Add metadata selection when downloading.

slapos/libnetworkcache.py

@@ -522,10 +522,13 @@ def cmd_upload(*args):
 
 def cmd_download(*args):
   parser = _newArgumentParser("URL of data to download." + key_help)
+  parser.add_argument('meta', nargs='*', metavar='KEY=VALUE',
+    help="Extra metadata.")
   args = parser.parse_args(args or sys.argv[1:])
   nc = NetworkcacheClient(args.config)
+  kw = dict(x.split('=', 1) for x in args.meta)
   urlmd5 = hashlib.md5(args.url.encode()).hexdigest()
   key = args.prefix_key + urlmd5 + args.suffix_key
   f = sys.stdout
-  shutil.copyfileobj(nc.download(next(nc.select(key))['sha512']),
+  shutil.copyfileobj(nc.download(next(nc.select(key, kw))['sha512']),
                      getattr(f, 'buffer', f))