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Merge pull request #75 from hashicorp/h-spawn-daemon-build-dep 

Make spawn-daemon only defined on linux
This commit is contained in:
Alex Dadgar 2015-09-21 17:27:08 -07:00
parent 6fb7d45acf 96b81124bf
commit 33117772b7
3 changed files with 131 additions and 115 deletions
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116
command/spawn_daemon.go
View File

@ -2,34 +2,14 @@ package command
import (
"encoding/json"
"fmt"
"os"
"os/exec"
"strconv"
"strings"
"syscall"
cgroupFs "github.com/opencontainers/runc/libcontainer/cgroups/fs"
cgroupConfig "github.com/opencontainers/runc/libcontainer/configs"
)
type SpawnDaemonCommand struct {
Meta
}
// Configuration for the command to start as a daemon.
type DaemonConfig struct {
exec.Cmd
// The paths, if not /dev/null, must be either in the tasks root directory
// or in the shared alloc directory.
StdoutFile string
StdinFile string
StderrFile string
Groups *cgroupConfig.Cgroup
}
// Status of executing the user's command.
type SpawnStartStatus struct {
// ErrorMsg will be empty if the user command was started successfully.
@ -37,11 +17,6 @@ type SpawnStartStatus struct {
ErrorMsg string
}
// The exit status of the user's command.
type SpawnExitStatus struct {
Success bool
}
func (c *SpawnDaemonCommand) Help() string {
helpText := `
Usage: nomad spawn-daemon [options] <daemon_config>
@ -65,99 +40,10 @@ func (c *SpawnDaemonCommand) Synopsis() string {
return "Spawn a daemon command with configurable isolation."
}
func (c *SpawnDaemonCommand) Run(args []string) int {
flags := c.Meta.FlagSet("spawn-daemon", FlagSetClient)
flags.Usage = func() { c.Ui.Output(c.Help()) }
if err := flags.Parse(args); err != nil {
return 1
}
// Check that we got json input.
args = flags.Args()
if len(args) != 1 {
c.Ui.Error(c.Help())
return 1
}
jsonInput, err := strconv.Unquote(args[0])
if err != nil {
return outputStartStatus(fmt.Errorf("Failed to unquote json input: %v", err), 1)
}
// De-serialize the passed command.
var cmd DaemonConfig
dec := json.NewDecoder(strings.NewReader(jsonInput))
if err := dec.Decode(&cmd); err != nil {
return outputStartStatus(err, 1)
}
// Join this process to the cgroup.
if cmd.Groups != nil {
manager := cgroupFs.Manager{}
manager.Cgroups = cmd.Groups
// Apply will place the current pid into the tasks file for each of the
// created cgroups:
// /sys/fs/cgroup/memory/user/1000.user/4.session/<uuid>/tasks
//
// Apply requires superuser permissions, and may fail if Nomad is not run with
// the required permissions
if err := manager.Apply(os.Getpid()); err != nil {
return outputStartStatus(fmt.Errorf("Failed to join cgroup: %v", err), 1)
}
}
// Isolate the user process.
if _, err := syscall.Setsid(); err != nil {
return outputStartStatus(fmt.Errorf("Failed to join cgroup: %v",
fmt.Errorf("Failed setting sid: %v", err)), 1)
}
syscall.Umask(0)
// Redirect logs.
stdo, err := os.OpenFile(cmd.StdoutFile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0666)
if err != nil {
return outputStartStatus(fmt.Errorf("Error opening file to redirect Stdout: %v", err), 1)
}
stde, err := os.OpenFile(cmd.StderrFile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0666)
if err != nil {
return outputStartStatus(fmt.Errorf("Error opening file to redirect Stderr: %v", err), 1)
}
stdi, err := os.OpenFile(cmd.StdinFile, os.O_CREATE|os.O_RDONLY, 0666)
if err != nil {
return outputStartStatus(fmt.Errorf("Error opening file to redirect Stdin: %v", err), 1)
}
cmd.Stdout = stdo
cmd.Stderr = stde
cmd.Stdin = stdi
// Spawn the user process.
if err := cmd.Cmd.Start(); err != nil {
return outputStartStatus(fmt.Errorf("Error starting user command: %v", err), 1)
}
// Indicate that the command was started successfully.
outputStartStatus(nil, 0)
// Wait and then output the exit status.
exitStatus := &SpawnExitStatus{}
if err := cmd.Wait(); err == nil {
exitStatus.Success = true
}
enc := json.NewEncoder(os.Stdout)
enc.Encode(exitStatus)
return 0
}
// outputStartStatus is a helper function that outputs a SpawnStartStatus to
// Stdout with the passed error, which may be nil to indicate no error. It
// returns the passed status.
func outputStartStatus(err error, status int) int {
func (c *SpawnDaemonCommand) outputStartStatus(err error, status int) int {
startStatus := &SpawnStartStatus{}
enc := json.NewEncoder(os.Stdout)

121
command/spawn_daemon_linux.go Normal file
View File

@ -0,0 +1,121 @@
package command
import (
"encoding/json"
"fmt"
"os"
"os/exec"
"strconv"
"strings"
"syscall"
cgroupFs "github.com/opencontainers/runc/libcontainer/cgroups/fs"
cgroupConfig "github.com/opencontainers/runc/libcontainer/configs"
)
// Configuration for the command to start as a daemon.
type DaemonConfig struct {
exec.Cmd
// The paths, if not /dev/null, must be either in the tasks root directory
// or in the shared alloc directory.
StdoutFile string
StdinFile string
StderrFile string
Groups *cgroupConfig.Cgroup
}
// The exit status of the user's command.
type SpawnExitStatus struct {
Success bool
}
func (c *SpawnDaemonCommand) Run(args []string) int {
flags := c.Meta.FlagSet("spawn-daemon", FlagSetClient)
flags.Usage = func() { c.Ui.Output(c.Help()) }
if err := flags.Parse(args); err != nil {
return 1
}
// Check that we got json input.
args = flags.Args()
if len(args) != 1 {
c.Ui.Error(c.Help())
return 1
}
jsonInput, err := strconv.Unquote(args[0])
if err != nil {
return c.outputStartStatus(fmt.Errorf("Failed to unquote json input: %v", err), 1)
}
// De-serialize the passed command.
var cmd DaemonConfig
dec := json.NewDecoder(strings.NewReader(jsonInput))
if err := dec.Decode(&cmd); err != nil {
return c.outputStartStatus(err, 1)
}
// Join this process to the cgroup.
if cmd.Groups != nil {
manager := cgroupFs.Manager{}
manager.Cgroups = cmd.Groups
// Apply will place the current pid into the tasks file for each of the
// created cgroups:
// /sys/fs/cgroup/memory/user/1000.user/4.session/<uuid>/tasks
//
// Apply requires superuser permissions, and may fail if Nomad is not run with
// the required permissions
if err := manager.Apply(os.Getpid()); err != nil {
return c.outputStartStatus(fmt.Errorf("Failed to join cgroup: %v", err), 1)
}
}
// Isolate the user process.
if _, err := syscall.Setsid(); err != nil {
return c.outputStartStatus(fmt.Errorf("Failed to join cgroup: %v",
fmt.Errorf("Failed setting sid: %v", err)), 1)
}
syscall.Umask(0)
// Redirect logs.
stdo, err := os.OpenFile(cmd.StdoutFile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0666)
if err != nil {
return c.outputStartStatus(fmt.Errorf("Error opening file to redirect Stdout: %v", err), 1)
}
stde, err := os.OpenFile(cmd.StderrFile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0666)
if err != nil {
return c.outputStartStatus(fmt.Errorf("Error opening file to redirect Stderr: %v", err), 1)
}
stdi, err := os.OpenFile(cmd.StdinFile, os.O_CREATE|os.O_RDONLY, 0666)
if err != nil {
return c.outputStartStatus(fmt.Errorf("Error opening file to redirect Stdin: %v", err), 1)
}
cmd.Stdout = stdo
cmd.Stderr = stde
cmd.Stdin = stdi
// Spawn the user process.
if err := cmd.Cmd.Start(); err != nil {
return c.outputStartStatus(fmt.Errorf("Error starting user command: %v", err), 1)
}
// Indicate that the command was started successfully.
c.outputStartStatus(nil, 0)
// Wait and then output the exit status.
exitStatus := &SpawnExitStatus{}
if err := cmd.Wait(); err == nil {
exitStatus.Success = true
}
enc := json.NewEncoder(os.Stdout)
enc.Encode(exitStatus)
return 0
}

9
command/spawn_daemon_universal.go Normal file
View File

@ -0,0 +1,9 @@
// +build !linux
package command
import "errors"
func (c *SpawnDaemonCommand) Run(args []string) int {
return c.outputStartStatus(errors.New("spawn-daemon not supported"), 1)
}