nickva commented on a change in pull request #756: Make couch_peruser a proper
Erlang app
URL: https://github.com/apache/couchdb/pull/756#discussion_r143628756
##########
File path: src/couch_peruser/src/couch_peruser.erl
##########
@@ -157,54 +250,98 @@ remove_user(User, Prop, {Modified, SecProps}) ->
{<<"names">>, lists:delete(User, Names)})}})}
end.
+-spec ensure_security(User :: binary(), UserDb :: binary(), TransformFun ::
fun()) -> ok.
ensure_security(User, UserDb, TransformFun) ->
- {ok, Shards} = fabric:get_all_security(UserDb, [?ADMIN_CTX]),
- {_ShardInfo, {SecProps}} = hd(Shards),
- % assert that shards have the same security object
- true = lists:all(fun ({_, {SecProps1}}) ->
- SecProps =:= SecProps1
- end, Shards),
- case lists:foldl(
- fun (Prop, SAcc) -> TransformFun(User, Prop, SAcc) end,
- {false, SecProps},
- [<<"admins">>, <<"members">>]) of
- {false, _} ->
- ok;
- {true, SecProps1} ->
- ok = fabric:set_security(UserDb, {SecProps1}, [?ADMIN_CTX])
+ case fabric:get_all_security(UserDb, [?ADMIN_CTX]) of
+ {error, no_majority} ->
+ % TODO: make sure this is still true: single node, ignore
+ ok;
+ {ok, Shards} ->
+ {_ShardInfo, {SecProps}} = hd(Shards),
+ % assert that shards have the same security object
+ true = lists:all(fun ({_, {SecProps1}}) ->
+ SecProps =:= SecProps1
+ end, Shards),
+ case lists:foldl(
+ fun (Prop, SAcc) -> TransformFun(User, Prop, SAcc) end,
+ {false, SecProps},
+ [<<"admins">>, <<"members">>]) of
+ {false, _} ->
+ ok;
+ {true, SecProps1} ->
+ ok = fabric:set_security(UserDb, {SecProps1}, [?ADMIN_CTX])
+ end
end.
+-spec user_db_name(User :: binary()) -> binary().
user_db_name(User) ->
HexUser = list_to_binary(
[string:to_lower(integer_to_list(X, 16)) || <<X>> <= User]),
<<?USERDB_PREFIX,HexUser/binary>>.
+-spec exit_changes(State :: #state{}) -> ok.
+exit_changes(State) ->
+ lists:foreach(fun (ChangesState) ->
+ demonitor(State#changes_state.changes_ref, [flush]),
+ unlink(ChangesState#changes_state.changes_pid),
+ exit(ChangesState#changes_state.changes_pid, kill)
+ end, State#state.states).
-%% gen_server callbacks
+-spec is_stable() -> true | false.
+is_stable() ->
+ gen_server:call(?MODULE, is_stable).
+
+-spec subscribe_for_changes() -> ok.
+subscribe_for_changes() ->
+ config:subscribe_for_changes([
+ {"couch_httpd_auth", "authentication_db"},
+ "couch_peruser"
+ ]).
+
+% Mem3 cluster callbacks
+
+% TODO: find out what type Server is
+-spec cluster_unstable(Server :: any()) -> any().
+cluster_unstable(Server) ->
+ gen_server:cast(Server, cluster_unstable),
+ Server.
+% TODO: find out what type Server is
+-spec cluster_stable(Server :: any()) -> any().
+cluster_stable(Server) ->
+ gen_server:cast(Server, cluster_stable),
+ Server.
+
+%% gen_server callbacks
+-spec init(Options :: list()) -> {ok, #state{}}.
init([]) ->
ok = subscribe_for_changes(),
- {ok, init()}.
+ {ok, init_state()}.
+handle_call(is_stable, _From, #state{cluster_stable = IsStable} = State) ->
+ {reply, IsStable, State};
handle_call(_Msg, _From, State) ->
{reply, error, State}.
-handle_cast(update_config, ClusterState) when ClusterState#clusterState.states
=/= undefined ->
- lists:foreach(fun (State) ->
- demonitor(State#state.changes_ref, [flush]),
- exit(State#state.changes_pid, kill)
- end, ClusterState#clusterState.states),
-
- {noreply, init()};
+handle_cast(update_config, State) when State#state.states =/= undefined ->
+ exit_changes(State),
+ {noreply, init_state()};
handle_cast(update_config, _) ->
- {noreply, init()};
+ {noreply, init_state()};
handle_cast(stop, State) ->
{stop, normal, State};
+handle_cast(cluster_unstable, State) when State#state.states =/= undefined ->
+ exit_changes(State),
+ {noreply, init_state()};
+handle_cast(cluster_unstable, _) ->
+ {noreply, init_state()};
+handle_cast(cluster_stable, State) ->
+ {noreply, start_listening(State)};
handle_cast(_Msg, State) ->
{noreply, State}.
-handle_info({'DOWN', Ref, _, _, _Reason}, #state{changes_ref=Ref} = State) ->
+handle_info({'DOWN', Ref, _, _, _Reason}, #changes_state{changes_ref=Ref} =
State) ->
Review comment:
This would be #state because it is the state of the gen_server.
I am not sure about the intent of this clause in general. This is clause
would handle a monitor 'DOWN' from a changes feed started with `spawn_opt` with
`monitor` enabled that process is also linked, so if it dies unexpectedly this
gen_server will also restart. I guess, this monitor would catch the `normal`
exits, though a continuous change feed with infinity timeout shouldn't exit?.
The correct fix in that case we have to check that the Ref is one of the
refs in State#state.states then stop, normal. However since we're stopping
anyway, maybe it isn't terrible to not even match on Ref and instead just
always {stop, normal, State} if any {'DOWN', _Ref, _, _, _Reason} message
arrives knowing it has to be one of the change feed processes. Then the only
fix would be to replace `#changes_state{changes_ref=Ref} = State` with `State`
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