Add possibility to limit the list of examined network interfaces during fact gathering

examples/ansible.cfg

@@ -52,6 +52,10 @@
 # environment. 
 # gather_timeout = 10
 
+# by default retrieve facts for all interfaces
+# list interfaces to limit the gather process to here
+#gather_network_interfaces = lo,eth0,eth1
+
 # additional paths to search for roles in, colon separated
 #roles_path    = /etc/ansible/roles
 

lib/ansible/constants.py

@@ -184,6 +184,8 @@ def load_config_file():
 DEFAULT_GATHERING         = get_config(p, DEFAULTS, 'gathering', 'ANSIBLE_GATHERING', 'implicit').lower()
 DEFAULT_GATHER_SUBSET     = get_config(p, DEFAULTS, 'gather_subset', 'ANSIBLE_GATHER_SUBSET', 'all').lower()
 DEFAULT_GATHER_TIMEOUT    = get_config(p, DEFAULTS, 'gather_timeout', 'ANSIBLE_GATHER_TIMEOUT', 10, integer=True)
+DEFAULT_GATHER_NETWORK_INTERFACES = get_config(p, DEFAULTS, 'gather_network_interfaces', 'ANSIBLE_GATHER_NETWORK_INTERFACES', None)
+
 DEFAULT_LOG_PATH          = get_config(p, DEFAULTS, 'log_path',           'ANSIBLE_LOG_PATH', '', ispath=True)
 DEFAULT_FORCE_HANDLERS    = get_config(p, DEFAULTS, 'force_handlers', 'ANSIBLE_FORCE_HANDLERS', False, boolean=True)
 DEFAULT_INVENTORY_IGNORE  = get_config(p, DEFAULTS, 'inventory_ignore_extensions', 'ANSIBLE_INVENTORY_IGNORE', ["~", ".orig", ".bak", ".ini", ".cfg", ".retry", ".pyc", ".pyo"], islist=True)

lib/ansible/executor/play_iterator.py

@@ -159,20 +159,25 @@ def __init__(self, inventory, play, play_context, variable_manager, all_vars, st
         # Default options to gather
         gather_subset = C.DEFAULT_GATHER_SUBSET
         gather_timeout = C.DEFAULT_GATHER_TIMEOUT
+        gather_interfaces = C.DEFAULT_GATHER_NETWORK_INTERFACES
 
         # Retrieve subset to gather
         if self._play.gather_subset is not None:
             gather_subset = self._play.gather_subset
         # Retrieve timeout for gather
         if self._play.gather_timeout is not None:
             gather_timeout = self._play.gather_timeout
+        # Retrieve list of interfaces to gather
+        if self._play.gather_network_interfaces is not None:
+            gather_interfaces = self._play.gather_network_interfaces
 
         setup_block = Block(play=self._play)
         setup_task = Task(block=setup_block)
         setup_task.action = 'setup'
         setup_task.tags   = ['always']
         setup_task.args   = {
           'gather_subset': gather_subset,
+          'gather_network_interfaces': gather_interfaces,
         }
         if gather_timeout:
             setup_task.args['gather_timeout'] = gather_timeout

lib/ansible/module_utils/facts.py

@@ -2158,6 +2158,22 @@ def __new__(cls, *arguments, **keyword):
     def populate(self):
         return self.facts
 
+    def _include_interface(self, device_name, default_ipv4=dict(), default_ipv6=dict()):
+        interfaces_list = self.module.params.get('gather_network_interfaces', None)
+        # if no limits are set include all interfaces
+        if interfaces_list is None:
+            return True
+        # always include the default interfaces
+        if default_ipv4 and device_name == default_ipv4.get('interface', None):
+            return True
+        if default_ipv6 and device_name == default_ipv6.get('interface', None):
+            return True
+        # include all requested interfaces
+        for pat in interfaces_list:
+            if fnmatch.fnmatch(device_name, pat):
+                return True
+        return False
+
 class LinuxNetwork(Network):
     """
     This is a Linux-specific subclass of Network.  It defines
@@ -2228,6 +2244,8 @@ def get_interfaces_info(self, ip_path, default_ipv4, default_ipv6):
             if not os.path.isdir(path):
                 continue
             device = os.path.basename(path)
+            if not self._include_interface(device, default_ipv4, default_ipv6):
+                continue
             interfaces[device] = { 'device': device }
             if os.path.exists(os.path.join(path, 'address')):
                 macaddress = get_file_content(os.path.join(path, 'address'), default='')
@@ -2432,7 +2450,7 @@ def populate(self):
             return self.facts
 
         default_ipv4, default_ipv6 = self.get_default_interfaces(route_path)
-        interfaces, ips = self.get_interfaces_info(ifconfig_path)
+        interfaces, ips = self.get_interfaces_info(ifconfig_path, default_ipv4, default_ipv6)
         self.merge_default_interface(default_ipv4, interfaces, 'ipv4')
         self.merge_default_interface(default_ipv6, interfaces, 'ipv6')
         self.facts['interfaces'] = interfaces.keys()
@@ -2482,9 +2500,10 @@ def get_default_interfaces(self, route_path):
 
         return interface['v4'], interface['v6']
 
-    def get_interfaces_info(self, ifconfig_path, ifconfig_options='-a'):
+    def get_interfaces_info(self, ifconfig_path, default_ipv4, default_ipv6, ifconfig_options='-a'):
         interfaces = {}
         current_if = {}
+        skip_current_if = False
         ips = dict(
             all_ipv4_addresses = [],
             all_ipv6_addresses = [],
@@ -2497,12 +2516,19 @@ def get_interfaces_info(self, ifconfig_path, ifconfig_options='-a'):
         for line in out.split('\n'):
 
             if line:
+                if skip_current_if and not (re.match('^\S', line) and len(words) > 3):
+                    continue
+
                 words = line.split()
 
                 if words[0] == 'pass':
                     continue
                 elif re.match('^\S', line) and len(words) > 3:
+                    skip_current_if = False
                     current_if = self.parse_interface_line(words)
+                    if not self._include_interface(current_if['device'], default_ipv4, default_ipv6):
+                        skip_current_if = True
+                        continue
                     interfaces[ current_if['device'] ] = current_if
                 elif words[0].startswith('options='):
                     self.parse_options_line(words, current_if, ips)

lib/ansible/playbook/play.py

@@ -66,6 +66,7 @@ class Play(Base, Taggable, Become):
     _gather_facts        = FieldAttribute(isa='bool', default=None, always_post_validate=True)
     _gather_subset       = FieldAttribute(isa='barelist', default=None, always_post_validate=True)
     _gather_timeout      = FieldAttribute(isa='int', default=None, always_post_validate=True)
+    _gather_network_interfaces = FieldAttribute(isa='barelist', default=None, always_post_validate=True)
     _hosts               = FieldAttribute(isa='list', required=True, listof=string_types, always_post_validate=True)
     _name                = FieldAttribute(isa='string', default='', always_post_validate=True)