Add even more ways to populate localinterfaces

IPython/utils/localinterfaces.py

@@ -5,12 +5,14 @@
             machine.  It will *almost* always be '127.0.0.1'
 
 LOCAL_IPS : A list of IP addresses, loopback first, that point to this machine.
+            This will include LOCALHOST, PUBLIC_IPS, and aliases for all hosts,
+            such as '0.0.0.0'.
 
 PUBLIC_IPS : A list of public IP addresses that point to this machine.
              Use these to tell remote clients where to find you.
 """
 #-----------------------------------------------------------------------------
-#  Copyright (C) 2010-2011  The IPython Development Team
+#  Copyright (C) 2010  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
@@ -20,9 +22,13 @@
 # Imports
 #-----------------------------------------------------------------------------
 
+import os
 import socket
 
 from .data import uniq_stable
+from .process import get_output_error_code
+from .py3compat import bytes_to_str
+from .warn import warn
 
 #-----------------------------------------------------------------------------
 # Code
@@ -31,7 +37,7 @@
 LOCAL_IPS = []
 PUBLIC_IPS = []
 
-LOCALHOST = '127.0.0.1'
+LOCALHOST = ''
 
 def _only_once(f):
     """decorator to only run a function once"""
@@ -51,17 +57,124 @@ def ips_loaded(*args, **kwargs):
         return f(*args, **kwargs)
     return ips_loaded
 
-@_only_once
-def _load_ips():
-    """load the IPs that point to this machine
+# subprocess-parsing ip finders
+class NoIPAddresses(Exception):
+    pass
+
+def _populate_from_list(addrs):
+    """populate local and public IPs from flat list of all IPs"""
+    if not addrs:
+        raise NoIPAddresses
 
-    This function will only ever be called once.
+    global LOCALHOST
+    public_ips = []
+    local_ips = []
+
+    for ip in addrs:
+        local_ips.append(ip)
+        if not ip.startswith('127.'):
+            public_ips.append(ip)
+        elif not LOCALHOST:
+            LOCALHOST = ip
+
+    if not LOCALHOST:
+        LOCALHOST = '127.0.0.1'
+        local_ips.insert(0, LOCALHOST)
+
+    local_ips.extend(['0.0.0.0', ''])
+
+    LOCAL_IPS[:] = uniq_stable(local_ips)
+    PUBLIC_IPS[:] = uniq_stable(public_ips)
+
+def _load_ips_ifconfig():
+    """load ip addresses from `ifconfig` output (posix)"""
+
+    out, err, rc = get_output_error_code('ifconfig')
+    if rc:
+        # no ifconfig, it's usually in /sbin and /sbin is not on everyone's PATH
+        out, err, rc = get_output_error_code('/sbin/ifconfig')
+    if rc:
+        raise IOError("no ifconfig: %s" % err)
+
+    lines = bytes_to_str(out).splitlines()
+    addrs = []
+    for line in lines:
+        blocks = line.lower().split()
+        if blocks[0] == 'inet':
+            addrs.append(blocks[1])
+    _populate_from_list(addrs)
+
+
+def _load_ips_ip():
+    """load ip addresses from `ip addr` output (Linux)"""
+    out, err, rc = get_output_error_code('ip addr')
+    if rc:
+        raise IOError("no ip: %s" % err)
+
+    lines = bytes_to_str(out).splitlines()
+    addrs = []
+    for line in lines:
+        blocks = line.lower().split()
+        if blocks[0] == 'inet':
+            addrs.append(blocks[1].split('/')[0])
+    _populate_from_list(addrs)
+
+
+def _load_ips_ipconfig():
+    """load ip addresses from `ipconfig` output (Windows)"""
+    out, err, rc = get_output_error_code('ipconfig')
+    if rc:
+        raise IOError("no ipconfig: %s" % err)
+
+    lines = bytes_to_str(out).splitlines()
+    addrs = ['127.0.0.1']
+    for line in lines:
+        line = line.lower().split()
+        if line[:2] == ['ipv4', 'address']:
+            addrs.append(line.split()[-1])
+    _populate_from_list(addrs)
+
+
+def _load_ips_netifaces():
+    """load ip addresses with netifaces"""
+    import netifaces
+    global LOCALHOST
+    local_ips = []
+    public_ips = []
+
+    # list of iface names, 'lo0', 'eth0', etc.
+    for iface in netifaces.interfaces():
+        # list of ipv4 addrinfo dicts
+        ipv4s = netifaces.ifaddresses(iface).get(netifaces.AF_INET, [])
+        for entry in ipv4s:
+            addr = entry.get('addr')
+            if not addr:
+                continue
+            if not (iface.startswith('lo') or addr.startswith('127.')):
+                public_ips.append(addr)
+            elif not LOCALHOST:
+                LOCALHOST = addr
+            local_ips.append(addr)
+    if not LOCALHOST:
+        # we never found a loopback interface (can this ever happen?), assume common default
+        LOCALHOST = '127.0.0.1'
+        local_ips.insert(0, LOCALHOST)
+    local_ips.extend(['0.0.0.0', ''])
+    LOCAL_IPS[:] = uniq_stable(local_ips)
+    PUBLIC_IPS[:] = uniq_stable(public_ips)
+
+
+def _load_ips_gethostbyname():
+    """load ip addresses with socket.gethostbyname_ex
+
+    This can be slow.
     """
     global LOCALHOST
     try:
         LOCAL_IPS[:] = socket.gethostbyname_ex('localhost')[2]
     except socket.error:
-        pass
+        # assume common default
+        LOCAL_IPS[:] = ['127.0.0.1']
 
     try:
         hostname = socket.gethostname()
@@ -74,14 +187,65 @@ def _load_ips():
     finally:
         PUBLIC_IPS[:] = uniq_stable(PUBLIC_IPS)
         LOCAL_IPS.extend(PUBLIC_IPS)
-
+    
     # include all-interface aliases: 0.0.0.0 and ''
     LOCAL_IPS.extend(['0.0.0.0', ''])
 
     LOCAL_IPS[:] = uniq_stable(LOCAL_IPS)
 
     LOCALHOST = LOCAL_IPS[0]
 
+def _load_ips_dumb():
+    """Fallback in case of unexpected failure"""
+    global LOCALHOST
+    LOCALHOST = '127.0.0.1'
+    LOCAL_IPS[:] = [LOCALHOST, '0.0.0.0', '']
+    PUBLIC_IPS[:] = []
+
+@_only_once
+def _load_ips():
+    """load the IPs that point to this machine
+
+    This function will only ever be called once.
+
+    It will use netifaces to do it quickly if available.
+    Then it will fallback on parsing the output of ifconfig / ip addr / ipconfig, as appropriate.
+    Finally, it will fallback on socket.gethostbyname_ex, which can be slow.
+    """
+
+    try:
+        # first priority, use netifaces
+        try:
+            return _load_ips_netifaces()
+        except ImportError:
+            pass
+
+        # second priority, parse subprocess output (how reliable is this?)
+
+        if os.name == 'nt':
+            try:
+                return _load_ips_ipconfig()
+            except (IOError, NoIPAddresses):
+                pass
+        else:
+            try:
+                return _load_ips_ifconfig()
+            except (IOError, NoIPAddresses):
+                pass
+            try:
+                return _load_ips_ip()
+            except (IOError, NoIPAddresses):
+                pass
+
+        # lowest priority, use gethostbyname
+
+        return _load_ips_gethostbyname()
+    except Exception as e:
+        # unexpected error shouldn't crash, load dumb default values instead.
+        warn("Unexpected error discovering local network interfaces: %s" % e)
+    _load_ips_dumb()
+
+
 @_requires_ips
 def local_ips():
     """return the IP addresses that point to this machine"""