[medium] agents summary queries added to the API dashboard

src/mig/api/api.go

@@ -555,6 +555,19 @@ func getDashboard(respWriter http.ResponseWriter, request *http.Request) {
 		}
 		ctx.Channels.Log <- mig.Log{OpID: opid, Desc: "leaving getDashboard()"}.Debug()
 	}()
+
+	// get summary of agents active in the last 5 minutes
+	sum, err := ctx.DB.SumAgentsByVersion(time.Now().Add(-5 * time.Minute))
+	if err != nil {
+		panic(err)
+	}
+	count, err := ctx.DB.CountNewAgents(time.Now().Add(-24 * time.Hour))
+	if err != nil {
+		panic(err)
+	}
+	sumItem, err := agentsSummaryToItem(sum, count, ctx)
+	resource.AddItem(sumItem)
+
 	// add the last 10 actions
 	actions, err := ctx.DB.Last10Actions()
 	if err != nil {

src/mig/api/convert.go

@@ -38,6 +38,7 @@ package main
 import (
 	"fmt"
 	"mig"
+	migdb "mig/database"
 
 	"github.com/jvehent/cljs"
 )
@@ -81,3 +82,26 @@ func commandToItem(cmd mig.Command) (item cljs.Item, err error) {
 	}
 	return
 }
+
+// agentsSumToItem receives an AgentsSum and returns an Item
+// in the Collection+JSON format
+func agentsSummaryToItem(sum []migdb.AgentsSum, count float64, ctx Context) (item cljs.Item, err error) {
+	item.Href = fmt.Sprintf("%s/dashboard", ctx.Server.BaseURL)
+	var total float64 = 0
+	for _, asum := range sum {
+		total += asum.Count
+	}
+	item.Data = []cljs.Data{
+		{Name: "active agents", Value: total},
+		{Name: "agents versions count", Value: sum},
+		{Name: "agents started in the last 24 hours", Value: count},
+	}
+	links := make([]cljs.Link, 0)
+	link := cljs.Link{
+		Rel:  "agents dashboard",
+		Href: fmt.Sprintf("%s/agents/dashboard", ctx.Server.BaseURL),
+	}
+	links = append(links, link)
+	item.Links = links
+	return
+}

src/mig/database/queries.go

@@ -768,3 +768,45 @@ func (db *DB) MarkAgentDestroyed(agent mig.Agent) (err error) {
 	}
 	return
 }
+
+type AgentsSum struct {
+	Version string  `json:"version"`
+	Count   float64 `json:"count"`
+}
+
+// SumAgentsByVersion retrieves a sum of agents grouped by version
+func (db *DB) SumAgentsByVersion(pointInTime time.Time) (sum []AgentsSum, err error) {
+	rows, err := db.c.Query(`SELECT COUNT(*), version FROM agents
+		WHERE agents.heartbeattime >= $1 AND agents.heartbeattime <= NOW()
+		GROUP BY version`, pointInTime)
+	if err != nil {
+		err = fmt.Errorf("Error while counting agents: '%v'", err)
+		return
+	}
+	for rows.Next() {
+		var asum AgentsSum
+		err = rows.Scan(&asum.Count, &asum.Version)
+		if err != nil {
+			rows.Close()
+			err = fmt.Errorf("Failed to retrieve summary data: '%v'", err)
+			return
+		}
+		sum = append(sum, asum)
+	}
+	rows.Close()
+	return
+}
+
+// NewAgents retrieves a count of agents that started after `pointInTime`
+func (db *DB) CountNewAgents(pointInTime time.Time) (sum float64, err error) {
+	err = db.c.QueryRow(`SELECT COUNT(name) FROM agents
+		WHERE starttime >= $1 AND starttime <= NOW()`, pointInTime).Scan(&sum)
+	if err != nil {
+		err = fmt.Errorf("Error while counting agents: '%v'", err)
+		return
+	}
+	if err == sql.ErrNoRows {
+		return
+	}
+	return
+}