Merge pull request #4788 from hashicorp/r-clientv2-exec

drivers/exec: add exec implementation

client/driver/executor/executor.go

@@ -276,12 +276,12 @@ func (e *UniversalExecutor) Launch(command *ExecCommand) (*ProcessState, error)
 	e.childCmd.Stderr = stderr
 
 	// Look up the binary path and make it executable
-	absPath, err := e.lookupBin(command.Cmd)
+	absPath, err := lookupBin(command.TaskDir, command.Cmd)
 	if err != nil {
 		return nil, err
 	}
 
-	if err := e.makeExecutable(absPath); err != nil {
+	if err := makeExecutable(absPath); err != nil {
 		return nil, err
 	}
 
@@ -476,55 +476,6 @@ func (e *UniversalExecutor) Shutdown(signal string, grace time.Duration) error {
 	return nil
 }
 
-// lookupBin looks for path to the binary to run by looking for the binary in
-// the following locations, in-order: task/local/, task/, based on host $PATH.
-// The return path is absolute.
-func (e *UniversalExecutor) lookupBin(bin string) (string, error) {
-	// Check in the local directory
-	local := filepath.Join(e.commandCfg.TaskDir, allocdir.TaskLocal, bin)
-	if _, err := os.Stat(local); err == nil {
-		return local, nil
-	}
-
-	// Check at the root of the task's directory
-	root := filepath.Join(e.commandCfg.TaskDir, bin)
-	if _, err := os.Stat(root); err == nil {
-		return root, nil
-	}
-
-	// Check the $PATH
-	if host, err := exec.LookPath(bin); err == nil {
-		return host, nil
-	}
-
-	return "", fmt.Errorf("binary %q could not be found", bin)
-}
-
-// makeExecutable makes the given file executable for root,group,others.
-func (e *UniversalExecutor) makeExecutable(binPath string) error {
-	if runtime.GOOS == "windows" {
-		return nil
-	}
-
-	fi, err := os.Stat(binPath)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return fmt.Errorf("binary %q does not exist", binPath)
-		}
-		return fmt.Errorf("specified binary is invalid: %v", err)
-	}
-
-	// If it is not executable, make it so.
-	perm := fi.Mode().Perm()
-	req := os.FileMode(0555)
-	if perm&req != req {
-		if err := os.Chmod(binPath, perm|req); err != nil {
-			return fmt.Errorf("error making %q executable: %s", binPath, err)
-		}
-	}
-	return nil
-}
-
 // Signal sends the passed signal to the task
 func (e *UniversalExecutor) Signal(s os.Signal) error {
 	if e.childCmd.Process == nil {
@@ -548,3 +499,52 @@ func (e *UniversalExecutor) Stats() (*cstructs.TaskResourceUsage, error) {
 	}
 	return aggregatedResourceUsage(e.systemCpuStats, pidStats), nil
 }
+
+// lookupBin looks for path to the binary to run by looking for the binary in
+// the following locations, in-order: task/local/, task/, based on host $PATH.
+// The return path is absolute.
+func lookupBin(taskDir string, bin string) (string, error) {
+	// Check in the local directory
+	local := filepath.Join(taskDir, allocdir.TaskLocal, bin)
+	if _, err := os.Stat(local); err == nil {
+		return local, nil
+	}
+
+	// Check at the root of the task's directory
+	root := filepath.Join(taskDir, bin)
+	if _, err := os.Stat(root); err == nil {
+		return root, nil
+	}
+
+	// Check the $PATH
+	if host, err := exec.LookPath(bin); err == nil {
+		return host, nil
+	}
+
+	return "", fmt.Errorf("binary %q could not be found", bin)
+}
+
+// makeExecutable makes the given file executable for root,group,others.
+func makeExecutable(binPath string) error {
+	if runtime.GOOS == "windows" {
+		return nil
+	}
+
+	fi, err := os.Stat(binPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return fmt.Errorf("binary %q does not exist", binPath)
+		}
+		return fmt.Errorf("specified binary is invalid: %v", err)
+	}
+
+	// If it is not executable, make it so.
+	perm := fi.Mode().Perm()
+	req := os.FileMode(0555)
+	if perm&req != req {
+		if err := os.Chmod(binPath, perm|req); err != nil {
+			return fmt.Errorf("error making %q executable: %s", binPath, err)
+		}
+	}
+	return nil
+}

client/driver/executor/executor_linux.go

@@ -101,6 +101,10 @@ func (l *LibcontainerExecutor) Launch(command *ExecCommand) (*ProcessState, erro
 		return nil, fmt.Errorf("unable to find the nomad binary: %v", err)
 	}
 
+	if command.Resources == nil {
+		command.Resources = &Resources{}
+	}
+
 	l.command = command
 
 	// Move to the root cgroup until process is started
@@ -129,7 +133,26 @@ func (l *LibcontainerExecutor) Launch(command *ExecCommand) (*ProcessState, erro
 	}
 	l.container = container
 
-	combined := append([]string{command.Cmd}, command.Args...)
+	// Look up the binary path and make it executable
+	absPath, err := lookupBin(command.TaskDir, command.Cmd)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := makeExecutable(absPath); err != nil {
+		return nil, err
+	}
+
+	path := absPath
+
+	// Determine the path to run as it may have to be relative to the chroot.
+	rel, err := filepath.Rel(command.TaskDir, path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to determine relative path base=%q target=%q: %v", command.TaskDir, path, err)
+	}
+	path = rel
+
+	combined := append([]string{path}, command.Args...)
 	stdout, err := command.Stdout()
 	if err != nil {
 		return nil, err

drivers/exec/driver.go

@@ -0,0 +1,440 @@
+package exec
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"time"
+
+	"github.com/hashicorp/consul-template/signals"
+	hclog "github.com/hashicorp/go-hclog"
+	plugin "github.com/hashicorp/go-plugin"
+	"github.com/hashicorp/nomad/client/driver/executor"
+	dstructs "github.com/hashicorp/nomad/client/driver/structs"
+	cstructs "github.com/hashicorp/nomad/client/structs"
+	"github.com/hashicorp/nomad/drivers/shared/eventer"
+	"github.com/hashicorp/nomad/plugins/base"
+	"github.com/hashicorp/nomad/plugins/drivers"
+	"github.com/hashicorp/nomad/plugins/drivers/utils"
+	"github.com/hashicorp/nomad/plugins/shared/hclspec"
+	"golang.org/x/net/context"
+)
+
+const (
+	// pluginName is the name of the plugin
+	pluginName = "exec"
+
+	// fingerprintPeriod is the interval at which the driver will send fingerprint responses
+	fingerprintPeriod = 30 * time.Second
+)
+
+var (
+	// pluginInfo is the response returned for the PluginInfo RPC
+	pluginInfo = &base.PluginInfoResponse{
+		Type:             base.PluginTypeDriver,
+		PluginApiVersion: "0.0.1",
+		PluginVersion:    "0.1.0",
+		Name:             pluginName,
+	}
+
+	// configSpec is the hcl specification returned by the ConfigSchema RPC
+	configSpec = hclspec.NewObject(map[string]*hclspec.Spec{
+		"enabled": hclspec.NewDefault(
+			hclspec.NewAttr("enabled", "bool", false),
+			hclspec.NewLiteral("true"),
+		),
+	})
+
+	// taskConfigSpec is the hcl specification for the driver config section of
+	// a task within a job. It is returned in the TaskConfigSchema RPC
+	taskConfigSpec = hclspec.NewObject(map[string]*hclspec.Spec{
+		"command": hclspec.NewAttr("command", "string", true),
+		"args":    hclspec.NewAttr("args", "list(string)", false),
+	})
+
+	// capabilities is returned by the Capabilities RPC and indicates what
+	// optional features this driver supports
+	capabilities = &drivers.Capabilities{
+		SendSignals: true,
+		Exec:        true,
+		FSIsolation: cstructs.FSIsolationChroot,
+	}
+)
+
+// ExecDriver fork/execs tasks using many of the underlying OS's isolation
+// features where configured.
+type ExecDriver struct {
+	// eventer is used to handle multiplexing of TaskEvents calls such that an
+	// event can be broadcast to all callers
+	eventer *eventer.Eventer
+
+	// config is the driver configuration set by the SetConfig RPC
+	config *Config
+
+	// tasks is the in memory datastore mapping taskIDs to execDriverHandles
+	tasks *taskStore
+
+	// ctx is the context for the driver. It is passed to other subsystems to
+	// coordinate shutdown
+	ctx context.Context
+
+	// signalShutdown is called when the driver is shutting down and cancels the
+	// ctx passed to any subsystems
+	signalShutdown context.CancelFunc
+
+	// logger will log to the plugin output which is usually an 'executor.out'
+	// file located in the root of the TaskDir
+	logger hclog.Logger
+}
+
+// Config is the driver configuration set by the SetConfig RPC call
+type Config struct {
+	// Enabled is set to true to enable the driver
+	Enabled bool `cty:"enabled"`
+}
+
+// TaskConfig is the driver configuration of a task within a job
+type TaskConfig struct {
+	Command string   `cty:"command"`
+	Args    []string `cty:"args"`
+}
+
+// TaskState is the state which is encoded in the handle returned in
+// StartTask. This information is needed to rebuild the task state and handler
+// during recovery.
+type TaskState struct {
+	ReattachConfig *utils.ReattachConfig
+	TaskConfig     *drivers.TaskConfig
+	Pid            int
+	StartedAt      time.Time
+}
+
+// NewExecDriver returns a new DrivePlugin implementation
+func NewExecDriver(logger hclog.Logger) drivers.DriverPlugin {
+	ctx, cancel := context.WithCancel(context.Background())
+	logger = logger.Named(pluginName)
+	return &ExecDriver{
+		eventer:        eventer.NewEventer(ctx, logger),
+		config:         &Config{},
+		tasks:          newTaskStore(),
+		ctx:            ctx,
+		signalShutdown: cancel,
+		logger:         logger,
+	}
+}
+
+func (*ExecDriver) PluginInfo() (*base.PluginInfoResponse, error) {
+	return pluginInfo, nil
+}
+
+func (*ExecDriver) ConfigSchema() (*hclspec.Spec, error) {
+	return configSpec, nil
+}
+
+func (d *ExecDriver) SetConfig(data []byte) error {
+	var config Config
+	if err := base.MsgPackDecode(data, &config); err != nil {
+		return err
+	}
+
+	d.config = &config
+	return nil
+}
+
+func (d *ExecDriver) Shutdown(ctx context.Context) error {
+	d.signalShutdown()
+	return nil
+}
+
+func (d *ExecDriver) TaskConfigSchema() (*hclspec.Spec, error) {
+	return taskConfigSpec, nil
+}
+
+func (d *ExecDriver) Capabilities() (*drivers.Capabilities, error) {
+	return capabilities, nil
+}
+
+func (d *ExecDriver) Fingerprint(ctx context.Context) (<-chan *drivers.Fingerprint, error) {
+	ch := make(chan *drivers.Fingerprint)
+	go d.handleFingerprint(ctx, ch)
+	return ch, nil
+
+}
+func (d *ExecDriver) handleFingerprint(ctx context.Context, ch chan *drivers.Fingerprint) {
+	defer close(ch)
+	ticker := time.NewTimer(0)
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-d.ctx.Done():
+			return
+		case <-ticker.C:
+			ticker.Reset(fingerprintPeriod)
+			ch <- d.buildFingerprint()
+		}
+	}
+}
+
+func (d *ExecDriver) RecoverTask(handle *drivers.TaskHandle) error {
+	var taskState TaskState
+	logger := d.logger.With("task_id", handle.Config.ID)
+
+	err := handle.GetDriverState(&taskState)
+	if err != nil {
+		logger.Error("failed to decode driver state during task recovery", "error", err)
+		return fmt.Errorf("failed to decode state: %v", err)
+	}
+
+	plugRC, err := utils.ReattachConfigToGoPlugin(taskState.ReattachConfig)
+	if err != nil {
+		logger.Error("failed to build reattach config during task recovery", "error", err)
+		return fmt.Errorf("failed to build reattach config: %v", err)
+	}
+
+	pluginConfig := &plugin.ClientConfig{
+		Reattach: plugRC,
+	}
+
+	exec, pluginClient, err := utils.CreateExecutorWithConfig(pluginConfig, os.Stderr)
+	if err != nil {
+		logger.Error("failed to build executor during task recovery", "error", err)
+		return fmt.Errorf("failed to build executor: %v", err)
+	}
+
+	h := &execTaskHandle{
+		exec:         exec,
+		pid:          taskState.Pid,
+		pluginClient: pluginClient,
+		task:         taskState.TaskConfig,
+		procState:    drivers.TaskStateRunning,
+		startedAt:    taskState.StartedAt,
+		exitCh:       make(chan struct{}),
+	}
+
+	d.tasks.Set(taskState.TaskConfig.ID, h)
+
+	go h.run()
+	return nil
+}
+
+func (d *ExecDriver) StartTask(cfg *drivers.TaskConfig) (*drivers.TaskHandle, *cstructs.DriverNetwork, error) {
+	if _, ok := d.tasks.Get(cfg.ID); ok {
+		return nil, nil, fmt.Errorf("task with ID '%s' already started", cfg.ID)
+	}
+
+	var driverConfig TaskConfig
+	if err := cfg.DecodeDriverConfig(&driverConfig); err != nil {
+		return nil, nil, fmt.Errorf("failed to decode driver config: %v", err)
+	}
+
+	handle := drivers.NewTaskHandle(pluginName)
+	handle.Config = cfg
+
+	pluginLogFile := filepath.Join(cfg.TaskDir().Dir, "executor.out")
+	executorConfig := &dstructs.ExecutorConfig{
+		LogFile:     pluginLogFile,
+		LogLevel:    "debug",
+		FSIsolation: true,
+	}
+
+	// TODO: best way to pass port ranges in from client config
+	exec, pluginClient, err := utils.CreateExecutor(os.Stderr, hclog.Debug, 14000, 14512, executorConfig)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	execCmd := &executor.ExecCommand{
+		Cmd:            driverConfig.Command,
+		Args:           driverConfig.Args,
+		Env:            cfg.EnvList(),
+		User:           cfg.User,
+		ResourceLimits: true,
+		TaskDir:        cfg.TaskDir().Dir,
+		StdoutPath:     cfg.StdoutPath,
+		StderrPath:     cfg.StderrPath,
+	}
+
+	ps, err := exec.Launch(execCmd)
+	if err != nil {
+		pluginClient.Kill()
+		return nil, nil, err
+	}
+
+	h := &execTaskHandle{
+		exec:         exec,
+		pid:          ps.Pid,
+		pluginClient: pluginClient,
+		task:         cfg,
+		procState:    drivers.TaskStateRunning,
+		startedAt:    time.Now().Round(time.Millisecond),
+		logger:       d.logger,
+		exitCh:       make(chan struct{}),
+	}
+
+	driverState := &TaskState{
+		ReattachConfig: utils.ReattachConfigFromGoPlugin(pluginClient.ReattachConfig()),
+		Pid:            ps.Pid,
+		TaskConfig:     cfg,
+		StartedAt:      h.startedAt,
+	}
+
+	if err := handle.SetDriverState(&driverState); err != nil {
+		d.logger.Error("failed to start task, error setting driver state", "error", err)
+		exec.Shutdown("", 0)
+		pluginClient.Kill()
+		return nil, nil, err
+	}
+
+	d.tasks.Set(cfg.ID, h)
+	go h.run()
+	return handle, nil, nil
+}
+
+func (d *ExecDriver) WaitTask(ctx context.Context, taskID string) (<-chan *drivers.ExitResult, error) {
+	ch := make(chan *drivers.ExitResult)
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return nil, drivers.ErrTaskNotFound
+	}
+	go d.handleWait(ctx, handle, ch)
+
+	return ch, nil
+}
+
+func (d *ExecDriver) handleWait(ctx context.Context, handle *execTaskHandle, ch chan *drivers.ExitResult) {
+	defer close(ch)
+
+	select {
+	case <-ctx.Done():
+		return
+	case <-d.ctx.Done():
+		return
+	case <-handle.exitCh:
+		ch <- handle.exitResult
+	}
+}
+
+func (d *ExecDriver) StopTask(taskID string, timeout time.Duration, signal string) error {
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return drivers.ErrTaskNotFound
+	}
+
+	if err := handle.exec.Shutdown(signal, timeout); err != nil {
+		if handle.pluginClient.Exited() {
+			return nil
+		}
+		return fmt.Errorf("executor Shutdown failed: %v", err)
+	}
+
+	return nil
+}
+
+func (d *ExecDriver) DestroyTask(taskID string, force bool) error {
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return drivers.ErrTaskNotFound
+	}
+
+	if handle.IsRunning() && !force {
+		return fmt.Errorf("cannot destroy running task")
+	}
+
+	if !handle.pluginClient.Exited() {
+		if handle.IsRunning() {
+			if err := handle.exec.Shutdown("", 0); err != nil {
+				handle.logger.Error("destroying executor failed", "err", err)
+			}
+		}
+
+		handle.pluginClient.Kill()
+	}
+
+	d.tasks.Delete(taskID)
+	return nil
+}
+
+func (d *ExecDriver) InspectTask(taskID string) (*drivers.TaskStatus, error) {
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return nil, drivers.ErrTaskNotFound
+	}
+
+	handle.stateLock.RLock()
+	defer handle.stateLock.RUnlock()
+
+	status := &drivers.TaskStatus{
+		ID:          handle.task.ID,
+		Name:        handle.task.Name,
+		State:       handle.procState,
+		StartedAt:   handle.startedAt,
+		CompletedAt: handle.completedAt,
+		ExitResult:  handle.exitResult,
+		DriverAttributes: map[string]string{
+			"pid": strconv.Itoa(handle.pid),
+		},
+	}
+
+	return status, nil
+}
+
+func (d *ExecDriver) TaskStats(taskID string) (*cstructs.TaskResourceUsage, error) {
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return nil, drivers.ErrTaskNotFound
+	}
+
+	stats, err := handle.exec.Stats()
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve stats from executor: %v", err)
+	}
+
+	return stats, nil
+}
+
+func (d *ExecDriver) TaskEvents(ctx context.Context) (<-chan *drivers.TaskEvent, error) {
+	return d.eventer.TaskEvents(ctx)
+}
+
+func (d *ExecDriver) SignalTask(taskID string, signal string) error {
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return drivers.ErrTaskNotFound
+	}
+
+	sig := os.Interrupt
+	if s, ok := signals.SignalLookup[signal]; ok {
+		d.logger.Warn("signal to send to task unknown, using SIGINT", "signal", signal, "task_id", handle.task.ID)
+		sig = s
+	}
+	return handle.exec.Signal(sig)
+}
+
+func (d *ExecDriver) ExecTask(taskID string, cmd []string, timeout time.Duration) (*drivers.ExecTaskResult, error) {
+	if len(cmd) == 0 {
+		return nil, fmt.Errorf("error cmd must have atleast one value")
+	}
+	handle, ok := d.tasks.Get(taskID)
+	if !ok {
+		return nil, drivers.ErrTaskNotFound
+	}
+
+	args := []string{}
+	if len(cmd) > 1 {
+		args = cmd[1:]
+	}
+
+	out, exitCode, err := handle.exec.Exec(time.Now().Add(timeout), cmd[0], args)
+	if err != nil {
+		return nil, err
+	}
+
+	return &drivers.ExecTaskResult{
+		Stdout: out,
+		ExitResult: &drivers.ExitResult{
+			ExitCode: exitCode,
+		},
+	}, nil
+}

drivers/exec/driver_default.go

@@ -0,0 +1,12 @@
+//+build !linux
+
+package exec
+
+import "github.com/hashicorp/nomad/plugins/drivers"
+
+func (d *ExecDriver) buildFingerprint() *drivers.Fingerprint {
+	return &drivers.Fingerprint{
+		Health:            drivers.HealthStateUndetected,
+		HealthDescription: "exec driver unsupported on client OS",
+	}
+}

drivers/exec/driver_linux.go

@@ -0,0 +1,38 @@
+package exec
+
+import (
+	"github.com/hashicorp/nomad/client/fingerprint"
+	"github.com/hashicorp/nomad/plugins/drivers"
+	"golang.org/x/sys/unix"
+)
+
+func (d *ExecDriver) buildFingerprint() *drivers.Fingerprint {
+	fp := &drivers.Fingerprint{
+		Attributes:        map[string]string{},
+		Health:            drivers.HealthStateHealthy,
+		HealthDescription: "healthy",
+	}
+
+	mount, err := fingerprint.FindCgroupMountpointDir()
+	if err != nil {
+		fp.Health = drivers.HealthStateUnhealthy
+		fp.HealthDescription = "failed to discover cgroup mount point"
+		d.logger.Warn(fp.HealthDescription, "error", err)
+		return fp
+	}
+
+	if mount == "" {
+		fp.Health = drivers.HealthStateUnhealthy
+		fp.HealthDescription = "cgroups are unavailable"
+		return fp
+	}
+
+	if unix.Geteuid() != 0 {
+		fp.Health = drivers.HealthStateUnhealthy
+		fp.HealthDescription = "exec driver must run as root"
+		return fp
+	}
+
+	fp.Attributes["driver.exec"] = "1"
+	return fp
+}

drivers/exec/driver_test.go

@@ -0,0 +1,442 @@
+package exec
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/hashicorp/hcl2/hcl"
+	ctestutils "github.com/hashicorp/nomad/client/testutil"
+	"github.com/hashicorp/nomad/helper/testlog"
+	"github.com/hashicorp/nomad/helper/testtask"
+	"github.com/hashicorp/nomad/helper/uuid"
+	"github.com/hashicorp/nomad/plugins/drivers"
+	"github.com/hashicorp/nomad/plugins/shared"
+	"github.com/hashicorp/nomad/plugins/shared/hclspec"
+	"github.com/hashicorp/nomad/testutil"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMain(m *testing.M) {
+	if !testtask.Run() {
+		os.Exit(m.Run())
+	}
+}
+
+func TestExecDriver_Fingerprint_NonLinux(t *testing.T) {
+	if !testutil.IsTravis() {
+		t.Parallel()
+	}
+	require := require.New(t)
+	if runtime.GOOS == "linux" {
+		t.Skip("Test only available not on Linux")
+	}
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+
+	fingerCh, err := harness.Fingerprint(context.Background())
+	require.NoError(err)
+	select {
+	case finger := <-fingerCh:
+		require.Equal(drivers.HealthStateUndetected, finger.Health)
+	case <-time.After(time.Duration(testutil.TestMultiplier()*5) * time.Second):
+		require.Fail("timeout receiving fingerprint")
+	}
+}
+
+func TestExecDriver_Fingerprint(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+
+	fingerCh, err := harness.Fingerprint(context.Background())
+	require.NoError(err)
+	select {
+	case finger := <-fingerCh:
+		require.Equal(drivers.HealthStateHealthy, finger.Health)
+		require.Equal("1", finger.Attributes["driver.exec"])
+	case <-time.After(time.Duration(testutil.TestMultiplier()*5) * time.Second):
+		require.Fail("timeout receiving fingerprint")
+	}
+}
+
+func TestExecDriver_StartWait(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "test",
+	}
+
+	taskConfig := map[string]interface{}{
+		"command": "cat",
+		"args":    []string{"/proc/self/cgroup"},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+	fmt.Println(task.AllocDir)
+
+	handle, _, err := harness.StartTask(task)
+	require.NoError(err)
+
+	ch, err := harness.WaitTask(context.Background(), handle.Config.ID)
+	require.NoError(err)
+	result := <-ch
+	require.Zero(result.ExitCode)
+	require.NoError(harness.DestroyTask(task.ID, true))
+}
+
+func TestExecDriver_StartWaitStop(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "test",
+	}
+
+	taskConfig := map[string]interface{}{
+		"command": "/bin/sleep",
+		"args":    []string{"5"},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+
+	handle, _, err := harness.StartTask(task)
+	require.NoError(err)
+
+	ch, err := harness.WaitTask(context.Background(), handle.Config.ID)
+	require.NoError(err)
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		result := <-ch
+		require.Equal(2, result.Signal)
+	}()
+
+	require.NoError(harness.WaitUntilStarted(task.ID, 1*time.Second))
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		err := harness.StopTask(task.ID, 2*time.Second, "SIGINT")
+		require.NoError(err)
+	}()
+
+	waitCh := make(chan struct{})
+	go func() {
+		defer close(waitCh)
+		wg.Wait()
+	}()
+
+	select {
+	case <-waitCh:
+		status, err := harness.InspectTask(task.ID)
+		require.NoError(err)
+		require.Equal(drivers.TaskStateExited, status.State)
+	case <-time.After(1 * time.Second):
+		require.Fail("timeout waiting for task to shutdown")
+	}
+
+	require.NoError(harness.DestroyTask(task.ID, true))
+}
+
+func TestExecDriver_StartWaitRecover(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "test",
+	}
+
+	taskConfig := map[string]interface{}{
+		"command": "/bin/sleep",
+		"args":    []string{"5"},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+
+	handle, _, err := harness.StartTask(task)
+	require.NoError(err)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	ch, err := harness.WaitTask(ctx, handle.Config.ID)
+	require.NoError(err)
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		result := <-ch
+		require.Error(result.Err)
+	}()
+
+	require.NoError(harness.WaitUntilStarted(task.ID, 1*time.Second))
+	cancel()
+
+	waitCh := make(chan struct{})
+	go func() {
+		defer close(waitCh)
+		wg.Wait()
+	}()
+
+	select {
+	case <-waitCh:
+		status, err := harness.InspectTask(task.ID)
+		require.NoError(err)
+		require.Equal(drivers.TaskStateRunning, status.State)
+	case <-time.After(1 * time.Second):
+		require.Fail("timeout waiting for task wait to cancel")
+	}
+
+	// Loose task
+	d.(*ExecDriver).tasks.Delete(task.ID)
+	_, err = harness.InspectTask(task.ID)
+	require.Error(err)
+
+	require.NoError(harness.RecoverTask(handle))
+	status, err := harness.InspectTask(task.ID)
+	require.NoError(err)
+	require.Equal(drivers.TaskStateRunning, status.State)
+
+	require.NoError(harness.StopTask(task.ID, 0, ""))
+	require.NoError(harness.DestroyTask(task.ID, true))
+}
+
+func TestExecDriver_Stats(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "test",
+	}
+
+	taskConfig := map[string]interface{}{
+		"command": "/bin/sleep",
+		"args":    []string{"5"},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+
+	handle, _, err := harness.StartTask(task)
+	require.NoError(err)
+	require.NotNil(handle)
+
+	require.NoError(harness.WaitUntilStarted(task.ID, 1*time.Second))
+	stats, err := harness.TaskStats(task.ID)
+	require.NoError(err)
+	require.NotZero(stats.ResourceUsage.MemoryStats.RSS)
+
+	require.NoError(harness.DestroyTask(task.ID, true))
+}
+
+func TestExecDriver_Start_Wait_AllocDir(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "sleep",
+	}
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+
+	exp := []byte{'w', 'i', 'n'}
+	file := "output.txt"
+	taskConfig := map[string]interface{}{
+		"command": "/bin/bash",
+		"args": []string{
+			"-c",
+			fmt.Sprintf(`sleep 1; echo -n %s > /alloc/%s`, string(exp), file),
+		},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	handle, _, err := harness.StartTask(task)
+	require.NoError(err)
+	require.NotNil(handle)
+
+	// Task should terminate quickly
+	waitCh, err := harness.WaitTask(context.Background(), task.ID)
+	require.NoError(err)
+	select {
+	case res := <-waitCh:
+		require.True(res.Successful(), "task should have exited successfully: %v", res)
+	case <-time.After(time.Duration(testutil.TestMultiplier()*5) * time.Second):
+		require.Fail("timeout waiting for task")
+	}
+
+	// Check that data was written to the shared alloc directory.
+	outputFile := filepath.Join(task.TaskDir().SharedAllocDir, file)
+	act, err := ioutil.ReadFile(outputFile)
+	require.NoError(err)
+	require.Exactly(exp, act)
+
+	require.NoError(harness.DestroyTask(task.ID, true))
+}
+
+func TestExecDriver_User(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "sleep",
+		User: "alice",
+	}
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+
+	taskConfig := map[string]interface{}{
+		"command": "/bin/sleep",
+		"args":    []string{"100"},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	handle, _, err := harness.StartTask(task)
+	require.Error(err)
+	require.Nil(handle)
+
+	msg := "user alice"
+	if !strings.Contains(err.Error(), msg) {
+		t.Fatalf("Expecting '%v' in '%v'", msg, err)
+	}
+}
+
+// TestExecDriver_HandlerExec ensures the exec driver's handle properly
+// executes commands inside the container.
+func TestExecDriver_HandlerExec(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	ctestutils.ExecCompatible(t)
+
+	d := NewExecDriver(testlog.HCLogger(t))
+	harness := drivers.NewDriverHarness(t, d)
+	task := &drivers.TaskConfig{
+		ID:   uuid.Generate(),
+		Name: "sleep",
+	}
+	cleanup := harness.MkAllocDir(task, false)
+	defer cleanup()
+
+	taskConfig := map[string]interface{}{
+		"command": "/bin/sleep",
+		"args":    []string{"9000"},
+	}
+	encodeDriverHelper(require, task, taskConfig)
+
+	handle, _, err := harness.StartTask(task)
+	require.NoError(err)
+	require.NotNil(handle)
+
+	// Exec a command that should work and dump the environment
+	// TODO: enable section when exec env is fully loaded
+	/*res, err := harness.ExecTask(task.ID, []string{"/bin/sh", "-c", "env | grep ^NOMAD"}, time.Second)
+	require.NoError(err)
+	require.True(res.ExitResult.Successful())
+
+	// Assert exec'd commands are run in a task-like environment
+	scriptEnv := make(map[string]string)
+	for _, line := range strings.Split(string(res.Stdout), "\n") {
+		if line == "" {
+			continue
+		}
+		parts := strings.SplitN(string(line), "=", 2)
+		if len(parts) != 2 {
+			t.Fatalf("Invalid env var: %q", line)
+		}
+		scriptEnv[parts[0]] = parts[1]
+	}
+	if v, ok := scriptEnv["NOMAD_SECRETS_DIR"]; !ok || v != "/secrets" {
+		t.Errorf("Expected NOMAD_SECRETS_DIR=/secrets but found=%t value=%q", ok, v)
+	}*/
+
+	// Assert cgroup membership
+	res, err := harness.ExecTask(task.ID, []string{"/bin/cat", "/proc/self/cgroup"}, time.Second)
+	require.NoError(err)
+	require.True(res.ExitResult.Successful())
+	found := false
+	for _, line := range strings.Split(string(res.Stdout), "\n") {
+		// Every cgroup entry should be /nomad/$ALLOC_ID
+		if line == "" {
+			continue
+		}
+		// Skip systemd cgroup
+		if strings.HasPrefix(line, "1:name=systemd") {
+			continue
+		}
+		if !strings.Contains(line, ":/nomad/") {
+			t.Errorf("Not a member of the alloc's cgroup: expected=...:/nomad/... -- found=%q", line)
+			continue
+		}
+		found = true
+	}
+	require.True(found, "exec'd command isn't in the task's cgroup")
+
+	// Exec a command that should fail
+	res, err = harness.ExecTask(task.ID, []string{"/usr/bin/stat", "lkjhdsaflkjshowaisxmcvnlia"}, time.Second)
+	require.NoError(err)
+	require.False(res.ExitResult.Successful())
+	if expected := "No such file or directory"; !bytes.Contains(res.Stdout, []byte(expected)) {
+		t.Fatalf("expected output to contain %q but found: %q", expected, res.Stdout)
+	}
+
+	require.NoError(harness.DestroyTask(task.ID, true))
+}
+
+func encodeDriverHelper(require *require.Assertions, task *drivers.TaskConfig, taskConfig map[string]interface{}) {
+	evalCtx := &hcl.EvalContext{
+		Functions: shared.GetStdlibFuncs(),
+	}
+	spec, diag := hclspec.Convert(taskConfigSpec)
+	require.False(diag.HasErrors())
+	taskConfigCtyVal, diag := shared.ParseHclInterface(taskConfig, spec, evalCtx)
+	require.False(diag.HasErrors())
+	err := task.EncodeDriverConfig(taskConfigCtyVal)
+	require.Nil(err)
+}

drivers/exec/handle.go

@@ -0,0 +1,52 @@
+package exec
+
+import (
+	"sync"
+	"time"
+
+	hclog "github.com/hashicorp/go-hclog"
+	plugin "github.com/hashicorp/go-plugin"
+	"github.com/hashicorp/nomad/client/driver/executor"
+	"github.com/hashicorp/nomad/plugins/drivers"
+)
+
+type execTaskHandle struct {
+	exec         executor.Executor
+	pid          int
+	pluginClient *plugin.Client
+	logger       hclog.Logger
+
+	// stateLock syncs access to all fields below
+	stateLock sync.RWMutex
+
+	task        *drivers.TaskConfig
+	procState   drivers.TaskState
+	startedAt   time.Time
+	completedAt time.Time
+	exitResult  *drivers.ExitResult
+	exitCh      chan struct{}
+}
+
+func (h *execTaskHandle) IsRunning() bool {
+	return h.procState == drivers.TaskStateRunning
+}
+
+func (h *execTaskHandle) run() {
+	defer close(h.exitCh)
+	if h.exitResult == nil {
+		h.exitResult = &drivers.ExitResult{}
+	}
+
+	ps, err := h.exec.Wait()
+	if err != nil {
+		h.exitResult.Err = err
+		h.procState = drivers.TaskStateUnknown
+		h.completedAt = time.Now()
+		return
+	}
+	h.procState = drivers.TaskStateExited
+	h.exitResult.ExitCode = ps.ExitCode
+	h.exitResult.Signal = ps.Signal
+	h.completedAt = ps.Time
+	// TODO: plumb OOM bool
+}

drivers/exec/state.go

@@ -0,0 +1,33 @@
+package exec
+
+import (
+	"sync"
+)
+
+type taskStore struct {
+	store map[string]*execTaskHandle
+	lock  sync.RWMutex
+}
+
+func newTaskStore() *taskStore {
+	return &taskStore{store: map[string]*execTaskHandle{}}
+}
+
+func (ts *taskStore) Set(id string, handle *execTaskHandle) {
+	ts.lock.Lock()
+	defer ts.lock.Unlock()
+	ts.store[id] = handle
+}
+
+func (ts *taskStore) Get(id string) (*execTaskHandle, bool) {
+	ts.lock.RLock()
+	defer ts.lock.RUnlock()
+	t, ok := ts.store[id]
+	return t, ok
+}
+
+func (ts *taskStore) Delete(id string) {
+	ts.lock.Lock()
+	defer ts.lock.Unlock()
+	delete(ts.store, id)
+}

plugins/drivers/server.go

@@ -1,6 +1,7 @@
 package drivers
 
 import (
+	"fmt"
 	"io"
 
 	"golang.org/x/net/context"
@@ -125,7 +126,19 @@ func (b *driverPluginServer) WaitTask(ctx context.Context, req *proto.WaitTaskRe
 		return nil, err
 	}
 
-	result := <-ch
+	var ok bool
+	var result *ExitResult
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case result, ok = <-ch:
+		if !ok {
+			return &proto.WaitTaskResponse{
+				Err: "channel closed",
+			}, nil
+		}
+	}
+
 	var errStr string
 	if result.Err != nil {
 		errStr = result.Err.Error()
@@ -206,7 +219,7 @@ func (b *driverPluginServer) TaskStats(ctx context.Context, req *proto.TaskStats
 
 	pb, err := taskStatsToProto(stats)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to encode task stats: %v", err)
 	}
 
 	resp := &proto.TaskStatsResponse{

plugins/drivers/testing.go

@@ -14,6 +14,7 @@ import (
 	hclog "github.com/hashicorp/go-hclog"
 	plugin "github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/nomad/client/allocdir"
+	"github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/client/logmon"
 	cstructs "github.com/hashicorp/nomad/client/structs"
 	"github.com/hashicorp/nomad/helper/testlog"
@@ -55,6 +56,7 @@ func NewDriverHarness(t testing.T, d DriverPlugin) *DriverHarness {
 		server:       server,
 		DriverPlugin: dClient,
 		logger:       logger,
+		t:            t,
 	}
 
 	raw, err = client.Dispense("logmon")
@@ -84,7 +86,16 @@ func (h *DriverHarness) MkAllocDir(t *TaskConfig, enableLogs bool) func() {
 	allocDir := allocdir.NewAllocDir(h.logger, dir)
 	require.NoError(h.t, allocDir.Build())
 	taskDir := allocDir.NewTaskDir(t.Name)
-	require.NoError(h.t, taskDir.Build(false, nil, 0))
+
+	caps, err := h.Capabilities()
+	require.NoError(h.t, err)
+
+	var entries map[string]string
+	fsi := caps.FSIsolation
+	if fsi == cstructs.FSIsolationChroot {
+		entries = config.DefaultChrootEnv
+	}
+	require.NoError(h.t, taskDir.Build(false, entries, fsi))
 
 	//logmon
 	if enableLogs {

plugins/drivers/utils.go

@@ -263,7 +263,7 @@ func taskStatusFromProto(pb *proto.TaskStatus) (*TaskStatus, error) {
 }
 
 func taskStatsToProto(stats *cstructs.TaskResourceUsage) (*proto.TaskStats, error) {
-	timestamp, err := ptypes.TimestampProto(time.Unix(stats.Timestamp, 0))
+	timestamp, err := ptypes.TimestampProto(time.Unix(0, stats.Timestamp))
 	if err != nil {
 		return nil, err
 	}