drivers: Add/Use go-getter to fetch remote binaries

Updates Qemu, Java drivers to use go-getter to fetch binaries
Adds remote artifact support for Exec, Raw Exec drivers

client/driver/exec.go

@@ -2,10 +2,15 @@ package driver
 
 import (
 	"fmt"
+	"log"
+	"path"
+	"path/filepath"
 	"runtime"
 	"syscall"
 	"time"
 
+	"github.com/hashicorp/go-getter"
+	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/executor"
 	"github.com/hashicorp/nomad/nomad/structs"
@@ -41,12 +46,44 @@ func (d *ExecDriver) Fingerprint(cfg *config.Config, node *structs.Node) (bool,
 }
 
 func (d *ExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle, error) {
-	// Get the command
+	// Get the command to be ran, or if omitted, download an artifact for
+	// execution. Currently a supplied command takes precedence, and an artifact
+	// is only downloaded if no command is supplied
 	command, ok := task.Config["command"]
 	if !ok || command == "" {
 		return nil, fmt.Errorf("missing command for exec driver")
 	}
 
+	source, ok := task.Config["artifact_source"]
+	if ok && source != "" {
+		// 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
+
+		// Create a location to download the artifact.
+		taskDir, ok := ctx.AllocDir.TaskDirs[d.DriverContext.taskName]
+		if !ok {
+			return nil, fmt.Errorf("[Err] driver.Exec: Could not find task directory for task: %v", d.DriverContext.taskName)
+		}
+		destDir := filepath.Join(taskDir, allocdir.TaskLocal)
+
+		artifactName := path.Base(source)
+		artifactFile := filepath.Join(destDir, artifactName)
+		if err := getter.GetFile(artifactFile, source); err != nil {
+			return nil, fmt.Errorf("[Err] driver.Exec: Error downloading source for Exec driver: %s", err)
+		}
+
+		// Add execution permissions to the newly downloaded artifact
+		if runtime.GOOS != "windows" {
+			if err := syscall.Chmod(artifactFile, 0655); 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, command)
+	}
+
 	// Get the environment variables.
 	envVars := TaskEnvironmentVariables(ctx, task)
 

client/driver/exec_test.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 	"path/filepath"
 	"reflect"
+	"runtime"
 	"testing"
 	"time"
 
@@ -120,6 +121,55 @@ func TestExecDriver_Start_Wait(t *testing.T) {
 	}
 }
 
+func TestExecDriver_Start_Artifact_Wait(t *testing.T) {
+	ctestutils.ExecCompatible(t)
+	var file string
+	switch runtime.GOOS {
+	case "darwin":
+		file = "hi_darwin_amd64"
+	default:
+		file = "hi_linux_amd64"
+	}
+
+	task := &structs.Task{
+		Name: "sleep",
+		Config: map[string]string{
+			"artifact_source": fmt.Sprintf("https://dl.dropboxusercontent.com/u/47675/jar_thing/%s", file),
+			"command":         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")
+	}
+
+	// Update should be a no-op
+	err = handle.Update(task)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Task should terminate quickly
+	select {
+	case err := <-handle.WaitCh():
+		if err != nil {
+			t.Fatalf("err: %v", err)
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatalf("timeout")
+	}
+}
+
 func TestExecDriver_Start_Wait_AllocDir(t *testing.T) {
 	ctestutils.ExecCompatible(t)
 

client/driver/java.go

@@ -3,9 +3,6 @@ package driver
 import (
 	"bytes"
 	"fmt"
-	"io"
-	"net/http"
-	"os"
 	"os/exec"
 	"path"
 	"path/filepath"
@@ -14,6 +11,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/hashicorp/go-getter"
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/executor"
@@ -97,37 +95,18 @@ func (d *JavaDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 		return nil, fmt.Errorf("missing jar source for Java Jar driver")
 	}
 
-	// Attempt to download the thing
-	// Should be extracted to some kind of Http Fetcher
-	// Right now, assume publicly accessible HTTP url
-	resp, err := http.Get(source)
-	if err != nil {
-		return nil, fmt.Errorf("Error downloading source for Java driver: %s", err)
-	}
-
-	// Get the tasks local directory.
 	taskDir, ok := ctx.AllocDir.TaskDirs[d.DriverContext.taskName]
 	if !ok {
 		return nil, fmt.Errorf("Could not find task directory for task: %v", d.DriverContext.taskName)
 	}
-	taskLocal := filepath.Join(taskDir, allocdir.TaskLocal)
 
-	// Create a location to download the binary.
-	fName := path.Base(source)
-	fPath := filepath.Join(taskLocal, fName)
-	f, err := os.OpenFile(fPath, os.O_CREATE|os.O_WRONLY, 0666)
-	if err != nil {
-		return nil, fmt.Errorf("Error opening file to download to: %s", err)
-	}
-
-	defer f.Close()
-	defer resp.Body.Close()
+	destDir := filepath.Join(taskDir, allocdir.TaskLocal)
 
-	// Copy remote file to local directory for execution
-	// TODO: a retry of sort if io.Copy fails, for large binaries
-	_, ioErr := io.Copy(f, resp.Body)
-	if ioErr != nil {
-		return nil, fmt.Errorf("Error copying jar from source: %s", ioErr)
+	// Create a location to download the binary.
+	jarName := path.Base(source)
+	jarPath := filepath.Join(destDir, jarName)
+	if err := getter.GetFile(jarPath, source); err != nil {
+		return nil, fmt.Errorf("Error downloading source for Java driver: %s", err)
 	}
 
 	// Get the environment variables.
@@ -141,10 +120,8 @@ func (d *JavaDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 		args = append(args, jvm_options)
 	}
 
-	// Build the argument list
-	args = append(args, "-jar", filepath.Join(allocdir.TaskLocal, fName))
-
 	// Build the argument list.
+	args = append(args, "-jar", filepath.Join(allocdir.TaskLocal, jarName))
 	if argRaw, ok := task.Config["args"]; ok {
 		args = append(args, argRaw)
 	}

client/driver/qemu.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"io"
 	"log"
-	"net/http"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -19,6 +18,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/hashicorp/go-getter"
 	"github.com/hashicorp/nomad/client/allocdir"
 	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/nomad/structs"
@@ -94,45 +94,25 @@ func (d *QemuDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 		return nil, fmt.Errorf("Missing required Task Resource: Memory")
 	}
 
-	// Attempt to download the thing
-	// Should be extracted to some kind of Http Fetcher
-	// Right now, assume publicly accessible HTTP url
-	resp, err := http.Get(source)
-	if err != nil {
-		return nil, fmt.Errorf("Error downloading source for Qemu driver: %s", err)
-	}
-
 	// Get the tasks local directory.
 	taskDir, ok := ctx.AllocDir.TaskDirs[d.DriverContext.taskName]
 	if !ok {
 		return nil, fmt.Errorf("Could not find task directory for task: %v", d.DriverContext.taskName)
 	}
-	taskLocal := filepath.Join(taskDir, allocdir.TaskLocal)
 
-	// Create a location in the local directory to download and store the image.
-	// TODO: Caching
+	// Create a location to download the binary.
+	destDir := filepath.Join(taskDir, allocdir.TaskLocal)
 	vmID := fmt.Sprintf("qemu-vm-%s-%s", structs.GenerateUUID(), filepath.Base(source))
-	fPath := filepath.Join(taskLocal, vmID)
-	vmPath, err := os.OpenFile(fPath, os.O_CREATE|os.O_WRONLY, 0666)
-	if err != nil {
-		return nil, fmt.Errorf("Error opening file to download to: %s", err)
-	}
-
-	defer vmPath.Close()
-	defer resp.Body.Close()
-
-	// Copy remote file to local AllocDir for execution
-	// TODO: a retry of sort if io.Copy fails, for large binaries
-	_, ioErr := io.Copy(vmPath, resp.Body)
-	if ioErr != nil {
-		return nil, fmt.Errorf("Error copying Qemu image from source: %s", ioErr)
+	vmPath := filepath.Join(destDir, vmID)
+	if err := getter.GetFile(vmPath, source); err != nil {
+		return nil, fmt.Errorf("Error downloading source for Java driver: %s", err)
 	}
 
 	// compute and check checksum
 	if check, ok := task.Config["checksum"]; ok {
 		d.logger.Printf("[DEBUG] Running checksum on (%s)", vmID)
 		hasher := sha256.New()
-		file, err := os.Open(vmPath.Name())
+		file, err := os.Open(vmPath)
 		if err != nil {
 			return nil, fmt.Errorf("Failed to open file for checksum")
 		}
@@ -163,7 +143,7 @@ func (d *QemuDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 		"-machine", "type=pc,accel=" + accelerator,
 		"-name", vmID,
 		"-m", mem,
-		"-drive", "file=" + vmPath.Name(),
+		"-drive", "file=" + vmPath,
 		"-nodefconfig",
 		"-nodefaults",
 		"-nographic",
@@ -240,7 +220,7 @@ func (d *QemuDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	// Create and Return Handle
 	h := &qemuHandle{
 		proc:   cmd.Process,
-		vmID:   vmPath.Name(),
+		vmID:   vmPath,
 		doneCh: make(chan struct{}),
 		waitCh: make(chan error, 1),
 	}

client/driver/raw_exec.go

@@ -2,14 +2,18 @@ package driver
 
 import (
 	"fmt"
+	"log"
 	"os"
 	"os/exec"
+	"path"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
+	"syscall"
 	"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 +65,6 @@ 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 +73,40 @@ func (d *RawExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandl
 	}
 	taskLocal := filepath.Join(taskDir, allocdir.TaskLocal)
 
+	// Get the command to be ran, or if omitted, download an artifact for
+	// execution. Currently a supplied command takes precedence, and an artifact
+	// is only downloaded if no command is supplied
+	command, ok := task.Config["command"]
+	if !ok || command == "" {
+		return nil, fmt.Errorf("missing command for exec driver")
+	}
+
+	source, ok := task.Config["artifact_source"]
+	if ok && source != "" {
+		// 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
+
+		// Create a location to download the artifact.
+		destDir := filepath.Join(taskDir, allocdir.TaskLocal)
+
+		artifactName := path.Base(source)
+		artifactFile := filepath.Join(destDir, artifactName)
+		if err := getter.GetFile(artifactFile, source); err != nil {
+			return nil, fmt.Errorf("[Err] driver.Exec: Error downloading source for Exec driver: %s", err)
+		}
+
+		// Add execution permissions to the newly downloaded artifact
+		if runtime.GOOS != "windows" {
+			if err := syscall.Chmod(artifactFile, 0655); 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, command)
+	}
+
 	// Get the environment variables.
 	envVars := TaskEnvironmentVariables(ctx, task)