116 lines
4.2 KiB
Python
116 lines
4.2 KiB
Python
# (c) 2012, Zettar Inc.
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# Written by Chin Fang <fangchin@zettar.com>
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#
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# This file is part of Ansible
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#
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# This module is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This software is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this software. If not, see <http://www.gnu.org/licenses/>.
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#
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'''
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This module is for enhancing ansible's inventory parsing capability such
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that it can deal with hostnames specified using a simple pattern in the
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form of [beg:end], example: [1:5], [a:c], [D:G]. If beg is not specified,
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it defaults to 0.
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If beg is given and is left-zero-padded, e.g. '001', it is taken as a
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formatting hint when the range is expanded. e.g. [001:010] is to be
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expanded into 001, 002 ...009, 010.
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Note that when beg is specified with left zero padding, then the length of
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end must be the same as that of beg, else an exception is raised.
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'''
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import string
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from ansible import errors
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def detect_range(line = None):
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'''
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A helper function that checks a given host line to see if it contains
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a range pattern described in the docstring above.
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Returnes True if the given line contains a pattern, else False.
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'''
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if 0 <= line.find("[") < line.find(":") < line.find("]"):
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return True
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else:
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return False
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def expand_hostname_range(line = None):
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'''
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A helper function that expands a given line that contains a pattern
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specified in top docstring, and returns a list that consists of the
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expanded version.
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The '[' and ']' characters are used to maintain the pseudo-code
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appearance. They are replaced in this function with '|' to ease
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string splitting.
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References: http://ansible.github.com/patterns.html#hosts-and-groups
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'''
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all_hosts = []
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if line:
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# A hostname such as db[1:6]-node is considered to consists
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# three parts:
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# head: 'db'
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# nrange: [1:6]; range() is a built-in. Can't use the name
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# tail: '-node'
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# Add support for multiple ranges in a host so:
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# db[01:10:3]node-[01:10]
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# - to do this we split off at the first [...] set, getting the list
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# of hosts and then repeat until none left.
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# - also add an optional third parameter which contains the step. (Default: 1)
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# so range can be [01:10:2] -> 01 03 05 07 09
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# FIXME: make this work for alphabetic sequences too.
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(head, nrange, tail) = line.replace('[','|',1).replace(']','|',1).split('|')
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bounds = nrange.split(":")
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if len(bounds) != 2 and len(bounds) != 3:
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raise errors.AnsibleError("host range incorrectly specified")
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beg = bounds[0]
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end = bounds[1]
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if len(bounds) == 2:
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step = 1
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else:
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step = bounds[2]
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if not beg:
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beg = "0"
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if not end:
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raise errors.AnsibleError("host range end value missing")
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if beg[0] == '0' and len(beg) > 1:
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rlen = len(beg) # range length formatting hint
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if rlen != len(end):
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raise errors.AnsibleError("host range format incorrectly specified!")
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fill = lambda _: str(_).zfill(rlen) # range sequence
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else:
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fill = str
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try:
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i_beg = string.ascii_letters.index(beg)
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i_end = string.ascii_letters.index(end)
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if i_beg > i_end:
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raise errors.AnsibleError("host range format incorrectly specified!")
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seq = string.ascii_letters[i_beg:i_end+1]
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except ValueError: # not an alpha range
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seq = range(int(beg), int(end)+1, int(step))
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for rseq in seq:
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hname = ''.join((head, fill(rseq), tail))
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if detect_range(hname):
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all_hosts.extend( expand_hostname_range( hname ) )
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else:
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all_hosts.append(hname)
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return all_hosts
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