Ensure calling order of plugins during dispatch
If there are multiple plugins providing same service they will be called
in the order they listed in application:get_env(couch_epi, plugins).
diff --git a/README.md b/README.md
index 3f15a62..685d314 100644
--- a/README.md
+++ b/README.md
@@ -96,6 +96,10 @@
Notes:
- `concurrent` is incompatible with `pipe`
+ - if there are multiple plugins providing same service they will be called in the order
+ they listed in application:get_env(couch_epi, plugins)
+ - if the same plugin provides multiple implementations of the same service
+ the order is undefined (fixable)
# couch_epi_plugin behaviour
diff --git a/src/couch_epi_functions.erl b/src/couch_epi_functions.erl
index 34d1a06..ac93739 100644
--- a/src/couch_epi_functions.erl
+++ b/src/couch_epi_functions.erl
@@ -43,6 +43,7 @@
[{M, M:module_info(exports) -- Blacklist} || M <- Modules].
group(KV) ->
- dict:to_list(lists:foldr(fun({K,V}, D) ->
+ Dict = lists:foldr(fun({K,V}, D) ->
dict:append_list(K, V, D)
- end, dict:new(), KV)).
+ end, dict:new(), KV),
+ [{K, lists:reverse(V)} || {K, V} <- dict:to_list(Dict)].
diff --git a/src/couch_epi_plugin.erl b/src/couch_epi_plugin.erl
index 05aa591..718e5fb 100644
--- a/src/couch_epi_plugin.erl
+++ b/src/couch_epi_plugin.erl
@@ -68,7 +68,7 @@
Filtered = filter_by_key(Definitions, Kind, Key),
case group_specs(Filtered) of
[] -> [];
- [{_, Defs}] -> Defs
+ [{_, Defs}] -> lists:reverse(Defs)
end.
notify(Key, OldData, NewData, Specs) ->
diff --git a/test/couch_epi_tests.erl b/test/couch_epi_tests.erl
index fc2daa8..56733b1 100644
--- a/test/couch_epi_tests.erl
+++ b/test/couch_epi_tests.erl
@@ -86,7 +86,7 @@
%% couch_epi_plugin behaviour
%% ------------------------------------------------------------------
-plugin_module([KV, Spec]) ->
+plugin_module([KV, Spec]) when is_tuple(Spec) ->
SpecStr = io_lib:format("~w", [Spec]),
KVStr = "'" ++ atom_to_list(KV) ++ "'",
"
@@ -114,7 +114,7 @@
notify(Key, OldData, Data) ->
couch_epi_tests:notify_cb(Key, OldData, Data, " ++ KVStr ++ ").
";
-plugin_module([KV]) ->
+plugin_module([KV, Provider]) when is_atom(Provider) ->
KVStr = "'" ++ atom_to_list(KV) ++ "'",
"
-compile([export_all]).
@@ -122,13 +122,12 @@
app() -> test_app.
providers() ->
[
- {my_service, provider1},
- {my_service, provider2}
+ {my_service, " ++ atom_to_list(Provider) ++ "}
].
services() ->
[
- {my_service, provider1}
+ {my_service, " ++ atom_to_list(Provider) ++ "}
].
data_providers() ->
@@ -203,7 +202,10 @@
KV = start_state_storage(),
- ok = start_epi([{provider_epi, plugin_module([KV])}]),
+ ok = start_epi([
+ {provider_epi1, plugin_module([KV, provider1])},
+ {provider_epi2, plugin_module([KV, provider2])}
+ ]),
Pid = whereis(couch_epi:get_handle(Key)),
Handle = couch_epi:get_handle(Key),
@@ -285,6 +287,20 @@
}
}.
+epi_providers_order_test_() ->
+ {
+ "epi providers' order test",
+ {
+ foreach,
+ fun() -> setup(functions) end,
+ fun teardown/1,
+ [
+ fun check_providers_order/1
+ ]
+ }
+ }.
+
+
epi_reload_test_() ->
Cases = [
data_file,
@@ -525,6 +541,14 @@
?assertEqual(error, get(Ctx, is_called))
end).
+check_providers_order(#ctx{handle = Handle, kv = KV, key = Key} = Ctx) ->
+ ?_test(begin
+ Result = couch_epi:apply(Handle, Key, inc, [KV, 2], [pipe]),
+ ?assertMatch([KV, 4], Result),
+ Order = [element(2, get(Ctx, K)) || K <- [inc1, inc2]],
+ ?assertEqual(Order, [3, 4]),
+ ok
+ end).
%% ------------------------------------------------------------------
%% Internal Function Definitions
