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authorSteve Vinoski <[email protected]>2009-11-27 12:37:13 -0500
committerSteve Vinoski <[email protected]>2009-12-01 21:31:30 -0500
commit88b530ea24977081020feb2123124063e58dfc12 (patch)
tree3e1fa8301f22328d0b1cf70edc585bfca5fd8729
parent2a9b7a1c7816812dd637933a8fbf61bed6742785 (diff)
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Teach sys:get_status/1,2 to call Mod:format_status/2
Restore the ability for gen_server and gen_fsm callback modules to format their own state for display under the sys:get_status/1,2 calls. This ability is extremely useful for new behavior modules based on gen_server or gen_fsm, so that they can display their status in a more meaningful way than just dumping the state record. It is also generally useful for applications wanting to display their gen_server or gen_fsm callback module state in something other than the default manner. Also document the previously undocumented the gen_server:format_status/2 and gen_fsm:format_status/2 optional callback functions that, if exported by the callback module, are invoked when sys:get_status/1,2 are called. Add unit tests to ensure that format_status/2 functions exported from a gen_fsm callback module and a gen_server callback module are called when sys:get_status/1,2 are called.
-rw-r--r--lib/stdlib/doc/src/gen_fsm.xml30
-rw-r--r--lib/stdlib/doc/src/gen_server.xml29
-rw-r--r--lib/stdlib/doc/src/sys.xml11
-rw-r--r--lib/stdlib/src/sys.erl11
-rw-r--r--lib/stdlib/test/gen_fsm_SUITE.erl16
-rw-r--r--lib/stdlib/test/gen_server_SUITE.erl29
6 files changed, 117 insertions, 9 deletions
diff --git a/lib/stdlib/doc/src/gen_fsm.xml b/lib/stdlib/doc/src/gen_fsm.xml
index f5d8b9bb48..739cd0bffd 100644
--- a/lib/stdlib/doc/src/gen_fsm.xml
+++ b/lib/stdlib/doc/src/gen_fsm.xml
@@ -729,6 +729,36 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
updated internal data.</p>
</desc>
</func>
+ <func>
+ <name>Module:format_status(normal, [PDict, StateData]) -> Status</name>
+ <fsummary>Optional function for providing a term describing the
+ current gen_fsm status.</fsummary>
+ <type>
+ <v>PDict = [{Key, Value}]</v>
+ <v>StateData = term()</v>
+ <v>Status = [term()]</v>
+ </type>
+ <desc>
+ <p><em>This callback is optional, so callback modules need not
+ export it. The gen_fsm module provides a default
+ implementation of this function that returns the callback
+ module state data.</em></p>
+ <p>This function is called by a gen_fsm process when one
+ of <seealso marker="sys#get_status/1">sys:get_status/1,2</seealso>
+ is invoked to get the gen_fsm status. A callback module
+ wishing to customise the <c>sys:get_status/1,2</c> return
+ value exports an instance of <c>format_status/2</c> that
+ returns a term describing the current status of the
+ gen_fsm.</p>
+ <p><c>PDict</c> is the current value of the gen_fsm's
+ process dictionary.</p>
+ <p><c>StateData</c> is the internal state data of the
+ gen_fsm.</p>
+ <p>The function should return <c>Status</c>, a list of one or
+ more terms that customise the details of the current state
+ and status of the gen_fsm.</p>
+ </desc>
+ </func>
</funcs>
<section>
diff --git a/lib/stdlib/doc/src/gen_server.xml b/lib/stdlib/doc/src/gen_server.xml
index 8496802259..30c04d1d52 100644
--- a/lib/stdlib/doc/src/gen_server.xml
+++ b/lib/stdlib/doc/src/gen_server.xml
@@ -598,6 +598,35 @@ gen_server:abcast -----> Module:handle_cast/2
<p>The function should return the updated internal state.</p>
</desc>
</func>
+ <func>
+ <name>Module:format_status(normal, [PDict, State]) -> Status</name>
+ <fsummary>Optional function for providing a term describing the
+ current gen_server status.</fsummary>
+ <type>
+ <v>PDict = [{Key, Value}]</v>
+ <v>State = term()</v>
+ <v>Status = [term()]</v>
+ </type>
+ <desc>
+ <p><em>This callback is optional, so callback modules need not
+ export it. The gen_server module provides a default
+ implementation of this function that returns the callback
+ module state.</em></p>
+ <p>This function is called by a gen_server process when one
+ of <seealso marker="sys#get_status/1">sys:get_status/1,2</seealso>
+ is invoked to get the gen_server status. A callback module
+ wishing to customise the <c>sys:get_status/1,2</c> return
+ value exports an instance of <c>format_status/2</c> that
+ returns a term describing the current status of the
+ gen_server.</p>
+ <p><c>PDict</c> is the current value of the gen_server's
+ process dictionary.</p>
+ <p><c>State</c> is the internal state of the gen_server.</p>
+ <p>The function should return <c>Status</c>, a list of one or
+ more terms that customise the details of the current state
+ and status of the gen_server.</p>
+ </desc>
+ </func>
</funcs>
<section>
diff --git a/lib/stdlib/doc/src/sys.xml b/lib/stdlib/doc/src/sys.xml
index a395a8a415..51fd5ee8d4 100644
--- a/lib/stdlib/doc/src/sys.xml
+++ b/lib/stdlib/doc/src/sys.xml
@@ -237,6 +237,17 @@
</type>
<desc>
<p>Gets the status of the process.</p>
+ <p>The value of <c>Misc</c> varies for different types of
+ processes. For example, a <c>gen_server</c> process returns
+ the callback module's state, and a <c>gen_fsm</c> process
+ returns information such as its current state name. Callback
+ modules for <c>gen_server</c> and <c>gen_fsm</c> can also
+ customise the value of <c>Misc</c> by exporting
+ a <c>format_status/2</c> function that contributes
+ module-specific information;
+ see <seealso marker="gen_server#format_status/2">gen_server:format_status/2</seealso>
+ and <seealso marker="gen_fsm#format_status/2">gen_fsm:format_status/2</seealso>
+ for more details.</p>
</desc>
</func>
<func>
diff --git a/lib/stdlib/src/sys.erl b/lib/stdlib/src/sys.erl
index e0f2dbcd3c..12209c16d7 100644
--- a/lib/stdlib/src/sys.erl
+++ b/lib/stdlib/src/sys.erl
@@ -245,8 +245,17 @@ do_cmd(SysState, Other, _Parent, _Mod, Debug, Misc) ->
{SysState, {error, {unknown_system_msg, Other}}, Debug, Misc}.
get_status(SysState, Parent, Mod, Debug, Misc) ->
+ PDict = get(),
+ FmtMisc =
+ case erlang:function_exported(Mod, format_status, 2) of
+ true ->
+ FmtArgs = [PDict, SysState, Parent, Debug, Misc],
+ Mod:format_status(normal, FmtArgs);
+ _ ->
+ Misc
+ end,
{status, self(), {module, Mod},
- [get(), SysState, Parent, Debug, Misc]}.
+ [PDict, SysState, Parent, Debug, FmtMisc]}.
%%-----------------------------------------------------------------
%% These are the system debug commands.
diff --git a/lib/stdlib/test/gen_fsm_SUITE.erl b/lib/stdlib/test/gen_fsm_SUITE.erl
index 62f8b2f9dd..23c1d9a193 100644
--- a/lib/stdlib/test/gen_fsm_SUITE.erl
+++ b/lib/stdlib/test/gen_fsm_SUITE.erl
@@ -30,7 +30,7 @@
-export([shutdown/1]).
--export([sys/1, sys1/1]).
+-export([sys/1, sys1/1, call_format_status/1]).
-export([hibernate/1,hiber_idle/3,hiber_wakeup/3,hiber_idle/2,hiber_wakeup/2]).
@@ -42,7 +42,7 @@
% The gen_fsm behaviour
-export([init/1, handle_event/3, handle_sync_event/4, terminate/3,
- handle_info/3]).
+ handle_info/3, format_status/2]).
-export([idle/2, idle/3,
timeout/2,
wfor_conf/2, wfor_conf/3,
@@ -305,7 +305,7 @@ shutdown(Config) when is_list(Config) ->
ok.
-sys(suite) -> [sys1].
+sys(suite) -> [sys1, call_format_status].
sys1(Config) when is_list(Config) ->
?line {ok, Pid} =
@@ -317,6 +317,13 @@ sys1(Config) when is_list(Config) ->
?line sys:resume(Pid),
?line stop_it(Pid).
+call_format_status(Config) when is_list(Config) ->
+ ?line {ok, Pid} = gen_fsm:start(gen_fsm_SUITE, [], []),
+ ?line Status = sys:get_status(Pid),
+ ?line {status, Pid, _Mod, [_PDict, running, _Parent, _, Data]} = Status,
+ ?line [format_status_called | _] = lists:reverse(Data),
+ ?line stop_it(Pid).
+
%% Hibernation
hibernate(suite) -> [];
@@ -836,3 +843,6 @@ handle_sync_event(stop_shutdown_reason, _From, _State, Data) ->
{stop, {shutdown,reason}, {shutdown,reason}, Data};
handle_sync_event({get, _Pid}, _From, State, Data) ->
{reply, {state, State, Data}, State, Data}.
+
+format_status(_Opt, [_Pdict, _StateData]) ->
+ [format_status_called].
diff --git a/lib/stdlib/test/gen_server_SUITE.erl b/lib/stdlib/test/gen_server_SUITE.erl
index 86a5a65ba3..6efdce78a1 100644
--- a/lib/stdlib/test/gen_server_SUITE.erl
+++ b/lib/stdlib/test/gen_server_SUITE.erl
@@ -30,7 +30,7 @@
call_remote_n1/1, call_remote_n2/1, call_remote_n3/1, spec_init/1,
spec_init_local_registered_parent/1,
spec_init_global_registered_parent/1,
- otp_5854/1, hibernate/1, otp_7669/1
+ otp_5854/1, hibernate/1, otp_7669/1, call_format_status/1
]).
% spawn export
@@ -42,7 +42,7 @@
% The gen_server behaviour
-export([init/1, handle_call/3, handle_cast/2,
- handle_info/2, terminate/2]).
+ handle_info/2, terminate/2, format_status/2]).
all(suite) ->
[start, crash, call, cast, cast_fast, info,
@@ -51,7 +51,7 @@ all(suite) ->
call_remote_n2, call_remote_n3, spec_init,
spec_init_local_registered_parent,
spec_init_global_registered_parent,
- otp_5854,hibernate,otp_7669].
+ otp_5854, hibernate, otp_7669, call_format_status].
-define(default_timeout, ?t:minutes(1)).
@@ -851,7 +851,7 @@ otp_5854(Config) when is_list(Config) ->
ok.
%% If initialization fails (with ignore or {stop,Reason}),
-%% make sure that the process is not registered when gen_sever:start()
+%% make sure that the process is not registered when gen_server:start()
%% returns.
otp_7669(Config) when is_list(Config) ->
@@ -887,6 +887,24 @@ do_otp_7669_stop() ->
?MODULE, stop, []),
?line undefined = global:whereis_name(?MODULE).
+%% Verify that sys:get_status correctly calls our format_status/2 fun
+%%
+call_format_status(suite) ->
+ [];
+call_format_status(doc) ->
+ ["Test that sys:get_status/1,2 calls format_status/2"];
+call_format_status(Config) when is_list(Config) ->
+ ?line {ok, Pid} = gen_server:start_link({local, call_format_status},
+ gen_server_SUITE, [], []),
+ ?line Status1 = sys:get_status(call_format_status),
+ ?line {status, Pid, _Mod, [_PDict, running, _Parent, _, Data1]} = Status1,
+ ?line [format_status_called | _] = lists:reverse(Data1),
+ ?line Status2 = sys:get_status(call_format_status, 5000),
+ ?line {status, Pid, _Mod, [_PDict, running, _Parent, _, Data2]} = Status2,
+ ?line [format_status_called | _] = lists:reverse(Data2),
+ ok.
+
+
%%--------------------------------------------------------------
%% Help functions to spec_init_*
start_link(Init, Options) ->
@@ -1046,4 +1064,5 @@ terminate({From, stopped_info}, _State) ->
terminate(_Reason, _State) ->
ok.
-
+format_status(_Opt, [_PDict, _State]) ->
+ [format_status_called].