fix: shutdown should wait for in flight requests

Author: mkleczek

CHANGELOG.md

@@ -19,6 +19,10 @@ All notable changes to this project will be documented in this file. From versio
 - Log error when `db-schemas` config contains schema `pg_catalog` or `information_schema` by @taimoorzaeem in #4359
   + Now fails at startup. Prior to this, it failed with `PGRST205` on requests related to these schemas.
 
+### Fixed
+
+- Shutdown should wait for in flight requests by @mkleczek in #4702
+
 ## [14.6] - 2026-03-06
 
 ### Fixed

src/PostgREST/App.hs

@@ -22,6 +22,7 @@ import GHC.IO.Exception (IOErrorType (..))
 import System.IO.Error  (ioeGetErrorType)
 
 import Control.Monad.Except     (liftEither)
+import Control.Monad.Extra      (whenJust)
 import Data.Either.Combinators  (mapLeft, whenLeft)
 import Data.Maybe               (fromJust)
 import Data.String              (IsString (..))
@@ -30,6 +31,7 @@ import Network.Wai.Handler.Warp (defaultSettings, setHost,
                                  setServerName)
 
 import qualified Data.Text.Encoding       as T
+import qualified Network.Socket           as NS
 import qualified Network.Wai              as Wai
 import qualified Network.Wai.Handler.Warp as Warp
 
@@ -72,7 +74,10 @@ run appState = do
   conf@AppConfig{..} <- AppState.getConfig appState
 
   AppState.schemaCacheLoader appState -- Loads the initial SchemaCache
-  Unix.installSignalHandlers (AppState.getMainThreadId appState) (AppState.schemaCacheLoader appState) (AppState.readInDbConfig False appState)
+  let closeSockets = do
+        whenJust (AppState.getSocketAdmin appState) NS.close
+        NS.close $ AppState.getSocketREST appState
+  Unix.installSignalHandlers closeSockets (AppState.schemaCacheLoader appState) (AppState.readInDbConfig False appState)
 
   Listener.runListener appState
 

src/PostgREST/Unix.hs

@@ -18,10 +18,9 @@ import           System.Directory (removeFile)
 import           System.IO.Error  (isDoesNotExistError)
 
 -- | Set signal handlers, only for systems with signals
-installSignalHandlers :: ThreadId -> IO () -> IO () -> IO ()
+installSignalHandlers :: IO () -> IO () -> IO () -> IO ()
 #ifndef mingw32_HOST_OS
-installSignalHandlers tid usr1 usr2 = do
-  let interrupt = throwTo tid UserInterrupt
+installSignalHandlers interrupt usr1 usr2 = do
   install Signals.sigINT interrupt
   install Signals.sigTERM interrupt
   install Signals.sigUSR1 usr1

test/io/test_io.py

@@ -105,7 +105,6 @@ def sleep():
         t.join()
 
 
-@pytest.mark.xfail(reason="Graceful shutdown is currently failing")
 def test_graceful_shutdown_waits_for_in_flight_request(defaultenv):
     "SIGTERM should allow in-flight requests to finish before exiting"