Merging bug 22554 onto default

10 files changed, 374 insertions, 42 deletions

diff --git a/.hgignore b/.hgignore
index 75ccfb73..caaa3ace 100644
--- a/.hgignore
+++ b/.hgignore
@@ -11,8 +11,7 @@ syntax: regexp
 ^dist/
 ^include/rabbit_framing\.hrl$
 ^src/rabbit_framing\.erl$
-^src/rabbitmqctl_usage\.erl$
-^src/rabbitmqmulti_usage\.erl$
+^src/.*\_usage.erl$
 ^rabbit\.plt$
 ^basic.plt$
 ^ebin/rabbit\.(app|rel|boot|script)$
@@ -28,4 +27,3 @@ syntax: regexp
 
 ^docs/.*\.[15]\.gz$
 ^docs/.*\.man\.xml$
-^docs/.*\.usage.erl$
diff --git a/Makefile b/Makefile
index 5dae522c..c946f92b 100644
--- a/Makefile
+++ b/Makefile
@@ -10,14 +10,16 @@ DEPS_FILE=deps.mk
 SOURCE_DIR=src
 EBIN_DIR=ebin
 INCLUDE_DIR=include
+DOCS_DIR=docs
 INCLUDES=$(wildcard $(INCLUDE_DIR)/*.hrl) $(INCLUDE_DIR)/rabbit_framing.hrl
-SOURCES=$(wildcard $(SOURCE_DIR)/*.erl) $(SOURCE_DIR)/rabbit_framing.erl $(SOURCE_DIR)/rabbitmqctl_usage.erl $(SOURCE_DIR)/rabbitmqmulti_usage.erl
+SOURCES=$(wildcard $(SOURCE_DIR)/*.erl) $(SOURCE_DIR)/rabbit_framing.erl $(USAGES_ERL)
 BEAM_TARGETS=$(patsubst $(SOURCE_DIR)/%.erl, $(EBIN_DIR)/%.beam, $(SOURCES))
 TARGETS=$(EBIN_DIR)/rabbit.app $(INCLUDE_DIR)/rabbit_framing.hrl $(BEAM_TARGETS)
 WEB_URL=http://stage.rabbitmq.com/
-MANPAGES=$(patsubst %.xml, %.gz, $(wildcard docs/*.[0-9].xml))
-WEB_MANPAGES=$(patsubst %.xml, %.man.xml, $(wildcard docs/*.[0-9].xml) docs/rabbitmq-service.xml)
-USAGES=$(patsubst %.1.xml, %.usage.erl, $(wildcard docs/*.[0-9].xml))
+MANPAGES=$(patsubst %.xml, %.gz, $(wildcard $(DOCS_DIR)/*.[0-9].xml))
+WEB_MANPAGES=$(patsubst %.xml, %.man.xml, $(wildcard $(DOCS_DIR)/*.[0-9].xml) $(DOCS_DIR)/rabbitmq-service.xml)
+USAGES_XML=$(DOCS_DIR)/rabbitmqctl.1.xml $(DOCS_DIR)/rabbitmq-multi.1.xml
+USAGES_ERL=$(foreach XML, $(USAGES_XML), $(call usage_xml_to_erl, $(XML)))
 
 ifeq ($(shell python -c 'import simplejson' 2>/dev/null && echo yes),yes)
 PYTHON=python
@@ -60,6 +62,14 @@ ERL_CALL=erl_call -sname $(RABBITMQ_NODENAME) -e
 
 ERL_EBIN=erl -noinput -pa $(EBIN_DIR)
 
+define usage_xml_to_erl
+  $(subst __,_,$(patsubst $(DOCS_DIR)/rabbitmq%.1.xml, $(SOURCE_DIR)/rabbit_%_usage.erl, $(subst -,_,$(1))))
+endef
+
+define usage_dep
+  $(call usage_xml_to_erl, $(1)): $(1) $(DOCS_DIR)/usage.xsl
+endef
+
 all: $(TARGETS)
 
 $(DEPS_FILE): $(SOURCES) $(INCLUDES)
@@ -68,9 +78,8 @@ $(DEPS_FILE): $(SOURCES) $(INCLUDES)
 $(EBIN_DIR)/rabbit.app: $(EBIN_DIR)/rabbit_app.in $(BEAM_TARGETS) generate_app
 	escript generate_app $(EBIN_DIR) $@ < $<
 
-$(EBIN_DIR)/%.beam: $(SOURCE_DIR)/%.erl
+$(EBIN_DIR)/%.beam:
 	erlc $(ERLC_OPTS) -pa $(EBIN_DIR) $<
-#	ERLC_EMULATOR="erl -smp" erlc $(ERLC_OPTS) -pa $(EBIN_DIR) $<
 
 $(INCLUDE_DIR)/rabbit_framing.hrl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_PATH)
 	$(PYTHON) codegen.py header $(AMQP_SPEC_JSON_PATH) $@
@@ -78,12 +87,6 @@ $(INCLUDE_DIR)/rabbit_framing.hrl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.p
 $(SOURCE_DIR)/rabbit_framing.erl: codegen.py $(AMQP_CODEGEN_DIR)/amqp_codegen.py $(AMQP_SPEC_JSON_PATH)
 	$(PYTHON) codegen.py body   $(AMQP_SPEC_JSON_PATH) $@
 
-$(SOURCE_DIR)/rabbitmqctl_usage.erl: docs/rabbitmqctl.usage.erl
-	cp docs/rabbitmqctl.usage.erl $@
-
-$(SOURCE_DIR)/rabbitmqmulti_usage.erl: docs/rabbitmq-multi.usage.erl
-	cp docs/rabbitmq-multi.usage.erl $@
-
 dialyze: $(BEAM_TARGETS) $(BASIC_PLT)
 	$(ERL_EBIN) -eval \
 		"rabbit_dialyzer:halt_with_code(rabbit_dialyzer:dialyze_files(\"$(BASIC_PLT)\", \"$(BEAM_TARGETS)\"))."
@@ -107,8 +110,8 @@ $(BASIC_PLT): $(BEAM_TARGETS)
 clean:
 	rm -f $(EBIN_DIR)/*.beam
 	rm -f $(EBIN_DIR)/rabbit.app $(EBIN_DIR)/rabbit.boot $(EBIN_DIR)/rabbit.script $(EBIN_DIR)/rabbit.rel
-	rm -f $(INCLUDE_DIR)/rabbit_framing.hrl $(SOURCE_DIR)/rabbit_framing.erl $(SOURCE_DIR)/rabbitmqctl_usage.erl codegen.pyc
-	rm -f docs/*.[0-9].gz docs/*.usage.erl docs/*.man.xml docs/*.erl
+	rm -f $(INCLUDE_DIR)/rabbit_framing.hrl $(SOURCE_DIR)/rabbit_framing.erl codegen.pyc
+	rm -f $(DOCS_DIR)/*.[0-9].gz $(DOCS_DIR)/*.man.xml $(DOCS_DIR)/*.erl $(USAGES_ERL)
 	rm -f $(RABBIT_PLT)
 	rm -f $(DEPS_FILE)
 
@@ -184,7 +187,7 @@ srcdist: distclean
 	cp codegen.py Makefile generate_app generate_deps calculate-relative $(TARGET_SRC_DIR)
 
 	cp -r scripts $(TARGET_SRC_DIR)
-	cp -r docs $(TARGET_SRC_DIR)
+	cp -r $(DOCS_DIR) $(TARGET_SRC_DIR)
 	chmod 0755 $(TARGET_SRC_DIR)/scripts/*
 
 	(cd dist; tar -zcf $(TARBALL_NAME).tar.gz $(TARBALL_NAME))
@@ -197,25 +200,25 @@ distclean: clean
 	find . -regex '.*\(~\|#\|\.swp\|\.dump\)' -exec rm {} \;
 
 # xmlto can not read from standard input, so we mess with a tmp file.
-%.gz: %.xml docs/examples-to-end.xsl
-	xsltproc docs/examples-to-end.xsl $< > $<.tmp && \
-	xmlto man -o docs --stringparam man.indent.verbatims=0 $<.tmp && \
-	gzip -f docs/`basename $< .xml`
+%.gz: %.xml $(DOCS_DIR)/examples-to-end.xsl
+	xsltproc $(DOCS_DIR)/examples-to-end.xsl $< > $<.tmp && \
+	xmlto man -o $(DOCS_DIR) --stringparam man.indent.verbatims=0 $<.tmp && \
+	gzip -f $(DOCS_DIR)/`basename $< .xml`
 	rm -f $<.tmp
 
-%.usage.erl: %.1.xml docs/usage.xsl
-	xsltproc --stringparam modulename "`basename $< .1.xml | tr -d -`_usage" \
-	  docs/usage.xsl $< | sed -e s/\\\"/\\\\\\\"/g | sed -e s/%QUOTE%/\\\"/g | \
-	  fold -s > docs/`basename $< .1.xml`.usage.erl
+$(SOURCE_DIR)/%_usage.erl:
+	xsltproc --stringparam modulename "`basename $@ .erl`" \
+	  $(DOCS_DIR)/usage.xsl $< | sed -e s/\\\"/\\\\\\\"/g | sed -e s/%QUOTE%/\\\"/g | \
+	  fold -s > $@
 
 # We rename the file before xmlto sees it since xmlto will use the name of
 # the file to make internal links.
-%.man.xml: %.xml docs/html-to-website-xml.xsl
+%.man.xml: %.xml $(DOCS_DIR)/html-to-website-xml.xsl
 	cp $< `basename $< .xml`.xml && \
 		xmlto xhtml-nochunks `basename $< .xml`.xml ; rm `basename $< .xml`.xml
 	cat `basename $< .xml`.html | \
-	    xsltproc --novalid docs/remove-namespaces.xsl - | \
-		xsltproc --stringparam original `basename $<` docs/html-to-website-xml.xsl - | \
+	    xsltproc --novalid $(DOCS_DIR)/remove-namespaces.xsl - | \
+		xsltproc --stringparam original `basename $<` $(DOCS_DIR)/html-to-website-xml.xsl - | \
 		xmllint --format - > $@
 	rm `basename $< .xml`.html
 
@@ -237,7 +240,7 @@ install: all docs_all install_dirs
 	done
 	for section in 1 5; do \
 		mkdir -p $(MAN_DIR)/man$$section; \
-		for manpage in docs/*.$$section.gz; do \
+		for manpage in $(DOCS_DIR)/*.$$section.gz; do \
 			cp $$manpage $(MAN_DIR)/man$$section; \
 		done; \
 	done
@@ -246,4 +249,22 @@ install_dirs:
 	mkdir -p $(SBIN_DIR)
 	mkdir -p $(TARGET_DIR)/sbin
 
+$(foreach XML, $(USAGES_XML), $(eval $(call usage_dep, $(XML))))
+
+# Note that all targets which depend on clean must have clean in their
+# name.  Also any target that doesn't depend on clean should not have
+# clean in its name, unless you know that you don't need any of the
+# automatic dependency generation for that target (eg cleandb).
+
+# We want to load the dep file if *any* target *doesn't* contain
+# "clean" - i.e. if removing all clean-like targets leaves something
+
+ifeq "$(MAKECMDGOALS)" ""
+TESTABLEGOALS:=$(.DEFAULT_GOAL)
+else
+TESTABLEGOALS:=$(MAKECMDGOALS)
+endif
+
+ifneq "$(strip $(patsubst clean%,,$(patsubst %clean,,$(TESTABLEGOALS))))" ""
 -include $(DEPS_FILE)
+endif
diff --git a/generate_deps b/generate_deps
index e16624d2..29587b5a 100644
--- a/generate_deps
+++ b/generate_deps
@@ -23,10 +23,11 @@ main([IncludeDir, ErlDir, EbinDir, TargetFile]) ->
               ok;
           (Path, Dep, ok) ->
               Module = filename:basename(Path, ".erl"),
-              ok = file:write(Hdl, [EbinDir, "/", Module, ".beam:"]),
+              ok = file:write(Hdl, [EbinDir, "/", Module, ".beam: ",
+                                   Path]),
               ok = sets:fold(fun (E, ok) -> file:write(Hdl, [" ", E]) end,
                              ok, Dep),
-              file:write(Hdl, [" ", ErlDir, "/", Module, ".erl\n"])
+              file:write(Hdl, ["\n"])
       end, ok, Deps),
     ok = file:write(Hdl, [TargetFile, ": ", escript:script_name(), "\n"]),
     ok = file:sync(Hdl),
diff --git a/src/rabbit.erl b/src/rabbit.erl
index 700acede..b1204997 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -51,27 +51,39 @@
 
 -rabbit_boot_step({database,
                    [{mfa,         {rabbit_mnesia, init, []}},
-                    {enables,     kernel_ready}]}).
+                    {enables,     external_infrastructure}]}).
+
+-rabbit_boot_step({worker_pool,
+                   [{description, "worker pool"},
+                    {mfa,         {rabbit_sup, start_child, [worker_pool_sup]}},
+                    {enables,     external_infrastructure}]}).
+
+-rabbit_boot_step({external_infrastructure,
+                   [{description, "external infrastructure ready"}]}).
 
 -rabbit_boot_step({rabbit_exchange_type_registry,
                    [{description, "exchange type registry"},
                     {mfa,         {rabbit_sup, start_child,
                                    [rabbit_exchange_type_registry]}},
-                    {enables,     kernel_ready}]}).
+                    {enables,     kernel_ready},
+                    {requires,    external_infrastructure}]}).
 
 -rabbit_boot_step({rabbit_log,
                    [{description, "logging server"},
                     {mfa,         {rabbit_sup, start_restartable_child,
                                    [rabbit_log]}},
-                    {enables,     kernel_ready}]}).
+                    {enables,     kernel_ready},
+                    {requires,    external_infrastructure}]}).
 
 -rabbit_boot_step({rabbit_hooks,
                    [{description, "internal event notification system"},
                     {mfa,         {rabbit_hooks, start, []}},
-                    {enables,     kernel_ready}]}).
+                    {enables,     kernel_ready},
+                    {requires,    external_infrastructure}]}).
 
 -rabbit_boot_step({kernel_ready,
-                   [{description, "kernel ready"}]}).
+                   [{description, "kernel ready"},
+                    {requires,    external_infrastructure}]}).
 
 -rabbit_boot_step({rabbit_alarm,
                    [{description, "alarm handler"},
diff --git a/src/rabbit_control.erl b/src/rabbit_control.erl
index 6f564b1d..f2f29169 100644
--- a/src/rabbit_control.erl
+++ b/src/rabbit_control.erl
@@ -46,6 +46,7 @@
 -spec(stop/0 :: () -> 'ok').
 -spec(action/4 :: (atom(), erlang_node(), [string()],
                    fun ((string(), [any()]) -> 'ok')) -> 'ok').
+-spec(usage/0 :: () -> no_return()).
 
 -endif.
 
@@ -129,8 +130,8 @@ parse_args([], _) ->
 stop() ->
     ok.
 
-usage() -> 
-    rabbitmqctl_usage:usage().
+usage() ->
+    rabbit_ctl_usage:usage().
 
 action(stop, Node, [], Inform) ->
     Inform("Stopping and halting node ~p", [Node]),
diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index 9abc1695..81cecb38 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -307,7 +307,7 @@ execute_mnesia_transaction(TxFun) ->
     %% Making this a sync_transaction allows us to use dirty_read
     %% elsewhere and get a consistent result even when that read
     %% executes on a different node.
-    case mnesia:sync_transaction(TxFun) of
+    case worker_pool:submit({mnesia, sync_transaction, [TxFun]}) of
         {atomic,  Result} -> Result;
         {aborted, Reason} -> throw({error, Reason})
     end.
diff --git a/src/rabbit_multi.erl b/src/rabbit_multi.erl
index bc04357b..9ff2c5cb 100644
--- a/src/rabbit_multi.erl
+++ b/src/rabbit_multi.erl
@@ -42,6 +42,7 @@
 
 -spec(start/0 :: () -> no_return()).
 -spec(stop/0 :: () -> 'ok').
+-spec(usage/0 :: () -> no_return()).
 
 -endif.
 
@@ -85,8 +86,8 @@ parse_args([Command | Args]) ->
 stop() ->
     ok.
 
-usage() -> 
-    rabbitmqmulti_usage:usage().
+usage() ->
+    rabbit_multi_usage:usage().
 
 action(start_all, [NodeCount], RpcTimeout) ->
     io:format("Starting all nodes...~n", []),
diff --git a/src/worker_pool.erl b/src/worker_pool.erl
new file mode 100644
index 00000000..b883d4f0
--- /dev/null
+++ b/src/worker_pool.erl
@@ -0,0 +1,135 @@
+%%   The contents of this file are subject to the Mozilla Public License
+%%   Version 1.1 (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.mozilla.org/MPL/
+%%
+%%   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.
+%%
+%%   The Original Code is RabbitMQ.
+%%
+%%   The Initial Developers of the Original Code are LShift Ltd,
+%%   Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
+%%   Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
+%%   are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
+%%   Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
+%%   Ltd. Portions created by Cohesive Financial Technologies LLC are
+%%   Copyright (C) 2007-2010 Cohesive Financial Technologies
+%%   LLC. Portions created by Rabbit Technologies Ltd are Copyright
+%%   (C) 2007-2010 Rabbit Technologies Ltd.
+%%
+%%   All Rights Reserved.
+%%
+%%   Contributor(s): ______________________________________.
+%%
+
+-module(worker_pool).
+
+%% Generic worker pool manager.
+%%
+%% Supports nested submission of jobs (nested jobs always run
+%% immediately in current worker process).
+%%
+%% Possible future enhancements:
+%%
+%% 1. Allow priorities (basically, change the pending queue to a
+%% priority_queue).
+%%
+%% 2. Allow the submission to the pool_worker to be async.
+
+-behaviour(gen_server2).
+
+-export([start_link/0, submit/1, idle/1]).
+
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
+         terminate/2, code_change/3]).
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-spec(start_link/0 :: () -> {'ok', pid()} | 'ignore' | {'error', any()}).
+-spec(submit/1 :: (fun (() -> A) | {atom(), atom(), [any()]}) -> A).
+
+-endif.
+
+%%----------------------------------------------------------------------------
+
+-define(SERVER, ?MODULE).
+-define(HIBERNATE_AFTER_MIN, 1000).
+-define(DESIRED_HIBERNATE, 10000).
+
+-record(state, { available, pending }).
+
+%%----------------------------------------------------------------------------
+
+start_link() ->
+    gen_server2:start_link({local, ?SERVER}, ?MODULE, [],
+                           [{timeout, infinity}]).
+
+submit(Fun) ->
+    case get(worker_pool_worker) of
+        true -> worker_pool_worker:run(Fun);
+        _    -> Pid = gen_server2:call(?SERVER, next_free, infinity),
+                worker_pool_worker:submit(Pid, Fun)
+    end.
+
+idle(WId) ->
+    gen_server2:cast(?SERVER, {idle, WId}).
+
+%%----------------------------------------------------------------------------
+
+init([]) ->
+    {ok, #state { pending = queue:new(), available = queue:new() }, hibernate,
+     {backoff, ?HIBERNATE_AFTER_MIN, ?HIBERNATE_AFTER_MIN, ?DESIRED_HIBERNATE}}.
+
+handle_call(next_free, From, State = #state { available = Avail,
+                                              pending = Pending }) ->
+    case queue:out(Avail) of
+        {empty, _Avail} ->
+            {noreply, State #state { pending = queue:in(From, Pending) }};
+        {{value, WId}, Avail1} ->
+            {reply, get_worker_pid(WId), State #state { available = Avail1 }}
+    end;
+
+handle_call(Msg, _From, State) ->
+    {stop, {unexpected_call, Msg}, State}.
+
+handle_cast({idle, WId}, State = #state { available = Avail,
+                                          pending = Pending }) ->
+    {noreply, case queue:out(Pending) of
+                  {empty, _Pending} ->
+                      State #state { available = queue:in(WId, Avail) };
+                  {{value, From}, Pending1} ->
+                      gen_server2:reply(From, get_worker_pid(WId)),
+                      State #state { pending = Pending1 }
+              end};
+
+handle_cast(Msg, State) ->
+    {stop, {unexpected_cast, Msg}, State}.
+
+handle_info(Msg, State) ->
+    {stop, {unexpected_info, Msg}, State}.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+terminate(_Reason, State) ->
+    State.
+
+%%----------------------------------------------------------------------------
+
+get_worker_pid(WId) ->
+    [{WId, Pid, _Type, _Modules} | _] =
+        lists:dropwhile(fun ({Id, _Pid, _Type, _Modules})
+                              when Id =:= WId -> false;
+                            (_)               -> true
+                        end,
+                        supervisor:which_children(worker_pool_sup)),
+    Pid.
diff --git a/src/worker_pool_sup.erl b/src/worker_pool_sup.erl
new file mode 100644
index 00000000..4ded63a8
--- /dev/null
+++ b/src/worker_pool_sup.erl
@@ -0,0 +1,69 @@
+%%   The contents of this file are subject to the Mozilla Public License
+%%   Version 1.1 (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.mozilla.org/MPL/
+%%
+%%   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.
+%%
+%%   The Original Code is RabbitMQ.
+%%
+%%   The Initial Developers of the Original Code are LShift Ltd,
+%%   Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
+%%   Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
+%%   are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
+%%   Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
+%%   Ltd. Portions created by Cohesive Financial Technologies LLC are
+%%   Copyright (C) 2007-2010 Cohesive Financial Technologies
+%%   LLC. Portions created by Rabbit Technologies Ltd are Copyright
+%%   (C) 2007-2010 Rabbit Technologies Ltd.
+%%
+%%   All Rights Reserved.
+%%
+%%   Contributor(s): ______________________________________.
+%%
+
+-module(worker_pool_sup).
+
+-behaviour(supervisor).
+
+-export([start_link/0, start_link/1]).
+
+-export([init/1]).
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-spec(start_link/0 :: () -> {'ok', pid()} | 'ignore' | {'error', any()}).
+-spec(start_link/1 ::
+        (non_neg_integer()) -> {'ok', pid()} | 'ignore' | {'error', any()}).
+
+-endif.
+
+%%----------------------------------------------------------------------------
+
+-define(SERVER, ?MODULE).
+
+%%----------------------------------------------------------------------------
+
+start_link() ->
+    start_link(erlang:system_info(schedulers)).
+
+start_link(WCount) ->
+    supervisor:start_link({local, ?SERVER}, ?MODULE, [WCount]).
+
+%%----------------------------------------------------------------------------
+
+init([WCount]) ->
+    {ok, {{one_for_one, 10, 10},
+          [{worker_pool, {worker_pool, start_link, []}, transient,
+            16#ffffffff, worker, [worker_pool]} |
+           [{N, {worker_pool_worker, start_link, [N]}, transient, 16#ffffffff,
+             worker, [worker_pool_worker]} || N <- lists:seq(1, WCount)]]}}.
diff --git a/src/worker_pool_worker.erl b/src/worker_pool_worker.erl
new file mode 100644
index 00000000..fc3ce371
--- /dev/null
+++ b/src/worker_pool_worker.erl
@@ -0,0 +1,94 @@
+%%   The contents of this file are subject to the Mozilla Public License
+%%   Version 1.1 (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.mozilla.org/MPL/
+%%
+%%   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.
+%%
+%%   The Original Code is RabbitMQ.
+%%
+%%   The Initial Developers of the Original Code are LShift Ltd,
+%%   Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
+%%   Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
+%%   are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
+%%   Technologies LLC, and Rabbit Technologies Ltd.
+%%
+%%   Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
+%%   Ltd. Portions created by Cohesive Financial Technologies LLC are
+%%   Copyright (C) 2007-2010 Cohesive Financial Technologies
+%%   LLC. Portions created by Rabbit Technologies Ltd are Copyright
+%%   (C) 2007-2010 Rabbit Technologies Ltd.
+%%
+%%   All Rights Reserved.
+%%
+%%   Contributor(s): ______________________________________.
+%%
+
+-module(worker_pool_worker).
+
+-behaviour(gen_server2).
+
+-export([start_link/1, submit/2, run/1]).
+
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
+         terminate/2, code_change/3]).
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-spec(start_link/1 :: (any()) -> {'ok', pid()} | 'ignore' | {'error', any()}).
+-spec(submit/2 :: (pid(), fun (() -> A) | {atom(), atom(), [any()]}) -> A).
+
+-endif.
+
+%%----------------------------------------------------------------------------
+
+-define(HIBERNATE_AFTER_MIN, 1000).
+-define(DESIRED_HIBERNATE, 10000).
+
+%%----------------------------------------------------------------------------
+
+start_link(WId) ->
+    gen_server2:start_link(?MODULE, [WId], [{timeout, infinity}]).
+
+submit(Pid, Fun) ->
+    gen_server2:call(Pid, {submit, Fun}, infinity).
+
+init([WId]) ->
+    ok = worker_pool:idle(WId),
+    put(worker_pool_worker, true),
+    {ok, WId, hibernate,
+     {backoff, ?HIBERNATE_AFTER_MIN, ?HIBERNATE_AFTER_MIN, ?DESIRED_HIBERNATE}}.
+
+handle_call({submit, Fun}, From, WId) ->
+    gen_server2:reply(From, run(Fun)),
+    ok = worker_pool:idle(WId),
+    {noreply, WId};
+
+handle_call(Msg, _From, State) ->
+    {stop, {unexpected_call, Msg}, State}.
+
+handle_cast(Msg, State) ->
+    {stop, {unexpected_cast, Msg}, State}.
+
+handle_info(Msg, State) ->
+    {stop, {unexpected_info, Msg}, State}.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+terminate(_Reason, State) ->
+    State.
+
+%%----------------------------------------------------------------------------
+
+run({M, F, A}) ->
+    apply(M, F, A);
+run(Fun) ->
+    Fun().