runc/ps.go

103 lines
1.9 KiB
Go

// +build linux
package main
import (
"encoding/json"
"fmt"
"os"
"os/exec"
"strconv"
"strings"
"github.com/codegangsta/cli"
)
var psCommand = cli.Command{
Name: "ps",
Usage: "ps displays the processes running inside a container",
ArgsUsage: `<container-id> <ps options>`,
Flags: []cli.Flag{
cli.StringFlag{
Name: "format, f",
Value: "",
Usage: `select one of: ` + formatOptions + `.
The default format is table. The following will output the processes of a container
in json format:
# runc ps -f json`,
},
},
Action: func(context *cli.Context) error {
container, err := getContainer(context)
if err != nil {
return err
}
if context.String("format") == "json" {
pids, err := container.Processes()
if err != nil {
return err
}
if err := json.NewEncoder(os.Stdout).Encode(pids); err != nil {
return err
}
return nil
}
psArgs := context.Args().Get(1)
if psArgs == "" {
psArgs = "-ef"
}
output, err := exec.Command("ps", strings.Split(psArgs, " ")...).Output()
if err != nil {
return err
}
lines := strings.Split(string(output), "\n")
pidIndex, err := getPidIndex(lines[0])
if err != nil {
return err
}
pids, err := container.Processes()
if err != nil {
return err
}
fmt.Println(lines[0])
for _, line := range lines[1:] {
if len(line) == 0 {
continue
}
fields := strings.Fields(line)
p, err := strconv.Atoi(fields[pidIndex])
if err != nil {
return fmt.Errorf("unexpected pid '%s': %s", fields[pidIndex], err)
}
for _, pid := range pids {
if pid == p {
fmt.Println(line)
break
}
}
}
return nil
},
}
func getPidIndex(title string) (int, error) {
titles := strings.Fields(title)
pidIndex := -1
for i, name := range titles {
if name == "PID" {
return i, nil
}
}
return pidIndex, fmt.Errorf("couldn't find PID field in ps output")
}