From cb87439e7d29ef133151e55845a73f4fbaabc83a Mon Sep 17 00:00:00 2001
From: Jonathan Knowles <jonathan.knowles@iohk.io>
Date: Thu, 20 Aug 2020 04:16:24 +0000
Subject: [PATCH] Use `contramap` to simplify nested tracing.

---
 lib/core/src/Cardano/Pool/DB/Sqlite.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/core/src/Cardano/Pool/DB/Sqlite.hs b/lib/core/src/Cardano/Pool/DB/Sqlite.hs
index d4a52f530d1..13b9e3d0d27 100644
--- a/lib/core/src/Cardano/Pool/DB/Sqlite.hs
+++ b/lib/core/src/Cardano/Pool/DB/Sqlite.hs
@@ -75,7 +75,7 @@ import Control.Monad.IO.Class
 import Control.Monad.Trans.Except
     ( ExceptT (..) )
 import Control.Tracer
-    ( Tracer (..), traceWith )
+    ( Tracer, contramap, traceWith )
 import Data.Either
     ( rights )
 import Data.Generics.Internal.VL.Lens
@@ -183,7 +183,7 @@ newDBLayer trace fp timeInterpreter = do
     let io = startSqliteBackend
             (migrateManually trace)
             migrateAll
-            (Tracer $ traceWith trace . MsgGeneric)
+            (contramap MsgGeneric trace)
             fp
     ctx@SqliteContext{runQuery} <- handlingPersistError trace fp io
     return (ctx, DBLayer