive(agent models.Agent) {
 		Set(float64(time.Now().Sub(agent.StartTime).Seconds()))
 }
 
-func clientActive(client models.Client) {
+func findAgent(state *models.State, guid string) (*models.Agent, bool) {
-	prevClient, ok := lastClients[client.Guid]
+	for _, agent := range state.Agents {
-	if ok && prevClient != client {
+		if agent.Guid == guid {
+			return &agent, true
+		}
+	}
+	return nil, false
+}
+
+func findClient(state *models.State, guid string) (*models.Client, bool) {
+	for _, client := range state.Clients {
+		if client.Guid == guid {
+			return &client, true
+		}
+	}
+	return nil, false
+}
+
+func clientActive(client *models.Client) {
+	prevClient, ok := findClient(lastState, client.Guid)
+	if ok && *prevClient != *client {
 		removeClientInfoMetrics(prevClient)
 	}
 	clientInfo.With(clientLabels(client)).Set(1)
@@ -202,12 +219,12 @@ func updateMetrics(state *models.State) {
 }
 
 func updateDurations() {
-	for _, agent := range lastAgents {
+	for _, agent := range lastState.Agents {
 		agentDuration.
 			With(prometheus.Labels{"agent_guid": agent.Guid}).
 			Set(float64(time.Now().Sub(agent.StartTime).Seconds()))
 	}
-	for _, client := range lastClients {
+	for _, client := range lastState.Clients {
 		clientDuration.
 			With(prometheus.Labels{"client_guid": client.Guid}).
 			Set(float64(time.Now().Sub(client.StartTime).Seconds()))
@@ -220,48 +237,48 @@ func updateMetricsImpl(state *models.State) {
 
 	agentCount.Set(float64(len(state.Agents)))
 	disconnectedAgents := make(map[string]models.Agent)
-	for k, v := range lastAgents {
+	for _, agent := range lastState.Agents {
-		disconnectedAgents[k] = v
+		disconnectedAgents[agent.Guid] = agent
 	}
 	for _, agent := range state.Agents {
-		if _, ok := lastAgents[agent.Guid]; !ok {
+		if _, ok := findAgent(lastState, agent.Guid); !ok {
 			cumulativeAgentCount.Inc()
 		}
 		delete(disconnectedAgents, agent.Guid)
 		agentGuids[agent.Guid] = agent
-		agentActive(agent)
+		agentActive(&agent)
 	}
 	for _, agent := range disconnectedAgents {
-		removeAgentMetrics(agent)
+		removeAgentMetrics(&agent)
 	}
-	lastAgents = agentGuids
 
 	clientCount.Set(float64(len(state.Clients)))
 
 	// with this app
 	disconnectedClients := make(map[string]models.Client)
-	for k, v := range lastClients {
+	for _, client := range lastState.Clients {
-		disconnectedClients[k] = v
+		disconnectedClients[client.Guid] = client
 	}
 	for _, client := range state.Clients {
-		if _, ok := lastClients[client.Guid]; !ok {
+		if _, ok := findClient(lastState, client.Guid); !ok {
 			cumulativeClientCount.Inc()
 		}
 		delete(disconnectedClients, client.Guid)
 		clientGuids[client.Guid] = client
-		clientActive(client)
+		clientActive(&client)
 	}
 	for _, client := range disconnectedClients {
-		removeClientMetrics(client)
+		removeClientMetrics(&client)
-	}
-	lastClients = clientGuids
 	}
 
-func removeAgentInfoMetrics(agent models.Agent) bool {
+	lastState = state
+}
+
+func removeAgentInfoMetrics(agent *models.Agent) bool {
 	return agentInfo.Delete(agentLabels(agent))
 }
 
-func removeAgentMetrics(agent models.Agent) {
+func removeAgentMetrics(agent *models.Agent) {
 	ok1 := removeAgentInfoMetrics(agent)
 	guidLabels := prometheus.Labels{"agent_guid": agent.Guid}
 	ok2 := agentStartTime.Delete(guidLabels)
@@ -279,11 +296,11 @@ func removeAgentMetrics(agent models.Agent) {
 	}
 }
 
-func removeClientInfoMetrics(client models.Client) bool {
+func removeClientInfoMetrics(client *models.Client) bool {
 	return clientInfo.Delete(clientLabels(client))
 }
 
-func removeClientMetrics(client models.Client) {
+func removeClientMetrics(client *models.Client) {
 	ok1 := removeClientInfoMetrics(client)
 	guidLabels := prometheus.Labels{"client_guid": client.Guid}
 	ok2 := clientStartTime.Delete(guidLabels)

pkg/models/state.go

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