%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2003-2017. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%% @doc Generic connection owner process.
%%%
%%% @type handle() = pid(). A handle for using a connection implemented
%%% with ct_gen_conn.erl.
-module(ct_gen_conn).
-export([start/4, stop/1, get_conn_pid/1, check_opts/1]).
-export([call/2, call/3, return/2, do_within_time/2]).
-export([log/3, start_log/1, cont_log/2, cont_log_no_timestamp/2, end_log/0]).
-ifdef(debug).
-define(dbg,true).
-else.
-define(dbg,false).
-endif.
-record(gen_opts,{callback,
name,
address,
init_data,
reconnect = true,
forward = false,
use_existing = true,
old = false,
conn_pid,
cb_state,
ct_util_server}).
%%%-----------------------------------------------------------------
%%% @spec start(Address,InitData,CallbackMod,Opts) ->
%%% {ok,Handle} | {error,Reason}
%%% Name = term()
%%% CallbackMod = atom()
%%% InitData = term()
%%% Address = term()
%%% Opts = [Opt]
%%% Opt = {name,Name} | {use_existing_connection,boolean()} |
%%% {reconnect,boolean()} | {forward_messages,boolean()}
%%%
%%% @doc Open a connection and start the generic connection owner process.
%%%
%%% <p>The <code>CallbackMod</code> is a specific callback module for
%%% each type of connection (e.g. telnet, ftp,...). It must export the
%%% function <code>init/3</code> which takes the arguments
%%% <code>Name</code>, <code>Addresse</code>) and
%%% <code>InitData</code> and returna
%%% <code>{ok,ConnectionPid,State}</code> or
%%% <code>{error,Reason}</code>.</p>
%%%
%%% If no name is given, the <code>Name</code> argument in init/3 will
%%% have the value <code>undefined</code>.
%%%
%%% The callback modules must also export
%%% ```
%%% handle_msg(Msg,From,State) -> {reply,Reply,State} |
%%% {noreply,State} |
%%% {stop,Reply,State}
%%% terminate(ConnectionPid,State) -> term()
%%% close(Handle) -> term()
%%% '''
%%%
%%% The <code>close/1</code> callback function is actually a callback
%%% for ct_util, for closing registered connections when
%%% ct_util_server is terminated. <code>Handle</code> is the Pid of
%%% the ct_gen_conn process.
%%%
%%% If option <code>reconnect</code> is <code>true</code>, then the
%%% callback must also export
%%% ```
%%% reconnect(Address,State) -> {ok,ConnectionPid,State}
%%% '''
%%%
%%% If option <code>forward_messages</code> is <ocde>true</code>, then
%%% the callback must also export
%%% ```
%%% handle_msg(Msg,State) -> {noreply,State} | {stop,State}
%%% '''
%%%
%%% An old interface still exists. This is used by ct_telnet, ct_ftp
%%% and ct_ssh. The start function then has an explicit
%%% <code>Name</code> argument, and no <code>Opts</code> argument. The
%%% callback must export:
%%%
%%% ```
%%% init(Name,Address,InitData) -> {ok,ConnectionPid,State}
%%% handle_msg(Msg,State) -> {Reply,State}
%%% reconnect(Address,State) -> {ok,ConnectionPid,State}
%%% terminate(ConnectionPid,State) -> term()
%%% close(Handle) -> term()
%%% '''
%%%
start(Address,InitData,CallbackMod,Opts) when is_list(Opts) ->
do_start(Address,InitData,CallbackMod,Opts);
start(Name,Address,InitData,CallbackMod) ->
do_start(Address,InitData,CallbackMod,[{name,Name},{old,true}]).
%%%-----------------------------------------------------------------
%%% @spec stop(Handle) -> ok
%%% Handle = handle()
%%%
%%% @doc Close the connection and stop the process managing it.
stop(Handle) ->
call(Handle,stop,5000).
%%%-----------------------------------------------------------------
%%% @spec get_conn_pid(Handle) -> ok
%%% Handle = handle()
%%%
%%% @doc Return the connection pid associated with Handle
get_conn_pid(Handle) ->
call(Handle,get_conn_pid).
%%%-----------------------------------------------------------------
%%% @spec log(Heading,Format,Args) -> ok
%%%
%%% @doc Log activities on the current connection (tool-internal use only).
%%% @see ct_logs:log/3
log(Heading,Format,Args) ->
log(log,[Heading,Format,Args]).
%%%-----------------------------------------------------------------
%%% @spec start_log(Heading) -> ok
%%%
%%% @doc Log activities on the current connection (tool-internal use only).
%%% @see ct_logs:start_log/1
start_log(Heading) ->
log(start_log,[Heading]).
%%%-----------------------------------------------------------------
%%% @spec cont_log(Format,Args) -> ok
%%%
%%% @doc Log activities on the current connection (tool-internal use only).
%%% @see ct_logs:cont_log/2
cont_log(Format,Args) ->
log(cont_log,[Format,Args]).
%%%-----------------------------------------------------------------
%%% @spec cont_log_no_timestamp(Format,Args) -> ok
%%%
%%% @doc Log activities on the current connection (tool-internal use only).
%%% @see ct_logs:cont_log/2
cont_log_no_timestamp(Format,Args) ->
log(cont_log_no_timestamp,[Format,Args]).
%%%-----------------------------------------------------------------
%%% @spec end_log() -> ok
%%%
%%% @doc Log activities on the current connection (tool-internal use only).
%%% @see ct_logs:end_log/0
end_log() ->
log(end_log,[]).
%%%-----------------------------------------------------------------
%%% @spec do_within_time(Fun,Timeout) -> FunResult | {error,Reason}
%%% Fun = function()
%%% Timeout = integer()
%%%
%%% @doc Execute a function within a limited time (tool-internal use only).
%%%
%%% <p>Execute the given <code>Fun</code>, but interrupt if it takes
%%% more than <code>Timeout</code> milliseconds.</p>
%%%
%%% <p>The execution is also interrupted if the connection is
%%% closed.</p>
do_within_time(Fun,Timeout) ->
Self = self(),
Silent = get(silent),
TmpPid = spawn_link(fun() -> put(silent,Silent),
R = Fun(),
Self ! {self(),R}
end),
ConnPid = get(conn_pid),
receive
{TmpPid,Result} ->
Result;
{'EXIT',ConnPid,_Reason}=M ->
unlink(TmpPid),
exit(TmpPid,kill),
self() ! M,
{error,connection_closed}
after
Timeout ->
exit(TmpPid,kill),
receive
{TmpPid,Result} ->
%% TmpPid just managed to send the result at the same time
%% as the timeout expired.
receive {'EXIT',TmpPid,_reason} -> ok end,
Result;
{'EXIT',TmpPid,killed} ->
%% TmpPid did not send the result before the timeout expired.
{error,timeout}
end
end.
%%%=================================================================
%%% Internal functions
do_start(Address,InitData,CallbackMod,Opts0) ->
Opts = check_opts(Opts0,#gen_opts{callback=CallbackMod,
address=Address,
init_data=InitData}),
case ct_util:does_connection_exist(Opts#gen_opts.name,
Address,CallbackMod) of
{ok,Pid} when Opts#gen_opts.use_existing ->
log("ct_gen_conn:start","Using existing connection!\n",[]),
{ok,Pid};
{ok,Pid} when not Opts#gen_opts.use_existing ->
{error,{connection_exists,Pid}};
false ->
do_start(Opts)
end.
do_start(Opts) ->
Self = self(),
Pid = spawn(fun() -> init_gen(Self, Opts) end),
MRef = erlang:monitor(process,Pid),
receive
{connected,Pid} ->
erlang:demonitor(MRef, [flush]),
ct_util:register_connection(Opts#gen_opts.name,
Opts#gen_opts.address,
Opts#gen_opts.callback, Pid),
{ok,Pid};
{Error,Pid} ->
receive {'DOWN',MRef,process,_,_} -> ok end,
Error;
{'DOWN',MRef,process,_,Reason} ->
log("ct_gen_conn:start",
"Connection process died: ~tp\n",
[Reason]),
{error,{connection_process_died,Reason}}
end.
check_opts(Opts0) ->
check_opts(Opts0,#gen_opts{}).
check_opts([{name,Name}|T],Opts) ->
check_opts(T,Opts#gen_opts{name=Name});
check_opts([{reconnect,Bool}|T],Opts) ->
check_opts(T,Opts#gen_opts{reconnect=Bool});
check_opts([{forward_messages,Bool}|T],Opts) ->
check_opts(T,Opts#gen_opts{forward=Bool});
check_opts([{use_existing_connection,Bool}|T],Opts) ->
check_opts(T,Opts#gen_opts{use_existing=Bool});
check_opts([{old,Bool}|T],Opts) ->
check_opts(T,Opts#gen_opts{old=Bool});
check_opts([],Opts) ->
Opts.
call(Pid, Msg) ->
call(Pid, Msg, infinity).
call(Pid, Msg, Timeout) ->
MRef = erlang:monitor(process,Pid),
Ref = make_ref(),
Pid ! {Msg,{self(),Ref}},
receive
{Ref, Result} ->
erlang:demonitor(MRef, [flush]),
case Result of
{retry,_Data} ->
call(Pid,Result);
Other ->
Other
end;
{'DOWN',MRef,process,_,Reason} ->
{error,{process_down,Pid,Reason}}
after Timeout ->
erlang:demonitor(MRef, [flush]),
log("ct_gen_conn",
"Connection process ~w not responding. Killing now!",
[Pid]),
exit(Pid, kill),
{error,{process_down,Pid,forced_termination}}
end.
return({To,Ref},Result) ->
To ! {Ref, Result},
ok.
init_gen(Parent,Opts) ->
process_flag(trap_exit,true),
put(silent,false),
try (Opts#gen_opts.callback):init(Opts#gen_opts.name,
Opts#gen_opts.address,
Opts#gen_opts.init_data) of
{ok,ConnPid,State} when is_pid(ConnPid) ->
link(ConnPid),
put(conn_pid,ConnPid),
CtUtilServer = whereis(ct_util_server),
link(CtUtilServer),
Parent ! {connected,self()},
loop(Opts#gen_opts{conn_pid=ConnPid,
cb_state=State,
ct_util_server=CtUtilServer});
{error,Reason} ->
Parent ! {{error,Reason},self()}
catch
throw:{error,Reason} ->
Parent ! {{error,Reason},self()}
end.
loop(Opts) ->
receive
{'EXIT',Pid,Reason} when Pid==Opts#gen_opts.conn_pid ->
case Opts#gen_opts.reconnect of
true ->
log("Connection down!\nOpening new!",
"Reason: ~tp\nAddress: ~tp\n",
[Reason,Opts#gen_opts.address]),
case reconnect(Opts) of
{ok, NewPid, NewState} ->
link(NewPid),
put(conn_pid,NewPid),
loop(Opts#gen_opts{conn_pid=NewPid,
cb_state=NewState});
Error ->
ct_util:unregister_connection(self()),
log("Reconnect failed. Giving up!",
"Reason: ~tp\n",
[Error])
end;
false ->
ct_util:unregister_connection(self()),
log("Connection closed!","Reason: ~tp\n",[Reason])
end;
{'EXIT',Pid,Reason} ->
case Opts#gen_opts.ct_util_server of
Pid ->
exit(Reason);
_ ->
loop(Opts)
end;
{stop, From} ->
ct_util:unregister_connection(self()),
ConnPid = Opts#gen_opts.conn_pid,
unlink(ConnPid),
(Opts#gen_opts.callback):terminate(ConnPid,Opts#gen_opts.cb_state),
return(From,ok),
ok;
{{retry,{Error,_Name,CPid,_Msg}}, From} when
CPid == Opts#gen_opts.conn_pid ->
%% only retry if failure is because of a reconnection
Return = case Error of
{error,_} -> Error;
Reason -> {error,Reason}
end,
return(From, Return),
loop(Opts);
{{retry,{_Error,_Name,_CPid,Msg}}, From} ->
log("Rerunning command","Connection reestablished. "
"Rerunning command...",[]),
{Return,NewState} =
(Opts#gen_opts.callback):handle_msg(Msg,Opts#gen_opts.cb_state),
return(From, Return),
loop(Opts#gen_opts{cb_state=NewState});
{get_conn_pid, From} ->
return(From, Opts#gen_opts.conn_pid),
loop(Opts);
{Msg, From={Pid,_Ref}} when is_pid(Pid), Opts#gen_opts.old==true ->
{Return,NewState} =
(Opts#gen_opts.callback):handle_msg(Msg,Opts#gen_opts.cb_state),
return(From, Return),
loop(Opts#gen_opts{cb_state=NewState});
{Msg,From={Pid,_Ref}} when is_pid(Pid) ->
case (Opts#gen_opts.callback):handle_msg(Msg,From,
Opts#gen_opts.cb_state) of
{reply,Reply,NewState} ->
return(From,Reply),
loop(Opts#gen_opts{cb_state=NewState});
{noreply,NewState} ->
loop(Opts#gen_opts{cb_state=NewState});
{stop,Reply,NewState} ->
ct_util:unregister_connection(self()),
ConnPid = Opts#gen_opts.conn_pid,
unlink(ConnPid),
(Opts#gen_opts.callback):terminate(ConnPid,NewState),
return(From,Reply)
end;
Msg when Opts#gen_opts.forward==true ->
case (Opts#gen_opts.callback):handle_msg(Msg,
Opts#gen_opts.cb_state) of
{noreply,NewState} ->
loop(Opts#gen_opts{cb_state=NewState});
{stop,NewState} ->
ct_util:unregister_connection(self()),
ConnPid = Opts#gen_opts.conn_pid,
unlink(ConnPid),
(Opts#gen_opts.callback):terminate(ConnPid,NewState)
end
end.
reconnect(Opts) ->
(Opts#gen_opts.callback):reconnect(Opts#gen_opts.address,
Opts#gen_opts.cb_state).
log(Func,Args) ->
case get(silent) of
true when not ?dbg->
ok;
_ ->
apply(ct_logs,Func,Args)
end.
