Use constructor to generate stats (#1)

agent/agent.go

@@ -12,14 +12,11 @@ import (
 	"net"
 	"os"
 	"os/signal"
-	"runtime"
 	"strconv"
 	"strings"
 	"sync"
 	"syscall"
 
-	"github.com/shirou/gopsutil/process"
-
 	"github.com/nakabonne/gosivy/pidfile"
 	"github.com/nakabonne/gosivy/stats"
 )
@@ -158,22 +155,11 @@ func listen() {
 }
 
 func handle(conn io.ReadWriter, msg []byte) error {
-	// TODO: Make it singleton if possible.
-	process, err := process.NewProcess(int32(os.Getpid()))
-	if err != nil {
-		return err
-	}
 	switch msg[0] {
 	case stats.SignalMeta:
-		meta := stats.Meta{
-			GoMaxProcs: runtime.GOMAXPROCS(0),
-			NumCPU:     runtime.NumCPU(),
-		}
-		if u, err := process.Username(); err == nil {
-			meta.Username = u
-		}
-		if c, err := process.Cmdline(); err == nil {
-			meta.Cmmand = c
+		meta, err := stats.NewMeta()
+		if err != nil {
+			return err
 		}
 		b, err := json.Marshal(meta)
 		if err != nil {
@@ -182,12 +168,9 @@ func handle(conn io.ReadWriter, msg []byte) error {
 		_, err = conn.Write(b)
 		return err
 	case stats.SignalStats:
-		s := stats.Stats{
-			Goroutines: runtime.NumGoroutine(),
-		}
-		runtime.ReadMemStats(&s.MemStats)
-		if c, err := process.CPUPercent(); err == nil {
-			s.CPUUsage = c
+		s, err := stats.NewStats()
+		if err != nil {
+			return err
 		}
 		b, err := json.Marshal(s)
 		if err != nil {

stats/meta.go

@@ -1,10 +1,39 @@
 package stats
 
-// Meta represents process metadata. This will be not changed
+import (
+	"os"
+	"runtime"
+
+	"github.com/shirou/gopsutil/process"
+)
+
+// Meta represents process metadata, which will be not changed
 // as long as the process continues.
 type Meta struct {
 	Username   string
-	Cmmand     string
+	Command    string
 	GoMaxProcs int
 	NumCPU     int
 }
+
+func NewMeta() (*Meta, error) {
+	// TODO: Make it singleton if possible.
+	process, err := process.NewProcess(int32(os.Getpid()))
+	if err != nil {
+		return nil, err
+	}
+
+	var username, command string
+	if u, err := process.Username(); err == nil {
+		username = u
+	}
+	if c, err := process.Cmdline(); err == nil {
+		command = c
+	}
+	return &Meta{
+		Username:   username,
+		Command:    command,
+		GoMaxProcs: runtime.GOMAXPROCS(0),
+		NumCPU:     runtime.NumCPU(),
+	}, nil
+}

stats/stats.go

@@ -1,12 +1,47 @@
 package stats
 
-import "runtime"
+import (
+	"os"
+	"runtime"
+
+	"github.com/shirou/gopsutil/process"
+)
 
 // Stats represents the statistical data of the process at the time of measurement.
 type Stats struct {
 	// The number of goroutines that currently exist.
 	Goroutines int
 	// How many percent of the CPU time this process uses
 	CPUUsage float64
-	MemStats runtime.MemStats
+	MemStats
+}
+
+// MemStats records statistics about the memory allocator.
+type MemStats struct {
+	HeapAlloc uint64
+	HeapIdle  uint64
+	HeapInuse uint64
+}
+
+func NewStats() (*Stats, error) {
+	// TODO: Make it singleton if possible.
+	process, err := process.NewProcess(int32(os.Getpid()))
+	if err != nil {
+		return nil, err
+	}
+	var cpuUsage float64
+	if c, err := process.CPUPercent(); err == nil {
+		cpuUsage = c
+	}
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+	return &Stats{
+		Goroutines: runtime.NumGoroutine(),
+		CPUUsage:   cpuUsage,
+		MemStats: MemStats{
+			HeapAlloc: m.HeapAlloc,
+			HeapIdle:  m.HeapIdle,
+			HeapInuse: m.HeapInuse,
+		},
+	}, nil
 }