Security group的流程分析nova篇

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Security group在G版本中可由nova和quantum分别来完成。Nova部分的底层由iptables完成，quantum部分应该也是。本文档主要分析nova部分，quantum部分待续。

1 首先由python-novaclient接收处理请求

/novaclient/v1_1/shell.py

def _get_secgroup(cs, secgroup):
    # Check secgroup is an ID
    if uuidutils.is_uuid_like(strutils.safe_encode(secgroup)):
        try:
            return cs.security_groups.get(secgroup)
        except exceptions.NotFound:
            pass

    # Check secgroup as a name
    match_found = False
    for s in cs.security_groups.list():
        encoding = (locale.getpreferredencoding() or
            sys.stdin.encoding or
            'UTF-8')
        s.name = s.name.encode(encoding)
        if secgroup == s.name:
            if match_found != False:
                msg = ("Multiple security group matches found for name"
                       " '%s', use an ID to be more specific." % secgroup)
                raise exceptions.NoUniqueMatch(msg)
            match_found = s
    if match_found is False:
        raise exceptions.CommandError("Secgroup ID or name '%s' not found."
                                      % secgroup)
return match_found

2./novaclient/v1_1/security_groups.py

def get(self, group_id):
        """
        Get a security group

        :param group_id: The security group to get by ID
        :rtype: :class:`SecurityGroup`