topotato: kill scapy nameserver warning

topotato doesn't want scapy to use any nameservers. Monkey patch scapy's `read_nameservers` and make it not print a confusing warning. Signed-off-by: David Lamparter <[email protected]>
opensourcerouting · Oct 1, 2024 · ef186b1 · ef186b1
1 parent f4d21af
commit ef186b1
Showing 1 changed file with 12 additions and 2 deletions.
diff --git a/topotato/topolinux.py b/topotato/topolinux.py
@@ -29,8 +29,18 @@
 
 import pytest
 
-import scapy.all  # type: ignore
-import scapy.config  # type: ignore
+import scapy.arch  # type: ignore[import-untyped]
+
+# this is here for 2 reasons (and needs to be before "import scapy.all":
+# - topotato neither needs nor wants scapy to use any nameservers, the list
+#   *should* be empty
+# - scapy prints a confusing message if it can't read resolv.conf
+#   ("Could not retrieve the OS's nameserver !")
+scapy.arch.read_nameservers = lambda: []
+
+# pylint: disable=wrong-import-position
+import scapy.all  # type: ignore[import-untyped]
+import scapy.config  # type: ignore[import-untyped]
 
 from .defer import subprocess
 from .utils import exec_find, EnvcheckResult