Introduce new _dbs_info endpoint to get info of a list of databases

Fixes #822

6 files changed, 214 insertions, 0 deletions

diff --git a/rel/overlay/etc/default.ini b/rel/overlay/etc/default.ini
index 9d6d30d07..17a9a4f3d 100644
--- a/rel/overlay/etc/default.ini
+++ b/rel/overlay/etc/default.ini
@@ -69,6 +69,10 @@ require_valid_user = false
 ; List of headers that will be kept when the header Prefer: return=minimal is included in a request.
 ; If Server header is left out, Mochiweb will add its own one in.
 prefer_minimal = Cache-Control, Content-Length, Content-Range, Content-Type, ETag, Server, Transfer-Encoding, Vary
+;
+; Limit maximum number of databases when tying to get detailed information using
+; _dbs_info in a request
+max_db_number_for_dbs_info_req = 100
 
 [database_compaction]
 ; larger buffer sizes can originate smaller files
diff --git a/src/chttpd/src/chttpd_auth_request.erl b/src/chttpd/src/chttpd_auth_request.erl
index 4e2e0dbf2..05c5e8e35 100644
--- a/src/chttpd/src/chttpd_auth_request.erl
+++ b/src/chttpd/src/chttpd_auth_request.erl
@@ -35,6 +35,8 @@ authorize_request_int(#httpd{path_parts=[<<"favicon.ico">>|_]}=Req) ->
     Req;
 authorize_request_int(#httpd{path_parts=[<<"_all_dbs">>|_]}=Req) ->
     Req;
+authorize_request_int(#httpd{path_parts=[<<"_dbs_info">>|_]}=Req) ->
+    Req;
 authorize_request_int(#httpd{path_parts=[<<"_replicator">>], method='PUT'}=Req) ->
     require_admin(Req);
 authorize_request_int(#httpd{path_parts=[<<"_replicator">>], method='DELETE'}=Req) ->
@@ -81,6 +83,8 @@ server_authorization_check(#httpd{path_parts=[<<"_stats">>]}=Req) ->
     Req;
 server_authorization_check(#httpd{path_parts=[<<"_active_tasks">>]}=Req) ->
     Req;
+server_authorization_check(#httpd{path_parts=[<<"_dbs_info">>]}=Req) ->
+    Req;
 server_authorization_check(#httpd{method=Method, path_parts=[<<"_utils">>|_]}=Req)
   when Method =:= 'HEAD' orelse Method =:= 'GET' ->
     Req;
diff --git a/src/chttpd/src/chttpd_httpd_handlers.erl b/src/chttpd/src/chttpd_httpd_handlers.erl
index 9c3044126..cb52e2c40 100644
--- a/src/chttpd/src/chttpd_httpd_handlers.erl
+++ b/src/chttpd/src/chttpd_httpd_handlers.erl
@@ -18,6 +18,7 @@ url_handler(<<>>)                  -> fun chttpd_misc:handle_welcome_req/1;
 url_handler(<<"favicon.ico">>)     -> fun chttpd_misc:handle_favicon_req/1;
 url_handler(<<"_utils">>)          -> fun chttpd_misc:handle_utils_dir_req/1;
 url_handler(<<"_all_dbs">>)        -> fun chttpd_misc:handle_all_dbs_req/1;
+url_handler(<<"_dbs_info">>)       -> fun chttpd_misc:handle_dbs_info_req/1;
 url_handler(<<"_active_tasks">>)   -> fun chttpd_misc:handle_task_status_req/1;
 url_handler(<<"_scheduler">>)      -> fun couch_replicator_httpd:handle_scheduler_req/1;
 url_handler(<<"_node">>)           -> fun chttpd_misc:handle_node_req/1;
diff --git a/src/chttpd/src/chttpd_misc.erl b/src/chttpd/src/chttpd_misc.erl
index 15eabbfbd..253da233e 100644
--- a/src/chttpd/src/chttpd_misc.erl
+++ b/src/chttpd/src/chttpd_misc.erl
@@ -14,6 +14,7 @@
 
 -export([
     handle_all_dbs_req/1,
+    handle_dbs_info_req/1,
     handle_node_req/1,
     handle_favicon_req/1,
     handle_favicon_req/2,
@@ -37,6 +38,8 @@
     [send_json/2,send_json/3,send_method_not_allowed/2,
     send_chunk/2,start_chunked_response/3]).
 
+-define(MAX_DB_NUM_FOR_DBS_INFO, 100).
+
 % httpd global handlers
 
 handle_welcome_req(Req) ->
@@ -141,6 +144,38 @@ all_dbs_callback({error, Reason}, #vacc{resp=Resp0}=Acc) ->
     {ok, Resp1} = chttpd:send_delayed_error(Resp0, Reason),
     {ok, Acc#vacc{resp=Resp1}}.
 
+handle_dbs_info_req(#httpd{method='POST'}=Req) ->
+    chttpd:validate_ctype(Req, "application/json"),
+    Props = chttpd:json_body_obj(Req),
+    Keys = couch_mrview_util:get_view_keys(Props),
+    case Keys of
+        undefined -> throw({bad_request, "`keys` member must exist."});
+        _ -> ok
+    end,
+    MaxNumber = config:get_integer("chttpd",
+        "max_db_number_for_dbs_info_req", ?MAX_DB_NUM_FOR_DBS_INFO),
+    case length(Keys) =< MaxNumber of
+        true -> ok;
+        false -> throw({bad_request, too_many_keys})
+    end,
+    {ok, Resp} = chttpd:start_json_response(Req, 200),
+    send_chunk(Resp, "["),
+    lists:foldl(fun(DbName, AccSeparator) ->
+        case catch fabric:get_db_info(DbName) of
+            {ok, Result} ->
+                Json = ?JSON_ENCODE({[{key, DbName}, {info, {Result}}]}),
+                send_chunk(Resp, AccSeparator ++ Json);
+            _ ->
+                Json = ?JSON_ENCODE({[{key, DbName}, {error, not_found}]}),
+                send_chunk(Resp, AccSeparator ++ Json)
+        end,
+        "," % AccSeparator now has a comma
+    end, "", Keys),
+    send_chunk(Resp, "]"),
+    chttpd:end_json_response(Resp);
+handle_dbs_info_req(Req) ->
+    send_method_not_allowed(Req, "POST").
+
 handle_task_status_req(#httpd{method='GET'}=Req) ->
     {Replies, _BadNodes} = gen_server:multi_call(couch_task_status, all),
     Response = lists:flatmap(fun({Node, Tasks}) ->
diff --git a/src/chttpd/test/chttpd_dbs_info_test.erl b/src/chttpd/test/chttpd_dbs_info_test.erl
new file mode 100644
index 000000000..5b61d8831
--- /dev/null
+++ b/src/chttpd/test/chttpd_dbs_info_test.erl
@@ -0,0 +1,169 @@
+% Licensed 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.
+
+-module(chttpd_dbs_info_test).
+
+-include_lib("couch/include/couch_eunit.hrl").
+-include_lib("couch/include/couch_db.hrl").
+
+-define(USER, "chttpd_db_test_admin").
+-define(PASS, "pass").
+-define(AUTH, {basic_auth, {?USER, ?PASS}}).
+-define(CONTENT_JSON, {"Content-Type", "application/json"}).
+
+
+setup() ->
+    Hashed = couch_passwords:hash_admin_password(?PASS),
+    ok = config:set("admins", ?USER, ?b2l(Hashed), _Persist=false),
+    Addr = config:get("chttpd", "bind_address", "127.0.0.1"),
+    Port = mochiweb_socket_server:get(chttpd, port),
+    Url = lists:concat(["http://", Addr, ":", Port, "/"]),
+    Db1Url = lists:concat([Url, "db1"]),
+    create_db(Db1Url),
+    Db2Url = lists:concat([Url, "db2"]),
+    create_db(Db2Url),
+    Url.
+
+teardown(Url) ->
+    Db1Url = lists:concat([Url, "db1"]),
+    Db2Url = lists:concat([Url, "db2"]),
+    delete_db(Db1Url),
+    delete_db(Db2Url),
+    ok = config:delete("admins", ?USER, _Persist=false).
+
+create_db(Url) ->
+    {ok, Status, _, _} = test_request:put(Url, [?CONTENT_JSON, ?AUTH], "{}"),
+    ?assert(Status =:= 201 orelse Status =:= 202).
+
+delete_db(Url) ->
+    {ok, 200, _, _} = test_request:delete(Url, [?AUTH]).
+
+dbs_info_test_() ->
+    {
+        "chttpd dbs info tests",
+        {
+            setup,
+            fun chttpd_test_util:start_couch/0, fun chttpd_test_util:stop_couch/1,
+            {
+                foreach,
+                fun setup/0, fun teardown/1,
+                [
+                    fun should_return_error_for_get_db_info/1,
+                    fun should_return_dbs_info_for_single_db/1,
+                    fun should_return_dbs_info_for_multiple_dbs/1,
+                    fun should_return_error_for_exceeded_keys/1,
+                    fun should_return_error_for_missing_keys/1,
+                    fun should_return_dbs_info_for_dbs_with_mixed_state/1
+                ]
+            }
+        }
+    }.
+
+
+should_return_error_for_get_db_info(Url) ->
+    ?_test(begin
+        {ok, Code, _, ResultBody} = test_request:get(Url ++ "/_dbs_info?"
+            ++ "keys=[\"db1\"]", [?CONTENT_JSON, ?AUTH]),
+        {Body} = jiffy:decode(ResultBody),
+        [
+            ?assertEqual(<<"method_not_allowed">>,
+                couch_util:get_value(<<"error">>, Body)),
+            ?assertEqual(405, Code)
+        ]
+    end).
+
+
+should_return_dbs_info_for_single_db(Url) ->
+    ?_test(begin
+        NewDoc = "{\"keys\": [\"db1\"]}",
+        {ok, _, _, ResultBody} = test_request:post(Url ++ "/_dbs_info/",
+            [?CONTENT_JSON, ?AUTH], NewDoc),
+        BodyJson = jiffy:decode(ResultBody),
+        {Db1Data} = lists:nth(1, BodyJson),
+        [
+            ?assertEqual(<<"db1">>,
+                couch_util:get_value(<<"key">>, Db1Data)),
+            ?assertNotEqual(undefined,
+                couch_util:get_value(<<"info">>, Db1Data))
+        ]
+    end).
+
+
+should_return_dbs_info_for_multiple_dbs(Url) ->
+    ?_test(begin
+        NewDoc = "{\"keys\": [\"db1\", \"db2\"]}",
+        {ok, _, _, ResultBody} = test_request:post(Url ++ "/_dbs_info/",
+            [?CONTENT_JSON, ?AUTH], NewDoc),
+        BodyJson = jiffy:decode(ResultBody),
+        {Db1Data} = lists:nth(1, BodyJson),
+        {Db2Data} = lists:nth(2, BodyJson),
+        [
+            ?assertEqual(<<"db1">>,
+                couch_util:get_value(<<"key">>, Db1Data)),
+            ?assertNotEqual(undefined,
+                couch_util:get_value(<<"info">>, Db1Data)),
+            ?assertEqual(<<"db2">>,
+                couch_util:get_value(<<"key">>, Db2Data)),
+            ?assertNotEqual(undefined,
+                couch_util:get_value(<<"info">>, Db2Data))
+        ]
+    end).
+
+
+should_return_error_for_exceeded_keys(Url) ->
+    ?_test(begin
+        NewDoc = "{\"keys\": [\"db1\", \"db2\"]}",
+        ok = config:set("chttpd", "max_db_number_for_dbs_info_req", "1"),
+        {ok, Code, _, ResultBody} = test_request:post(Url ++ "/_dbs_info/",
+                   [?CONTENT_JSON, ?AUTH], NewDoc),
+        {Body} = jiffy:decode(ResultBody),
+        ok = config:delete("chttpd", "max_db_number_for_dbs_info_req"),
+        [
+            ?assertEqual(<<"bad_request">>,
+                couch_util:get_value(<<"error">>, Body)),
+            ?assertEqual(400, Code)
+        ]
+    end).
+
+
+should_return_error_for_missing_keys(Url) ->
+    ?_test(begin
+        NewDoc = "{\"missingkeys\": [\"db1\", \"db2\"]}",
+        {ok, Code, _, ResultBody} = test_request:post(Url ++ "/_dbs_info/",
+            [?CONTENT_JSON, ?AUTH], NewDoc),
+        {Body} = jiffy:decode(ResultBody),
+        [
+            ?assertEqual(<<"bad_request">>,
+                couch_util:get_value(<<"error">>, Body)),
+            ?assertEqual(400, Code)
+        ]
+    end).
+
+
+should_return_dbs_info_for_dbs_with_mixed_state(Url) ->
+    ?_test(begin
+        NewDoc = "{\"keys\": [\"db1\", \"noexisteddb\"]}",
+        {ok, _, _, ResultBody} = test_request:post(Url ++ "/_dbs_info/",
+            [?CONTENT_JSON, ?AUTH], NewDoc),
+        Json = jiffy:decode(ResultBody),
+        {Db1Data} = lists:nth(1, Json),
+        {Db2Data} = lists:nth(2, Json),
+        [
+            ?assertEqual(
+                <<"db1">>, couch_util:get_value(<<"key">>, Db1Data)),
+            ?assertNotEqual(undefined,
+                couch_util:get_value(<<"info">>, Db1Data)),
+            ?assertEqual(
+                <<"noexisteddb">>, couch_util:get_value(<<"key">>, Db2Data)),
+            ?assertEqual(undefined, couch_util:get_value(<<"info">>, Db2Data))
+        ]
+    end).
diff --git a/src/couch/test/chttpd_endpoints_tests.erl b/src/couch/test/chttpd_endpoints_tests.erl
index 715576713..9b7430823 100644
--- a/src/couch/test/chttpd_endpoints_tests.erl
+++ b/src/couch/test/chttpd_endpoints_tests.erl
@@ -41,6 +41,7 @@ handlers(url_handler) ->
         {<<"favicon.ico">>, chttpd_misc, handle_favicon_req},
         {<<"_utils">>, chttpd_misc, handle_utils_dir_req},
         {<<"_all_dbs">>, chttpd_misc, handle_all_dbs_req},
+        {<<"_dbs_info">>, chttpd_misc, handle_dbs_info_req},
         {<<"_active_tasks">>, chttpd_misc, handle_task_status_req},
         {<<"_node">>, chttpd_misc, handle_node_req},
         {<<"_reload_query_servers">>, chttpd_misc, handle_reload_query_servers_req},