Code cleanups

data.go

@@ -4,7 +4,7 @@ import "time"
 
 // UIData represents data to be passed to UI.
 type UIData struct {
-	Services      Services
+	Services      []*Service
 	Vars          []VarName
 	LastTimestamp time.Time
 }
@@ -15,17 +15,3 @@ func NewUIData(vars []VarName) *UIData {
 		Vars: vars,
 	}
 }
-
-// FindService returns existing service by port.
-func (d *UIData) FindService(port string) *Service {
-	if d.Services == nil {
-		return nil
-	}
-	for _, service := range d.Services {
-		if service.Port == port {
-			return service
-		}
-	}
-
-	return nil
-}

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"log"
+	"sync"
 	"time"
 
 	"github.com/divan/termui"
@@ -10,9 +11,8 @@ import (
 
 var (
 	interval = flag.Duration("i", 5*time.Second, "Polling interval")
-	portsArg    = flag.String("ports", "40001,40002,40000,40004,1233,1234,1235", "Ports for accessing services expvars")
+	portsArg = flag.String("ports", "1234", "Ports for accessing services expvars")
-	defaultVars = flag.String("vars", "memstats.Alloc,memstats.Sys", "Default vars to monitor")
+	varsArg  = flag.String("vars", "memstats.Alloc,memstats.Sys", "Default vars to monitor")
-	extraVars   = flag.String("extravars", "", "Comma-separated extra vars exported with expvars")
 	dummy    = flag.Bool("dummy", false, "Use dummy (console) output")
 )
 
@@ -23,7 +23,7 @@ func main() {
 		log.Fatal("cannot parse ports:", err)
 	}
 
-	vars, err := ParseVars(*defaultVars, *extraVars)
+	vars, err := ParseVars(*varsArg)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -46,25 +46,11 @@ func main() {
 	tick := time.NewTicker(*interval)
 	evtCh := termui.EventCh()
 
-	update := func() {
+	UpdateAll(ui, data)
-		for _, port := range ports {
-			service := data.FindService(port)
-			if service == nil {
-				continue
-			}
-
-			service.Update()
-		}
-
-		data.LastTimestamp = time.Now()
-
-		ui.Update(*data)
-	}
-	update()
 	for {
 		select {
 		case <-tick.C:
-			update()
+			UpdateAll(ui, data)
 		case e := <-evtCh:
 			if e.Type == termui.EventKey && e.Ch == 'q' {
 				return
@@ -76,3 +62,17 @@ func main() {
 		}
 	}
 }
+
+// UpdateAll collects data from expvars and refreshes UI.
+func UpdateAll(ui UI, data *UIData) {
+	var wg sync.WaitGroup
+	for _, service := range data.Services {
+		wg.Add(1)
+		go service.Update(&wg)
+	}
+	wg.Wait()
+
+	data.LastTimestamp = time.Now()
+
+	ui.Update(*data)
+}

service.go

@@ -5,11 +5,9 @@ import (
 	"net"
 	"strconv"
 	"strings"
+	"sync"
 )
 
-// Services is just a slice of Service.
-type Services []*Service
-
 // Service represents constantly updating info about single service.
 type Service struct {
 	Port    string
@@ -36,7 +34,8 @@ func NewService(port string, vars []VarName) *Service {
 }
 
 // Update updates Service info from Expvar variable.
-func (s *Service) Update() {
+func (s *Service) Update(wg *sync.WaitGroup) {
+	defer wg.Done()
 	expvar, err := FetchExpvar(s.Addr())
 	s.Err = err
 

ui_termui.go

@@ -74,7 +74,7 @@ func (t *TermUI) Init(data UIData) error {
 		s := termui.NewSparklines(sparklines...)
 		s.Height = 2*len(data.Services) + 2
 		s.HasBorder = true
-		s.Border.Label = fmt.Sprintf("Sparklines for %s", data.Vars[0])
+		s.Border.Label = fmt.Sprintf("Monitoring %s", data.Vars[0])
 		return s
 	}()
 

utils.go

@@ -7,22 +7,15 @@ import (
 
 // ParseVars returns parsed and validated slice of strings with
 // variables names that will be used for monitoring.
-func ParseVars(def, extra string) ([]VarName, error) {
+func ParseVars(vars string) ([]VarName, error) {
-	if def == "" && extra == "" {
+	if vars == "" {
 		return nil, errors.New("no vars specified")
 	}
 
-	fields := func(s string) []VarName {
+	ss := strings.FieldsFunc(vars, func(r rune) bool { return r == ',' })
-		ss := strings.FieldsFunc(s, func(r rune) bool { return r == ',' })
-		ret := []VarName{}
-		for _, str := range ss {
-			ret = append(ret, VarName(str))
-		}
-		return ret
-	}
-
 	var ret []VarName
-	ret = append(ret, fields(def)...)
+	for _, s := range ss {
-	ret = append(ret, fields(extra)...)
+		ret = append(ret, VarName(s))
+	}
 	return ret, nil
 }

utils_test.go

@@ -3,10 +3,9 @@ package main
 import "testing"
 
 func TestUtils(t *testing.T) {
-	def := "memstats.Alloc,memstats.Sys"
+	str := "memstats.Alloc,memstats.Sys"
-	extra := ""
 
-	vars, err := ParseVars(def, extra)
+	vars, err := ParseVars(str)
 	if err != nil {
 		t.Fatalf("Err not nil: %v", err)
 	}
@@ -15,10 +14,9 @@ func TestUtils(t *testing.T) {
 		t.Fatalf("vars should contain 2 elements, but has %d", len(vars))
 	}
 
-	def = "memstats.Alloc,memstats.Sys"
+	str = "memstats.Alloc,memstats.Sys,goroutines,Counter.A"
-	extra = "goroutines,counter.A"
 
-	vars, err = ParseVars(def, extra)
+	vars, err = ParseVars(str)
 	if err != nil {
 		t.Fatalf("Err not nil: %v", err)
 	}

var_test.go

@@ -11,4 +11,9 @@ func TestVarName(t *testing.T) {
 	if len(slice) != 2 || slice[0] != "memstats" || slice[1] != "Alloc" {
 		t.Fatalf("ToSlice failed: %v", slice)
 	}
+
+	short := v.Short()
+	if short != "Alloc" {
+		t.Fatalf("Expecting Short() to be 'Alloc', but got: %s", short)
+	}
 }