From 5fbdc822cfc7ce0cde701b1e1b3cccad444c4a40 Mon Sep 17 00:00:00 2001
From: Tim Gross <tgross@hashicorp.com>
Date: Tue, 17 Mar 2020 09:36:11 -0400
Subject: [PATCH] volumes: add task environment interpolation to volume_mount

---
 client/allocrunner/taskrunner/volume_hook.go  | 19 ++++-
 .../taskrunner/volume_hook_test.go            | 71 +++++++++++++++++++
 2 files changed, 87 insertions(+), 3 deletions(-)

diff --git a/client/allocrunner/taskrunner/volume_hook.go b/client/allocrunner/taskrunner/volume_hook.go
index 5e35f99d3543..5447c50290f3 100644
--- a/client/allocrunner/taskrunner/volume_hook.go
+++ b/client/allocrunner/taskrunner/volume_hook.go
@@ -7,14 +7,16 @@ import (
 	log "github.com/hashicorp/go-hclog"
 	multierror "github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/nomad/client/allocrunner/interfaces"
+	"github.com/hashicorp/nomad/client/taskenv"
 	"github.com/hashicorp/nomad/nomad/structs"
 	"github.com/hashicorp/nomad/plugins/drivers"
 )
 
 type volumeHook struct {
-	alloc  *structs.Allocation
-	runner *TaskRunner
-	logger log.Logger
+	alloc   *structs.Allocation
+	runner  *TaskRunner
+	logger  log.Logger
+	taskEnv *taskenv.TaskEnv
 }
 
 func newVolumeHook(runner *TaskRunner, logger log.Logger) *volumeHook {
@@ -169,6 +171,9 @@ func (h *volumeHook) prepareCSIVolumes(req *interfaces.TaskPrestartRequest, volu
 }
 
 func (h *volumeHook) Prestart(ctx context.Context, req *interfaces.TaskPrestartRequest, resp *interfaces.TaskPrestartResponse) error {
+	h.taskEnv = req.TaskEnv
+	interpolateVolumeMounts(req.Task.VolumeMounts, h.taskEnv)
+
 	volumes := partitionVolumesByType(h.alloc.Job.LookupTaskGroup(h.alloc.TaskGroup).Volumes)
 
 	hostVolumeMounts, err := h.prepareHostVolumes(req, volumes[structs.VolumeTypeHost])
@@ -196,3 +201,11 @@ func (h *volumeHook) Prestart(ctx context.Context, req *interfaces.TaskPrestartR
 
 	return nil
 }
+
+func interpolateVolumeMounts(mounts []*structs.VolumeMount, taskEnv *taskenv.TaskEnv) {
+	for _, mount := range mounts {
+		mount.Volume = taskEnv.ReplaceEnv(mount.Volume)
+		mount.Destination = taskEnv.ReplaceEnv(mount.Destination)
+		mount.PropagationMode = taskEnv.ReplaceEnv(mount.PropagationMode)
+	}
+}
diff --git a/client/allocrunner/taskrunner/volume_hook_test.go b/client/allocrunner/taskrunner/volume_hook_test.go
index 8c0e924fb042..f06896d5ddbb 100644
--- a/client/allocrunner/taskrunner/volume_hook_test.go
+++ b/client/allocrunner/taskrunner/volume_hook_test.go
@@ -6,7 +6,9 @@ import (
 	"github.com/hashicorp/nomad/client/allocrunner/interfaces"
 	"github.com/hashicorp/nomad/client/pluginmanager/csimanager"
 	cstructs "github.com/hashicorp/nomad/client/structs"
+	"github.com/hashicorp/nomad/client/taskenv"
 	"github.com/hashicorp/nomad/helper/testlog"
+	"github.com/hashicorp/nomad/nomad/mock"
 	"github.com/hashicorp/nomad/nomad/structs"
 	"github.com/hashicorp/nomad/plugins/drivers"
 	"github.com/stretchr/testify/require"
@@ -109,3 +111,72 @@ func TestVolumeHook_prepareCSIVolumes(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, expected, mounts)
 }
+
+func TestVolumeHook_Interpolation(t *testing.T) {
+
+	alloc := mock.Alloc()
+	task := alloc.Job.TaskGroups[0].Tasks[0]
+	taskEnv := taskenv.NewBuilder(mock.Node(), alloc, task, "global").SetHookEnv("volume",
+		map[string]string{
+			"PROPAGATION_MODE": "private",
+			"VOLUME_ID":        "my-other-volume",
+		},
+	).Build()
+
+	mounts := []*structs.VolumeMount{
+		{
+			Volume:          "foo",
+			Destination:     "/tmp",
+			ReadOnly:        false,
+			PropagationMode: "bidirectional",
+		},
+		{
+			Volume:          "foo",
+			Destination:     "/bar-${NOMAD_JOB_NAME}",
+			ReadOnly:        false,
+			PropagationMode: "bidirectional",
+		},
+		{
+			Volume:          "${VOLUME_ID}",
+			Destination:     "/baz",
+			ReadOnly:        false,
+			PropagationMode: "bidirectional",
+		},
+		{
+			Volume:          "foo",
+			Destination:     "/quux",
+			ReadOnly:        false,
+			PropagationMode: "${PROPAGATION_MODE}",
+		},
+	}
+
+	expected := []*structs.VolumeMount{
+		{
+			Volume:          "foo",
+			Destination:     "/tmp",
+			ReadOnly:        false,
+			PropagationMode: "bidirectional",
+		},
+		{
+			Volume:          "foo",
+			Destination:     "/bar-my-job",
+			ReadOnly:        false,
+			PropagationMode: "bidirectional",
+		},
+		{
+			Volume:          "my-other-volume",
+			Destination:     "/baz",
+			ReadOnly:        false,
+			PropagationMode: "bidirectional",
+		},
+		{
+			Volume:          "foo",
+			Destination:     "/quux",
+			ReadOnly:        false,
+			PropagationMode: "private",
+		},
+	}
+
+	interpolateVolumeMounts(mounts, taskEnv)
+	require.Equal(t, expected, mounts)
+}