mod_pubsub_serverinfo: add option pubsub_host

Also when choosing a pubsub host were now acknowledgin mod_pubsub's `hosts`
option, especially since `host` is deprecated.

Author: sstrigler

mod_pubsub_serverinfo/README.md

@@ -2,15 +2,25 @@ mod_pubsub_serverinfo - Exposes server information over Pub/Sub
 ==============================================================
 
 * Author: Guus der Kinderen <[email protected]>
+* Author: Stefan Strigler <[email protected]>
 
 Description
 -----------
 
 Announces support for the ProtoXEP PubSub Server Information, by adding
 its Service Discovery feature.
 
-Future versions of this plugin are expected to publish data describing
-the local XMPP domain(s).
+Active S2S connections are published to a local pubsub node as advertised by
+Service Discovery. Only those connections that support this feature as well are
+exposed with their domain names, otherwise they are shown as anonymous nodes. At
+startup a list of well known public servers is being fetched. Those are not
+shown as anonymous even if they don't support this feature.
+
+Currently the name of the node is hardcoded as "serverinfo". The local service
+to be used can be configured as `pubsub_host`. Otherwise a good guess is taken.
+
+This module has a hard dependency on `mod_pubsub` for this reason. Also
+`mod_disco` must be configured for this feature to work.
 
 > [!NOTE]
 > The module only shows S2S connections established while the module is running:
@@ -20,9 +30,12 @@ the local XMPP domain(s).
 Configuration
 -------------
 
-This module does not have any configurable settings for now.
+Configurable options for `mod_pubsub_serverinfo`:
+
+- `pubsub_host` (default: undefined)
 
-> [!NOTE] 
-> As of now your pubsub component must be reachable at `pubsub.<yourhost>` (the
-> default), otherwise this module would advertise the wrong address.
-> See: https://github.com/processone/ejabberd-contrib/issues/343
+  This option specifies which pubsub host to use to advertise S2S connections.
+  This must be a vhost local to this service and handled by `mod_pubsub`. This
+  is only needed if your configuration has more than one vhost in mod_pubsub's
+  `hosts` option. If there's more than one and this option is not given, we just
+  pick the first one.

mod_pubsub_serverinfo/src/mod_pubsub_serverinfo.erl

@@ -33,7 +33,7 @@
 -include_lib("xmpp/include/xmpp.hrl").
 
 %% gen_mod callbacks.
--export([start/2, stop/1, depends/2, mod_options/1, get_local_features/5, mod_doc/0]).
+-export([start/2, stop/1, depends/2, mod_options/1, mod_opt_type/1, get_local_features/5, mod_doc/0]).
 -export([init/1, handle_cast/2, handle_call/3, handle_info/2, terminate/2]).
 -export([in_auth_result/3, out_auth_result/2, get_info/5]).
 
@@ -43,12 +43,17 @@
 -record(state, {host, pubsub_host, node, monitors = #{}, timer = undefined, public_hosts = []}).
 
 start(Host, Opts) ->
-    xmpp:register_codec(pubsub_serverinfo_codec),
-    ejabberd_hooks:add(disco_local_features, Host, ?MODULE, get_local_features, 50),
-    ejabberd_hooks:add(disco_info, Host, ?MODULE, get_info, 50),
-    ejabberd_hooks:add(s2s_out_auth_result, Host, ?MODULE, out_auth_result, 50),
-    ejabberd_hooks:add(s2s_in_auth_result, Host, ?MODULE, in_auth_result, 50),
-    gen_mod:start_child(?MODULE, Host, Opts).
+    case pubsub_host(Host, Opts) of
+	{error, _Reason} = Error  ->
+	    Error;
+	PubsubHost ->
+	    xmpp:register_codec(pubsub_serverinfo_codec),
+	    ejabberd_hooks:add(disco_local_features, Host, ?MODULE, get_local_features, 50),
+	    ejabberd_hooks:add(disco_info, Host, ?MODULE, get_info, 50),
+	    ejabberd_hooks:add(s2s_out_auth_result, Host, ?MODULE, out_auth_result, 50),
+	    ejabberd_hooks:add(s2s_in_auth_result, Host, ?MODULE, in_auth_result, 50),
+	    gen_mod:start_child(?MODULE, Host, PubsubHost)
+    end.
 
 stop(Host) ->
     ejabberd_hooks:delete(disco_local_features, Host, ?MODULE, get_local_features, 50),
@@ -57,11 +62,10 @@ stop(Host) ->
     ejabberd_hooks:delete(s2s_in_auth_result, Host, ?MODULE, in_auth_result, 50),
     gen_mod:stop_child(?MODULE, Host).
 
-init([Host, _Opts]) ->
+init([Host, PubsubHost]) ->
     TRef = timer:send_interval(timer:minutes(5), self(), update_pubsub),
     Monitors = init_monitors(Host),
     PublicHosts = fetch_public_hosts(),
-    PubsubHost = gen_mod:get_module_opt(Host, mod_pubsub, host),
     State = #state{host = Host,
                    pubsub_host = PubsubHost,
                    node = <<"serverinfo">>,
@@ -171,7 +175,10 @@ depends(_Host, _Opts) ->
     [{mod_pubsub, hard}].
 
 mod_options(_Host) ->
-    [].
+    [{pubsub_host, undefined}].
+
+mod_opt_type(pubsub_host) ->
+    econf:either(undefined, econf:host()).
 
 mod_doc() -> #{}.
 
@@ -251,15 +258,15 @@ get_local_features(Acc, _From, _To, _Node, _Lang) ->
 get_info(Acc, Host, Mod, Node, Lang) when (Mod == undefined orelse Mod == mod_disco), Node == <<"">> ->
     case mod_disco:get_info(Acc, Host, Mod, Node, Lang) of
 	[#xdata{fields = Fields} = XD | Rest] ->
-	    PubsubHost = gen_mod:get_module_opt(Host, mod_pubsub, host),
+	    PubsubHost = pubsub_host(Host),
 	    NodeField = #xdata_field{var = <<"serverinfo-pubsub-node">>,
 	                             values = [<<"xmpp:", PubsubHost/binary, "?;node=serverinfo">>]},
 	    {stop, [XD#xdata{fields = Fields ++ [NodeField]} | Rest]};
 	_ ->
 	    Acc
     end;
 get_info(Acc, Host, Mod, Node, _Lang) when Node == <<"">>, is_atom(Mod) ->
-    PubsubHost = gen_mod:get_module_opt(Host, mod_pubsub, host),
+    PubsubHost = pubsub_host(Host),
     [#xdata{type = result,
 	fields = [
 	    #xdata_field{type = hidden,
@@ -269,3 +276,37 @@ get_info(Acc, Host, Mod, Node, _Lang) when Node == <<"">>, is_atom(Mod) ->
                          values = [<<"xmpp:", PubsubHost/binary, "?;node=serverinfo">>]}]} | Acc];
 get_info(Acc, _Host, _Mod, _Node, _Lang) ->
     Acc.
+
+pubsub_host(Host) ->
+    case pubsub_host(Host, gen_mod:get_module_opts(Host, mod_pubsub)) of
+	{error, _Reason} = Error ->
+	    throw(Error);
+	PubsubHost ->
+	    PubsubHost
+    end.
+
+pubsub_host(Host, Opts) ->
+    case gen_mod:get_opt(pubsub_host, Opts) of
+	undefined ->
+	    PubsubHost = hd(get_mod_pubsub_hosts(Host)),
+	    ?INFO_MSG("No pubsub_host in configuration for ~p, choosing ~s", [?MODULE, PubsubHost]),
+	    PubsubHost;
+	PubsubHost ->
+	    case check_pubsub_host_exists(Host, PubsubHost) of
+		true ->
+		    PubsubHost;
+		false ->
+		    {error, {pubsub_host_does_not_exist, PubsubHost}}
+	    end
+    end.
+
+check_pubsub_host_exists(Host, PubsubHost) ->
+    lists:member(PubsubHost, get_mod_pubsub_hosts(Host)).
+
+get_mod_pubsub_hosts(Host) ->
+    case gen_mod:get_module_opt(Host, mod_pubsub, hosts) of
+	[] ->
+	    [gen_mod:get_module_opt(Host, mod_pubsub, host)];
+	PubsubHosts ->
+	    PubsubHosts
+    end.