napalm.nxos.traceroute - VRF traces and handle AS in hops (napalm-aut…

…omation#989)

* Adding traceroute from a specific VRF

* Combination of source and vrf command

* On some devices running BGP, an AS number will appear after the IP address of the hop

* E261 at least two spaces before inline comment [pep8]

napalm/nxos/nxos.py

@@ -399,7 +399,8 @@ def traceroute(
             r"(",  # beginning of host_name (ip_address) group only
             r"([a-zA-Z0-9\.:-]*)",  # hostname
             r"\s+",
-            r"\(?([a-fA-F0-9\.:][^\)]*)\)?"  # IP Address between brackets
+            r"\(?([a-fA-F0-9\.:][^\)]*)\)?",  # IP Address between brackets
+            r"(?:\s+\(AS\s+[0-9]+\))?",  # AS number -- may or may not be present
             r")?",  # end of host_name (ip_address) group only
             # also hostname/ip are optional -- they can or cannot be specified
             # if not specified, means the current probe followed the same path as the previous
@@ -432,6 +433,9 @@ def traceroute(
                 version=version, destination=destination
             )
 
+        if vrf != "":
+            command += " vrf {vrf}".format(vrf=vrf)
+
         try:
             traceroute_raw_output = self._send_command(command, raw_text=True)
         except CommandErrorException: