update raw_exec to support artifact_source

client/driver/exec_test.go

@@ -120,7 +120,7 @@ func TestExecDriver_Start_Wait(t *testing.T) {
 	}
 }
 
-func TestExecDriver_Start_Artifact_Wait(t *testing.T) {
+func TestRawExecDriver_Start_Artifact_Wait(t *testing.T) {
 	ctestutils.ExecCompatible(t)
 	task := &structs.Task{
 		Name: "sleep",

client/driver/raw_exec.go

@@ -2,14 +2,17 @@ package driver
 
 import (
 	"fmt"
+	"log"
 	"os"
 	"os/exec"
+	"path"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
 	"time"
 
+	"github.com/hashicorp/go-getter"
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/driver/args"
@@ -61,12 +64,6 @@ func (d *RawExecDriver) Fingerprint(cfg *config.Config, node *structs.Node) (boo
 }
 
 func (d *RawExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle, error) {
-	// Get the command
-	command, ok := task.Config["command"]
-	if !ok || command == "" {
-		return nil, fmt.Errorf("missing command for raw_exec driver")
-	}
-
 	// Get the tasks local directory.
 	taskName := d.DriverContext.taskName
 	taskDir, ok := ctx.AllocDir.TaskDirs[taskName]
@@ -75,6 +72,35 @@ func (d *RawExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandl
 	}
 	taskLocal := filepath.Join(taskDir, allocdir.TaskLocal)
 
+	// Get the command
+	command, ok := task.Config["command"]
+	if !ok || command == "" {
+		source, sok := task.Config["artifact_source"]
+		if !sok || source == "" {
+			return nil, fmt.Errorf("missing command or source for exec driver")
+		}
+
+		// Proceed to download an artifact to be executed.
+		// We use go-getter to support a variety of protocols, but need to change
+		// file permissions of the resulted download to be executable
+		destDir := filepath.Join(taskDir, allocdir.TaskLocal)
+
+		// Create a location to download the artifact.
+		artifactName := path.Base(source)
+		command = filepath.Join(destDir, artifactName)
+		if err := getter.GetFile(command, source); err != nil {
+			return nil, fmt.Errorf("[Err] driver.Exec: Error downloading source for Exec driver: %s", err)
+		}
+
+		cmd := exec.Command("chmod", "+x", command)
+		if err := cmd.Run(); err != nil {
+			log.Printf("[Err] driver.Exec: Error making artifact executable: %s", err)
+		}
+
+		// re-assign the command to be the local execution path
+		command = filepath.Join(allocdir.TaskLocal, artifactName)
+	}
+
 	// Get the environment variables.
 	envVars := TaskEnvironmentVariables(ctx, task)
 

client/driver/raw_exec_test.go

@@ -92,6 +92,50 @@ func TestRawExecDriver_StartOpen_Wait(t *testing.T) {
 	}
 }
 
+func TestRawExecDriver_StartOpen_Artifact_Source_Wait(t *testing.T) {
+	task := &structs.Task{
+		Name: "sleep",
+		Config: map[string]string{
+			"artifact_source": "https://dl.dropboxusercontent.com/u/47675/jar_thing/hi_linux_amd64",
+		},
+	}
+	driverCtx := testDriverContext(task.Name)
+	ctx := testDriverExecContext(task, driverCtx)
+	defer ctx.AllocDir.Destroy()
+
+	d := NewRawExecDriver(driverCtx)
+	handle, err := d.Start(ctx, task)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if handle == nil {
+		t.Fatalf("missing handle")
+	}
+
+	// Attempt to open
+	handle2, err := d.Open(ctx, handle.ID())
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if handle2 == nil {
+		t.Fatalf("missing handle")
+	}
+
+	// Task should terminate quickly
+	select {
+	case <-handle2.WaitCh():
+	case <-time.After(2 * time.Second):
+		t.Fatalf("timeout")
+	}
+
+	// Check they are both tracking the same PID.
+	pid1 := handle.(*rawExecHandle).proc.Pid
+	pid2 := handle2.(*rawExecHandle).proc.Pid
+	if pid1 != pid2 {
+		t.Fatalf("tracking incorrect Pid; %v != %v", pid1, pid2)
+	}
+}
+
 func TestRawExecDriver_Start_Wait(t *testing.T) {
 	task := &structs.Task{
 		Name: "sleep",

website/source/docs/drivers/raw_exec.html.md

@@ -19,7 +19,8 @@ As such, it should be used with extreme care and is disabled by default.
 The `raw_exec` driver supports the following configuration in the job spec:
 
 * `command` - The command to execute. Must be provided.
-
+* `artifact_source` – Source location of an executable artifact. Must be accessible
+from the Nomad client
 * `args` - The argument list to the command, space seperated. Optional.
 
 ## Client Requirements
@@ -35,6 +36,9 @@ options = {
 }
 ```
 
+You must specify either a `command` or a `artifact_source` to be executed. Any
+`command` is assumed to be present on the running client.
+
 ## Client Attributes
 
 The `raw_exec` driver will set the following client attributes: