drivers: Implement InternalPluginDriver interface

This implements the InternalPluginDriver interface in each driver, and
calls the cancellation fn for their respective eventers.

This fixes a per task goroutine leak during test suite execution.

drivers/docker/driver.go

@@ -1242,3 +1242,7 @@ func sliceMergeUlimit(ulimitsRaw map[string]string) ([]docker.ULimit, error) {
 	}
 	return ulimits, nil
 }
+
+func (d *Driver) Shutdown() {
+	d.signalShutdown()
+}

drivers/exec/driver.go

@@ -143,9 +143,8 @@ func (d *Driver) SetConfig(cfg *base.Config) error {
 	return nil
 }
 
-func (d *Driver) Shutdown(ctx context.Context) error {
+func (d *Driver) Shutdown() {
 	d.signalShutdown()
-	return nil
 }
 
 func (d *Driver) TaskConfigSchema() (*hclspec.Spec, error) {

drivers/java/driver.go

@@ -556,3 +556,7 @@ func GetAbsolutePath(bin string) (string, error) {
 
 	return filepath.EvalSymlinks(lp)
 }
+
+func (d *Driver) Shutdown() {
+	d.signalShutdown()
+}

drivers/lxc/driver.go

@@ -216,9 +216,8 @@ func (d *Driver) SetConfig(cfg *base.Config) error {
 	return nil
 }
 
-func (d *Driver) Shutdown(ctx context.Context) error {
+func (d *Driver) Shutdown() {
 	d.signalShutdown()
-	return nil
 }
 
 func (d *Driver) TaskConfigSchema() (*hclspec.Spec, error) {

drivers/mock/driver.go

@@ -550,3 +550,7 @@ func (d *Driver) GetHandle(taskID string) *taskHandle {
 	h, _ := d.tasks.Get(taskID)
 	return h
 }
+
+func (d *Driver) Shutdown() {
+	d.signalShutdown()
+}

drivers/qemu/driver.go

@@ -644,3 +644,7 @@ func sendQemuShutdown(logger hclog.Logger, monitorPath string, userPid int) erro
 	}
 	return err
 }
+
+func (d *Driver) Shutdown() {
+	d.signalShutdown()
+}

drivers/rawexec/driver.go

@@ -189,9 +189,8 @@ func (d *Driver) SetConfig(cfg *base.Config) error {
 	return nil
 }
 
-func (d *Driver) Shutdown(ctx context.Context) error {
+func (d *Driver) Shutdown() {
 	d.signalShutdown()
-	return nil
 }
 
 func (d *Driver) TaskConfigSchema() (*hclspec.Spec, error) {

drivers/rkt/driver.go

@@ -1054,3 +1054,7 @@ func (d *Driver) handleWait(ctx context.Context, handle *taskHandle, ch chan *dr
 	case ch <- result:
 	}
 }
+
+func (d *Driver) Shutdown() {
+	d.signalShutdown()
+}