lib/container: Add APIs to retrieve version conveniently

lib/src/container/store.rs

@@ -140,6 +140,13 @@ impl LayeredImageState {
             self.base_commit.as_str()
         }
     }
+
+    /// Retrieve the container image version.
+    pub fn version(&self) -> Option<&str> {
+        self.configuration
+            .as_ref()
+            .and_then(super::version_for_config)
+    }
 }
 
 /// Locally cached metadata for an update to an existing image.
@@ -153,6 +160,13 @@ pub struct CachedImageUpdate {
     pub manifest_digest: String,
 }
 
+impl CachedImageUpdate {
+    /// Retrieve the container image version.
+    pub fn version(&self) -> Option<&str> {
+        super::version_for_config(&self.config)
+    }
+}
+
 /// Context for importing a container image.
 #[derive(Debug)]
 pub struct ImageImporter {

lib/tests/it/main.rs

@@ -780,13 +780,15 @@ r usr/bin/bash bash-v0
     {
         let cached = store::query_image_ref(fixture.destrepo(), &imgref.imgref)
             .unwrap()
-            .unwrap()
-            .cached_update
             .unwrap();
+        assert_eq!(cached.version(), Some("42.0"));
+
+        let cached_update = cached.cached_update.unwrap();
         assert_eq!(
-            cached.manifest_digest.as_str(),
+            cached_update.manifest_digest.as_str(),
             prep.manifest_digest.as_str()
         );
+        assert_eq!(cached_update.version(), Some("42.0"));
     }
     let to_fetch = prep.layers_to_fetch().collect::<Result<Vec<_>>>()?;
     assert_eq!(to_fetch.len(), 2);