Support volume annotations (#40)

* Add volume annotation support

Signed-off-by: Lantao Liu <lantaol@google.com>

* Add unit test.

Signed-off-by: Lantao Liu <lantaol@google.com>

4 files changed, 444 insertions, 0 deletions

diff --git a/pkg/v1/shim/service.go b/pkg/v1/shim/service.go
index b9e1c0ced..e06a5562c 100644
--- a/pkg/v1/shim/service.go
+++ b/pkg/v1/shim/service.go
@@ -555,6 +555,10 @@ func newInit(ctx context.Context, path, workDir, runtimeRoot, namespace string,
 	if err != nil {
 		return nil, errors.Wrap(err, "read oci spec")
 	}
+	if err := utils.UpdateVolumeAnnotations(r.Bundle, spec); err != nil {
+		return nil, errors.Wrap(err, "update volume annotations")
+	}
+
 	runsc.FormatLogPath(r.ID, config)
 	rootfs := filepath.Join(path, "rootfs")
 	runtime := proc.NewRunsc(runtimeRoot, path, namespace, r.Runtime, config)
diff --git a/pkg/v1/utils/volumes.go b/pkg/v1/utils/volumes.go
new file mode 100644
index 000000000..cd27f6de5
--- /dev/null
+++ b/pkg/v1/utils/volumes.go
@@ -0,0 +1,162 @@
+/*
+Copyright 2019 Google LLC.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+
+	"github.com/containerd/cri/pkg/annotations"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+const volumeKeyPrefix = "gvisor.dev/spec/mount/"
+
+var kubeletPodsDir = "/var/lib/kubelet/pods"
+
+// volumeName gets volume name from volume annotation key, example:
+// gvisor.dev/spec/mount/NAME/share
+func volumeName(k string) string {
+	return strings.SplitN(strings.TrimPrefix(k, volumeKeyPrefix), "/", 2)[0]
+}
+
+// volumeFieldName gets volume field name from volume annotation key, example:
+// `type` is the field of gvisor.dev/spec/mount/NAME/type
+func volumeFieldName(k string) string {
+	parts := strings.Split(strings.TrimPrefix(k, volumeKeyPrefix), "/")
+	return parts[len(parts)-1]
+}
+
+// podUID gets pod UID from the pod log path.
+func podUID(s *specs.Spec) (string, error) {
+	sandboxLogDir := s.Annotations[annotations.SandboxLogDir]
+	if sandboxLogDir == "" {
+		return "", errors.New("no sandbox log path annotation")
+	}
+	fields := strings.Split(filepath.Base(sandboxLogDir), "_")
+	switch len(fields) {
+	case 1: // This is the old CRI logging path
+		return fields[0], nil
+	case 3: // This is the new CRI logging path
+		return fields[2], nil
+	}
+	return "", errors.Errorf("unexpected sandbox log path %q", sandboxLogDir)
+}
+
+// isVolumeKey checks whether an annotation key is for volume.
+func isVolumeKey(k string) bool {
+	return strings.HasPrefix(k, volumeKeyPrefix)
+}
+
+// volumeSourceKey constructs the annotation key for volume source.
+func volumeSourceKey(volume string) string {
+	return volumeKeyPrefix + volume + "/source"
+}
+
+// volumePath searches the volume path in the kubelet pod directory.
+func volumePath(volume, uid string) (string, error) {
+	// TODO: Support subpath when gvisor supports pod volume bind mount.
+	volumeSearchPath := fmt.Sprintf("%s/%s/volumes/*/%s", kubeletPodsDir, uid, volume)
+	dirs, err := filepath.Glob(volumeSearchPath)
+	if err != nil {
+		return "", err
+	}
+	if len(dirs) != 1 {
+		return "", errors.Errorf("unexpected matched volume list %v", dirs)
+	}
+	return dirs[0], nil
+}
+
+// isVolumePath checks whether a string is the volume path.
+func isVolumePath(volume, path string) (bool, error) {
+	// TODO: Support subpath when gvisor supports pod volume bind mount.
+	volumeSearchPath := fmt.Sprintf("%s/*/volumes/*/%s", kubeletPodsDir, volume)
+	return filepath.Match(volumeSearchPath, path)
+}
+
+// UpdateVolumeAnnotations add necessary OCI annotations for gvisor
+// volume optimization.
+func UpdateVolumeAnnotations(bundle string, s *specs.Spec) error {
+	var (
+		uid string
+		err error
+	)
+	if IsSandbox(s) {
+		uid, err = podUID(s)
+		if err != nil {
+			// Skip if we can't get pod UID, because this doesn't work
+			// for containerd 1.1.
+			logrus.WithError(err).Error("Can't get pod uid")
+			return nil
+		}
+	}
+	var updated bool
+	for k, v := range s.Annotations {
+		if !isVolumeKey(k) {
+			continue
+		}
+		if volumeFieldName(k) != "type" {
+			continue
+		}
+		if v != "tmpfs" {
+			// Only tmpfs is supported now.
+			continue
+		}
+		volume := volumeName(k)
+		if uid != "" {
+			// This is a sandbox
+			path, err := volumePath(volume, uid)
+			if err != nil {
+				return errors.Wrapf(err, "get volume path for %q", volume)
+			}
+			s.Annotations[volumeSourceKey(volume)] = path
+			updated = true
+		} else {
+			// This is a container
+			for i := range s.Mounts {
+				// An error is returned for sandbox if source annotation
+				// is not successfully applied, so it is guaranteed that
+				// the source annotation for sandbox has already been
+				// successfully applied at this point.
+				// The volume name is unique inside a pod, so matching without
+				// podUID is fine here.
+				// TODO: Pass podUID down to shim for containers to do
+				// more accurate matching.
+				if yes, _ := isVolumePath(volume, s.Mounts[i].Source); yes {
+					// gVisor requires the container mount type to match
+					// sandbox mount type for tmpfs.
+					s.Mounts[i].Type = "tmpfs"
+					updated = true
+				}
+			}
+		}
+	}
+	if !updated {
+		return nil
+	}
+	// Update bundle
+	b, err := json.Marshal(s)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(filepath.Join(bundle, "config.json"), b, 0666)
+}
diff --git a/pkg/v1/utils/volumes_test.go b/pkg/v1/utils/volumes_test.go
new file mode 100644
index 000000000..8e7d4a940
--- /dev/null
+++ b/pkg/v1/utils/volumes_test.go
@@ -0,0 +1,275 @@
+/*
+Copyright 2019 Google LLC.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+
+	"github.com/containerd/cri/pkg/annotations"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+func TestUpdateVolumeAnnotations(t *testing.T) {
+	dir, err := ioutil.TempDir("", "test-update-volume-annotations")
+	if err != nil {
+		t.Fatalf("create tempdir: %v", err)
+	}
+	defer os.RemoveAll(dir)
+	kubeletPodsDir = dir
+
+	const (
+		testPodUID           = "testuid"
+		testVolumeName       = "testvolume"
+		testLogDirPath       = "/var/log/pods/testns_testname_" + testPodUID
+		testLegacyLogDirPath = "/var/log/pods/" + testPodUID
+	)
+	testVolumePath := fmt.Sprintf("%s/%s/volumes/kubernetes.io~empty-dir/%s", dir, testPodUID, testVolumeName)
+
+	if err := os.MkdirAll(testVolumePath, 0755); err != nil {
+		t.Fatalf("Create test volume: %v", err)
+	}
+
+	for _, test := range []struct {
+		desc         string
+		spec         *specs.Spec
+		expected     *specs.Spec
+		expectErr    bool
+		expectUpdate bool
+	}{
+		{
+			desc: "volume annotations for sandbox",
+			spec: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir:                              testLogDirPath,
+					annotations.ContainerType:                              annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+				},
+			},
+			expected: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir:                              testLogDirPath,
+					annotations.ContainerType:                              annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/source":  testVolumePath,
+				},
+			},
+			expectUpdate: true,
+		},
+		{
+			desc: "volume annotations for sandbox with legacy log path",
+			spec: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir:                              testLegacyLogDirPath,
+					annotations.ContainerType:                              annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+				},
+			},
+			expected: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir:                              testLegacyLogDirPath,
+					annotations.ContainerType:                              annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/source":  testVolumePath,
+				},
+			},
+			expectUpdate: true,
+		},
+		{
+			desc: "volume annotations for container",
+			spec: &specs.Spec{
+				Mounts: []specs.Mount{
+					{
+						Destination: "/test",
+						Type:        "bind",
+						Source:      testVolumePath,
+						Options:     []string{"ro"},
+					},
+					{
+						Destination: "/random",
+						Type:        "bind",
+						Source:      "/random",
+						Options:     []string{"ro"},
+					},
+				},
+				Annotations: map[string]string{
+					annotations.ContainerType:                              annotations.ContainerTypeContainer,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+				},
+			},
+			expected: &specs.Spec{
+				Mounts: []specs.Mount{
+					{
+						Destination: "/test",
+						Type:        "tmpfs",
+						Source:      testVolumePath,
+						Options:     []string{"ro"},
+					},
+					{
+						Destination: "/random",
+						Type:        "bind",
+						Source:      "/random",
+						Options:     []string{"ro"},
+					},
+				},
+				Annotations: map[string]string{
+					annotations.ContainerType:                              annotations.ContainerTypeContainer,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+				},
+			},
+			expectUpdate: true,
+		},
+		{
+			desc: "should not return error without pod log directory",
+			spec: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.ContainerType:                              annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+				},
+			},
+			expected: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.ContainerType:                              annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/" + testVolumeName + "/share":   "pod",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/type":    "tmpfs",
+					"gvisor.dev/spec/mount/" + testVolumeName + "/options": "ro",
+				},
+			},
+		},
+		{
+			desc: "should return error if volume path does not exist",
+			spec: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir:                testLogDirPath,
+					annotations.ContainerType:                annotations.ContainerTypeSandbox,
+					"gvisor.dev/spec/mount/notexist/share":   "pod",
+					"gvisor.dev/spec/mount/notexist/type":    "tmpfs",
+					"gvisor.dev/spec/mount/notexist/options": "ro",
+				},
+			},
+			expectErr: true,
+		},
+		{
+			desc: "no volume annotations for sandbox",
+			spec: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir: testLogDirPath,
+					annotations.ContainerType: annotations.ContainerTypeSandbox,
+				},
+			},
+			expected: &specs.Spec{
+				Annotations: map[string]string{
+					annotations.SandboxLogDir: testLogDirPath,
+					annotations.ContainerType: annotations.ContainerTypeSandbox,
+				},
+			},
+		},
+		{
+			desc: "no volume annotations for container",
+			spec: &specs.Spec{
+				Mounts: []specs.Mount{
+					{
+						Destination: "/test",
+						Type:        "bind",
+						Source:      "/test",
+						Options:     []string{"ro"},
+					},
+					{
+						Destination: "/random",
+						Type:        "bind",
+						Source:      "/random",
+						Options:     []string{"ro"},
+					},
+				},
+				Annotations: map[string]string{
+					annotations.ContainerType: annotations.ContainerTypeContainer,
+				},
+			},
+			expected: &specs.Spec{
+				Mounts: []specs.Mount{
+					{
+						Destination: "/test",
+						Type:        "bind",
+						Source:      "/test",
+						Options:     []string{"ro"},
+					},
+					{
+						Destination: "/random",
+						Type:        "bind",
+						Source:      "/random",
+						Options:     []string{"ro"},
+					},
+				},
+				Annotations: map[string]string{
+					annotations.ContainerType: annotations.ContainerTypeContainer,
+				},
+			},
+		},
+	} {
+		t.Run(test.desc, func(t *testing.T) {
+			bundle, err := ioutil.TempDir(dir, "test-bundle")
+			if err != nil {
+				t.Fatalf("Create test bundle: %v", err)
+			}
+			err = UpdateVolumeAnnotations(bundle, test.spec)
+			if test.expectErr {
+				if err == nil {
+					t.Fatal("Expected error, but got nil")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Unexpected error: %v", err)
+			}
+			if !reflect.DeepEqual(test.expected, test.spec) {
+				t.Fatalf("Expected %+v, got %+v", test.expected, test.spec)
+			}
+			if test.expectUpdate {
+				b, err := ioutil.ReadFile(filepath.Join(bundle, "config.json"))
+				if err != nil {
+					t.Fatalf("Read spec from bundle: %v", err)
+				}
+				var spec specs.Spec
+				if err := json.Unmarshal(b, &spec); err != nil {
+					t.Fatalf("Unmarshal spec: %v", err)
+				}
+				if !reflect.DeepEqual(test.expected, &spec) {
+					t.Fatalf("Expected %+v, got %+v", test.expected, &spec)
+				}
+			}
+		})
+	}
+}
diff --git a/pkg/v2/service.go b/pkg/v2/service.go
index 63a2f0da6..eade660c9 100644
--- a/pkg/v2/service.go
+++ b/pkg/v2/service.go
@@ -709,6 +709,9 @@ func newInit(ctx context.Context, path, workDir, namespace string, platform rpro
 	if err != nil {
 		return nil, errors.Wrap(err, "read oci spec")
 	}
+	if err := utils.UpdateVolumeAnnotations(r.Bundle, spec); err != nil {
+		return nil, errors.Wrap(err, "update volume annotations")
+	}
 	runsc.FormatLogPath(r.ID, options.RunscConfig)
 	runtime := proc.NewRunsc(options.Root, path, namespace, options.BinaryName, options.RunscConfig)
 	p := proc.New(r.ID, runtime, rproc.Stdio{