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Viewing changes to hooks/lib/charmhelpers/contrib/network/ip.py

  • Committer: Robin Winslow
  • Date: 2014-05-27 14:00:44 UTC
  • Revision ID: robin.winslow@canonical.com-20140527140044-8rpmb3wx4djzwa83
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hooks/lib/charmhelpers/contrib/network/ip.py
 
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import sys
 
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from charmhelpers.fetch import apt_install
 
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from charmhelpers.core.hookenv import (
 
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    ERROR, log,
 
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)
 
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try:
 
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    import netifaces
 
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except ImportError:
 
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    apt_install('python-netifaces')
 
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    import netifaces
 
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try:
 
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    import netaddr
 
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except ImportError:
 
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    apt_install('python-netaddr')
 
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    import netaddr
 
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def _validate_cidr(network):
 
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    try:
 
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        netaddr.IPNetwork(network)
 
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    except (netaddr.core.AddrFormatError, ValueError):
 
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        raise ValueError("Network (%s) is not in CIDR presentation format" %
 
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                         network)
 
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def get_address_in_network(network, fallback=None, fatal=False):
 
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    """
 
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    Get an IPv4 address within the network from the host.
 
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    Args:
 
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        network (str): CIDR presentation format. For example,
 
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                       '192.168.1.0/24'.
 
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        fallback (str): If no address is found, return fallback.
 
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        fatal (boolean): If no address is found, fallback is not
 
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                         set and fatal is True then exit(1).
 
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    """
 
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    def not_found_error_out():
 
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        log("No IP address found in network: %s" % network,
 
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            level=ERROR)
 
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        sys.exit(1)
 
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    if network is None:
 
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        if fallback is not None:
 
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            return fallback
 
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        else:
 
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            if fatal:
 
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                not_found_error_out()
 
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    _validate_cidr(network)
 
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    for iface in netifaces.interfaces():
 
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        addresses = netifaces.ifaddresses(iface)
 
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        if netifaces.AF_INET in addresses:
 
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            addr = addresses[netifaces.AF_INET][0]['addr']
 
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            netmask = addresses[netifaces.AF_INET][0]['netmask']
 
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            cidr = netaddr.IPNetwork("%s/%s" % (addr, netmask))
 
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            if cidr in netaddr.IPNetwork(network):
 
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                return str(cidr.ip)
 
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    if fallback is not None:
 
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        return fallback
 
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    if fatal:
 
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        not_found_error_out()
 
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    return None