Cleanups for netinfo.py

- Handle ipv6 route information not existing
  gracefully (for systems that don't have it)
- Fix the getgateway function (broken due to
  ipv4/ipv6 keys now existing in route info)
- Separate the centering of the route info ipv4
  information from the centering of the ipv6 information
  so that this looks prettier...
- Use try: except: else instead of settings value to
  None and then later checking for None (more pythonic
  this way)

1 files changed, 54 insertions, 56 deletions

diff --git a/cloudinit/netinfo.py b/cloudinit/netinfo.py
index d891315b..fb40cc0d 100644
--- a/cloudinit/netinfo.py
+++ b/cloudinit/netinfo.py
@@ -97,7 +97,6 @@ def netdev_info(empty=""):
 
 def route_info():
     (route_out, _err) = util.subp(["netstat", "-rn"])
-    (route_out6, _err6) = util.subp(["netstat", "-A inet6", "-n"])
 
     routes = {}
     routes['ipv4'] = []
@@ -108,7 +107,6 @@ def route_info():
         if not line:
             continue
         toks = line.split()
-
         # FreeBSD shows 6 items in the routing table:
         #  Destination  Gateway    Flags Refs    Use  Netif Expire
         #  default      10.65.0.1  UGS      0  34920 vtnet0
@@ -120,13 +118,11 @@ def route_info():
                 toks[0] == "Destination" or toks[0] == "Internet" or
                 toks[0] == "Internet6" or toks[0] == "Routing"):
             continue
-
         if len(toks) < 8:
             toks.append("-")
             toks.append("-")
             toks[7] = toks[5]
             toks[5] = "-"
-
         entry = {
             'destination': toks[0],
             'gateway': toks[1],
@@ -137,39 +133,42 @@ def route_info():
             'use': toks[6],
             'iface': toks[7],
         }
-
         routes['ipv4'].append(entry)
 
-    entries6 = route_out6.splitlines()[1:]
-    for line in entries6:
-        if not line:
-            continue
-        toks = line.split()
-
-        if (len(toks) < 6 or toks[0] == "Kernel" or
-                toks[0] == "Proto" or toks[0] == "Active"):
-            continue
-        entry = {
-            'proto': toks[0],
-            'recv-q': toks[1],
-            'send-q': toks[2],
-            'local address': toks[3],
-            'foreign address': toks[4],
-            'state': toks[5],
-        }
-        routes['ipv6'].append(entry)
+    try:
+        (route_out6, _err6) = util.subp(["netstat", "-A", "inet6", "-n"])
+    except util.ProcessExecutionError:
+        pass
+    else:
+        entries6 = route_out6.splitlines()[1:]
+        for line in entries6:
+            if not line:
+                continue
+            toks = line.split()
+            if (len(toks) < 6 or toks[0] == "Kernel" or
+                    toks[0] == "Proto" or toks[0] == "Active"):
+                continue
+            entry = {
+                'proto': toks[0],
+                'recv-q': toks[1],
+                'send-q': toks[2],
+                'local address': toks[3],
+                'foreign address': toks[4],
+                'state': toks[5],
+            }
+            routes['ipv6'].append(entry)
     return routes
 
 
 def getgateway():
-    routes = []
     try:
         routes = route_info()
     except:
         pass
-    for r in routes:
-        if r['flags'].find("G") >= 0:
-            return "%s[%s]" % (r['gateway'], r['iface'])
+    else:
+        for r in routes.get('ipv4', []):
+            if r['flags'].find("G") >= 0:
+                return "%s[%s]" % (r['gateway'], r['iface'])
     return None
 
 
@@ -179,14 +178,14 @@ def netdev_pformat():
         netdev = netdev_info(empty=".")
     except Exception:
         lines.append(util.center("Net device info failed", '!', 80))
-        netdev = None
-    if netdev is not None:
+    else:
         fields = ['Device', 'Up', 'Address', 'Mask', 'Scope', 'Hw-Address']
         tbl = PrettyTable(fields)
         for (dev, d) in netdev.iteritems():
             tbl.add_row([dev, d["up"], d["addr"], d["mask"], ".", d["hwaddr"]])
-            if d["addr6"]:
-                tbl.add_row([dev, d["up"], d["addr6"], ".", d["scope6"], d["hwaddr"]])
+            if d.get('addr6'):
+                tbl.add_row([dev, d["up"],
+                             d["addr6"], ".", d.get("scope6"), d["hwaddr"]])
         netdev_s = tbl.get_string()
         max_len = len(max(netdev_s.splitlines(), key=len))
         header = util.center("Net device info", "+", max_len)
@@ -201,35 +200,34 @@ def route_pformat():
     except Exception as e:
         lines.append(util.center('Route info failed', '!', 80))
         util.logexc(LOG, "Route info failed: %s" % e)
-        routes = None
-    if routes is not None:
-        fields_v4 = ['Route', 'Destination', 'Gateway',
-                  'Genmask', 'Interface', 'Flags']
-
-        if routes.get('ipv6') is not None:
-            fields_v6 = ['Route', 'Proto', 'Recv-Q', 'Send-Q', 'Local Address',
-                           'Foreign Address', 'State']
-
-        tbl_v4 = PrettyTable(fields_v4)
-        for (n, r) in enumerate(routes.get('ipv4')):
-            route_id = str(n)
-            tbl_v4.add_row([route_id, r['destination'],
-                        r['gateway'], r['genmask'],
-                        r['iface'], r['flags']])
-        route_s = tbl_v4.get_string()
-        if fields_v6:
+    else:
+        if routes.get('ipv4'):
+            fields_v4 = ['Route', 'Destination', 'Gateway',
+                         'Genmask', 'Interface', 'Flags']
+            tbl_v4 = PrettyTable(fields_v4)
+            for (n, r) in enumerate(routes.get('ipv4')):
+                route_id = str(n)
+                tbl_v4.add_row([route_id, r['destination'],
+                                r['gateway'], r['genmask'],
+                                r['iface'], r['flags']])
+            route_s = tbl_v4.get_string()
+            max_len = len(max(route_s.splitlines(), key=len))
+            header = util.center("Route IPv4 info", "+", max_len)
+            lines.extend([header, route_s])
+        if routes.get('ipv6'):
+            fields_v6 = ['Route', 'Proto', 'Recv-Q', 'Send-Q',
+                         'Local Address', 'Foreign Address', 'State']
             tbl_v6 = PrettyTable(fields_v6)
             for (n, r) in enumerate(routes.get('ipv6')):
                 route_id = str(n)
                 tbl_v6.add_row([route_id, r['proto'],
-                            r['recv-q'], r['send-q'],
-                            r['local address'], r['foreign address'],
-                            r['state']])
-            route_s = route_s + tbl_v6.get_string()
-
-        max_len = len(max(route_s.splitlines(), key=len))
-        header = util.center("Route info", "+", max_len)
-        lines.extend([header, route_s])
+                                r['recv-q'], r['send-q'],
+                                r['local address'], r['foreign address'],
+                                r['state']])
+            route_s = tbl_v6.get_string()
+            max_len = len(max(route_s.splitlines(), key=len))
+            header = util.center("Route IPv6 info", "+", max_len)
+            lines.extend([header, route_s])
     return "\n".join(lines)