docker dev start: only import netifaces if needed

docker_dev_start.py

@@ -13,7 +13,6 @@
 import ConfigParser
 
 import docker # apt python-docker (1.9)
-from netifaces import interfaces, ifaddresses, AF_INET # apt python-netifaces
 from psycopg2 import connect, OperationalError # apt python-psycopg2
 
 # TODO auto create list of module
@@ -22,7 +21,7 @@
 
 __version__ = '0.1.0'
 __date__ = '2017-08-11'
-__updated__ = '2017-08-24'
+__updated__ = '2017-08-25'
 
 # Check the version of the "docker" package
 if docker.__version__.split('.') < [2]:
@@ -124,7 +123,7 @@
     )
     network_group.add_argument(
         '--docker-network',
-        help="Use docker network [default: %(default)s]",
+        help="Use docker network (work better with python-netifaces installed) [default: %(default)s]",
         action='store_true',
     )
 
@@ -217,9 +216,14 @@
         options.append('--network')
         options.append('host')
     else:
-        ifaceName = 'docker0'
-        addresses = [i['addr'] for i in ifaddresses(ifaceName).setdefault(AF_INET, [{'addr':'No IP addr'}])]
-        if addresses:
-            local_ip = addresses[0]
-        else:
+        local_ip = None
+        try:
+            from netifaces import ifaddresses, AF_INET # apt python-netifaces
+            ifaceName = 'docker0'
+            addresses = [i['addr'] for i in ifaddresses(ifaceName).setdefault(AF_INET, [{'addr':'No IP addr'}])]
+            if addresses:
+                local_ip = addresses[0]
+        except ImportError:
+            logging.warn('Consider installing python netifaces to ease local IP detection')
+        if not local_ip:
             import socket
@@ -225,4 +229,5 @@
             import socket
+            logging.info('Contacting Google Public DNS to find our IP')
             local_ip = [(s.connect(('8.8.8.8', 53)), s.getsockname()[0], s.close()) for s in [socket.socket(socket.AF_INET, socket.SOCK_DGRAM)]][0][1]
         logging.debug('IP found %s', local_ip)
     arg.append('--db_host')