operator: fix upgradeImages

Operatorhub bundle can have sha256 image tags that are put through
env vars. When operator controller manager gets upgraded, its
operands (plugin daemonsets) should be updated to the image in the
env vars. But it has not been working properly because of wrong
parsing.

Fix it to parse the image names that have sha256 tags correctly so
env vars in operator can be used as intended.

Additionatlly, add comments with an example result to the part
where parsing, trimming, or transforming the name of images happens
in UpgradImages to make the process intuitive.

Signed-off-by: Hyeongju Johannes Lee <hyeongju.lee@intel.com>

Author: hj-johannes-lee

pkg/controllers/reconciler.go

@@ -158,10 +158,13 @@ func UpgradeImages(ctx context.Context, image *string, initimage *string) (upgra
 		if s == nil {
 			continue
 		}
-
+		// e.g. intel-dsa-plugin@sha256:hash -> [intel-dsa-plugin@sha256, hash]
 		if parts := strings.SplitN(*s, ":", 2); len(parts) == 2 && len(parts[0]) > 0 {
-			name, version := parts[0], parts[1]
+			// e.g. [intel-dsa-plugin@sha256, hash] -> [intel-dsa-plugin, hash]
+			name, version := strings.TrimSuffix(parts[0], "@sha256"), parts[1]
 
+			// e.g. intel-dsa-plugin -> INTEL_DSA_PLUGIN_SHA
+			// and get the value of the env var INTEL_DSA_PLUGIN_SHA
 			envVarValue := os.Getenv(strings.ReplaceAll(strings.ToUpper(filepath.Base(name)), "-", "_") + "_SHA")
 
 			if envVarValue != "" && *s != envVarValue {