3 files changed, 22 insertions, 24 deletions

diff --git a/pkg/shim/utils/annotations.go b/pkg/shim/utils/annotations.go
index 1e9d3f365..c744800bb 100644
--- a/pkg/shim/utils/annotations.go
+++ b/pkg/shim/utils/annotations.go
@@ -19,7 +19,9 @@ package utils
 // These are vendor due to import conflicts.
 const (
 	sandboxLogDirAnnotation = "io.kubernetes.cri.sandbox-log-directory"
-	containerTypeAnnotation = "io.kubernetes.cri.container-type"
+	// ContainerTypeAnnotation is they key that defines sandbox or container.
+	ContainerTypeAnnotation = "io.kubernetes.cri.container-type"
 	containerTypeSandbox    = "sandbox"
-	containerTypeContainer  = "container"
+	// ContainerTypeContainer is the value for container.
+	ContainerTypeContainer = "container"
 )
diff --git a/pkg/shim/utils/utils.go b/pkg/shim/utils/utils.go
index 7b1cd983e..f183b1bbc 100644
--- a/pkg/shim/utils/utils.go
+++ b/pkg/shim/utils/utils.go
@@ -18,19 +18,16 @@ package utils
 import (
 	"encoding/json"
 	"io/ioutil"
-	"os"
 	"path/filepath"
 
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 )
 
+const configFilename = "config.json"
+
 // ReadSpec reads OCI spec from the bundle directory.
 func ReadSpec(bundle string) (*specs.Spec, error) {
-	f, err := os.Open(filepath.Join(bundle, "config.json"))
-	if err != nil {
-		return nil, err
-	}
-	b, err := ioutil.ReadAll(f)
+	b, err := ioutil.ReadFile(filepath.Join(bundle, configFilename))
 	if err != nil {
 		return nil, err
 	}
@@ -41,9 +38,18 @@ func ReadSpec(bundle string) (*specs.Spec, error) {
 	return &spec, nil
 }
 
+// WriteSpec writes OCI spec to the bundle directory.
+func WriteSpec(bundle string, spec *specs.Spec) error {
+	b, err := json.Marshal(spec)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(filepath.Join(bundle, configFilename), b, 0666)
+}
+
 // IsSandbox checks whether a container is a sandbox container.
 func IsSandbox(spec *specs.Spec) bool {
-	t, ok := spec.Annotations[containerTypeAnnotation]
+	t, ok := spec.Annotations[ContainerTypeAnnotation]
 	return !ok || t == containerTypeSandbox
 }
 
diff --git a/pkg/shim/utils/volumes.go b/pkg/shim/utils/volumes.go
index cdcb88229..6bc75139d 100644
--- a/pkg/shim/utils/volumes.go
+++ b/pkg/shim/utils/volumes.go
@@ -15,9 +15,7 @@
 package utils
 
 import (
-	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"path/filepath"
 	"strings"
 
@@ -89,8 +87,8 @@ func isVolumePath(volume, path string) (bool, error) {
 }
 
 // UpdateVolumeAnnotations add necessary OCI annotations for gvisor
-// volume optimization.
-func UpdateVolumeAnnotations(bundle string, s *specs.Spec) error {
+// volume optimization. Returns true if the spec was modified.
+func UpdateVolumeAnnotations(s *specs.Spec) (bool, error) {
 	var uid string
 	if IsSandbox(s) {
 		var err error
@@ -98,7 +96,7 @@ func UpdateVolumeAnnotations(bundle string, s *specs.Spec) error {
 		if err != nil {
 			// Skip if we can't get pod UID, because this doesn't work
 			// for containerd 1.1.
-			return nil
+			return false, nil
 		}
 	}
 	var updated bool
@@ -114,7 +112,7 @@ func UpdateVolumeAnnotations(bundle string, s *specs.Spec) error {
 			// This is a sandbox.
 			path, err := volumePath(volume, uid)
 			if err != nil {
-				return fmt.Errorf("get volume path for %q: %w", volume, err)
+				return false, fmt.Errorf("get volume path for %q: %w", volume, err)
 			}
 			s.Annotations[volumeSourceKey(volume)] = path
 			updated = true
@@ -138,15 +136,7 @@ func UpdateVolumeAnnotations(bundle string, s *specs.Spec) error {
 			}
 		}
 	}
-	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)
+	return updated, nil
 }
 
 func changeMountType(m *specs.Mount, newType string) {