riakc doesn't save metadata properly?

Christian Dahlqvist christian at whitenode.com
Tue Oct 23 00:48:51 EDT 2012

On 22/10/2012 22:25, David Parfitt wrote:
> Hello Metin -
> I'm trying to get that into the docs right now. Will italics do? :-)
> https://github.com/basho/riak-erlang-client/pull/74
> Cheers -
> Dave
> On Mon, Oct 22, 2012 at 5:22 PM, Metin Akat<akat.metin at gmail.com>  wrote:
>> Oh, I see, thanks for this clarification, much appreciated.
>> I think this should be written somewhere in bold, as 3 days later, I still
>> wasn't able to find anything on google.
>> On Tue, Oct 23, 2012 at 12:08 AM, David Parfitt<dparfitt at basho.com>  wrote:
>>> Hello Metin -
>>>    Sorry for the delay. At the moment, all metadata needs to be stored
>>> under the <<"X-Riak-Meta">> dict key. The following example
>>> illustrates how this works:
>>> %% To store metadata:
>>> Object = riakc_obj:new(<<"groceries">>, <<"mine">>, <<"eggs & bacon">>).
>>> MetaData  =dict:from_list([{<<"X-Riak-Meta">>, [{"Foo", "Bar"}]}]),
>>> Object2 = riakc_obj:update_metadata(Object, MetaData).
>>> riakc_pb_socket:put(Pid, Object2).
>>> %% To retrieve metadata:
>>> {ok, O} = riakc_pb_socket:get(Pid, <<"groceries">>, <<"mine">>).
>>> {ok, MD} =dict:find(<<"X-Riak-Meta">>, riakc_obj:get_metadata(O)).
>>> We're kicking around ways to improve this in the future.
>>> Cheers -
>>> Dave
>>> On Fri, Oct 19, 2012 at 8:31 AM, Metin Akat<akat.metin at gmail.com>  wrote:
>>>> I am trying to do something like:
>>>>      Meta1 =dict:store(<<"ver">>, Ver, Meta0),
>>>>      Obj1 = riakc_obj:update_metadata(Obj, Meta1),
>>>> and then save the object. But on a subsequent read, the metadata k/v
>>>> pair is
>>>> not there.
>>>> Is there anything special that needs to be done for this to work, or is
>>>> this
>>>> illegal way to use Riak?
>>>> _______________________________________________
>>>> riak-users mailing list
>>>> riak-users at lists.basho.com
>>>> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
> _______________________________________________
> riak-users mailing list
> riak-users at lists.basho.com
> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com


As far as I can see there seems to be an inconsistency between the 
Erlang and HTTP APIs with respect to how metadata is handled.

When I query the record created in the example through the Erlang API 
(attached to console) I, as expected, get the following:

     {ok, RO} = C:get(<<"groceries">>, <<"mine">>).
     {ok, MD} = dict:find(<<"X-Riak-Meta">>, riak_object:get_metadata(RO)).

The metadata parameter is stored in the dictionary exactly as created, 
which is expected.

When I query this record through the HTTP interface the same metadata is 
returned as a header:

     curl -v -X HEAD http://localhost:8098/riak/groceries/mine
     > HEAD /riak/groceries/mine HTTP/1.1
     > User-Agent: curl/7.21.4 (universal-apple-darwin11.0) 
libcurl/7.21.4 OpenSSL/0.9.8r zlib/1.2.5
     > Host: localhost:8098
     > Accept: */*
     < HTTP/1.1 200 OK
     < X-Riak-Vclock: a85hYGBgzGDKBVIcypz/fga0yrzJYEpkzGNlEG36dZIvCwA=
     < Vary: Accept-Encoding
     < Server: MochiWeb/1.1 WebMachine/1.9.2 (someone had painted it blue)
     < Link: </riak/groceries>; rel="up"
*< Foo: Bar*
     < ETag: "5hdCr8ayy5j9orqA6nDJfs"
     < Content-Type: application/octet-stream
     < Content-Length: 12

When I tried to create another record with the same metadata as the 
first one through the HTTP interface, I had to prefix the metadata with 
"X-Riak-Meta-" in order for it to be saved on the record. When I did 
this the interface did however not seem to strip the "X-Riak-Meta-" 
prefix from the parameter, and when I query the record through the 
Erlang API, the parameter is stored in the metadata dict as 
"X-Riak-Meta-Foo" instead of just "Foo".

I was expecting the parameter to be stored as "Foo" internally in Riak 
and represented as "X-Riak-Meta-Foo" when getting or setting through the 
HTTP API, but that does not seem to be the case.

Is this an inconsistency or is there something I am doing wrong or have 
missed here?

Best regards,


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.basho.com/pipermail/riak-users_lists.basho.com/attachments/20121023/cb175365/attachment.html>

More information about the riak-users mailing list