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

  • Committer: james.page at ubuntu
  • Date: 2015-03-16 14:18:05 UTC
  • mfrom: (79.2.28 nova-compute)
  • Revision ID: james.page@ubuntu.com-20150316141805-eko8x0x1gfyrqzeo
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hooks/charmhelpers/contrib/network/ip.py
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import glob
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import re
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import subprocess
 
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import six
 
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import socket
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from functools import partial
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from charmhelpers.core.hookenv import unit_get
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from charmhelpers.fetch import apt_install
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from charmhelpers.core.hookenv import (
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    log
 
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    log,
 
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    WARNING,
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)
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try:
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            return True
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    return False
 
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def is_ip(address):
 
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    """
 
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    Returns True if address is a valid IP address.
 
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    """
 
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    try:
 
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        # Test to see if already an IPv4 address
 
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        socket.inet_aton(address)
 
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        return True
 
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    except socket.error:
 
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        return False
 
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def ns_query(address):
 
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    try:
 
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        import dns.resolver
 
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    except ImportError:
 
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        apt_install('python-dnspython')
 
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        import dns.resolver
 
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    if isinstance(address, dns.name.Name):
 
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        rtype = 'PTR'
 
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    elif isinstance(address, six.string_types):
 
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        rtype = 'A'
 
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    else:
 
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        return None
 
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    answers = dns.resolver.query(address, rtype)
 
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    if answers:
 
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        return str(answers[0])
 
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    return None
 
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def get_host_ip(hostname, fallback=None):
 
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    """
 
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    Resolves the IP for a given hostname, or returns
 
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    the input if it is already an IP.
 
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    """
 
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    if is_ip(hostname):
 
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        return hostname
 
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    ip_addr = ns_query(hostname)
 
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    if not ip_addr:
 
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        try:
 
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            ip_addr = socket.gethostbyname(hostname)
 
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        except:
 
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            log("Failed to resolve hostname '%s'" % (hostname),
 
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                level=WARNING)
 
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            return fallback
 
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    return ip_addr
 
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def get_hostname(address, fqdn=True):
 
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    """
 
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    Resolves hostname for given IP, or returns the input
 
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    if it is already a hostname.
 
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    """
 
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    if is_ip(address):
 
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        try:
 
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            import dns.reversename
 
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        except ImportError:
 
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            apt_install("python-dnspython")
 
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            import dns.reversename
 
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        rev = dns.reversename.from_address(address)
 
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        result = ns_query(rev)
 
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        if not result:
 
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            return None
 
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    else:
 
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        result = address
 
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    if fqdn:
 
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        # strip trailing .
 
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        if result.endswith('.'):
 
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            return result[:-1]
 
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        else:
 
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            return result
 
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    else:
 
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        return result.split('.')[0]