Safe Haskell	None
Language	Haskell2010

Control.Eff.Concurrent.Protocol.Watchdog

Description

Monitor a process and act when it is unresponsive.

Behaviour of the watchdog:

When a child crashes: * if the allowed maximum number crashes per time span has been reached for the process, ** cancel all other timers ** don't start the child again ** if this is a permanent watchdog crash the watchdog * otherwise ** tell the broker to start the child ** record a crash and start a timer to remove the record later ** monitor the child

When a child crash timer elapses: * remove the crash record

Since: 0.30.0

Synopsis

startLink :: forall child e q. (HasCallStack, Typeable child, FilteredLogging (Processes q), Member Logs q, HasProcesses e q, Tangible (ChildId child), Ord (ChildId child), HasPdu (ServerPdu child), Lifted IO q) => CrashRate -> Eff e (Endpoint (Watchdog child))
data Watchdog (child :: Type)
attachTemporary :: forall child q e. (HasCallStack, FilteredLogging e, Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), HasProcesses e q) => Endpoint (Watchdog child) -> Endpoint (Broker child) -> Eff e ()
attachPermanent :: forall child q e. (HasCallStack, FilteredLogging e, Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), HasProcesses e q) => Endpoint (Watchdog child) -> Endpoint (Broker child) -> Eff e ()
getCrashReports :: forall child q e. (HasCallStack, FilteredLogging e, Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), HasProcesses e q, Lifted IO q, Lifted IO e, Member Logs e) => Endpoint (Watchdog child) -> Eff e (Map (ChildId child) (ChildWatch child))
data CrashRate = CrashesPerSeconds {
- _crashCount :: CrashCount
- _crashTimeSpan :: CrashTimeSpan
}
crashCount :: Lens' CrashRate CrashCount
crashTimeSpan :: Lens' CrashRate CrashTimeSpan
crashesPerSeconds :: CrashCount -> CrashTimeSpan -> CrashRate
type CrashCount = Int
type CrashTimeSpan = Int
data ChildWatch child = MkChildWatch {
- _parent :: Endpoint (Broker child)
- _crashes :: Set (CrashReport (ChildId child))
}
parent :: Lens' (ChildWatch child) (Endpoint (Broker child))
crashes :: Lens' (ChildWatch child) (Set (CrashReport (ChildId child)))
data ExonerationTimer a = MkExonerationTimer !a !TimerReference
data CrashReport a = MkCrashReport {
}
crashTime :: Lens' (CrashReport a) UTCTime
crashReason :: Lens' (CrashReport a) (Interrupt NoRecovery)
exonerationTimerReference :: Lens' (CrashReport a) TimerReference

Documentation

startLink :: forall child e q. (HasCallStack, Typeable child, FilteredLogging (Processes q), Member Logs q, HasProcesses e q, Tangible (ChildId child), Ord (ChildId child), HasPdu (ServerPdu child), Lifted IO q) => CrashRate -> Eff e (Endpoint (Watchdog child)) Source #

Start and link a new watchdog process.

The watchdog process will register itself to the ChildEvents and restart crashed children.

Since: 0.30.0

data Watchdog (child :: Type) Source #

The phantom for watchdog processes, that watch the given type of servers

This type is used for the Server and HasPdu instances.

Since: 0.30.0

Instances

(Show (ChildId child), Typeable (ChildId child), Typeable child) => Show (Model (Watchdog child)) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods showsPrec :: Int -> Model (Watchdog child) -> ShowS # show :: Model (Watchdog child) -> String # showList :: [Model (Watchdog child)] -> ShowS #
Default (Model (Watchdog child)) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods def :: Model (Watchdog child) #
Typeable child => HasPdu (Watchdog child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Associated Types type EmbeddedPduList (Watchdog child) :: [Type] Source # data Pdu (Watchdog child) reply :: Type Source #
(Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), Eq (ChildId child), Lifted IO e, Member Logs e) => Server (Watchdog child) (Processes e) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Associated Types data StartArgument (Watchdog child) :: Type Source # type Protocol (Watchdog child) :: Type Source # data Model (Watchdog child) :: Type Source # type Settings (Watchdog child) :: Type Source # Methods title :: StartArgument (Watchdog child) -> ProcessTitle Source # setup :: Endpoint (Protocol (Watchdog child)) -> StartArgument (Watchdog child) -> Eff (Processes e) (Model (Watchdog child), Settings (Watchdog child)) Source # update :: Endpoint (Protocol (Watchdog child)) -> StartArgument (Watchdog child) -> Event (Protocol (Watchdog child)) -> Eff (ModelState (Watchdog child) ': (SettingsReader (Watchdog child) ': Processes e)) () Source #
Typeable child => HasPduPrism (Watchdog child) (Observer (ChildEvent child)) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods embeddedPdu :: Prism' (Pdu (Watchdog child) result) (Pdu (Observer (ChildEvent child)) result) Source # embedPdu :: Pdu (Observer (ChildEvent child)) result -> Pdu (Watchdog child) result Source # fromPdu :: Pdu (Watchdog child) result -> Maybe (Pdu (Observer (ChildEvent child)) result) Source #
(Show (ChildId child), Typeable child, Typeable (ServerPdu child)) => Show (Pdu (Watchdog child) r) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods showsPrec :: Int -> Pdu (Watchdog child) r -> ShowS # show :: Pdu (Watchdog child) r -> String # showList :: [Pdu (Watchdog child) r] -> ShowS #
NFData (ChildId child) => NFData (Pdu (Watchdog child) r) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods rnf :: Pdu (Watchdog child) r -> () #
type EmbeddedPduList (Watchdog child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog type EmbeddedPduList (Watchdog child) = Observer (ChildEvent child) ': ([] :: [Type])
data Pdu (Watchdog child) r Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog data Pdu (Watchdog child) r where Attach :: forall child (r :: Synchronicity). Endpoint (Broker child) -> Bool -> Pdu (Watchdog child) (Synchronous ()) GetCrashReports :: forall child (r :: Synchronicity). Pdu (Watchdog child) (Synchronous (Map (ChildId child) (ChildWatch child))) OnChildEvent :: forall child (r :: Synchronicity). ChildEvent child -> Pdu (Watchdog child) Asynchronous
data StartArgument (Watchdog child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog data StartArgument (Watchdog child) = StartWatchDog { _crashRate :: CrashRate }
type Protocol (Watchdog child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog type Protocol (Watchdog child) = Watchdog child
data Model (Watchdog child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog data Model (Watchdog child) = WatchdogModel { _brokers :: Map (Endpoint (Broker child)) BrokerWatch _watched :: Map (ChildId child) (ChildWatch child) }
type Settings (Watchdog child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog type Settings (Watchdog child) = ()

attachTemporary :: forall child q e. (HasCallStack, FilteredLogging e, Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), HasProcesses e q) => Endpoint (Watchdog child) -> Endpoint (Broker child) -> Eff e () Source #

Restart children of the given broker.

When the broker exits, ignore the children of that broker.

Since: 0.30.0

attachPermanent :: forall child q e. (HasCallStack, FilteredLogging e, Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), HasProcesses e q) => Endpoint (Watchdog child) -> Endpoint (Broker child) -> Eff e () Source #

Restart children of the given broker.

When the broker exits, the watchdog process will exit, too.

Since: 0.30.0

getCrashReports :: forall child q e. (HasCallStack, FilteredLogging e, Typeable child, HasPdu (ServerPdu child), Tangible (ChildId child), Ord (ChildId child), HasProcesses e q, Lifted IO q, Lifted IO e, Member Logs e) => Endpoint (Watchdog child) -> Eff e (Map (ChildId child) (ChildWatch child)) Source #

Return a list of CrashReports.

Useful for diagnostics

Since: 0.30.0

data CrashRate Source #

The limit of crashes (see CrashCount) per time span (see CrashTimeSpan) that justifies restarting child processes.

Used as parameter for startLink.

Use crashesPerSeconds to construct a value.

This governs how long the ExonerationTimer runs before cleaning up a CrashReport in a ChildWatch.

Since: 0.30.0

Constructors

CrashesPerSeconds
Fields _crashCount :: CrashCount _crashTimeSpan :: CrashTimeSpan

Instances

Eq CrashRate Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods (==) :: CrashRate -> CrashRate -> Bool # (/=) :: CrashRate -> CrashRate -> Bool #
Ord CrashRate Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods compare :: CrashRate -> CrashRate -> Ordering # (<) :: CrashRate -> CrashRate -> Bool # (<=) :: CrashRate -> CrashRate -> Bool # (>) :: CrashRate -> CrashRate -> Bool # (>=) :: CrashRate -> CrashRate -> Bool # max :: CrashRate -> CrashRate -> CrashRate # min :: CrashRate -> CrashRate -> CrashRate #
Show CrashRate Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods showsPrec :: Int -> CrashRate -> ShowS # show :: CrashRate -> String # showList :: [CrashRate] -> ShowS #
Default CrashRate Source #	The default is three crashes in 30 seconds. Since: 0.30.0
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods def :: CrashRate #
NFData CrashRate Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods rnf :: CrashRate -> () #

crashCount :: Lens' CrashRate CrashCount Source #

A lens for _crashCount.

Since: 0.30.0

crashTimeSpan :: Lens' CrashRate CrashTimeSpan Source #

A lens for _crashTimeSpan.

Since: 0.30.0

crashesPerSeconds :: CrashCount -> CrashTimeSpan -> CrashRate Source #

A smart constructor for CrashRate.

The first parameter is the number of crashes allowed per number of seconds (second parameter) until the watchdog should give up restarting a child.

Since: 0.30.0

type CrashCount = Int Source #

Number of crashes in CrashRate.

Since: 0.30.0

type CrashTimeSpan = Int Source #

Time span in which crashes are counted in CrashRate.

Since: 0.30.0

data ChildWatch child Source #

An internal data structure that keeps the CrashReports of a child of an attached Broker monitored by a Watchdog.

See attachPermanent and attachTemporary, ExonerationTimer, CrashRate.

Since: 0.30.0

Constructors

MkChildWatch
Fields _parent :: Endpoint (Broker child) The attached `Broker` that started the child _crashes :: Set (CrashReport (ChildId child)) The crashes of the child. If the number of crashes surpasses the allowed number of crashes before the `ExonerationTimer`s clean them, the child is finally crashed.

Instances

(Typeable child, Typeable (ChildId child), Show (ChildId child)) => Show (ChildWatch child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods showsPrec :: Int -> ChildWatch child -> ShowS # show :: ChildWatch child -> String # showList :: [ChildWatch child] -> ShowS #
NFData (ChildWatch child) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods rnf :: ChildWatch child -> () #

parent :: Lens' (ChildWatch child) (Endpoint (Broker child)) Source #

A lens for _parent.

Since: 0.30.0

crashes :: Lens' (ChildWatch child) (Set (CrashReport (ChildId child))) Source #

A lens for _crashes

Since: 0.30.0

data ExonerationTimer a Source #

The timer started based on the CrashRate _crashTimeSpan when a CrashReport is recorded.

After this timer elapses, the Watchdog server will remove the CrashReport from the ChildWatch of that child.

Since: 0.30.0

Constructors

MkExonerationTimer !a !TimerReference

Instances

Eq a => Eq (ExonerationTimer a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods (==) :: ExonerationTimer a -> ExonerationTimer a -> Bool # (/=) :: ExonerationTimer a -> ExonerationTimer a -> Bool #
Ord a => Ord (ExonerationTimer a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods compare :: ExonerationTimer a -> ExonerationTimer a -> Ordering # (<) :: ExonerationTimer a -> ExonerationTimer a -> Bool # (<=) :: ExonerationTimer a -> ExonerationTimer a -> Bool # (>) :: ExonerationTimer a -> ExonerationTimer a -> Bool # (>=) :: ExonerationTimer a -> ExonerationTimer a -> Bool # max :: ExonerationTimer a -> ExonerationTimer a -> ExonerationTimer a # min :: ExonerationTimer a -> ExonerationTimer a -> ExonerationTimer a #
Show a => Show (ExonerationTimer a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods showsPrec :: Int -> ExonerationTimer a -> ShowS # show :: ExonerationTimer a -> String # showList :: [ExonerationTimer a] -> ShowS #
NFData a => NFData (ExonerationTimer a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods rnf :: ExonerationTimer a -> () #

data CrashReport a Source #

An internal data structure that records a single crash of a child of an attached Broker.

See attachPermanent and attachTemporary.

Since: 0.30.0

Constructors

MkCrashReport
Fields _exonerationTimerReference :: TimerReference After a crash, an `ExonerationTimer` according to the `CrashRate` of the `Watchdog` is started, this is the reference _crashTime :: UTCTime Recorded time of the crash _crashReason :: Interrupt NoRecovery Recorded crash reason

Instances

Eq (CrashReport a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods (==) :: CrashReport a -> CrashReport a -> Bool # (/=) :: CrashReport a -> CrashReport a -> Bool #
Ord (CrashReport a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods compare :: CrashReport a -> CrashReport a -> Ordering # (<) :: CrashReport a -> CrashReport a -> Bool # (<=) :: CrashReport a -> CrashReport a -> Bool # (>) :: CrashReport a -> CrashReport a -> Bool # (>=) :: CrashReport a -> CrashReport a -> Bool # max :: CrashReport a -> CrashReport a -> CrashReport a # min :: CrashReport a -> CrashReport a -> CrashReport a #
(Show a, Typeable a) => Show (CrashReport a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods showsPrec :: Int -> CrashReport a -> ShowS # show :: CrashReport a -> String # showList :: [CrashReport a] -> ShowS #
NFData (CrashReport a) Source #
Instance details Defined in Control.Eff.Concurrent.Protocol.Watchdog Methods rnf :: CrashReport a -> () #

crashTime :: Lens' (CrashReport a) UTCTime Source #

Lens for _crashTime

Since: 0.30.0

crashReason :: Lens' (CrashReport a) (Interrupt NoRecovery) Source #

Lens for _crashReason

Since: 0.30.0

exonerationTimerReference :: Lens' (CrashReport a) TimerReference Source #

Lens for _exonerationTimerReference

Since: 0.30.0