ENH be more precise when logging child processes

bin/xmonad.hs

@@ -208,6 +208,7 @@ withXmobar = bracket startXmobar stopXmobar
 
 startXmobar :: FIO (Process Handle () ())
 startXmobar = do
+  logInfo "starting xmobar child process"
   p <- proc "xmobar" [] start
   io $ hSetBuffering (getStdin p) LineBuffering
   return p
@@ -225,19 +226,35 @@ stopXmobar p = do
   logInfo "stopping xmobar child process"
   io $ killNoWait p
 
-withChildDaemons :: FeatureSet -> ([Process () () ()] -> FIO a) -> FIO a
+withChildDaemons
+  :: FeatureSet
+  -> ([(Utf8Builder, Process () () ())] -> FIO a)
+  -> FIO a
 withChildDaemons fs = bracket (startChildDaemons fs) stopChildDaemons
 
-startChildDaemons :: FeatureSet -> FIO [Process () () ()]
-startChildDaemons fs = catMaybes <$> mapM executeSometimes (fsDaemons fs)
+startChildDaemons :: FeatureSet -> FIO [(Utf8Builder, Process () () ())]
+startChildDaemons fs = catMaybes <$> mapM start (fsDaemons fs)
+  where
+    start s@(Sometimes sname _ _) = do
+      let sname_ = Utf8Builder $ encodeUtf8Builder sname
+      res <- executeSometimes s
+      case res of
+        Just p -> do
+          logInfo $ "starting child process: " <> sname_
+          return $ Just (sname_, p)
+        -- don't log anything here since presumably the feature itself will log
+        -- an error if it fails during execution
+        _ -> return Nothing
 
 stopChildDaemons
   :: (MonadReader env m, HasLogFunc env, MonadUnliftIO m)
-  => [Process () () ()]
+  => [(Utf8Builder, Process () () ())]
   -> m ()
-stopChildDaemons ps = do
-  logInfo "stopping child processes"
-  mapM_ (liftIO . killNoWait) ps
+stopChildDaemons = mapM_ stop
+  where
+    stop (n, p) = do
+      logInfo $ "stopping child process: " <> n
+      liftIO $ killNoWait p
 
 printDeps :: FIO ()
 printDeps = withDBus_ $ \db -> do
@@ -267,7 +284,7 @@ printDeps = withDBus_ $ \db -> do
 -- Concurrency configuration
 
 data Cleanup = Cleanup
-  { clChildren :: [Process () () ()]
+  { clChildren :: [(Utf8Builder, Process () () ())]
   , clXmobar :: Maybe (Process Handle () ())
   , clDBusUnexporters :: [FIO ()]
   }