Resolve #244 Trigger handler to pass request data to flow

trigger/context.go

@@ -25,3 +25,22 @@ func HandlerFromContext(ctx context.Context) (*HandlerInfo, bool) {
 	u, ok := ctx.Value(handlerKey).(*HandlerInfo)
 	return u, ok
 }
+
+// This allows trigger developer to pass request parameters to handler w/o going through output mapper, e.g.,
+//   ctx := trigger.NewContextWithValues(context.Background(), values)
+//   results, err := handler.Handle(ctx, triggerData.ToMap())
+
+type valueKey string
+
+const contextValueKey valueKey = "values"
+
+// NewContextWithValues returns a new Context that carries specified request parameter values
+func NewContextWithValues(ctx context.Context, values map[string]interface{}) context.Context {
+	return context.WithValue(ctx, contextValueKey, values)
+}
+
+// ValuesFromContext extracts request parameters from a context
+func ValuesFromContext(ctx context.Context) (map[string]interface{}, bool) {
+	values, ok := ctx.Value(contextValueKey).(map[string]interface{})
+	return values, ok
+}

trigger/handler.go

@@ -192,6 +192,13 @@ func (h *handlerImpl) Handle(ctx context.Context, triggerData interface{}) (resu
 		inputMap = triggerValues
 	}
 
+	// extract request parameters from trigger context, and make them available in actions
+	if reqParams, ok := ValuesFromContext(ctx); ok {
+		for k, v := range reqParams {
+			inputMap[k] = v
+		}
+	}
+
 	if ioMd := act.act.IOMetadata(); ioMd != nil {
 		for name, tv := range ioMd.Input {
 			if val, ok := inputMap[name]; ok {