Network.Wai.Handler.Warp.Systemd

This modules provides function that help start the Warp web server using systemd's socket activation feature.

Documentation

runSystemdWarp

Arguments

:: SystemdSettings

-> Settings

Web server settings

-> Application

Web application

-> IO ()

Run a web application, see SystemdSettings for details.

Note that Warp itself has some Settings settings related to the server process lifecycle, such as setInstallShutdownHandler. However, you do not have to include a ready notification using setBeforeMainloop, because runSystemdWarp does this for you.

Settings

data SystemdSettings

Warp-systemd integration settings. See the lenses in this module for details.

Note that Warp itself has some settings related to the server process lifecycle, for example setInstallShutdownHandler.

defaultSystemdSettings :: SystemdSettings

Default settings. See the lenses in this module for details.

logInfo :: Lens' SystemdSettings (String -> IO ())

How to log an info message.

Default: hPutStrLn stderr

setLogInfo :: (String -> IO ()) -> SystemdSettings -> SystemdSettings

See logInfo

logWarn :: Lens' SystemdSettings (String -> IO ())

How to log an info message.

Default: hPutStrLn stderr . ("WARNING: " ++)

setLogWarn :: (String -> IO ()) -> SystemdSettings -> SystemdSettings

See logWarn

requireSocketActivation :: Lens' SystemdSettings Bool

If True, runSystemdWarp throw a SocketActivationException if the server is started without socket activation.

Default: False (continue)

setRequireSocketActivation :: Bool -> SystemdSettings -> SystemdSettings

See requireSocketActivation

heartbeatInterval :: Lens' SystemdSettings (Maybe Int)

If Just n, runSystemdWarp emits a heartbeat notification to systemd every n seconds.

Default: Nothing

setHeartbeatInterval :: Maybe Int -> SystemdSettings -> SystemdSettings

See heartbeatInterval

heartbeatCheck :: Lens' SystemdSettings (IO ())

Run an action before emitting a hearbeat and if it throws an exception, print a warning and skip systemd notification.

Default: return ()

setHeartbeatCheck :: IO () -> SystemdSettings -> SystemdSettings

See heartbeatCheck

onBeginShutdown :: Lens' SystemdSettings (IO ())

Action to run on shutdown. This will be called when a shutdown signal has been received from systemd and the listening socket has been closed. This means that no new incoming requests will be received, but previous requests are still being processed.

Control flow should return to the caller of runSystemdWarp when all requests have been handled.

Default: 'return ()'

setOnBeginShutdown :: IO () -> SystemdSettings -> SystemdSettings

See onBeginShutdown

Low-level Settings

dontOverrideInstallShutdownHandler :: Lens' SystemdSettings Bool

If True, do not override Settings' with setInstallShutdownHandler. This lets you provide your own shutdown handler functionality. Enabling this setting will cause the default installShutdownHandler to not be set, with the effect of preventing the onBeginShutdown action and preventing the systemd ‘stopping’ notification.

Default: Nothing

setDontOverrideInstallShutdownHandler :: Bool -> SystemdSettings -> SystemdSettings

See dontOverrideInstallShutdownHandler

Exceptions

data SocketActivationException

These only occur during startup.

Constructors

SocketActivationException String

Instances

Show SocketActivationException

Defined in Network.Wai.Handler.Warp.Systemd

Methods

showsPrec :: Int -> SocketActivationException -> ShowS

show :: SocketActivationException -> String

showList :: [SocketActivationException] -> ShowS

Exception SocketActivationException

Defined in Network.Wai.Handler.Warp.Systemd

Methods

toException :: SocketActivationException -> SomeException

fromException :: SomeException -> Maybe SocketActivationException

displayException :: SocketActivationException -> String