[Kimchi-devel] [PATCH][Wok] Return collection list without resource with lookup problems

[Paulo Ricardo Paz Vital]

Reviewed-by: Paulo Ricardo Paz Vital <pvital at linux.vnet.ibm.com>

On Apr 21 01:59AM, Rodrigo Trujillo wrote:
> When a collection receives a GET request, it is going to fetch all
> resources names, in a list,  and perform a lookup for each resource,
> building the return list with all data.
> There is a potencial race condition problem in this approach. If a
> given resource is removed between list of names creation and its
> lookup call, wok is going to fail and the exception is not treated.
> This patch fix this problem catching the exception, logging the problem
> and completing the GET request. So, the resource with problem is
> discarted and other resources are returned.
> 
> Signed-off-by: Rodrigo Trujillo <rodrigo.trujillo at linux.vnet.ibm.com>
> ---
>  src/wok/control/base.py | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/src/wok/control/base.py b/src/wok/control/base.py
> index 7aeb844..f314d18 100644
> --- a/src/wok/control/base.py
> +++ b/src/wok/control/base.py
> @@ -34,7 +34,7 @@ from wok.exception import InvalidOperation, InvalidParameter
>  from wok.exception import MissingParameter, NotFoundError
>  from wok.exception import OperationFailed, UnauthorizedError, WokException
>  from wok.reqlogger import RequestRecord
> -from wok.utils import get_plugin_from_request, utf8_dict
> +from wok.utils import get_plugin_from_request, utf8_dict, wok_log
> 
> 
>  # Default request log messages
> @@ -364,7 +364,14 @@ class Collection(object):
>                  # internal text, get_list changes ident to unicode for sorted
>                  args = self.resource_args + [ident]
>                  res = self.resource(self.model, *args)
> -                res.lookup()
> +                try:
> +                    res.lookup()
> +                except Exception as e:
> +                    # In case of errors when fetching a resource info, pass and
> +                    # log the error, so, other resources are returned
> +                    wok_log.error("Problem in lookup of resource '%s'. "
> +                                  "Detail: %s" % (ident, e.message))
> +                    continue
>                  res_list.append(res)
>              return res_list
>          except AttributeError:
> -- 
> 2.1.0
> 
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> 

-- 
Paulo Ricardo Paz Vital
Linux Technology Center, IBM Systems
http://www.ibm.com/linux/ltc/