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_r143627829
##########
File path: src/couch_peruser/src/couch_peruser.erl
##########
@@ -12,62 +12,113 @@
-module(couch_peruser).
-behaviour(gen_server).
+-behaviour(mem3_cluster).
-include_lib("couch/include/couch_db.hrl").
-include_lib("mem3/include/mem3.hrl").
--define(USERDB_PREFIX, "userdb-").
-
% gen_server callbacks
-export([start_link/0, init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-export([init_changes_handler/1, changes_handler/3]).
--record(state, {parent, db_name, delete_dbs, changes_pid, changes_ref}).
--record(clusterState, {parent, db_name, delete_dbs, states}).
+% mem3_cluster callbacks
+-export([
+ cluster_stable/1,
+ cluster_unstable/1
+]).
+
+-record(changes_state, {
+ parent :: pid(),
+ db_name :: binary(),
+ delete_dbs :: boolean(),
+ changes_pid :: pid(),
+ changes_ref :: reference()
+}).
+
+-record(state, {
+ parent :: pid(),
+ db_name :: binary(),
+ delete_dbs :: boolean(),
+ states :: list(),
+ mem3_cluster_pid :: pid(),
+ cluster_stable :: boolean()
+}).
+-define(USERDB_PREFIX, "userdb-").
-define(RELISTEN_DELAY, 5000).
+-define(DEFAULT_QUIET_PERIOD, 60). % seconds
+-define(DEFAULT_START_PERIOD, 5). % seconds
-
+%%
+%% Please leave in the commented-out couch_log:debug calls, thanks! ? Jan
+%%
+-spec start_link() -> {ok, pid()} | ignore | {error, term()}.
start_link() ->
- gen_server:start_link(?MODULE, [], []).
+ gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
-init() ->
+-spec init_state() -> #state{}.
+init_state() ->
+ couch_log:debug("peruser: starting on node ~p in pid ~p", [node(),
self()]),
case config:get_boolean("couch_peruser", "enable", false) of
false ->
- #clusterState{};
+ couch_log:debug("peruser: disabled on node ~p", [node()]),
+ #state{};
true ->
+ couch_log:debug("peruser: enabled on node ~p", [node()]),
DbName = ?l2b(config:get(
"couch_httpd_auth", "authentication_db", "_users")),
DeleteDbs = config:get_boolean("couch_peruser", "delete_dbs", false),
- ClusterState = #clusterState{
+ % set up cluster-stable listener
+ Period = abs(config:get_integer("couch_peruser",
"cluster_quiet_period",
+ ?DEFAULT_QUIET_PERIOD)),
+ StartPeriod = abs(config:get_integer("couch_peruser",
"cluster_start_period",
+ ?DEFAULT_START_PERIOD)),
+
+ {ok, Mem3Cluster} = mem3_cluster:start_link(?MODULE, self(),
StartPeriod,
+ Period),
+
+ #state{
parent = self(),
db_name = DbName,
- delete_dbs = DeleteDbs
- },
- try
- States = lists:map(fun (A) ->
- S = #state{parent = ClusterState#clusterState.parent,
- db_name = A#shard.name,
- delete_dbs = DeleteDbs},
- {Pid, Ref} = spawn_opt(
- ?MODULE, init_changes_handler, [S], [link, monitor]),
- S#state{changes_pid=Pid, changes_ref=Ref}
- end, mem3:local_shards(DbName)),
-
- ClusterState#clusterState{states = States}
- catch error:database_does_not_exist ->
- couch_log:warning("couch_peruser can't proceed as underlying
database (~s) is missing, disables itself.", [DbName]),
- config:set("couch_peruser", "enable", "false",
lists:concat([binary_to_list(DbName), " is missing"]))
- end
+ delete_dbs = DeleteDbs,
+ mem3_cluster_pid = Mem3Cluster,
+ cluster_stable = false
+ }
end.
-init_changes_handler(#state{db_name=DbName} = State) ->
+
+-spec start_listening(State :: #state{}) -> #state{} | ok.
+start_listening(#state{states=ChangesStates}=State) when length(ChangesStates)
> 0 ->
+ % couch_log:debug("peruser: start_listening() already run on node ~p in
pid ~p", [node(), self()]),
+ State;
+start_listening(#state{db_name=DbName, delete_dbs=DeleteDbs} = State) ->
+ % couch_log:debug("peruser: start_listening() on node ~p", [node()]),
+ try
+ States = lists:map(fun (A) ->
+ S = #changes_state{parent = State#state.parent,
Review comment:
This was like this before, but wonder since it was copies and moved if it is
better to format it nicer, something like
```
S = #changes_state{
parent = State#state.parent,
db_name = A#shard.name,
delete_dbs = DeleteDbs
},
...
```
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