Rewrite the rabbitmqctl interface. Define trace_exchanges in rabbit.app.

5 files changed, 46 insertions, 70 deletions

diff --git a/docs/rabbitmqctl.1.xml b/docs/rabbitmqctl.1.xml
index 62869158..0e212f10 100644
--- a/docs/rabbitmqctl.1.xml
+++ b/docs/rabbitmqctl.1.xml
@@ -1266,59 +1266,38 @@
     </refsect2>
 
     <refsect2>
-      <title>Configuration variables</title>
-      <para>
-        Some configuration values can be changed at run time. Note
-        that this does not apply to all variables; many are only read
-        at startup - changing them will have no effect.
-      </para>
+      <title>Message Tracing</title>
       <variablelist>
         <varlistentry>
-          <term><cmdsynopsis><command>set_env</command> <arg choice="req"><replaceable>variable</replaceable></arg> <arg choice="req"><replaceable>value</replaceable></arg></cmdsynopsis></term>
+          <term><cmdsynopsis><command>start_tracing</command> <arg choice="opt">-p <replaceable>vhost</replaceable></arg> <arg choice="req"><replaceable>exchange</replaceable></arg></cmdsynopsis></term>
           <listitem>
             <variablelist>
               <varlistentry>
-                <term>variable</term>
-                <listitem><para>The name of the variable to set, as the string form of an Erlang term.</para></listitem>
+                <term>vhost</term>
+                <listitem><para>The name of the virtual host for which to start tracing.</para></listitem>
               </varlistentry>
               <varlistentry>
                 <term>value</term>
-                <listitem><para>The value to set it to, as the string form of an Erlang term.</para></listitem>
+                <listitem><para>The name of the exchange to which trace messages should be published.</para></listitem>
               </varlistentry>
             </variablelist>
             <para>
-              Set the value of a configuration variable.
+              Starts tracing.
             </para>
           </listitem>
         </varlistentry>
 
         <varlistentry>
-          <term><cmdsynopsis><command>get_env</command> <arg choice="req"><replaceable>variable</replaceable></arg></cmdsynopsis></term>
+          <term><cmdsynopsis><command>stop_tracing</command> <arg choice="opt">-p <replaceable>vhost</replaceable></arg></cmdsynopsis></term>
           <listitem>
             <variablelist>
               <varlistentry>
-                <term>variable</term>
-                <listitem><para>The name of the variable to get, as the string form of an Erlang term.</para></listitem>
-              </varlistentry>
-            </variablelist>
-            <para>
-              Get the value of a configuration variable, printing either
-              {ok,<command>Value</command>} or undefined.
-            </para>
-          </listitem>
-        </varlistentry>
-
-        <varlistentry>
-          <term><cmdsynopsis><command>unset_env</command> <arg choice="req"><replaceable>variable</replaceable></arg></cmdsynopsis></term>
-          <listitem>
-            <variablelist>
-              <varlistentry>
-                <term>variable</term>
-                <listitem><para>The name of the variable to clear, as the string form of an Erlang term.</para></listitem>
+                <term>vhost</term>
+                <listitem><para>The name of the virtual host for which to stop tracing.</para></listitem>
               </varlistentry>
             </variablelist>
             <para>
-              Clear the value of a configuration variable.
+              Stops tracing.
             </para>
           </listitem>
         </varlistentry>
diff --git a/ebin/rabbit_app.in b/ebin/rabbit_app.in
index 014c18b0..7972ba86 100644
--- a/ebin/rabbit_app.in
+++ b/ebin/rabbit_app.in
@@ -36,6 +36,7 @@
          {auth_mechanisms, ['PLAIN', 'AMQPLAIN']},
          {auth_backends, [rabbit_auth_backend_internal]},
          {delegate_count, 16},
+         {trace_exchanges, []},
          {tcp_listen_options, [binary,
                                {packet,        raw},
                                {reuseaddr,     true},
diff --git a/src/rabbit.erl b/src/rabbit.erl
index 9052f2f9..e6e80b4a 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -25,8 +25,6 @@
 
 -export([log_location/1]).
 
--export([get_env/1, set_env/2, unset_env/1]).
-
 %%---------------------------------------------------------------------------
 %% Boot steps.
 -export([maybe_insert_default_data/0, boot_delegate/0, recover/0]).
@@ -188,9 +186,6 @@
 -spec(maybe_insert_default_data/0 :: () -> 'ok').
 -spec(boot_delegate/0 :: () -> 'ok').
 -spec(recover/0 :: () -> 'ok').
--spec(get_env/1 :: (atom()) -> term()).
--spec(set_env/2 :: (atom(), term()) -> 'ok').
--spec(unset_env/1 :: (atom()) -> 'ok').
 
 -endif.
 
@@ -519,14 +514,3 @@ log_rotation_result(ok, {error, SaslLogError}) ->
     {error, {cannot_rotate_sasl_logs, SaslLogError}};
 log_rotation_result(ok, ok) ->
     ok.
-
-get_env(Key) ->
-    application:get_env(rabbit, Key).
-
-set_env(Key, Value) ->
-    application:set_env(rabbit, Key, Value),
-    rabbit_channel:refresh_config_all().
-
-unset_env(Key) ->
-    application:unset_env(rabbit, Key),
-    rabbit_channel:refresh_config_all().
diff --git a/src/rabbit_control.erl b/src/rabbit_control.erl
index 5a013711..2a9dd463 100644
--- a/src/rabbit_control.erl
+++ b/src/rabbit_control.erl
@@ -282,18 +282,15 @@ action(list_consumers, Node, _Args, Opts, Inform) ->
         Other             -> Other
     end;
 
-action(set_env, Node, [Var, Term], _Opts, Inform) ->
-    Inform("Setting control variable ~s for node ~p to ~s", [Var, Node, Term]),
-    rpc_call(Node, rabbit, set_env, [parse(Var), parse(Term)]);
+action(start_tracing, Node, [XName], Opts, Inform) ->
+    VHost = list_to_binary(proplists:get_value(?VHOST_OPT, Opts)),
+    Inform("Starting tracing", []),
+    rpc_call(Node, rabbit_trace, start, [VHost, XName]);
 
-action(get_env, Node, [Var], _Opts, Inform) ->
-    Inform("Getting control variable ~s for node ~p", [Var, Node]),
-    Val = rpc_call(Node, rabbit, get_env, [parse(Var)]),
-    io:format("~p~n", [Val]);
-
-action(unset_env, Node, [Var], _Opts, Inform) ->
-    Inform("Clearing control variable ~s for node ~p", [Var, Node]),
-    rpc_call(Node, rabbit, unset_env, [parse(Var)]);
+action(stop_tracing, Node, [], Opts, Inform) ->
+    VHost = list_to_binary(proplists:get_value(?VHOST_OPT, Opts)),
+    Inform("Stopping tracing", []),
+    rpc_call(Node, rabbit_trace, stop, [VHost]);
 
 action(set_permissions, Node, [Username, CPerm, WPerm, RPerm], Opts, Inform) ->
     VHost = proplists:get_value(?VHOST_OPT, Opts),
@@ -338,11 +335,6 @@ default_if_empty(List, Default) when is_list(List) ->
        true       -> [list_to_atom(X) || X <- List]
     end.
 
-parse(Str) ->
-    {ok, Tokens, _} = erl_scan:string(Str ++ "."),
-    {ok, Term} = erl_parse:parse_term(Tokens),
-    Term.
-
 display_info_list(Results, InfoItemKeys) when is_list(Results) ->
     lists:foreach(
       fun (Result) -> display_row(
diff --git a/src/rabbit_trace.erl b/src/rabbit_trace.erl
index 09f2545d..6228c54e 100644
--- a/src/rabbit_trace.erl
+++ b/src/rabbit_trace.erl
@@ -16,11 +16,13 @@
 
 -module(rabbit_trace).
 
--export([init/1, tap_trace_in/2, tap_trace_out/2]).
+-export([init/1, tap_trace_in/2, tap_trace_out/2, start/2, stop/1]).
 
 -include("rabbit.hrl").
 -include("rabbit_framing.hrl").
 
+-define(TRACE_EXCHANGES, trace_exchanges).
+
 %%----------------------------------------------------------------------------
 
 -ifdef(use_specs).
@@ -31,17 +33,18 @@
 -spec(tap_trace_in/2 :: (rabbit_types:basic_message(), state()) -> 'ok').
 -spec(tap_trace_out/2 :: (rabbit_amqqueue:qmsg(), state()) -> 'ok').
 
+-spec(start/2 :: (rabbit_types:vhost(), binary()) -> 'ok').
+-spec(stop/1 :: (rabbit_types:vhost()) -> 'ok').
+
 -endif.
 
 %%----------------------------------------------------------------------------
 
 init(VHost) ->
-    case application:get_env(rabbit, trace_exchanges) of
-        undefined  -> none;
-        {ok, XNs}  -> case proplists:get_value(VHost, XNs, none) of
-                          none -> none;
-                          Name -> rabbit_misc:r(VHost, exchange, Name)
-                      end
+    {ok, XNs} = application:get_env(rabbit, ?TRACE_EXCHANGES),
+    case proplists:get_value(VHost, XNs, none) of
+        none -> none;
+        Name -> rabbit_misc:r(VHost, exchange, Name)
     end.
 
 tap_trace_in(Msg = #basic_message{exchange_name = #resource{name = XName}},
@@ -54,6 +57,23 @@ tap_trace_out({#resource{name = QName}, _QPid, _QMsgId, Redelivered, Msg},
     maybe_trace(TraceXN, Msg, <<"deliver">>, QName,
                 [{<<"redelivered">>, signedint, RedeliveredNum}]).
 
+%%----------------------------------------------------------------------------
+
+start(VHost, XN) ->
+    update_config(fun (Xs) -> orddict:store(VHost, list_to_binary(XN), Xs) end).
+
+stop(VHost) ->
+    update_config(fun (Xs) -> orddict:erase(VHost, Xs) end).
+
+update_config(Fun) ->
+    {ok, Xs0} = application:get_env(rabbit, ?TRACE_EXCHANGES),
+    Xs = Fun(orddict:from_list(Xs0)),
+    application:set_env(rabbit, ?TRACE_EXCHANGES, Xs),
+    rabbit_channel:refresh_config_all(),
+    ok.
+
+%%----------------------------------------------------------------------------
+
 maybe_trace(none, _Msg, _RKPrefix, _RKSuffix, _Extra) ->
     ok;
 maybe_trace(XName, #basic_message{exchange_name = #resource{name = XName}},