Merge bug24579

Author: Simon MacMullen

docs/rabbitmqctl.1.xml

@@ -1315,6 +1315,22 @@
             </para>
           </listitem>
         </varlistentry>
+
+        <varlistentry>
+          <term><cmdsynopsis><command>eval</command> <arg choice="req"><replaceable>expr</replaceable></arg></cmdsynopsis></term>
+          <listitem>
+            <para>
+              Evaluate an arbitrary Erlang expression.
+            </para>
+            <para role="example-prefix">
+              For example:
+            </para>
+            <screen role="example">rabbitmqctl eval 'node().'</screen>
+            <para role="example">
+              This command returns the name of the node to which rabbitmqctl has connected.
+            </para>
+          </listitem>
+        </varlistentry>
       </variablelist>
     </refsect2>
 

src/mirrored_supervisor_tests.erl

@@ -158,7 +158,7 @@ test_no_migration_on_shutdown() ->
                       try
                           call(worker, ping),
                           exit(worker_should_not_have_migrated)
-                      catch exit:{timeout_waiting_for_server, _} ->
+                      catch exit:{timeout_waiting_for_server, _, _} ->
                               ok
                       end
               end, [evil, good]).
@@ -245,10 +245,10 @@ inc_group() ->
 get_group(Group) ->
     {Group, get(counter)}.
 
-call(Id, Msg) -> call(Id, Msg, 100, 10).
+call(Id, Msg) -> call(Id, Msg, 1000, 100).
 
 call(Id, Msg, 0, _Decr) ->
-    exit({timeout_waiting_for_server, {Id, Msg}});
+    exit({timeout_waiting_for_server, {Id, Msg}, erlang:get_stacktrace()});
 
 call(Id, Msg, MaxDelay, Decr) ->
     try

src/rabbit_control.erl

@@ -98,6 +98,9 @@ start() ->
         {error, Reason} ->
             print_error("~p", [Reason]),
             rabbit_misc:quit(2);
+        {error_string, Reason} ->
+            print_error("~s", [Reason]),
+            rabbit_misc:quit(2);
         {badrpc, {'EXIT', Reason}} ->
             print_error("~p", [Reason]),
             rabbit_misc:quit(2);
@@ -368,7 +371,23 @@ action(report, Node, _Args, _Opts, Inform) ->
     [print_report(Node, Q)      || Q <- ?GLOBAL_QUERIES],
     [print_report(Node, Q, [V]) || Q <- ?VHOST_QUERIES, V <- VHosts],
     io:format("End of server status report~n"),
-    ok.
+    ok;
+
+action(eval, Node, [Expr], _Opts, _Inform) ->
+    case erl_scan:string(Expr) of
+        {ok, Scanned, _} ->
+            case erl_parse:parse_exprs(Scanned) of
+                {ok, Parsed} ->
+                    {value, Value, _} = unsafe_rpc(
+                                          Node, erl_eval, exprs, [Parsed, []]),
+                    io:format("~p~n", [Value]),
+                    ok;
+                {error, E} ->
+                    {error_string, format_parse_error(E)}
+            end;
+        {error, E, _} ->
+            {error_string, format_parse_error(E)}
+    end.
 
 %%----------------------------------------------------------------------------
 
@@ -443,6 +462,9 @@ system(Cmd) ->
 escape_quotes(Cmd) ->
     lists:flatten(lists:map(fun ($') -> "'\\''"; (Ch) -> Ch end, Cmd)).
 
+format_parse_error({_Line, Mod, Err}) ->
+    lists:flatten(Mod:format_error(Err)).
+
 %%----------------------------------------------------------------------------
 
 default_if_empty(List, Default) when is_list(List) ->

src/rabbit_guid.erl

@@ -89,8 +89,15 @@ guid() ->
     erlang:md5(term_to_binary(G)).
 
 %% generate a readable string representation of a GUID.
+%%
+%% employs base64url encoding, which is safer in more contexts than
+%% plain base64.
 string_guid(Prefix) ->
-    Prefix ++ "-" ++ base64:encode_to_string(guid()).
+    Prefix ++ "-" ++ lists:foldl(fun ($\+, Acc) -> [$\- | Acc];
+                                     ($\/, Acc) -> [$\_ | Acc];
+                                     ($\=, Acc) -> Acc;
+                                     (Chr, Acc) -> [Chr | Acc]
+                                 end, [], base64:encode_to_string(guid())).
 
 binstring_guid(Prefix) ->
     list_to_binary(string_guid(Prefix)).