Control.Eff.Concurrent.Api.Server

Functions to implement Api servers.

Api Server

serve :: forall a effScheduler. (Servable a, SetMember Process (Process effScheduler) (ServerEff a), Member Interrupts (ServerEff a), HasCallStack) => SchedulerProxy effScheduler -> a -> Eff (ServerEff a) ()

Receive and process incoming requests until the process exits.

spawnServer :: forall a effScheduler eff. (Servable a, ServerEff a ~ InterruptableProcess effScheduler, SetMember Process (Process effScheduler) eff, Member Interrupts eff, HasCallStack) => SchedulerProxy effScheduler -> a -> Eff eff (ServerPids a)

Spawn a new process, that will receive and process incoming requests until the process exits.

spawnServerWithEffects :: forall a effScheduler eff. (Servable a, SetMember Process (Process effScheduler) (ServerEff a), SetMember Process (Process effScheduler) eff, Member Interrupts eff, Member Interrupts (ServerEff a), HasCallStack) => SchedulerProxy effScheduler -> a -> (Eff (ServerEff a) () -> Eff (InterruptableProcess effScheduler) ()) -> Eff eff (ServerPids a)

Spawn a new process, that will receive and process incoming requests until the process exits. Also handle all internal effects.

Api Callbacks

data ApiHandler api eff where

A record of callbacks, handling requests sent to a server Process, all belonging to a specific Api family instance. The values of this type can be serveed or combined via Servable or ServerCallbacks.

Constructors

ApiHandler

Fields

• :: { _castCallback :: Maybe (Api api Asynchronous -> Eff eff ApiServerCmd)

  A cast will not return a result directly. This is used for async methods. This returns an ApiServerCmd to the server loop.

•    , _callCallback :: forall reply. Maybe (Api api (Synchronous reply) -> (reply -> Eff eff ()) -> Eff eff ApiServerCmd)

  A call is a blocking operation, the caller is blocked until this handler calls the reply continuation. This returns an ApiServerCmd to the server loop.

•    , _terminateCallback :: Maybe (ExitReason Recoverable -> Eff eff ())

  This callback is called with Nothing if one of these things happen:

  • the process exits
  • _callCallback or _castCallback return StopApiServer

  If the process exist peacefully the parameter is Nothing, otherwise Just "error message..." if the process exits with an error.

  The default behavior is defined in defaultTermination.

•    } -> ApiHandler api eff

Instances

Default (ApiHandler api eff)

Defined in Control.Eff.Concurrent.Api.Server

Methods

def :: ApiHandler api eff

Typeable a => Servable (ApiHandler a eff)

Defined in Control.Eff.Concurrent.Api.Server

Associated Types

type ServerEff (ApiHandler a eff) :: [Type -> Type]

type ServerPids (ApiHandler a eff) :: Type

Methods

toServerPids :: proxy (ApiHandler a eff) -> ProcessId -> ServerPids (ApiHandler a eff)

toServerCallback :: (Member Interrupts (ServerEff (ApiHandler a eff)), SetMember Process (Process effScheduler) (ServerEff (ApiHandler a eff))) => SchedulerProxy effScheduler -> ApiHandler a eff -> ServerCallback (ServerEff (ApiHandler a eff))

type ServerEff (ApiHandler a eff)

Defined in Control.Eff.Concurrent.Api.Server

type ServerEff (ApiHandler a eff) = eff

type ServerPids (ApiHandler a eff)

Defined in Control.Eff.Concurrent.Api.Server

type ServerPids (ApiHandler a eff) = Server a

castCallback :: forall api eff. Lens' (ApiHandler api eff) (Maybe (Api api Asynchronous -> Eff eff ApiServerCmd))

callCallback :: forall api eff reply. Getter (ApiHandler api eff) (Maybe (Api api (Synchronous reply) -> (reply -> Eff eff ()) -> Eff eff ApiServerCmd))

terminateCallback :: forall api eff. Lens' (ApiHandler api eff) (Maybe (ExitReason Recoverable -> Eff eff ()))

apiHandler :: (Api api Asynchronous -> Eff e ApiServerCmd) -> (forall r. Api api (Synchronous r) -> (r -> Eff e ()) -> Eff e ApiServerCmd) -> (ExitReason Recoverable -> Eff e ()) -> ApiHandler api e

Create an ApiHandler with a _castCallback, a _callCallback and a _terminateCallback implementation.

apiHandlerForever :: (Api api Asynchronous -> Eff e ()) -> (forall r. Api api (Synchronous r) -> (r -> Eff e ()) -> Eff e ()) -> (ExitReason Recoverable -> Eff e ()) -> ApiHandler api e

Like apiHandler but the server will loop until an error is raised or the process exits. The callback actions won't decide wether to stop the server or not, instead the ApiServerCmd HandleNextRequest is used.

castHandler :: (Api api Asynchronous -> Eff eff ApiServerCmd) -> ApiHandler api eff

Create an ApiHandler with only a _castCallback implementation.

castHandlerForever :: (Api api Asynchronous -> Eff eff ()) -> ApiHandler api eff

Like castHandler but the server will loop until an error is raised or the process exits. See apiHandlerForver.

callHandler :: (forall r. Api api (Synchronous r) -> (r -> Eff e ()) -> Eff e ApiServerCmd) -> ApiHandler api e

Create an ApiHandler with only a _callCallback implementation.

callHandlerForever :: (forall r. Api api (Synchronous r) -> (r -> Eff e ()) -> Eff e ()) -> ApiHandler api e

Like callHandler but the server will loop until an error is raised or the process exits. See apiHandlerForver.

castAndCallHandler :: (Api api Asynchronous -> Eff e ApiServerCmd) -> (forall r. Api api (Synchronous r) -> (r -> Eff e ()) -> Eff e ApiServerCmd) -> ApiHandler api e

Create an ApiHandler with only a _castCallback and _callCallback implementation.

castAndCallHandlerForever :: (Api api Asynchronous -> Eff e ()) -> (forall r. Api api (Synchronous r) -> (r -> Eff e ()) -> Eff e ()) -> ApiHandler api e

Like castAndCallHandler but the server will loop until an error is raised or the process exits. See apiHandlerForver.

data ApiServerCmd where

A command to the server loop started e.g. by server or spawnServerWithEffects. Typically returned by an ApiHandler member to indicate if the server should continue or stop.

Constructors

HandleNextRequest :: ApiServerCmd

Tell the server to keep the server loop running

StopApiServer :: ExitReason Recoverable -> ApiServerCmd

Tell the server to exit, this will make serve stop handling requests without exitting the process. _terminateCallback will be invoked with the given optional reason.

Instances

Show ApiServerCmd

Defined in Control.Eff.Concurrent.Api.Server

Methods

showsPrec :: Int -> ApiServerCmd -> ShowS

show :: ApiServerCmd -> String

showList :: [ApiServerCmd] -> ShowS

Generic ApiServerCmd

Defined in Control.Eff.Concurrent.Api.Server

Associated Types

type Rep ApiServerCmd :: Type -> Type

Methods

from :: ApiServerCmd -> Rep ApiServerCmd x

to :: Rep ApiServerCmd x -> ApiServerCmd

NFData ApiServerCmd

Defined in Control.Eff.Concurrent.Api.Server

Methods

rnf :: ApiServerCmd -> ()

type Rep ApiServerCmd

Defined in Control.Eff.Concurrent.Api.Server

type Rep ApiServerCmd = D1 (MetaData "ApiServerCmd" "Control.Eff.Concurrent.Api.Server" "extensible-effects-concurrent-0.13.0-9SIHKBwWVl85L64mvpN8ux" False) (C1 (MetaCons "HandleNextRequest" PrefixI False) (U1 :: Type -> Type) :+: C1 (MetaCons "StopApiServer" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (ExitReason Recoverable))))

unhandledCallError :: forall p x r q. (Typeable p, HasCallStack, SetMember Process (Process q) r, Member Interrupts r) => SchedulerProxy q -> Api p (Synchronous x) -> (x -> Eff r ()) -> Eff r ApiServerCmd

A default handler to use in _callCallback in ApiHandler. It will call raiseError with a nice error message.

unhandledCastError :: forall p r q. (Typeable p, HasCallStack, SetMember Process (Process q) r, Member Interrupts r) => SchedulerProxy q -> Api p Asynchronous -> Eff r ApiServerCmd

A default handler to use in _castCallback in ApiHandler. It will call raiseError with a nice error message.

defaultTermination :: forall q r. (HasCallStack, SetMember Process (Process q) r, Member (Logs LogMessage) r) => SchedulerProxy q -> ExitReason Recoverable -> Eff r ()

Either do nothing, if the error message is Nothing, or call exitWithError with the error message.

Callback Composition

class Servable a where

Helper type class to allow composition of ApiHandler.

Associated Types

type ServerEff a :: [Type -> Type]

The effect of the callbacks

type ServerPids a

The is used to let the spawn function return multiple Server ProcessIds in a type safe way, e.g. for a tuple instance of this class (Server a, Server b)

Methods

toServerPids :: proxy a -> ProcessId -> ServerPids a

The is used to let the spawn function return multiple Server ProcessIds in a type safe way.

toServerCallback :: (Member Interrupts (ServerEff a), SetMember Process (Process effScheduler) (ServerEff a)) => SchedulerProxy effScheduler -> a -> ServerCallback (ServerEff a)

Convert the value to a ServerCallback

Instances

Servable (ServerCallback eff)

Defined in Control.Eff.Concurrent.Api.Server

Associated Types

type ServerEff (ServerCallback eff) :: [Type -> Type]

type ServerPids (ServerCallback eff) :: Type

Methods

toServerPids :: proxy (ServerCallback eff) -> ProcessId -> ServerPids (ServerCallback eff)

toServerCallback :: (Member Interrupts (ServerEff (ServerCallback eff)), SetMember Process (Process effScheduler) (ServerEff (ServerCallback eff))) => SchedulerProxy effScheduler -> ServerCallback eff -> ServerCallback (ServerEff (ServerCallback eff))

(ServerEff a ~ ServerEff b, Servable a, Servable b) => Servable (a, b)

Defined in Control.Eff.Concurrent.Api.Server

Associated Types

type ServerEff (a, b) :: [Type -> Type]

type ServerPids (a, b) :: Type

Methods

toServerPids :: proxy (a, b) -> ProcessId -> ServerPids (a, b)

toServerCallback :: (Member Interrupts (ServerEff (a, b)), SetMember Process (Process effScheduler) (ServerEff (a, b))) => SchedulerProxy effScheduler -> (a, b) -> ServerCallback (ServerEff (a, b))

Typeable a => Servable (ApiHandler a eff)

Defined in Control.Eff.Concurrent.Api.Server

Associated Types

type ServerEff (ApiHandler a eff) :: [Type -> Type]

type ServerPids (ApiHandler a eff) :: Type

Methods

toServerPids :: proxy (ApiHandler a eff) -> ProcessId -> ServerPids (ApiHandler a eff)

toServerCallback :: (Member Interrupts (ServerEff (ApiHandler a eff)), SetMember Process (Process effScheduler) (ServerEff (ApiHandler a eff))) => SchedulerProxy effScheduler -> ApiHandler a eff -> ServerCallback (ServerEff (ApiHandler a eff))

data ServerCallback eff

Building block for composition of ApiHandler. A wrapper for ApiHandler. Use this to combine ApiHandler, allowing a process to implement several Api instances. The termination will be evenly propagated. Create this via e.g. Servable instances To serve multiple apis use <> to combine server callbacks, e.g.

@@ let f = apiHandlerServerCallback px $ ApiHandler ... g = apiHandlerServerCallback px $ ApiHandler ... h = f <> g in serve px h @@

Constructors

ServerCallback

Fields

• _requestHandlerSelector :: MessageSelector (Eff eff ApiServerCmd)
• _terminationHandler :: ExitReason Recoverable -> Eff eff ()

Instances

Semigroup (ServerCallback eff)

Defined in Control.Eff.Concurrent.Api.Server

Methods

(<>) :: ServerCallback eff -> ServerCallback eff -> ServerCallback eff

sconcat :: NonEmpty (ServerCallback eff) -> ServerCallback eff

stimes :: Integral b => b -> ServerCallback eff -> ServerCallback eff

Monoid (ServerCallback eff)

Defined in Control.Eff.Concurrent.Api.Server

Methods

mempty :: ServerCallback eff

mappend :: ServerCallback eff -> ServerCallback eff -> ServerCallback eff

mconcat :: [ServerCallback eff] -> ServerCallback eff

Servable (ServerCallback eff)

Defined in Control.Eff.Concurrent.Api.Server

Associated Types

type ServerEff (ServerCallback eff) :: [Type -> Type]

type ServerPids (ServerCallback eff) :: Type

Methods

toServerPids :: proxy (ServerCallback eff) -> ProcessId -> ServerPids (ServerCallback eff)

toServerCallback :: (Member Interrupts (ServerEff (ServerCallback eff)), SetMember Process (Process effScheduler) (ServerEff (ServerCallback eff))) => SchedulerProxy effScheduler -> ServerCallback eff -> ServerCallback (ServerEff (ServerCallback eff))

type ServerEff (ServerCallback eff)

Defined in Control.Eff.Concurrent.Api.Server

type ServerEff (ServerCallback eff) = eff

type ServerPids (ServerCallback eff)

Defined in Control.Eff.Concurrent.Api.Server

type ServerPids (ServerCallback eff) = ProcessId

requestHandlerSelector :: forall eff. Lens' (ServerCallback eff) (MessageSelector (Eff eff ApiServerCmd))

terminationHandler :: forall eff. Lens' (ServerCallback eff) (ExitReason Recoverable -> Eff eff ())