ParseAndReplace args at the executor level

client/driver/exec.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"github.com/hashicorp/nomad/client/config"
-	"github.com/hashicorp/nomad/client/driver/args"
 	"github.com/hashicorp/nomad/client/executor"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
@@ -52,17 +51,13 @@ func (d *ExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	envVars := TaskEnvironmentVariables(ctx, task)
 
 	// Look for arguments
-	var cmdArgs []string
+	var args []string
 	if argRaw, ok := task.Config["args"]; ok {
-		parsed, err := args.ParseAndReplace(argRaw, envVars.Map())
-		if err != nil {
-			return nil, err
-		}
-		cmdArgs = append(cmdArgs, parsed...)
+		args = append(args, argRaw)
 	}
 
 	// Setup the command
-	cmd := executor.Command(command, cmdArgs...)
+	cmd := executor.Command(command, args...)
 	if err := cmd.Limit(task.Resources); err != nil {
 		return nil, fmt.Errorf("failed to constrain resources: %s", err)
 	}

client/driver/exec_test.go

@@ -1,10 +1,16 @@
 package driver
 
 import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"reflect"
 	"testing"
 	"time"
 
+	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
+	"github.com/hashicorp/nomad/client/driver/environment"
 	"github.com/hashicorp/nomad/nomad/structs"
 
 	ctestutils "github.com/hashicorp/nomad/client/testutil"
@@ -115,6 +121,55 @@ func TestExecDriver_Start_Wait(t *testing.T) {
 	}
 }
 
+func TestExecDriver_Start_Wait_AllocDir(t *testing.T) {
+	ctestutils.ExecCompatible(t)
+
+	exp := []byte{'w', 'i', 'n'}
+	file := "output.txt"
+	task := &structs.Task{
+		Name: "sleep",
+		Config: map[string]string{
+			"command": "/bin/bash",
+			"args":    fmt.Sprintf("-c \"sleep 1; echo -n %s > $%s/%s\"", string(exp), environment.AllocDir, file),
+		},
+		Resources: basicResources,
+	}
+
+	driverCtx := testDriverContext(task.Name)
+	ctx := testDriverExecContext(task, driverCtx)
+	defer ctx.AllocDir.Destroy()
+	d := NewExecDriver(driverCtx)
+
+	handle, err := d.Start(ctx, task)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if handle == nil {
+		t.Fatalf("missing handle")
+	}
+
+	// Task should terminate quickly
+	select {
+	case err := <-handle.WaitCh():
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatalf("timeout")
+	}
+
+	// Check that data was written to the shared alloc directory.
+	outputFile := filepath.Join(ctx.AllocDir.AllocDir, allocdir.SharedAllocName, file)
+	act, err := ioutil.ReadFile(outputFile)
+	if err != nil {
+		t.Fatalf("Couldn't read expected output: %v", err)
+	}
+
+	if !reflect.DeepEqual(act, exp) {
+		t.Fatalf("Command outputted %v; want %v", act, exp)
+	}
+}
+
 func TestExecDriver_Start_Kill_Wait(t *testing.T) {
 	ctestutils.ExecCompatible(t)
 	task := &structs.Task{

client/driver/java.go

@@ -16,7 +16,6 @@ import (
 
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
-	"github.com/hashicorp/nomad/client/driver/args"
 	"github.com/hashicorp/nomad/client/executor"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
@@ -135,18 +134,14 @@ func (d *JavaDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	envVars := TaskEnvironmentVariables(ctx, task)
 
 	// Build the argument list.
-	cmdArgs := []string{"-jar", filepath.Join(allocdir.TaskLocal, fName)}
+	args := []string{"-jar", filepath.Join(allocdir.TaskLocal, fName)}
 	if argRaw, ok := task.Config["args"]; ok {
-		parsed, err := args.ParseAndReplace(argRaw, envVars.Map())
-		if err != nil {
-			return nil, err
-		}
-		cmdArgs = append(cmdArgs, parsed...)
+		args = append(args, argRaw)
 	}
 
 	// Setup the command
 	// Assumes Java is in the $PATH, but could probably be detected
-	cmd := executor.Command("java", cmdArgs...)
+	cmd := executor.Command("java", args...)
 
 	// Populate environment variables
 	cmd.Command().Env = envVars.List()

client/executor/exec_linux.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/nomad/client/allocdir"
+	"github.com/hashicorp/nomad/client/driver/args"
 	"github.com/hashicorp/nomad/client/driver/environment"
 	"github.com/hashicorp/nomad/command"
 	"github.com/hashicorp/nomad/helper/discover"
@@ -133,7 +134,7 @@ func (e *LinuxExecutor) ConfigureTaskDir(taskName string, alloc *allocdir.AllocD
 	if err != nil {
 		return err
 	}
-	env.SetAllocDir(filepath.Join(taskDir, allocdir.SharedAllocName))
+	env.SetAllocDir(filepath.Join("/", allocdir.SharedAllocName))
 	e.Cmd.Env = env.List()
 
 	e.alloc = alloc
@@ -247,6 +248,20 @@ func (e *LinuxExecutor) Start() error {
 		return errors.New("ConfigureTaskDir() must be called before Start()")
 	}
 
+	// Parse the commands arguments and replace instances of Nomad environment
+	// variables.
+	envVars, err := environment.ParseFromList(e.Cmd.Env)
+	if err != nil {
+		return err
+	}
+
+	combined := strings.Join(e.Cmd.Args, " ")
+	parsed, err := args.ParseAndReplace(combined, envVars.Map())
+	if err != nil {
+		return err
+	}
+	e.Cmd.Args = parsed
+
 	return e.spawnDaemon()
 }