Embed nvd's downloading and storing of meta data into a function to help with resource management

ext/vulnmdsrc/nvd/nvd.go

@@ -165,24 +165,26 @@ func getDataFeeds(dataFeedHashes map[string]string, localPath string) (map[strin
 				}
 			}
 
+			downloadAndSave := func() error {
+
 				// Download data feed.
 				r, err := httputil.GetWithUserAgent(fmt.Sprintf(dataFeedURL, dataFeedName))
 				if err != nil {
 					log.WithError(err).WithField(logDataFeedName, dataFeedName).Error("could not download NVD data feed")
-				return dataFeedReaders, dataFeedHashes, commonerr.ErrCouldNotDownload
+					return commonerr.ErrCouldNotDownload
 				}
 				defer r.Body.Close()
 
 				if !httputil.Status2xx(r) {
 					log.WithField("StatusCode", r.StatusCode).Error("Failed to download NVD data feed")
-				return dataFeedReaders, dataFeedHashes, commonerr.ErrCouldNotDownload
+					return commonerr.ErrCouldNotDownload
 				}
 
 				// Un-gzip it.
 				gr, err := gzip.NewReader(r.Body)
 				if err != nil {
 					log.WithError(err).WithField(logDataFeedName, dataFeedName).Error("could not read NVD data feed")
-				return dataFeedReaders, dataFeedHashes, commonerr.ErrCouldNotDownload
+					return commonerr.ErrCouldNotDownload
 				}
 
 				// Store it to a file at the same time if possible.
@@ -191,11 +193,19 @@ func getDataFeeds(dataFeedHashes map[string]string, localPath string) (map[strin
 					if err != nil {
 						log.WithError(err).Warning("could not stream NVD data feed to filesystem")
 					}
+					defer f.Close()
 					dataFeedReaders[dataFeedName] = fileName
-				f.Close()
+
 				} else {
 					log.WithError(err).Warning("could not store NVD data feed to filesystem")
 				}
+				return nil
+			}
+
+			err := downloadAndSave()
+			if err != nil {
+				return dataFeedReaders, dataFeedHashes, err
+			}
 		}
 	}