Add utc_id_suffix UUID algorithm

CHANGES

@@ -46,6 +46,10 @@ Test Suite:
   * Improved tracebacks printed by the JS CLI tests
   * Improved the reliability of a number of tests
 
+UUID Algorithms:
+
+  * Added the utc_id algorithm.
+
 Version 1.2.1
 -------------
 

NEWS

@@ -22,6 +22,7 @@ This version has not been released yet.
  * Added Server-Sent Events protocol to db changes API.
  * Moved the JS test suite to the CLI
  * Make password hashing synchronous when using the /_config/admins API.
+ * Added utc_id UUID algorithm.
 
 Version 1.2.1
 -------------

etc/couchdb/default.ini.tpl.in

@@ -178,7 +178,12 @@ _view = {couch_mrview_http, handle_view_req}
 ;     random prefix is regenerated and the process starts over.
 ;   utc_random - Time since Jan 1, 1970 UTC with microseconds
 ;     First 14 characters are the time in hex. Last 18 are random.
+;   utc_id - Time since Jan 1, 1970 UTC with microseconds, plus utc_id_suffix string
+;     First 14 characters are the time in hex. uuids/utc_id_suffix string value is appended to these.
 algorithm = sequential
+; The utc_id_suffix value will be appended to uuids generated by the utc_id algorithm.
+; Replicating instances should have unique utc_id_suffix values to ensure uniqueness of utc_id ids.
+utc_id_suffix =
 
 [stats]
 ; rate is in milliseconds

share/www/script/test/uuids.js

@@ -117,4 +117,29 @@ couchTests.uuids = function(debug) {
     utc_testfun
   );
 
-};
+  // Test utc_id uuids
+  var utc_id_suffix = "frog";
+  var suffix_testfun = function() {
+    xhr = CouchDB.request("GET", "/_uuids?count=10");
+    T(xhr.status == 200);
+    result = JSON.parse(xhr.responseText);
+    for(var i = 1; i < result.uuids.length; i++) {
+      T(result.uuids[i].length == 14 + utc_id_suffix.length);
+      T(result.uuids[i].substring(14) == utc_id_suffix);
+      T(result.uuids[i-1] < result.uuids[i], "utc_id_suffix uuids are ordered.");
+    }
+  };
+
+  run_on_modified_server([{
+      "section": "uuids",
+      "key": "algorithm",
+      "value": "utc_id"
+    }, {
+      "section": "uuids",
+      "key": "utc_id_suffix",
+      "value": utc_id_suffix
+    }],
+    suffix_testfun
+  );
+
+ };

src/couchdb/couch_uuids.erl

@@ -33,12 +33,15 @@ random() ->
     list_to_binary(couch_util:to_hex(crypto:rand_bytes(16))).
 
 utc_random() ->
+    utc_suffix(couch_util:to_hex(crypto:rand_bytes(9))).
+
+utc_suffix(Suffix) ->
     Now = {_, _, Micro} = now(),
     Nowish = calendar:now_to_universal_time(Now),
     Nowsecs = calendar:datetime_to_gregorian_seconds(Nowish),
     Then = calendar:datetime_to_gregorian_seconds({{1970, 1, 1}, {0, 0, 0}}),
     Prefix = io_lib:format("~14.16.0b", [(Nowsecs - Then) * 1000000 + Micro]),
-    list_to_binary(Prefix ++ couch_util:to_hex(crypto:rand_bytes(9))).
+    list_to_binary(Prefix ++ Suffix).
 
 init([]) ->
     ok = couch_config:register(
@@ -53,6 +56,8 @@ handle_call(create, _From, random) ->
     {reply, random(), random};
 handle_call(create, _From, utc_random) ->
     {reply, utc_random(), utc_random};
+handle_call(create, _From, {utc_id, UtcIdSuffix}) ->
+    {reply, utc_suffix(UtcIdSuffix), {utc_id, UtcIdSuffix}};
 handle_call(create, _From, {sequential, Pref, Seq}) ->
     Result = ?l2b(Pref ++ io_lib:format("~6.16.0b", [Seq])),
     case Seq >= 16#fff000 of
@@ -88,6 +93,9 @@ state() ->
             random;
         utc_random ->
             utc_random;
+        utc_id ->
+            UtcIdSuffix = couch_config:get("uuids", "utc_id_suffix", ""),
+            {utc_id, UtcIdSuffix};
         sequential ->
             {sequential, new_prefix(), inc()};
         Unknown ->

test/etap/041-uuid-gen-id.ini

@@ -0,0 +1,20 @@
+; Licensed to the Apache Software Foundation (ASF) under one
+; or more contributor license agreements.  See the NOTICE file
+; distributed with this work for additional information
+; regarding copyright ownership.  The ASF licenses this file
+; 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.
+
+[uuids]
+algorithm = utc_id
+utc_id_suffix = bozo

test/etap/041-uuid-gen.t

@@ -22,6 +22,9 @@ seq_alg_config() ->
 utc_alg_config() ->
     test_util:source_file("test/etap/041-uuid-gen-utc.ini").
 
+utc_id_alg_config() ->
+    test_util:source_file("test/etap/041-uuid-gen-id.ini").
+
 % Run tests and wait for the gen_servers to shutdown
 run_test(IniFiles, Test) ->
     {ok, Pid} = couch_config:start_link(IniFiles),
@@ -40,7 +43,7 @@ run_test(IniFiles, Test) ->
 main(_) ->
     test_util:init_code_path(),
     application:start(crypto),
-    etap:plan(6),
+    etap:plan(9),
 
     case (catch test()) of
         ok ->
@@ -63,6 +66,7 @@ test() ->
     run_test([default_config()], TestUnique),
     run_test([default_config(), seq_alg_config()], TestUnique),
     run_test([default_config(), utc_alg_config()], TestUnique),
+    run_test([default_config(), utc_id_alg_config()], TestUnique),
 
     TestMonotonic = fun () ->
         etap:is(
@@ -73,6 +77,7 @@ test() ->
     end,
     run_test([default_config(), seq_alg_config()], TestMonotonic),
     run_test([default_config(), utc_alg_config()], TestMonotonic),
+    run_test([default_config(), utc_id_alg_config()], TestMonotonic),
 
     % Pretty sure that the average of a uniform distribution is the
     % midpoint of the range. Thus, to exceed a threshold, we need
@@ -94,7 +99,18 @@ test() ->
             "should roll over every so often."
         )
     end,
-    run_test([default_config(), seq_alg_config()], TestRollOver).
+    run_test([default_config(), seq_alg_config()], TestRollOver),
+
+    TestSuffix = fun() ->
+        UUID = binary_to_list(couch_uuids:new()),
+        Suffix = get_suffix(UUID),
+        etap:is(
+            test_same_suffix(100, Suffix),
+            true,
+            "utc_id ids should have the same suffix."
+        )
+    end,
+    run_test([default_config(), utc_id_alg_config()], TestSuffix).
 
 test_unique(0, _) ->
     true;
@@ -116,3 +132,16 @@ gen_until_pref_change(Prefix, N) ->
         Prefix -> gen_until_pref_change(Prefix, N+1);
         _ -> N
     end.
+
+get_suffix(UUID) when is_binary(UUID)->
+    get_suffix(binary_to_list(UUID));
+get_suffix(UUID) ->
+    element(2, lists:split(14, UUID)).
+
+test_same_suffix(0, _) ->
+    true;
+test_same_suffix(N, Suffix) ->
+    case get_suffix(couch_uuids:new()) of
+        Suffix -> test_same_suffix(N-1, Suffix);
+        _ -> false
+    end.