add wm module for GETing (and encoding) active preflist

src/riak_kv_web.erl

@@ -112,6 +112,9 @@ raw_dispatch(Name) ->
      {Prefix ++ ["buckets", bucket, "keys", key],
       riak_kv_wm_object, Props},
 
+     {Prefix ++ ["buckets", bucket, "keys", key, "preflist"],
+      riak_kv_wm_preflist, Props},
+
      {Prefix ++ ["buckets", bucket, "keys", key, '*'],
       riak_kv_wm_link_walker, Props},
 

src/riak_kv_wm_preflist.erl

@@ -0,0 +1,228 @@
+%% --------------------------------------------------------------------------
+%%
+%% riak_kv_wm_preflist - Webmachine resource for getting bucket/key active
+%%                       preflist.
+%%
+%%
+%% Copyright (c) 2015 Basho Technologies, Inc.
+%%
+%% This file is provided to you under the Apache License,
+%% Version 2.0 (the "License"); you may not use this file
+%% except in compliance with the License.  You may obtain
+%% a copy of the License at
+%%
+%%   http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing,
+%% software distributed under the License is distributed on an
+%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+%% KIND, either express or implied.  See the License for the
+%% specific language governing permissions and limitations
+%% under the License.
+%%
+%% --------------------------------------------------------------------------
+
+%% @doc Resource for getting Riak bucket/key active preflist over HTTP.
+%%
+%% Available operations:
+%%
+%% GET /types/Type/buckets/Bucket/keys/Key/preflist
+%% GET /buckets/Bucket/keys/Key/preflist
+%%   Get information about the active preflist for a particular buckey/key
+%%   combo.
+
+-module(riak_kv_wm_preflist).
+
+%% webmachine resource exports
+-export([
+         init/1,
+         service_available/2,
+         is_authorized/2,
+         forbidden/2,
+         allowed_methods/2,
+         resource_exists/2,
+         content_types_provided/2,
+         encodings_provided/2,
+         produce_preflist_body/2,
+         malformed_request/2
+        ]).
+
+-record(ctx, {
+          api_version,  %% integer() - Determine which version of the API to use.
+          bucket_type,  %% binary() - bucket type (from uri)
+          bucket,       %% binary() - Bucket name (from uri)
+          key,          %% binary() - Key (from uri)
+          client,       %% riak_client() - the store client
+          prefix,       %% string() - prefix for resource uris
+          riak,         %% local | {node(), atom()} - params for riak client
+          method,       %% atom() - HTTP method for the request
+          security      %% security context
+         }).
+
+-type context() :: #ctx{}.
+%% @doc Annotated preflist type
+-type preflist_with_number_ann() :: [ {{non_neg_integer(), node()},
+                                       primary|fallback} ].
+
+-include_lib("webmachine/include/webmachine.hrl").
+-include("riak_kv_wm_raw.hrl").
+
+-spec init(proplists:proplist()) -> {ok, context()}.
+%% @doc Initialize this resource.  This function extracts the
+%%      'prefix' and 'riak' properties from the dispatch args.
+init(Props) ->
+    {ok, #ctx{
+            api_version=proplists:get_value(api_version, Props),
+            prefix=proplists:get_value(prefix, Props),
+            riak=proplists:get_value(riak, Props),
+            bucket_type=proplists:get_value(bucket_type, Props)}}.
+
+-spec service_available(#wm_reqdata{}, context()) ->
+    {boolean(), #wm_reqdata{}, context()}.
+%% @doc Determine whether or not a connection to Riak
+%%      can be established.  This function also takes this
+%%      opportunity to extract the 'bucket' and 'key' path
+%%      bindings from the dispatch, as well as any vtag
+%%      query parameter.
+service_available(RD, Ctx0=#ctx{riak=RiakProps}) ->
+    Ctx = riak_kv_wm_utils:ensure_bucket_type(RD, Ctx0, #ctx.bucket_type),
+    case riak_kv_wm_utils:get_riak_client(RiakProps, riak_kv_wm_utils:get_client_id(RD)) of
+        {ok, C} ->
+            {true,
+             RD,
+             Ctx#ctx{
+               method=wrq:method(RD),
+               client=C,
+               bucket=case wrq:path_info(bucket, RD) of
+                         undefined -> undefined;
+                         B -> list_to_binary(riak_kv_wm_utils:maybe_decode_uri(RD, B))
+                      end,
+               key=case wrq:path_info(key, RD) of
+                       undefined -> undefined;
+                       K -> list_to_binary(riak_kv_wm_utils:maybe_decode_uri(RD, K))
+                   end
+              }};
+        Error ->
+            {false,
+             wrq:set_resp_body(
+               io_lib:format("Unable to connect to Riak: ~p~n", [Error]),
+               wrq:set_resp_header(?HEAD_CTYPE, "text/plain", RD)),
+             Ctx}
+    end.
+
+is_authorized(ReqData, Ctx) ->
+    case riak_api_web_security:is_authorized(ReqData) of
+        false ->
+            {"Basic realm=\"Riak\"", ReqData, Ctx};
+        {true, SecContext} ->
+            {true, ReqData, Ctx#ctx{security=SecContext}};
+        insecure ->
+            %% XXX 301 may be more appropriate here, but since the http and
+            %% https port are different and configurable, it is hard to figure
+            %% out the redirect URL to serve.
+            {{halt, 426}, wrq:append_to_resp_body(<<"Security is enabled and "
+                    "Riak does not accept credentials over HTTP. Try HTTPS "
+                    "instead.">>, ReqData), Ctx}
+    end.
+
+forbidden(RD, Ctx = #ctx{security=undefined}) ->
+    {riak_kv_wm_utils:is_forbidden(RD), RD, Ctx};
+forbidden(RD, Ctx) ->
+    case riak_kv_wm_utils:is_forbidden(RD) of
+        true ->
+            {true, RD, Ctx};
+        false ->
+            Res = riak_core_security:check_permission({"riak_kv.get_preflist",
+                                                       Ctx#ctx.bucket_type},
+                                                      Ctx#ctx.security),
+            case Res of
+                {false, Error, _} ->
+                    RD1 = wrq:set_resp_header("Content-Type", "text/plain", RD),
+                    {true, wrq:append_to_resp_body(
+                             unicode:characters_to_binary(
+                               Error, utf8, utf8), RD1), Ctx};
+                {true, _} ->
+                    {false, RD, Ctx}
+            end
+    end.
+
+-spec allowed_methods(#wm_reqdata{}, context()) ->
+    {[atom()], #wm_reqdata{}, context()}.
+%% @doc Get the list of methods this resource supports.
+%%      Properties allows, GET.
+allowed_methods(RD, Ctx) ->
+    {['GET'], RD, Ctx}.
+
+-spec content_types_provided(#wm_reqdata{}, context()) ->
+    {[{ContentType::string(), Producer::atom()}], #wm_reqdata{}, context()}.
+%% @doc List the content types available for representing this resource.
+%%      "application/json" is the content-type for listing keys.
+content_types_provided(RD, Ctx) ->
+    %% bucket-level: JSON description only
+    {[{"application/json", produce_preflist_body}], RD, Ctx}.
+
+-spec encodings_provided(#wm_reqdata{}, context()) ->
+    {[{Encoding::string(), Producer::function()}], #wm_reqdata{}, context()}.
+%% @doc List the encodings available for representing this resource.
+%%      "identity" and "gzip" are available for a preflist request.
+encodings_provided(RD, Ctx) ->
+    %% identity and gzip for top-level and bucket-level requests
+    {riak_kv_wm_utils:default_encodings(), RD, Ctx}.
+
+resource_exists(RD, #ctx{bucket_type=BType}=Ctx) ->
+    {riak_kv_wm_utils:bucket_type_exists(BType), RD, Ctx}.
+
+-spec malformed_request(#wm_reqdata{}, context()) ->
+    {boolean(), #wm_reqdata{}, context()}.
+malformed_request(RD, Ctx) ->
+    {false, RD, Ctx}.
+
+-spec produce_preflist_body(#wm_reqdata{}, context()) ->
+                                   {mochijson2:json_object()|{halt, 404},
+                                    #wm_reqdata{},
+                                    context()}.
+%% @doc Produce bucket/key annotated preflist as JSON.
+produce_preflist_body(RD, #ctx{bucket=Bucket0,
+                               bucket_type=BType,
+                               key=Key}=Ctx) ->
+    Bucket = riak_kv_wm_utils:maybe_bucket_type(BType, Bucket0),
+    Preflist = riak_core_apl:get_apl_ann_with_pnum({Bucket, Key}),
+    case Preflist of
+        [] ->
+            {{halt, 404},
+             wrq:set_resp_header("Content-Type", "text/plain",
+                 wrq:append_to_response_body(
+                     io_lib:format(
+                       "No preflist for bucket '~s' and key '~s'~n",
+                       [Bucket, Key]),
+                   RD)),
+             Ctx};
+        P ->
+            Json = mochijson2:encode({struct,
+                                      [{<<"preflist">>,
+                                        lists:flatten(encode_results(P))}]}),
+            {Json, RD, Ctx}
+    end.
+
+%% Private
+
+-spec encode_results(preflist_with_number_ann()) -> list().
+%% @doc Encode active preflist to json.
+encode_results(Preflist) ->
+    [encode_results({PartitionNumber, Node}, T) ||
+        {{PartitionNumber, Node}, T} <- Preflist].
+
+-spec encode_results({non_neg_integer(), node()}, primary|fallback) ->
+                            [{struct, list()}].
+
+encode_results({PartitionNumber, Node}, primary) ->
+    [{struct,
+      [{<<"partition">>, PartitionNumber},
+       {<<"node">>, atom_to_binary(Node, utf8)},
+       {<<"primary">>, true}]}]
+                               ;
+encode_results({PartitionNumber, Node}, fallback) ->
+    [{struct,
+      [{<<"partition">>, PartitionNumber},
+       {<<"node">>, atom_to_binary(Node, utf8)},
+       {<<"primary">>, false}]}].