reorganize couch .erl and driver code into rebar layout

1 files changed, 101 insertions, 0 deletions

diff --git a/apps/couch/src/couch_external_manager.erl b/apps/couch/src/couch_external_manager.erl
new file mode 100644
index 00000000..7e401389
--- /dev/null
+++ b/apps/couch/src/couch_external_manager.erl
@@ -0,0 +1,101 @@
+% 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.
+
+-module(couch_external_manager).
+-behaviour(gen_server).
+
+-export([start_link/0, execute/2, config_change/2]).
+-export([init/1, terminate/2, code_change/3, handle_call/3, handle_cast/2, handle_info/2]).
+
+-include("couch_db.hrl").
+
+start_link() ->
+    gen_server:start_link({local, couch_external_manager},
+        couch_external_manager, [], []).
+
+execute(UrlName, JsonReq) ->
+    Pid = gen_server:call(couch_external_manager, {get, UrlName}),
+    case Pid of
+    {error, Reason} ->
+        Reason;
+    _ ->
+        couch_external_server:execute(Pid, JsonReq)
+    end.
+
+config_change("external", UrlName) ->
+    gen_server:call(couch_external_manager, {config, UrlName}).
+
+% gen_server API
+
+init([]) ->
+    process_flag(trap_exit, true),
+    Handlers = ets:new(couch_external_manager_handlers, [set, private]),
+    couch_config:register(fun config_change/2),
+    {ok, Handlers}.
+
+terminate(_Reason, Handlers) ->
+    ets:foldl(fun({_UrlName, Pid}, nil) ->
+        couch_external_server:stop(Pid),
+        nil
+    end, nil, Handlers),
+    ok.
+
+handle_call({get, UrlName}, _From, Handlers) ->
+    case ets:lookup(Handlers, UrlName) of
+    [] ->
+        case couch_config:get("external", UrlName, nil) of
+        nil ->
+            Msg = lists:flatten(
+                io_lib:format("No server configured for ~p.", [UrlName])),
+            {reply, {error, {unknown_external_server, ?l2b(Msg)}}, Handlers};
+        Command ->
+            {ok, NewPid} = couch_external_server:start_link(UrlName, Command),
+            true = ets:insert(Handlers, {UrlName, NewPid}),
+            {reply, NewPid, Handlers}
+        end;
+    [{UrlName, Pid}] ->
+        {reply, Pid, Handlers}
+    end;
+handle_call({config, UrlName}, _From, Handlers) ->
+    % A newly added handler and a handler that had it's command
+    % changed are treated exactly the same.
+
+    % Shutdown the old handler.
+    case ets:lookup(Handlers, UrlName) of
+    [{UrlName, Pid}] ->
+        couch_external_server:stop(Pid);
+    [] ->
+        ok
+    end,
+    % Wait for next request to boot the handler.
+    {reply, ok, Handlers}.
+
+handle_cast(_Whatever, State) ->
+    {noreply, State}.
+
+handle_info({'EXIT', Pid, normal}, Handlers) ->
+    ?LOG_INFO("EXTERNAL: Server ~p terminated normally", [Pid]),
+    % The process terminated normally without us asking - Remove Pid from the
+    % handlers table so we don't attempt to reuse it
+    ets:match_delete(Handlers, {'_', Pid}),
+    {noreply, Handlers};
+
+handle_info({'EXIT', Pid, Reason}, Handlers) ->
+    ?LOG_INFO("EXTERNAL: Server ~p died. (reason: ~p)", [Pid, Reason]),
+    % Remove Pid from the handlers table so we don't try closing
+    % it a second time in terminate/2.
+    ets:match_delete(Handlers, {'_', Pid}),
+    {stop, normal, Handlers}.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+