kubernetes/pkg/util/procfs/procfs.go
Davanum Srinivas 1fdcea28e5 Remove kubelet dependency on pidof
Issue #26093 identified pidof as one of the dependencies of kublet
which could be worked around. In this PR, we just look at /proc
to construct the list of pids we need for a specified process
instead of running "pidof" executable

Related to #26093
2016-08-09 19:55:24 -04:00

107 lines
2.9 KiB
Go

/*
Copyright 2015 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package procfs
import (
"bytes"
"fmt"
"io/ioutil"
"os"
"path"
"path/filepath"
"strconv"
"strings"
"unicode"
"github.com/golang/glog"
)
type ProcFS struct{}
func NewProcFS() ProcFSInterface {
return &ProcFS{}
}
func containerNameFromProcCgroup(content string) (string, error) {
lines := strings.Split(content, "\n")
for _, line := range lines {
entries := strings.SplitN(line, ":", 3)
if len(entries) == 3 && entries[1] == "devices" {
return strings.TrimSpace(entries[2]), nil
}
}
return "", fmt.Errorf("could not find devices cgroup location")
}
// getFullContainerName gets the container name given the root process id of the container.
// Eg. If the devices cgroup for the container is stored in /sys/fs/cgroup/devices/docker/nginx,
// return docker/nginx. Assumes that the process is part of exactly one cgroup hierarchy.
func (pfs *ProcFS) GetFullContainerName(pid int) (string, error) {
filePath := path.Join("/proc", strconv.Itoa(pid), "cgroup")
content, err := ioutil.ReadFile(filePath)
if err != nil {
if os.IsNotExist(err) {
return "", os.ErrNotExist
}
return "", err
}
return containerNameFromProcCgroup(string(content))
}
func PidOf(name string) []int {
pids := []int{}
filepath.Walk("/proc", func(path string, info os.FileInfo, err error) error {
base := filepath.Base(path)
// Traverse only the directories we are interested in
if info.IsDir() && path != "/proc" {
// If the directory is not a number (i.e. not a PID), skip it
if _, err := strconv.Atoi(base); err != nil {
return filepath.SkipDir
}
}
if base != "cmdline" {
return nil
}
cmdline, err := ioutil.ReadFile(path)
if err != nil {
glog.V(4).Infof("Error reading file %s: %+v", path, err)
return nil
}
// The bytes we read have '\0' as a separator for the command line
parts := bytes.SplitN(cmdline, []byte{0}, 2)
if len(parts) == 0 {
return nil
}
// Split the command line itself we are interested in just the first part
exe := strings.FieldsFunc(string(parts[0]), func(c rune) bool {
return unicode.IsSpace(c) || c == ':'
})
if len(exe) == 0 {
return nil
}
// Check if the name of the executable is what we are looking for
if filepath.Base(exe[0]) == name {
dirname := filepath.Base(filepath.Dir(path))
// Grab the PID from the directory path
pid, _ := strconv.Atoi(dirname)
pids = append(pids, pid)
}
return nil
})
return pids
}