From 8e178ed5796628bd21a5c85fdc2c864a7b06ae70 Mon Sep 17 00:00:00 2001 From: Anders Svensson Date: Mon, 28 Nov 2011 12:13:56 +0100 Subject: Smarter diameter_callback The module was originally just intended as a minimal callback implementation that could be used as a template. Being able to order just a subset of callbacks (with reasonable defaults) makes for simpler code in many cases however so ready support for this can be useful. --- lib/diameter/include/diameter.hrl | 15 +++ lib/diameter/src/base/diameter.erl | 4 +- lib/diameter/src/base/diameter_callback.erl | 163 ++++++++++++++++++++++++++-- lib/diameter/src/base/diameter_config.erl | 15 +++ lib/diameter/src/modules.mk | 2 +- 5 files changed, 187 insertions(+), 12 deletions(-) diff --git a/lib/diameter/include/diameter.hrl b/lib/diameter/include/diameter.hrl index 0fa7fd406f..4273262015 100644 --- a/lib/diameter/include/diameter.hrl +++ b/lib/diameter/include/diameter.hrl @@ -107,6 +107,21 @@ transport = sctp, %% | tcp, protocol = diameter}). %% | radius | 'tacacs+' +%% A diameter_callback record can be specified as an application +%% module in order to selectively receive callbacks or alter their +%% form. +-record(diameter_callback, + {peer_up, + peer_down, + pick_peer, + prepare_request, + prepare_retransmit, + handle_request, + handle_answer, + handle_error, + default, + extra = []}). + %% The diameter service and diameter_apps records are only passed %% through the transport interface when starting a transport process, %% although typically a transport implementation will (and probably diff --git a/lib/diameter/src/base/diameter.erl b/lib/diameter/src/base/diameter.erl index ecd3d9542a..336f0c1f2d 100644 --- a/lib/diameter/src/base/diameter.erl +++ b/lib/diameter/src/base/diameter.erl @@ -73,6 +73,7 @@ 'IPFilterRule'/0, 'QoSFilterRule'/0]). +-include_lib("diameter/include/diameter.hrl"). -include("diameter_internal.hrl"). %% --------------------------------------------------------------------------- @@ -298,7 +299,8 @@ call(SvcName, App, Message) -> -type app_module() :: module() - | maybe_improper_list(module(), list()). + | maybe_improper_list(module(), list()) + | #diameter_callback{}. %% Identifier returned by add_transport/2 diff --git a/lib/diameter/src/base/diameter_callback.erl b/lib/diameter/src/base/diameter_callback.erl index 6d5c8cdca1..90431099b0 100644 --- a/lib/diameter/src/base/diameter_callback.erl +++ b/lib/diameter/src/base/diameter_callback.erl @@ -18,11 +18,58 @@ %% %% -%% A minimal application callback module. +%% A diameter callback module that can redirect selected callbacks, +%% providing reasonable default implementations otherwise. +%% +%% To order alternate callbacks, configure a #diameter_callback record +%% as the Diameter application callback in question. The record has +%% one field for each callback function as well as 'default' and +%% 'extra' fields. A function-specific field can be set to a +%% diameter:evaluable() in order to redirect the callback +%% corresponding to that field, or to 'false' to request the default +%% callback implemented in this module. If neither of these fields are +%% set then the 'default' field determines the form of the callback: a +%% module name results in the usual callback as if the module had been +%% configured directly as the callback module, a diameter_evaluable() +%% in a callback applied to the atom-valued callback name and argument +%% list. For all callbacks not to this module, the 'extra' field is a +%% list of additional arguments, following arguments supplied by +%% diameter but preceeding those of the diameter:evaluable() being +%% applied. +%% +%% For example, the following config to diameter:start_service/2, in +%% an 'application' tuple, would result in only a mymod:peer_down/3 +%% callback, this module implementing the remaining callbacks. +%% +%% {module, #diameter_callback{peer_down = {mymod, down, []}}} +%% +%% Equivalently, this can also be specified with a [Mod | Args] +%% field/value list as follows. +%% +%% {module, [diameter_callback, {peer_down, {mymod, down, []}}]} +%% +%% The following would result in this module suppying peer_up and +%% peer_down callback, others taking place in module mymod. +%% +%% {module, #diameter_callback{peer_up = false, +%% peer_down = false, +%% default = mymod}} +%% +%% The following would result in all callbacks taking place as +%% calls to mymod:diameter/2. +%% +%% {module, #diameter_callback{default = {mymod, diameter, []}}} +%% +%% The following are equivalent and result in all callbacks being +%% provided by this module. +%% +%% {module, #diameter_callback{}} +%% {module, diameter_callback} %% -module(diameter_callback). +%% Default callbacks when no aleternate is specified. -export([peer_up/3, peer_down/3, pick_peer/4, @@ -32,6 +79,16 @@ handle_answer/4, handle_error/4]). +%% Callbacks taking a #diameter_callback record. +-export([peer_up/4, + peer_down/4, + pick_peer/5, + prepare_request/4, + prepare_retransmit/4, + handle_request/4, + handle_answer/5, + handle_error/5]). + -include_lib("diameter/include/diameter.hrl"). %%% ---------------------------------------------------------- @@ -41,51 +98,137 @@ peer_up(_Svc, _Peer, State) -> State. +peer_up(Svc, Peer, State, D) -> + cb(peer_up, + [Svc, Peer, State], + D#diameter_callback.peer_up, + D). + %%% ---------------------------------------------------------- %%% # peer_down/3 %%% ---------------------------------------------------------- -peer_down(_SvcName, _Peer, State) -> +peer_down(_Svc, _Peer, State) -> State. +peer_down(Svc, Peer, State, D) -> + cb(peer_down, + [Svc, Peer, State], + D#diameter_callback.peer_down, + D). + %%% ---------------------------------------------------------- %%% # pick_peer/4 %%% ---------------------------------------------------------- -pick_peer([Peer|_], _, _SvcName, _State) -> - {ok, Peer}. +pick_peer([Peer|_], _, _Svc, _State) -> + {ok, Peer}; +pick_peer([], _, _Svc, _State) -> + false. + +pick_peer(PeersL, PeersR, Svc, State, D) -> + cb(pick_peer, + [PeersL, PeersR, Svc, State], + D#diameter_callback.pick_peer, + D). %%% ---------------------------------------------------------- %%% # prepare_request/3 %%% ---------------------------------------------------------- -prepare_request(Pkt, _SvcName, _Peer) -> +prepare_request(Pkt, _Svc, _Peer) -> {send, Pkt}. +prepare_request(Pkt, Svc, Peer, D) -> + cb(prepare_request, + [Pkt, Svc, Peer], + D#diameter_callback.prepare_request, + D). + %%% ---------------------------------------------------------- %%% # prepare_retransmit/3 %%% ---------------------------------------------------------- -prepare_retransmit(Pkt, _SvcName, _Peer) -> +prepare_retransmit(Pkt, _Svc, _Peer) -> {send, Pkt}. +prepare_retransmit(Pkt, Svc, Peer, D) -> + cb(prepare_retransmit, + [Pkt, Svc, Peer], + D#diameter_callback.prepare_retransmit, + D). + %%% ---------------------------------------------------------- %%% # handle_request/3 %%% ---------------------------------------------------------- -handle_request(_Pkt, _SvcName, _Peer) -> +handle_request(_Pkt, _Svc, _Peer) -> {protocol_error, 3001}. %% DIAMETER_COMMAND_UNSUPPORTED +handle_request(Pkt, Svc, Peer, D) -> + cb(handle_request, + [Pkt, Svc, Peer], + D#diameter_callback.handle_request, + D). + %%% ---------------------------------------------------------- %%% # handle_answer/4 %%% ---------------------------------------------------------- -handle_answer(#diameter_packet{msg = Ans}, _Req, _SvcName, _Peer) -> - Ans. +handle_answer(#diameter_packet{msg = Ans, errors = []}, _Req, _Svc, _Peer) -> + Ans; +handle_answer(#diameter_packet{msg = Ans, errors = Es}, _Req, _Svc, _Peer) -> + [Ans | Es]. + +handle_answer(Pkt, Req, Svc, Peer, D) -> + cb(handle_answer, + [Pkt, Req, Svc, Peer], + D#diameter_callback.handle_answer, + D). %%% --------------------------------------------------------------------------- %%% # handle_error/4 %%% --------------------------------------------------------------------------- -handle_error(Reason, _Req, _SvcName, _Peer) -> +handle_error(Reason, _Req, _Svc, _Peer) -> {error, Reason}. + +handle_error(Reason, Req, Svc, Peer, D) -> + cb(handle_error, + [Reason, Req, Svc, Peer], + D#diameter_callback.handle_error, + D). + +%% =========================================================================== + +%% cb/4 + +%% Unspecified callback: use default field to determine something +%% appropriate. +cb(CB, Args, undefined, D) -> + cb(CB, Args, D); + +%% Explicitly requested default. +cb(CB, Args, false, _) -> + apply(?MODULE, CB, Args); + +%% A specified callback. +cb(_, Args, F, #diameter_callback{extra = X}) -> + diameter_lib:eval([[F|X] | Args]). + +%% cb/3 + +%% No user-supplied default: call ours. +cb(CB, Args, #diameter_callback{default = undefined}) -> + apply(?MODULE, CB, Args); + +%% Default is a module name: make the usual callback. +cb(CB, Args, #diameter_callback{default = M, + extra = X}) + when is_atom(M) -> + apply(M, CB, Args ++ X); + +%% Default is something else: apply if to callback name and arguments. +cb(CB, Args, #diameter_callback{default = F, + extra = X}) -> + diameter_lib:eval([F, CB, Args | X]). diff --git a/lib/diameter/src/base/diameter_config.erl b/lib/diameter/src/base/diameter_config.erl index a6b48fe65b..9253af0de2 100644 --- a/lib/diameter/src/base/diameter_config.erl +++ b/lib/diameter/src/base/diameter_config.erl @@ -605,6 +605,13 @@ app_acc({application, Opts}, Acc) -> app_acc(_, Acc) -> Acc. +init_mod(#diameter_callback{} = R) -> + init_mod([diameter_callback, R]); +init_mod([diameter_callback, #diameter_callback{}] = L) -> + L; +init_mod([diameter_callback = M | L]) + when is_list(L) -> + [M, init_cb(L)]; init_mod(M) when is_atom(M) -> [M]; @@ -614,6 +621,14 @@ init_mod([M|_] = L) init_mod(M) -> ?THROW({module, M}). +init_cb(List) -> + Fields = record_info(fields, diameter_callback), + Defaults = lists:zip(Fields, tl(tuple_to_list(#diameter_callback{}))), + Values = [V || F <- Fields, + D <- [proplists:get_value(F, Defaults)], + V <- [proplists:get_value(F, List, D)]], + #diameter_callback{} = list_to_tuple([diameter_callback | Values]). + init_mutable(M) when M == true; M == false -> diff --git a/lib/diameter/src/modules.mk b/lib/diameter/src/modules.mk index d3125a7b57..c5d448b2ff 100644 --- a/lib/diameter/src/modules.mk +++ b/lib/diameter/src/modules.mk @@ -32,6 +32,7 @@ DICT_YRL = \ RT_MODULES = \ base/diameter \ base/diameter_app \ + base/diameter_callback \ base/diameter_capx \ base/diameter_config \ base/diameter_codec \ @@ -61,7 +62,6 @@ RT_MODULES = \ # Handwritten (compile time) modules not included in the app file. CT_MODULES = \ - base/diameter_callback \ base/diameter_dbg \ base/diameter_info \ compiler/diameter_codegen \ -- cgit v1.2.3