%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2010-2012. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
%% This module writes service/transport configuration to the table
%% diameter_config, so that the config will survive service process
%% death, and then turns it into calls towards diameter_service. It
%% also restarts services upon their death.
%%
%% The table diameter_config is only written here while
%% diameter_service reads. This is all somewhat after the fact. Once
%% upon a time the config was only stored in the service process,
%% causing much grief if these processes died (which they did with
%% some regularity) and one was forced to reconfigure. This module was
%% then inserted into the service start in order to keep a more
%% permanent record of the config. That said, service processes are
%% now much more robust than they once were and crashing is a thing of
%% the past.
%%
-module(diameter_config).
-compile({no_auto_import, [monitor/2]}).
-behaviour(gen_server).
-export([start_service/2,
stop_service/1,
add_transport/2,
remove_transport/2,
have_transport/2,
lookup/1]).
%% child server start
-export([start_link/0]).
%% gen_server callbacks
-export([init/1,
terminate/2,
handle_call/3,
handle_cast/2,
handle_info/2,
code_change/3]).
%% diameter_sync requests.
-export([sync/1]).
%% debug
-export([state/0,
uptime/0]).
-include_lib("diameter/include/diameter.hrl").
-include("diameter_internal.hrl").
%% Server state.
-record(state, {id = now()}).
%% Registered name of the server.
-define(SERVER, ?MODULE).
%% Table config is written to.
-define(TABLE, ?MODULE).
%% Workaround for dialyzer's lack of understanding of match specs.
-type match(T)
:: T | '_' | '$1' | '$2' | '$3' | '$4'.
%% Configuration records in ?TABLE.
-record(service,
{name,
rec :: match(#diameter_service{}),
options :: match(list())}).
-record(transport,
{service, %% name
ref = make_ref() :: match(reference()),
type :: match(connect | listen),
options :: match(list())}).
%% Monitor entry in ?TABLE.
-record(monitor, {mref = make_ref() :: reference(),
service}). %% name
%% The default sequence mask.
-define(NOMASK, {0,32}).
%% Time to lay low before restarting a dead service.
-define(RESTART_SLEEP, 2000).
%% A minimal diameter_caps for checking for valid capabilities values.
-define(EXAMPLE_CAPS,
#diameter_caps{origin_host = "TheHost",
origin_realm = "TheRealm",
host_ip_address = [{127,0,0,1}],
vendor_id = 42,
product_name = "TheProduct"}).
-define(VALUES(Rec), tl(tuple_to_list(Rec))).
%%% The return values below assume the server diameter_config is started.
%%% The functions will exit if it isn't.
%% --------------------------------------------------------------------------
%% # start_service(SvcName, Opts)
%%
%% Output: ok | {error, Reason}
%% --------------------------------------------------------------------------
start_service(SvcName, Opts)
when is_list(Opts) ->
start_rc(sync(SvcName, {start_service, SvcName, Opts})).
start_rc({ok = T, _Pid}) ->
T;
start_rc({error, _} = No) ->
No;
start_rc(timeout) ->
{error, application_not_started}.
%% --------------------------------------------------------------------------
%% # stop_service(SvcName)
%%
%% Output: ok
%% --------------------------------------------------------------------------
stop_service(SvcName) ->
sync(SvcName, {stop_service, SvcName}).
%% --------------------------------------------------------------------------
%% # add_transport(SvcName, {Type, Opts})
%%
%% Input: Type = connect | listen
%%
%% Output: {ok, Ref} | {error, Reason}
%% --------------------------------------------------------------------------
add_transport(SvcName, {T, Opts})
when is_list(Opts), (T == connect orelse T == listen) ->
sync(SvcName, {add, SvcName, T, Opts}).
%% --------------------------------------------------------------------------
%% # remove_transport(SvcName, Pred)
%%
%% Input: Pred = arity 3 fun on transport ref, connect|listen and Opts,
%% returning true if the transport is to be removed, false if
%% not
%% | arity 2 fun on Ref and Opts only
%% | arity 1 fun on Opts only
%% | Opts matching all transports that have all of the specified
%% options
%% | Ref matching only the transport with this reference.
%% | {M,F,A} applied to Ref, connect|listen and Opts
%% | boolean()
%%
%% Output: ok | {error, Reason}
%% --------------------------------------------------------------------------
remove_transport(SvcName, Pred) ->
try
sync(SvcName, {remove, SvcName, pred(Pred)})
catch
?FAILURE(Reason) ->
{error, Reason}
end.
pred(Pred)
when is_function(Pred, 3) ->
Pred;
pred(Pred)
when is_function(Pred, 2) ->
fun(R,_,O) -> Pred(R,O) end;
pred(Pred)
when is_function(Pred, 1) ->
fun(_,_,O) -> Pred(O) end;
pred(Opts)
when is_list(Opts) ->
fun(_,_,O) -> [] == Opts -- O end;
pred(Ref)
when is_reference(Ref) ->
fun(R,_,_) -> R == Ref end;
pred({M,F,A})
when is_atom(M), is_atom(F), is_list(A) ->
fun(R,T,O) -> apply(M,F,[R,T,O|A]) end;
pred({Type, Pred}) -> %% backwards compatibility
P = pred(Pred),
fun(R,T,O) -> T == Type andalso P(R,T,O) end;
pred(B)
when is_boolean(B) ->
fun(_,_,_) -> B end;
pred(_) ->
?THROW(pred).
%% --------------------------------------------------------------------------
%% # have_transport/2
%%
%% Output: true | false
%% --------------------------------------------------------------------------
have_transport(SvcName, Ref) ->
member([{#transport{service = '$1',
ref = '$2',
_ = '_'},
[{'andalso', {'=:=', '$1', {const, SvcName}},
{'=:=', '$2', {const, Ref}}}],
[true]}]).
%% --------------------------------------------------------------------------
%% # lookup/1
%% --------------------------------------------------------------------------
lookup(SvcName) ->
select([{#service{name = '$1', rec = '$2', options = '$3'},
[{'=:=', '$1', {const, SvcName}}],
[{{'$1', '$2', '$3'}}]},
{#transport{service = '$1',
ref = '$2',
type = '$3',
options = '$4'},
[{'=:=', '$1', {const, SvcName}}],
[{{'$2', '$3', '$4'}}]}]).
%% ---------------------------------------------------------
%% EXPORTED INTERNAL FUNCTIONS
%% ---------------------------------------------------------
start_link() ->
ServerName = {local, ?SERVER},
Module = ?MODULE,
Args = [],
Options = [{spawn_opt, diameter_lib:spawn_opts(server, [])}],
gen_server:start_link(ServerName, Module, Args, Options).
state() ->
call(state).
uptime() ->
call(uptime).
%%% ----------------------------------------------------------
%%% # init/1
%%% ----------------------------------------------------------
init([]) ->
{ok, #state{}}.
%%% ----------------------------------------------------------
%%% # handle_call/2
%%% ----------------------------------------------------------
handle_call(state, _, State) ->
{reply, State, State};
handle_call(uptime, _, #state{id = Time} = State) ->
{reply, diameter_lib:now_diff(Time), State};
handle_call(Req, From, State) ->
?UNEXPECTED([Req, From]),
Reply = {error, {bad_request, Req}},
{reply, Reply, State}.
%%% ----------------------------------------------------------
%%% # handle_cast/2
%%% ----------------------------------------------------------
handle_cast(Msg, State) ->
?UNEXPECTED([Msg]),
{noreply, State}.
%%% ----------------------------------------------------------
%%% # handle_info/2
%%% ----------------------------------------------------------
%% A service process has died. This is most likely a consequence of
%% stop_service, in which case the restart will find no config for the
%% service and do nothing. The entry keyed on the monitor ref is only
%% removed as a result of the 'DOWN' notification however.
handle_info({'DOWN', MRef, process, _, Reason}, State) ->
[#monitor{service = SvcName} = T] = select([{#monitor{mref = MRef,
_ = '_'},
[],
['$_']}]),
queue_restart(Reason, SvcName),
delete_object(T),
{noreply, State};
handle_info({monitor, SvcName, Pid}, State) ->
monitor(Pid, SvcName),
{noreply, State};
handle_info({restart, SvcName}, State) ->
restart(SvcName),
{noreply, State};
handle_info(restart, State) ->
restart(),
{noreply, State};
handle_info(Info, State) ->
?UNEXPECTED([Info]),
{noreply, State}.
%%--------------------------------------------------------------------
%% # terminate/2
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
ok.
%%% ----------------------------------------------------------
%%% # code_change/3
%%% ----------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%% ---------------------------------------------------------
%% INTERNAL FUNCTIONS
%% ---------------------------------------------------------
insert(T) ->
ets:insert(?TABLE, T).
%% ?TABLE is a bag: check only for a service entry.
have_service(SvcName) ->
member([{#service{name = '$1', _ = '_'},
[{'=:=', '$1', {const, SvcName}}],
[true]}]).
member(MatchSpec) ->
'$end_of_table' =/= ets:select(?TABLE, MatchSpec, 1).
delete_object(T) ->
ets:delete_object(?TABLE, T).
delete(Key) ->
ets:delete(?TABLE, Key).
select(MatchSpec) ->
ets:select(?TABLE, MatchSpec).
select_delete(MatchSpec) ->
ets:select_delete(?TABLE, MatchSpec).
%% sync/2
%%
%% Interface functions used to be implemented as calls to ?SERVER but
%% now serialize things per service instead since stopping a service
%% can take time if the server doesn't answer DPR. A caller who wants
%% to stop multiple services can then improve performance by spawning
%% processes to stop them concurrently.
sync(SvcName, T) ->
diameter_sync:call({?MODULE, SvcName},
{?MODULE, sync, [T]},
infinity,
infinity).
%% sync/1
sync({restart, SvcName}) ->
have_service(SvcName) andalso start(SvcName);
sync({start_service, SvcName, Opts}) ->
try
start(have_service(SvcName), SvcName, Opts)
catch
?FAILURE(Reason) -> {error, Reason}
end;
sync({stop_service, SvcName}) ->
stop(SvcName);
sync({add, SvcName, Type, Opts}) ->
try
add(SvcName, Type, Opts)
catch
?FAILURE(Reason) -> {error, Reason}
end;
sync({remove, SvcName, Pred}) ->
remove(select([{#transport{service = '$1', _ = '_'},
[{'=:=', '$1', {const, SvcName}}],
['$_']}]),
SvcName,
Pred).
%% start/3
start(true, _, _) ->
{error, already_started};
start(false, SvcName, Opts) ->
insert(make_config(SvcName, Opts)),
start(SvcName).
%% start/1
start(SvcName) ->
RC = diameter_service:start(SvcName),
startmon(SvcName, RC),
RC.
startmon(SvcName, {ok, Pid}) ->
?SERVER ! {monitor, SvcName, Pid};
startmon(_, {error, _}) ->
ok.
monitor(Pid, SvcName) ->
MRef = erlang:monitor(process, Pid),
insert(#monitor{mref = MRef, service = SvcName}).
%% queue_restart/2
%% Service has gone down on monitor death. Note that all service-related
%% config is deleted.
queue_restart({shutdown, {monitor, _}}, SvcName) ->
delete(SvcName);
%% Application shutdown: ignore.
queue_restart(shutdown, _) ->
ok;
%% Or not.
queue_restart(_, SvcName) ->
erlang:send_after(?RESTART_SLEEP, self(), {restart, SvcName}).
%% restart/1
restart(SvcName) ->
sync(SvcName, {restart, SvcName}).
%% restart/0
%%
%% Start anything configured as required. Bang 'restart' to the server
%% to kick things into gear manually. (Not that it should be required
%% but it's been useful for test.)
restart() ->
MatchSpec = [{#service{name = '$1', _ = '_'},
[],
['$1']}],
lists:foreach(fun restart/1, select(MatchSpec)).
%% stop/1
stop(SvcName) ->
%% If the call to the service returns error for any reason other
%% than the process not being alive then deleting the config from
%% under it will surely bring it down.
diameter_service:stop(SvcName),
%% Delete only the service entry, not everything keyed on the name,
select_delete([{#service{name = '$1', _ = '_'},
[{'=:=', '$1', {const, SvcName}}],
[true]}]),
ok.
%% Note that a transport has to be removed for its statistics to be
%% deleted.
%% add/3
add(SvcName, Type, Opts) ->
%% Ensure usable capabilities. diameter_service:merge_service/2
%% depends on this.
lists:foreach(fun(Os) ->
is_list(Os) orelse ?THROW({capabilities, Os}),
ok = encode_CER(Os)
end,
[Os || {capabilities, Os} <- Opts, is_list(Os)]),
Ref = make_ref(),
T = {Ref, Type, Opts},
%% The call to the service returns error if the service isn't
%% started yet, which is harmless. The transport will be started
%% when the service is in that case.
case start_transport(SvcName, T) of
ok ->
insert(#transport{service = SvcName,
ref = Ref,
type = Type,
options = Opts}),
{ok, Ref};
{error, _} = No ->
No
end.
start_transport(SvcName, T) ->
case diameter_service:start_transport(SvcName, T) of
{ok, _Pid} ->
ok;
{error, no_service} ->
ok;
{error, _} = No ->
No
end.
%% remove/3
remove(L, SvcName, Pred) ->
rm(SvcName, lists:filter(fun(#transport{ref = R, type = T, options = O}) ->
Pred(R,T,O)
end,
L)).
rm(_, []) ->
ok;
rm(SvcName, L) ->
Refs = lists:map(fun(#transport{ref = R}) -> R end, L),
case stop_transport(SvcName, Refs) of
ok ->
diameter_stats:flush(Refs),
lists:foreach(fun delete_object/1, L);
{error, _} = No ->
No
end.
stop_transport(SvcName, Refs) ->
case diameter_service:stop_transport(SvcName, Refs) of
ok ->
ok;
{error, no_service} ->
ok;
{error, _} = No ->
No
end.
%% make_config/2
make_config(SvcName, Opts) ->
Apps = init_apps(Opts),
[] == Apps andalso ?THROW(no_apps),
%% Use the fact that diameter_caps has the same field names as CER.
Fields = diameter_gen_base_rfc3588:'#info-'(diameter_base_CER) -- ['AVP'],
COpts = [T || {K,_} = T <- Opts, lists:member(K, Fields)],
Caps = make_caps(#diameter_caps{}, COpts),
ok = encode_CER(COpts),
Os = split(Opts, fun opt/2, [{false, share_peers},
{false, use_shared_peers},
{false, monitor},
{?NOMASK, sequence}]),
%% share_peers and use_shared_peers are currently undocumented.
#service{name = SvcName,
rec = #diameter_service{applications = Apps,
capabilities = Caps},
options = Os}.
split(Opts, F, Defs) ->
[{K, F(K, get_opt(K, Opts, D))} || {D,K} <- Defs].
opt(K, false = B)
when K /= sequence ->
B;
opt(K, true = B)
when K == share_peer;
K == use_shared_peers ->
B;
opt(monitor, P)
when is_pid(P) ->
P;
opt(sequence, {_,_} = T) ->
sequence(T);
opt(sequence, F) ->
try diameter_lib:eval(F) of
T -> sequence(T)
catch
E:R ->
?THROW({value, {sequence, E, R, ?STACK}})
end;
opt(K, _) ->
?THROW({value, K}).
sequence({H,N} = T)
when 0 =< N, N =< 32, 0 =< H, 0 == H bsr N ->
T;
sequence(_) ->
?THROW({value, sequence}).
make_caps(Caps, Opts) ->
case diameter_capx:make_caps(Caps, Opts) of
{ok, T} ->
T;
{error, Reason} ->
?THROW(Reason)
end.
%% Validate types by encoding a CER.
encode_CER(Opts) ->
{ok, CER} = diameter_capx:build_CER(make_caps(?EXAMPLE_CAPS, Opts)),
Hdr = #diameter_header{version = ?DIAMETER_VERSION,
end_to_end_id = 0,
hop_by_hop_id = 0},
try
diameter_codec:encode(?BASE, #diameter_packet{header = Hdr,
msg = CER}),
ok
catch
exit: Reason ->
?THROW(Reason)
end.
init_apps(Opts) ->
lists:foldl(fun app_acc/2, [], lists:reverse(Opts)).
app_acc({application, Opts}, Acc) ->
is_list(Opts) orelse ?THROW({application, Opts}),
[Dict, Mod] = get_opt([dictionary, module], Opts),
Alias = get_opt(alias, Opts, Dict),
ModS = get_opt(state, Opts, Alias),
M = get_opt(call_mutates_state, Opts, false),
A = get_opt(answer_errors, Opts, report),
[#diameter_app{alias = Alias,
dictionary = Dict,
id = cb(Dict, id),
module = init_mod(Mod),
init_state = ModS,
mutable = init_mutable(M),
options = [{answer_errors, init_answers(A)}]}
| 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];
init_mod([M|_] = L)
when is_atom(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 ->
M;
init_mutable(M) ->
?THROW({call_mutates_state, M}).
init_answers(A)
when callback == A;
report == A;
discard == A ->
A;
init_answers(A) ->
?THROW({answer_errors, A}).
%% Get a single value at the specified key.
get_opt(Keys, List)
when is_list(Keys) ->
[get_opt(K, List) || K <- Keys];
get_opt(Key, List) ->
case [V || {K,V} <- List, K == Key] of
[V] -> V;
_ -> ?THROW({arity, Key})
end.
%% Get an optional value at the specified key.
get_opt(Key, List, Def) ->
case [V || {K,V} <- List, K == Key] of
[] -> Def;
[V] -> V;
_ -> ?THROW({arity, Key})
end.
cb(M,F) ->
try M:F() of
V -> V
catch
E: Reason ->
?THROW({callback, E, Reason, ?STACK})
end.
%% call/1
call(Request) ->
gen_server:call(?SERVER, Request, infinity).
