Control.Eff.Concurrent.Process.SingleThreadedScheduler

A coroutine based, single threaded scheduler for Processes.

Documentation

scheduleM

Arguments

:: Monad m

=> (forall b. Eff r b -> m b)

-> m ()

An that performs a yield w.r.t. the underlying effect r. E.g. if Lift IO is present, this might be: @lift yield.

-> Eff (InterruptableProcess r) a

-> m (Either (ExitReason NoRecovery) a)

Handle the Process effect, as well as all lower effects using an effect handler function.

Execute the main Process and all the other processes spawned by it in the current thread concurrently, using a co-routine based, round-robin scheduler. If a process exits with eg.g exitNormally or exitWithError or is killed by another process Left ... is returned. Otherwise, the result will be wrapped in a Right.

Every time a process _yields_ the effects are evaluated down to the a value of type m (Either String a).

If the evaluator function runs the action down e.g. IO this might improve memory consumption, for long running services, with processes that loop endlessly.

Since: 0.4.0.0

schedulePure :: Eff (InterruptableProcess '[Logs, LogWriterReader PureLogWriter]) a -> Either (ExitReason NoRecovery) a

Like scheduleIO but pure. The yield effect is just return (). schedulePure == runIdentity . scheduleM (Identity . run) (return ())

Since: 0.3.0.2

scheduleIO :: MonadIO m => (forall b. Eff r b -> Eff '[Lift m] b) -> Eff (InterruptableProcess r) a -> m (Either (ExitReason NoRecovery) a)

Invoke scheduleM with lift yield as yield effect. scheduleIO runEff == scheduleM (runLift . runEff) (liftIO yield)

Since: 0.4.0.0

scheduleMonadIOEff :: MonadIO (Eff r) => Eff (InterruptableProcess r) a -> Eff r (Either (ExitReason NoRecovery) a)

Invoke scheduleM with lift yield as yield effect. scheduleMonadIOEff == scheduleM id (liftIO yield)

Since: 0.3.0.2

scheduleIOWithLogging :: HasCallStack => LogWriter IO -> Eff (InterruptableProcess LoggingAndIo) a -> IO (Either (ExitReason NoRecovery) a)

Run processes that have the Logs and the Lift effects. The user must provide a log handler function.

Log messages are evaluated strict.

scheduleIOWithLogging == scheduleIO . withLogging

Since: 0.4.0.0

defaultMainSingleThreaded :: HasCallStack => Eff (InterruptableProcess LoggingAndIo) () -> IO ()

Execute a Process using scheduleM on top of Lift IO and withLogging String effects.