HG-72: separate generic machine logic from business-specific error handling (#43)

apps/hellgate/src/hg_invoice.erl

@@ -145,10 +145,10 @@ process_callback(Tag, Callback, Context) ->
 %%
 
 get_history(_UserInfo, InvoiceID, Context) ->
-    map_error(hg_machine:get_history(?NS, InvoiceID, opts(Context))).
+    map_history_error(hg_machine:get_history(?NS, InvoiceID, opts(Context))).
 
 get_history(_UserInfo, InvoiceID, AfterID, Limit, Context) ->
-    map_error(hg_machine:get_history(?NS, InvoiceID, AfterID, Limit, opts(Context))).
+    map_history_error(hg_machine:get_history(?NS, InvoiceID, AfterID, Limit, opts(Context))).
 
 get_state(UserInfo, InvoiceID, Context0) ->
     {{History, _LastID}, Context} = get_history(UserInfo, InvoiceID, Context0),
@@ -180,14 +180,26 @@ start(ID, Args, Context) ->
 call(ID, Args, Context) ->
     map_error(hg_machine:call(?NS, {id, ID}, Args, opts(Context))).
 
-map_error({{ok, Result}, Context}) ->
-    {Result, Context};
+map_error({{ok, CallResult}, Context}) ->
+    case CallResult of
+        {ok, Result} ->
+            {Result, Context};
+        {exception, Reason} ->
+            throw({Reason, Context})
+    end;
 map_error({{error, notfound}, Context}) ->
     throw({#payproc_UserInvoiceNotFound{}, Context});
 map_error({{error, Reason}, _Context}) ->
     error(Reason).
 
-map_start_error({ok, Context}) ->
+map_history_error({{ok, Result}, Context}) ->
+    {Result, Context};
+map_history_error({{error, notfound}, Context}) ->
+    throw({#payproc_PartyNotFound{}, Context});
+map_history_error({{error, Reason}, _Context}) ->
+    error(Reason).
+
+map_start_error({{ok, _}, Context}) ->
     {ok, Context};
 map_start_error({{error, Reason}, _Context}) ->
     error(Reason).

apps/hellgate/src/hg_machine.erl

@@ -84,26 +84,21 @@
 %%
 
 -spec start(ns(), id(), term(), opts()) ->
-    {ok | {error, exists}, woody_client:context()}.
+    {{ok, term()} | {error, exists | term()}, woody_client:context()}.
 
 start(Ns, ID, Args, #{client_context := Context0}) ->
     call_automaton('Start', [Ns, ID, wrap_args(Args)], Context0).
 
 -spec call(ns(), ref(), term(), opts()) ->
-    {ok | {ok, term()} | {error, notfound | failed}, woody_client:context()} |
+    {{ok, term()} | {error, notfound | failed}, woody_client:context()} |
     no_return().
 
 call(Ns, Ref, Args, #{client_context := Context0}) ->
     case call_automaton('Call', [Ns, Ref, wrap_args(Args)], Context0) of
-        {Response, Context} when is_binary(Response) ->
+        {{ok, Response}, Context} when is_binary(Response) ->
             % should be specific to a processing interface already
-            case unmarshal_term(Response) of
-                {ok, _} = Ok ->
-                    {Ok, Context};
-                {exception, Exception} ->
-                    throw({Exception, Context})
-            end;
-        {Error = {error, _}, Context} ->
+            {{ok, unmarshal_term(Response)}, Context};
+        {{error, _} = Error, Context} ->
             {Error, Context}
     end.
 
@@ -122,7 +117,7 @@ get_history(Ns, ID, AfterID, Limit, Opts) ->
 get_history(Ns, ID, Range, #{client_context := Context0}) ->
     LastID = #'HistoryRange'.'after',
     case call_automaton('GetHistory', [Ns, {id, ID}, Range], Context0) of
-        {History, Context} when is_list(History) ->
+        {{ok, History}, Context} when is_list(History) ->
             {{ok, unwrap_history(History, LastID)}, Context};
         {Error, Context} ->
             {Error, Context}
@@ -134,7 +129,10 @@ call_automaton(Function, Args, Context0) ->
     % TODO: hg_config module, aware of config entry semantics
     Url = genlib_app:env(hellgate, automaton_service_url),
     Service = {dmsl_state_processing_thrift, 'Automaton'},
-    try woody_client:call(Context0, {Service, Function, Args}, #{url => Url}) catch
+    try
+        {Result, Context1} = woody_client:call(Context0, {Service, Function, Args}, #{url => Url}),
+        {{ok, Result}, Context1}
+    catch
         {{exception, #'MachineAlreadyExists'{}}, Context} ->
             {{error, exists}, Context};
         {{exception, #'MachineNotFound'{}}, Context} ->

apps/hellgate/src/hg_party.erl

@@ -147,14 +147,10 @@ handle_function('GetShopAccountSet', {UserInfo, PartyID, ShopID}, Context0, _Opt
 
 
 get_history(PartyID, Context) ->
-    assert_nonempty_history(
-        map_error(hg_machine:get_history(?NS, PartyID, opts(Context)))
-    ).
+    map_history_error(hg_machine:get_history(?NS, PartyID, opts(Context))).
 
 get_history(PartyID, AfterID, Limit, Context) ->
-    assert_nonempty_history(
-        map_error(hg_machine:get_history(?NS, PartyID, AfterID, Limit, opts(Context)))
-    ).
+    map_history_error(hg_machine:get_history(?NS, PartyID, AfterID, Limit, opts(Context))).
 
 %% TODO remove this hack as soon as machinegun learns to tell the difference between
 %%      nonexsitent machine and empty history
@@ -181,13 +177,25 @@ start(ID, Args, Context) ->
 call(ID, Args, Context) ->
     map_error(hg_machine:call(?NS, {id, ID}, Args, opts(Context))).
 
-map_start_error({ok, Context}) ->
+map_start_error({{ok, _}, Context}) ->
     {ok, Context};
 map_start_error({{error, exists}, Context}) ->
     throw({#payproc_PartyExists{}, Context}).
 
-map_error({{ok, Result}, Context}) ->
-    {Result, Context};
+map_history_error({{ok, Result}, Context}) ->
+    assert_nonempty_history({Result, Context});
+map_history_error({{error, notfound}, Context}) ->
+    throw({#payproc_PartyNotFound{}, Context});
+map_history_error({{error, Reason}, _Context}) ->
+    error(Reason).
+
+map_error({{ok, CallResult}, Context}) ->
+    case CallResult of
+        {ok, Result} ->
+            {Result, Context};
+        {exception, Reason} ->
+            throw({Reason, Context})
+    end;
 map_error({{error, notfound}, Context}) ->
     throw({#payproc_PartyNotFound{}, Context});
 map_error({{error, Reason}, _Context}) ->

apps/hellgate/src/hg_proxy_host_provider.erl

@@ -23,8 +23,13 @@
 handle_function('ProcessCallback', {Tag, Callback}, Context, _) ->
     map_error(hg_invoice:process_callback(Tag, {provider, Callback}, Context)).
 
-map_error({{ok, Result}, Context}) ->
-    {Result, Context};
+map_error({{ok, CallResult}, Context}) ->
+    case CallResult of
+        {ok, Result} ->
+            {Result, Context};
+        {exception, Reason} ->
+            throw({Reason, Context})
+    end;
 map_error({{error, notfound}, Context}) ->
     throw({#'InvalidRequest'{errors = [<<"notfound">>]}, Context});
 map_error({{error, Reason}, _Context}) ->