处理获取docker ID兼容k8s的情况

helper/docker/id.go

@@ -1,22 +1,50 @@
 package docker
 
 import (
+	"bufio"
 	"bytes"
-	"os/exec"
+	"errors"
+	"os"
 )
 
 var (
-	_dockerId string
+	_dockerId     string
+	dockerFeature = []byte("docker/")
+
+	errNotMatch = errors.New("not match")
 )
 
-func SelfContainerID() (string, error) {
+func SelfContainerID() (did string, err error) {
 	if _dockerId != "" {
 		return _dockerId, nil
 	}
-	if buf, err := exec.Command("/bin/sh", "-c", "cat /proc/self/cgroup | grep -o -e \"docker/.*\"| head -n 1 |sed \"s/docker\\/\\(.*\\)/\\\\1/\"").CombinedOutput(); err != nil {
-		return "", err
-	} else {
-		_dockerId = string(bytes.TrimSpace(buf))
-		return _dockerId, nil
+	var (
+		pos int
+		p   []byte
+		fp  *os.File
+	)
+	if fp, err = os.Open("/proc/self/cgroup"); err != nil {
+		return
+	}
+	defer func() {
+		_ = fp.Close()
+	}()
+	br := bufio.NewReader(fp)
+	for {
+		if p, _, err = br.ReadLine(); err != nil {
+			break
+		}
+		if pos = bytes.Index(p, dockerFeature); pos == -1 {
+			continue
+		}
+		p = bytes.TrimSpace(p[pos+len(dockerFeature):])
+		if pos = bytes.LastIndexByte(p, '/'); pos == -1 {
+			_dockerId = string(p)
+			return _dockerId, nil
+		} else {
+			_dockerId = string(p[pos+1:])
+			return _dockerId, nil
+		}
 	}
+	return "", errNotMatch
 }