code: protected String getSHA256FromManifest(String manifest) {
          if (StringUtils.isBlank(manifest)) {
              return Constants.EMPTY_STRING;
          }
  
          // sha256 regex, matched group will return string contains digits and chars, String length 64
          String sha256Regex = "sha256:([\\w\\d]{64})";
          Pattern pattern = Pattern.compile(sha256Regex);
          Matcher matcher = pattern.matcher(manifest);
  
          if(matcher.find()){
              return matcher.group(1);
          } else {
              logger.error("Could not get config -> digest -> sha256 value from manifest");
              logger.error("Manifest content - {}", manifest);
              return Constants.EMPTY_STRING;
          }
      }
docs: /*
  Get image sha256 extracted from digest from image manifest.