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

Make spawn-daemon only defined on linux

command/spawn_daemon.go

@@ -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)
 

command/spawn_daemon_linux.go

@@ -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
+}

command/spawn_daemon_universal.go

@@ -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)
+}