3826: Use /proc/PID/net/dev to get container net stats.

diff --git a/services/crunchstat/crunchstat.go b/services/crunchstat/crunchstat.go
index cc7acf28df7b046ce0830b779a2853b1b841beab..e8dc915d9328f7bea589648707e58beafa514879 100644 (file)
--- a/services/crunchstat/crunchstat.go
+++ b/services/crunchstat/crunchstat.go
@@ -3,6 +3,7 @@ package main
 import (
        "bufio"
        "flag"
+       "errors"
        "fmt"
        "io"
        "io/ioutil"
@@ -10,7 +11,6 @@ import (
        "os"
        "os/exec"
        "os/signal"
-       "path/filepath"
        "strings"
        "syscall"
        "time"
@@ -63,7 +63,7 @@ func OpenAndReadAll(filename string, log_chan chan<- string) ([]byte, error) {
        }
 }
 
-func FindStat(stderr chan<- string, cgroup Cgroup, statgroup string, stat string) string {
+func FindStat(stderr chan<- string, cgroup Cgroup, statgroup string, stat string, verbose bool) string {
        var path string
        path = fmt.Sprintf("%s/%s/%s/%s/%s", cgroup.root, statgroup, cgroup.parent, cgroup.cid, stat)
        if _, err := os.Stat(path); err != nil {
@@ -79,42 +79,32 @@ func FindStat(stderr chan<- string, cgroup Cgroup, statgroup string, stat string
                stderr <- fmt.Sprintf("crunchstat: did not find stats file (root %s, parent %s, cid %s, statgroup %s, stat %s)", cgroup.root, cgroup.parent, cgroup.cid, statgroup, stat)
                return ""
        }
-       stderr <- fmt.Sprintf("crunchstat: reading stats from %s", path)
+       if verbose {
+               stderr <- fmt.Sprintf("crunchstat: reading stats from %s", path)
+       }
        return path
 }
 
-func SetNetworkNamespace(stderr chan<- string, procsFilename string) (string) {
-       // Not supported yet -- we'll just report host-wide network stats.
-       return "host"
-
-       if procsFilename == "" { return "host" }
+func GetContainerNetStats(stderr chan<- string, cgroup Cgroup) (io.Reader, error) {
+       procsFilename := FindStat(stderr, cgroup, "cpuacct", "cgroup.procs", false)
        procsFile, err := os.Open(procsFilename)
        if err != nil {
                stderr <- fmt.Sprintf("crunchstat: open %s: %s", procsFilename, err)
-               return "host"
+               return nil, err
        }
        defer procsFile.Close()
        reader := bufio.NewScanner(procsFile)
        for reader.Scan() {
                taskPid := reader.Text()
-               netnsFilename := fmt.Sprintf("/proc/%s/ns/net", taskPid)
-               netnsFile, err := os.Open(netnsFilename)
+               statsFilename := fmt.Sprintf("/proc/%s/net/dev", taskPid)
+               stats, err := OpenAndReadAll(statsFilename, stderr)
                if err != nil {
-                       stderr <- fmt.Sprintf("crunchstat: open %s: %s", netnsFilename, err)
+                       stderr <- fmt.Sprintf("crunchstat: open %s: %s", statsFilename, err)
                        continue
                }
-               defer netnsFile.Close()
-
-               // syscall.Setns() doesn't exist yet, and doesn't work
-               // from a multithreaded program yet.
-               //
-               // if _, err2 := syscall.Setns(netnsFile.Fd()); err != nil {
-               //      stderr <- fmt.Sprintf("crunchstat: Setns: %s", err2)
-               //      continue
-               // }
-               return "task"
+               return strings.NewReader(string(stats)), nil
        }
-       return "host"
+       return nil, errors.New("Could not read stats for any proc in container")
 }
 
 type NetSample struct {
@@ -123,31 +113,43 @@ type NetSample struct {
        rxBytes    int64
 }
 
-func DoNetworkStats(stderr chan<- string, procsFilename string, lastStat map[string]NetSample) (map[string]NetSample) {
-       statScope := SetNetworkNamespace(stderr, procsFilename)
+func DoNetworkStats(stderr chan<- string, cgroup Cgroup, lastStat map[string]NetSample) (map[string]NetSample) {
+       stats, err := GetContainerNetStats(stderr, cgroup)
+       if err != nil { return lastStat }
 
-       ifDirs, err := filepath.Glob("/sys/class/net/*")
-       if err != nil {
-               stderr <- fmt.Sprintf("crunchstat: could not list interfaces", err)
-               return lastStat
-       }
        if lastStat == nil {
                lastStat = make(map[string]NetSample)
        }
-       for _, ifDir := range ifDirs {
-               ifName := filepath.Base(ifDir)
-               tx_s, tx_err := OpenAndReadAll(fmt.Sprintf("/sys/class/net/%s/statistics/tx_bytes", ifName), stderr)
-               rx_s, rx_err := OpenAndReadAll(fmt.Sprintf("/sys/class/net/%s/statistics/rx_bytes", ifName), stderr)
-               if rx_err != nil || tx_err != nil {
-                       return nil
+       scanner := bufio.NewScanner(stats)
+       Iface: for scanner.Scan() {
+               var ifName string
+               var rx, tx int64
+               words := bufio.NewScanner(strings.NewReader(scanner.Text()))
+               words.Split(bufio.ScanWords)
+               wordIndex := 0
+               for words.Scan() {
+                       word := words.Text()
+                       switch wordIndex {
+                       case 0:
+                               ifName = strings.TrimRight(word, ":")
+                       case 1:
+                               if _, err := fmt.Sscanf(word, "%d", &rx); err != nil {
+                                       continue Iface
+                               }
+                       case 9:
+                               if _, err := fmt.Sscanf(word, "%d", &tx); err != nil {
+                                       continue Iface
+                               }
+                       }
+                       wordIndex++
                }
+               if ifName == "lo" || ifName == "" { continue }
                nextSample := NetSample{}
                nextSample.sampleTime = time.Now()
-               fmt.Sscanf(string(tx_s), "%d", &nextSample.txBytes)
-               fmt.Sscanf(string(rx_s), "%d", &nextSample.rxBytes)
+               nextSample.txBytes = tx
+               nextSample.rxBytes = rx
                if lastSample, ok := lastStat[ifName]; ok {
-                       stderr <- fmt.Sprintf("crunchstat: %s net %s tx %d rx %d interval %.4f",
-                               statScope,
+                       stderr <- fmt.Sprintf("crunchstat: task net %s tx %d rx %d interval %.4f",
                                ifName,
                                nextSample.txBytes - lastSample.txBytes,
                                nextSample.rxBytes - lastSample.rxBytes,
@@ -174,12 +176,11 @@ func PollCgroupStats(cgroup Cgroup, stderr chan string, poll int64, stop_poll_ch
 
        user_hz := float64(C.sysconf(C._SC_CLK_TCK))
 
-       cpuacct_stat := FindStat(stderr, cgroup, "cpuacct", "cpuacct.stat")
-       blkio_io_service_bytes := FindStat(stderr, cgroup, "blkio", "blkio.io_service_bytes")
-       cpuset_cpus := FindStat(stderr, cgroup, "cpuset", "cpuset.cpus")
-       memory_stat := FindStat(stderr, cgroup, "memory", "memory.stat")
-       procs := FindStat(stderr, cgroup, "cpuacct", "cgroup.procs")
-       lastNetStat := DoNetworkStats(stderr, procs, nil)
+       cpuacct_stat := FindStat(stderr, cgroup, "cpuacct", "cpuacct.stat", true)
+       blkio_io_service_bytes := FindStat(stderr, cgroup, "blkio", "blkio.io_service_bytes", true)
+       cpuset_cpus := FindStat(stderr, cgroup, "cpuset", "cpuset.cpus", true)
+       memory_stat := FindStat(stderr, cgroup, "memory", "memory.stat", true)
+       lastNetStat := DoNetworkStats(stderr, cgroup, nil)
 
        poll_chan := make(chan bool, 1)
        go func() {
@@ -309,7 +310,7 @@ func PollCgroupStats(cgroup Cgroup, stderr chan string, poll int64, stop_poll_ch
                        c.Close()
                }
 
-               lastNetStat = DoNetworkStats(stderr, procs, lastNetStat)
+               lastNetStat = DoNetworkStats(stderr, cgroup, lastNetStat)
        }
 }