11:09 p.m.
Ok, please ignore this patch.
Rodrigo
On 03/14/2016 04:02 PM, Aline Manera wrote:
On 03/14/2016 02:54 PM, Rodrigo Trujillo wrote:
> There is a potential race condiction issue when some plugin tries to use
> the function get_next_clone_name(all_names, basename, name_suffix='').
> If clone requests are done so fast, it is possible that the plugin does
> not send all resource names in all_names parameter, then the function is
> going to select the same name for 2 or more clones, which is going to
> cause errors in the plugin.
>
> Supporting timestamps in microsecond precision, plugins can avoid this
> type of error coding its own race condiction fix or just using the
> timestamp function option.
> New name will be "basename-clone-timestamp-name-suffix".
>
> Signed-off-by: Rodrigo Trujillo <rodrigo.trujillo(a)linux.vnet.ibm.com>
> ---
> src/wok/utils.py | 33 +++++++++++++++++++++------------
> 1 file changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/src/wok/utils.py b/src/wok/utils.py
> index 7e9a928..b80a80b 100644
> --- a/src/wok/utils.py
> +++ b/src/wok/utils.py
> @@ -31,6 +31,7 @@ import re
> import sqlite3
> import subprocess
> import sys
> +import time
> import traceback
> import xml.etree.ElementTree as ET
>
> @@ -391,7 +392,7 @@ def remove_old_files(globexpr, hours):
> wok_log.error(str(e))
>
>
> -def get_next_clone_name(all_names, basename, name_suffix=''):
> +def get_next_clone_name(all_names, basename, name_suffix='', ts=False):
Please, move this whole function to Kimchi. It is not related to any
Wok feature so there is no reason to keep it here.
> """Find the next available name for a cloned resource.
>
> If any resource named
"<basename>-clone-<number><name_suffix>"
> is found
> @@ -406,26 +407,34 @@ def get_next_clone_name(all_names, basename,
> name_suffix=''):
> exist so that a resource named "foo.img" gets the name
> "foo-clone-1.img" instead of "foo.img-clone-1". If this
> parameter
> is used, the suffix should not be present in "basename".
> + ts -- use timestamp, instead of incremental numbers
>
> Return:
> A UTF-8 string in the format
> "<basename>-clone-<number><name_suffix>".
> """
> re_group_num = 'num'
>
> - re_expr = u'%s-clone-(?P<%s>\d+)' % (basename, re_group_num)
> - if name_suffix != '':
> - re_expr = u'%s%s' % (re_expr, name_suffix)
> + # Use timestamps or increase clone number
> + if ts:
> + # Microsecond precision
> + ts_suffix = int(time.time() * 1000000)
> + new_name = u'%s-clone-%d' % (basename, ts_suffix)
> + else:
> + re_expr = u'%s-clone-(?P<%s>\d+)' % (basename, re_group_num)
> + if name_suffix != '':
> + re_expr = u'%s%s' % (re_expr, name_suffix)
>
> - max_num = 0
> - re_compiled = re.compile(re_expr)
> + max_num = 0
> + re_compiled = re.compile(re_expr)
>
> - for n in all_names:
> - match = re_compiled.match(n)
> - if match is not None:
> - max_num = max(max_num, int(match.group(re_group_num)))
> + for n in all_names:
> + match = re_compiled.match(n)
> + if match is not None:
> + max_num = max(max_num, int(match.group(re_group_num)))
> +
> + # increments the maximum "clone number" found
> + new_name = u'%s-clone-%d' % (basename, max_num + 1)
>
> - # increments the maximum "clone number" found
> - new_name = u'%s-clone-%d' % (basename, max_num + 1)
> if name_suffix != '':
> new_name = new_name + name_suffix
>
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