func ListContainers() ([]string, error) {
out, err := linux.Exec("docker ps -q --no-trunc")
if err != nil {
return nil, err
}
return strings.Fields(out), nil
}
func GetNetInUsage(cont string) (int64, error) {
cmd := fmt.Sprintf("docker exec %s cat /sys/devices/virtual/net/eth0/statistics/rx_bytes", cont)
out, err := linux.Exec(cmd)
if err != nil {
return 0, err
}
net, err := strconv.ParseInt(strings.TrimSpace(out), 10, 64)
if err != nil {
return 0, err
}
return net, nil
}
func GetMemUsage(cont string) (int64, error) {
cmd := fmt.Sprintf("head -2 /sys/fs/cgroup/memory/system.slice/docker-%s.scope/memory.stat", cont)
out, err := linux.Exec(cmd)
if err != nil {
return 0, err
}
mem, err := strconv.ParseInt(strings.Fields(out)[3], 10, 64)
if err != nil {
return 0, err
}
return mem, nil
}
func main() {
// read arguments
if len(os.Args) < 3 {
fmt.Println("[ERROR] incomplete command!")
fmt.Printf("Usage: %s <cont-name> <freq>\n", os.Args[0])
os.Exit(1)
}
cont_name := os.Args[1]
freq, err := strconv.ParseInt(os.Args[2], 10, 32)
if err != nil {
fmt.Println("[ERROR] unknown frequency argument!")
os.Exit(1)
}
// get container id
out, err := linux.Exec(fmt.Sprintf("docker inspect --format='{{.Id}}' %s", cont_name))
if err != nil {
fmt.Printf("[ERROR] unable to run cmd, output: (%s)\n", out)
panic(err)
}
cont_id := strings.TrimSpace(string(out))
// check if feedgnuplot exists
command := exec.Command("which", "feedgnuplot")
empty, err := command.CombinedOutput()
if err != nil || string(empty) == "" {
panic("[ERROR] feedgnuplot doesn't exists!")
}
// CTRL+C signal handler
sigs := make(chan os.Signal, 1)
done := true
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
go func() {
_ = <-sigs
done = false
}()
// init feedgnuplot
command = exec.Command("feedgnuplot", "--lines --stream --title 'cpu-usage' --ylabel 'cpu (100% = 1core)' --xlabel 'time ticks'")
reader, writer := io.Pipe()
command.Stdin = reader
command.Stdout = os.Stdout
command.Stderr = os.Stderr
err = command.Start()
if err != nil {
fmt.Println("[ERROR] error while starting feedgnuplot!")
panic(err)
}
// init readings
cur_time := time.Now().UnixNano()
cur_cpu, err := docker.GetCPUUsage(cont_id)
if err != nil {
fmt.Println("[WARN] unable to get container CPU usage!")
cur_cpu = 0
}
// infinite loop for plotting data
for done {
new_cpu, err := docker.GetCPUUsage(cont_id)
if err != nil {
fmt.Println("[WARN] unable to get container CPU usage!")
new_cpu = 0
}
new_time := time.Now().UnixNano()
avg_cpu := float64(new_cpu-cur_cpu) / float64(new_time-cur_time) * 1000000000.0
cur_time = new_time
cur_cpu = new_cpu
_, err = io.WriteString(writer, fmt.Sprintf("%.6f\n", avg_cpu))
if err != nil {
panic("[ERROR] unable to write to feedgnuplot-stdin!")
}
time.Sleep(time.Duration(freq) * time.Millisecond)
}
_, err = io.WriteString(writer, "exit\n")
if err != nil {
panic("[ERROR] unable to write to feedgnuplot-stdin!")
}
command.Wait()
return
}
func sendNetUsage(interval time.Duration) {
out, err := linux.Exec("ifconfig -s")
now := time.Now()
if err != nil {
log.Printf("[WARN] unable to get system net usage: ", err.Error())
} else {
reader := csv.NewReader(strings.NewReader(out))
reader.Comma = ' '
reader.TrimLeadingSpace = true
net_data, err := reader.ReadAll()
if err != nil {
log.Println("[WARN] unable to get system net usage: ", err.Error())
} else {
for index, row := range net_data {
if index == 0 {
continue
}
net, err := strconv.ParseInt(row[3], 10, 64)
if err != nil {
log.Println("[WARN] error in converting to integer: ", err.Error())
} else {
ntup, ok := rxdata[row[0]]
if ok {
avg := float64(net-ntup.net) * 1000000000 / float64(now.Sub(ntup.time))
ntup.time = now
ntup.net = net
dispatch(row[0], now, avg, "rx")
} else {
rxdata[row[0]] = &ntuple{time: now, net: net}
}
}
net, err = strconv.ParseInt(row[7], 10, 64)
if err != nil {
log.Println("[WARN] error in converting to integer: ", err.Error())
} else {
ntup, ok := txdata[row[0]]
if ok {
avg := float64(net-ntup.net) * 1000000000 / float64(now.Sub(ntup.time))
ntup.time = now
ntup.net = net
dispatch(row[0], now, avg, "tx")
} else {
txdata[row[0]] = &ntuple{time: now, net: net}
}
}
}
}
}
conts, err := docker.ListContainers()
if err != nil {
log.Fatalln("[WARN] unable to get list of containers: ", err.Error())
}
for _, cont := range conts {
net, err := docker.GetNetInUsage(cont)
now = time.Now()
if err != nil {
log.Printf("[WARN] unable to get rx net usage for %s: %s\n", cont, err.Error())
} else {
ntup, ok := rxdata[cont]
if ok {
avg := float64(net-ntup.net) * 1000000000 / float64(now.Sub(ntup.time))
ntup.time = now
ntup.net = net
dispatch(cont, now, avg, "rx")
} else {
rxdata[cont] = &ntuple{time: now, net: net}
}
}
net, err = docker.GetNetOutUsage(cont)
now = time.Now()
if err != nil {
log.Printf("[WARN] unable to get tx net usage for %s: %s\n", cont, err.Error())
} else {
ntup, ok := txdata[cont]
if ok {
avg := float64(net-ntup.net) * 1000000000 / float64(now.Sub(ntup.time))
ntup.time = now
ntup.net = net
dispatch(cont, now, avg, "tx")
} else {
txdata[cont] = &ntuple{time: now, net: net}
}
}
}
for _, client := range clients {
client.Flush()
}
}