From 06bda07db18f7285e0581c090163436ddd25a30e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20K=C5=82eczek?= Date: Sun, 5 Jul 2026 11:42:43 +0200 Subject: [PATCH] refactor: encapsulate how main application liveness check is done This change makes Admin module independent from how liveness check is performed. It moves reachMainApp function to App module and makes Admin.runAdmin, instead of action to get the main socket, take an IO action checking liveness as a parameter. Thanks to this, any change in how liveness check is performed and, more importantly, what data it uses, does not require changing multiple modules (Admin and App). --- src/PostgREST/Admin.hs | 35 +++++++++-------------------------- src/PostgREST/App.hs | 22 +++++++++++++++++++++- 2 files changed, 30 insertions(+), 27 deletions(-) diff --git a/src/PostgREST/Admin.hs b/src/PostgREST/Admin.hs index 585811730..8438a795c 100644 --- a/src/PostgREST/Admin.hs +++ b/src/PostgREST/Admin.hs @@ -7,9 +7,7 @@ import qualified Network.HTTP.Types.Status as HTTP import qualified Network.Wai as Wai import qualified Network.Wai.Handler.Warp as Warp -import Control.Monad.Extra (whenJust) -import Network.Socket hiding (addrFamily) -import Network.Socket.ByteString +import Control.Monad.Extra (whenJust) import PostgREST.AppState (AppState, getConfig) import PostgREST.Config (AppConfig (..)) @@ -23,15 +21,15 @@ import qualified PostgREST.AppState as AppState import qualified Network.Socket as NS import Protolude -runAdmin :: AppState -> Maybe NS.Socket -> IO (Maybe NS.Socket) -> Warp.Settings -> IO () -runAdmin appState maybeAdminSocket getSocketREST settings = do +runAdmin :: AppState -> Maybe NS.Socket -> IO Bool -> Warp.Settings -> IO () +runAdmin appState maybeAdminSocket checkMainAppLive settings = do conf <- getConfig appState whenJust maybeAdminSocket $ \adminSocket -> do address <- resolveSocketToAddress adminSocket void . forkIO $ handle (onError adminSocket) $ Warp.runSettingsSocket (adminServerSettings conf address) adminSocket adminApp where - adminApp = admin appState getSocketREST + adminApp = admin appState checkMainAppLive observer = AppState.getObserver appState adminServerSettings config addr= settings @@ -43,19 +41,19 @@ runAdmin appState maybeAdminSocket getSocketREST settings = do NS.close adminSock -- we close the socket so request doesn't hang -- | PostgREST admin application -admin :: AppState.AppState -> IO (Maybe NS.Socket) -> Wai.Application -admin appState getSocketREST req respond = do - isMainAppReachable <- getSocketREST >>= maybe (pure False) (fmap isRight . reachMainApp) +admin :: AppState.AppState -> IO Bool -> Wai.Application +admin appState checkMainAppLive req respond = do + isMainAppLive <- checkMainAppLive isLoaded <- AppState.isLoaded appState isPending <- AppState.isPending appState case Wai.pathInfo req of ["live"] -> - respond $ Wai.responseLBS (if isMainAppReachable then HTTP.status200 else HTTP.status500) [] mempty + respond $ Wai.responseLBS (if isMainAppLive then HTTP.status200 else HTTP.status500) [] mempty ["ready"] -> let status | isPending = HTTP.status503 - | not isMainAppReachable = HTTP.status500 + | not isMainAppLive = HTTP.status500 | isLoaded = HTTP.status200 | otherwise = HTTP.status500 in @@ -68,18 +66,3 @@ admin appState getSocketREST req respond = do respond $ Wai.responseLBS HTTP.status200 [toContentType MTTextPlain] mets -- Content-Type is required for prometheus compliance _ -> respond $ Wai.responseLBS HTTP.status404 [] mempty - --- Try to connect to the main app socket --- Note that it doesn't even send a valid HTTP request, we just want to check that the main app is accepting connections -reachMainApp :: Socket -> IO (Either IOException ()) -reachMainApp appSock = do - sockAddr <- getSocketName appSock - sock <- socket (addrFamily sockAddr) Stream defaultProtocol - try $ do - connect sock sockAddr - withSocketsDo $ bracket (pure sock) close sendEmpty - where - sendEmpty sock = void $ send sock mempty - addrFamily (SockAddrInet _ _) = AF_INET - addrFamily (SockAddrInet6 {}) = AF_INET6 - addrFamily (SockAddrUnix _) = AF_UNIX diff --git a/src/PostgREST/App.hs b/src/PostgREST/App.hs index 5824af899..5ea9179d4 100644 --- a/src/PostgREST/App.hs +++ b/src/PostgREST/App.hs @@ -72,6 +72,7 @@ import qualified Data.Text as T import qualified Network.HTTP.Types as HTTP import Network.HTTP.Types.Header (hVary) import qualified Network.Socket as NS +import Network.Socket.ByteString (send) import PostgREST.Unix (createAndBindDomainSocket) import System.Posix.Types (FileMode) @@ -89,7 +90,7 @@ run appState = do readIORef mainSocketRef >>= foldMap NS.close Unix.installSignalHandlers observer closeSockets (AppState.schemaCacheLoader appState) (AppState.readInDbConfig False appState) - Admin.runAdmin appState adminSocket (readIORef mainSocketRef) (serverSettings conf) + Admin.runAdmin appState adminSocket (checkMainAppLive (readIORef mainSocketRef)) (serverSettings conf) Listener.runListener appState @@ -291,3 +292,22 @@ initAdminServerSocket AppConfig{..} = initSocket configAdminServerUnixSocket configAdminServerUnixSocketMode configAdminServerHost configAdminServerPort + +checkMainAppLive :: IO (Maybe NS.Socket) -> IO Bool +checkMainAppLive getMainSocket = + getMainSocket >>= maybe (pure False) (fmap isRight . reachMainApp) + +-- Try to connect to the main app socket +-- Note that it doesn't even send a valid HTTP request, we just want to check that the main app is accepting connections +reachMainApp :: NS.Socket -> IO (Either IOException ()) +reachMainApp appSock = do + sockAddr <- NS.getSocketName appSock + sock <- NS.socket (addrFamily sockAddr) NS.Stream NS.defaultProtocol + try $ do + NS.connect sock sockAddr + NS.withSocketsDo $ bracket (pure sock) NS.close sendEmpty + where + sendEmpty sock = void $ send sock mempty + addrFamily (NS.SockAddrInet _ _) = NS.AF_INET + addrFamily (NS.SockAddrInet6 {}) = NS.AF_INET6 + addrFamily (NS.SockAddrUnix _) = NS.AF_UNIX