Simplify channelHassEval now that the writer owns the flag decision

src/HomeAssistant/Runtime/Bus.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module HomeAssistant.Runtime.Bus
   ( Bus(..)
@@ -31,10 +32,8 @@ import System.IO (stdout)
 import System.Metrics.Counter (inc)
 import Data.UUID (toText)
 import AFRP (Request(..), Event(..))
-import Control.Monad (when)
 import Control.Monad.IO.Class (MonadIO, liftIO)
-import HomeAssistant.Runtime.Flags (Flags, isEnabled)
-import Data.Foldable (forM_)
+import HomeAssistant.Runtime.Flags (Flags)
 
 -- | Shared runtime state: inbound is a broadcast channel (controllers
 -- read from 'dupTChan' copies), outbound queues service calls for the
@@ -71,19 +70,16 @@ recordInbound bus = inc (amTriggersIn (busMetrics bus))
 recordOutbound :: Bus -> IO ()
 recordOutbound bus = inc (amServicesOut (busMetrics bus))
 
-channelHassEval :: (MonadIO m, KatipContext m) => Bus -> HASSEff a -> m a
+channelHassEval :: forall m a. (MonadIO m, KatipContext m) => Bus -> HASSEff a -> m a
 channelHassEval bus = \case
-  CallService req svc -> katipAddContext (sl "traceId" (toText (requestTraceId req))) $ do
-    logFM DebugS (ls $ show svc)
-    enabled <- isEnabled (busFlags bus) (requestHandler req)
-    when enabled $ liftIO $ atomically $ writeTChan (busOutbound bus) (req, svc)
-  CallServices req svcs -> katipAddContext (sl "traceId" (toText (requestTraceId req))) $ forM_ svcs $ \svc -> do
-    logFM DebugS (ls $ show svc)
-    enabled <- isEnabled (busFlags bus) (requestHandler req)
-    when enabled $ liftIO $ atomically $ writeTChan (busOutbound bus) (req, svc)
+  CallService req svc -> emit req svc
+  CallServices req svcs -> mapM_ (emit req) svcs
   Debug x -> logFM DebugS (ls $ show x)
   Trace req x -> katipAddContext (sl "traceId" (toText (requestTraceId req))) $
     logFM InfoS (ls $ show x)
+  where
+    emit :: Request -> Service -> m ()
+    emit req svc = liftIO $ atomically $ writeTChan (busOutbound bus) (req, svc)
 
 newtype CallIdGen = CallIdGen { generateCallId :: IO Int }
 

test/BusSpec.hs

@@ -43,14 +43,15 @@ spec = describe "Bus" $ do
     (_, svc') <- atomically $ readTChan (busOutbound bus)
     svc' `shouldBe` svc
 
-  it "channelHassEval drops CallService when the handler is disabled" $
+  it "channelHassEval writes CallService to the outbound channel even when the handler is disabled" $
     withTestFlagsBus $ \bus -> do
       setEnabled (busFlags bus) "test-handler" False
       let req = Request (UTCTime (toEnum 0) 0) utc nil "test-handler"
           svc = Service "light" "turn_on" Nothing [EntityId "light.test"]
       runKatipContextT (busLogEnv bus) () (Namespace ["test"]) $
         channelHassEval bus (CallService req svc)
-      atomically (isEmptyTChan (busOutbound bus)) `shouldReturn` True
+      (_, svc') <- atomically $ readTChan (busOutbound bus)
+      svc' `shouldBe` svc
 
 
   it "generates unique sequential call ids" $ do