Prod.Healthcheck

Documentation

type Host = Text

type Port = Int

type Error = Text

data Track

Constructors

HealthCheckStarted Host Port

HealthCheckFinished Host Port Check

BackgroundTrack Host Port (Track CheckSummary)

Instances

Show Track

Defined in Prod.Healthcheck

Methods

showsPrec :: Int -> Track -> ShowS

show :: Track -> String

showList :: [Track] -> ShowS

data Check

Constructors

Success UTCTime Readiness

Failed UTCTime Error

Instances

FromJSON Check

Defined in Prod.Healthcheck

Methods

parseJSON :: Value -> Parser Check

parseJSONList :: Value -> Parser [Check]

omittedField :: Maybe Check

ToJSON Check

Defined in Prod.Healthcheck

Methods

toJSON :: Check -> Value

toEncoding :: Check -> Encoding

toJSONList :: [Check] -> Value

toEncodingList :: [Check] -> Encoding

omitField :: Check -> Bool

Generic Check

Defined in Prod.Healthcheck

Associated Types

type Rep Check :: Type -> Type

Methods

from :: Check -> Rep Check x

to :: Rep Check x -> Check

Show Check

Defined in Prod.Healthcheck

Methods

showsPrec :: Int -> Check -> ShowS

show :: Check -> String

showList :: [Check] -> ShowS

type Rep Check

Defined in Prod.Healthcheck

type Rep Check = D1 ('MetaData "Check" "Prod.Healthcheck" "prodapi-0.1.0.0-JQUOoBQvqFbCBOZ6p0aEZ7" 'False) (C1 ('MetaCons "Success" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 UTCTime) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Readiness)) :+: C1 ('MetaCons "Failed" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 UTCTime) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Error)))

resultTime :: Check -> UTCTime

isSuccess :: Check -> Bool

getReadiness :: ClientM Readiness

check :: Manager -> Host -> Port -> IO (Either Error Check)

data CheckSummary

Constructors

CheckSummary

Fields

• lastReady :: Maybe Check
• recentChecks :: [Either Error Check]

Instances

FromJSON CheckSummary

Defined in Prod.Healthcheck

Methods

parseJSON :: Value -> Parser CheckSummary

parseJSONList :: Value -> Parser [CheckSummary]

omittedField :: Maybe CheckSummary

ToJSON CheckSummary

Defined in Prod.Healthcheck

Methods

toJSON :: CheckSummary -> Value

toEncoding :: CheckSummary -> Encoding

toJSONList :: [CheckSummary] -> Value

toEncodingList :: [CheckSummary] -> Encoding

omitField :: CheckSummary -> Bool

Generic CheckSummary

Defined in Prod.Healthcheck

Associated Types

type Rep CheckSummary :: Type -> Type

Methods

from :: CheckSummary -> Rep CheckSummary x

to :: Rep CheckSummary x -> CheckSummary

Show CheckSummary

Defined in Prod.Healthcheck

Methods

showsPrec :: Int -> CheckSummary -> ShowS

show :: CheckSummary -> String

showList :: [CheckSummary] -> ShowS

type Rep CheckSummary

Defined in Prod.Healthcheck

type Rep CheckSummary = D1 ('MetaData "CheckSummary" "Prod.Healthcheck" "prodapi-0.1.0.0-JQUOoBQvqFbCBOZ6p0aEZ7" 'False) (C1 ('MetaCons "CheckSummary" 'PrefixI 'True) (S1 ('MetaSel ('Just "lastReady") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (Maybe Check)) :*: S1 ('MetaSel ('Just "recentChecks") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Either Error Check])))

healthChecked :: CheckSummary -> Bool

Predicate to tell if a Summary contains a long-enough check history to be considered.

neverHealthy :: CheckSummary -> Bool

Predicate to tell if a Summary contains no recent successful healthcheck.

recentlyHealthy :: CheckSummary -> Bool

Predicate to tell if the most recent summary exists and is successful.

emptyCheckSummary :: CheckSummary

updateSummary :: Either Error Check -> CheckSummary -> CheckSummary

type CheckMap = Map (Host, Port) (BackgroundVal CheckSummary)

emptyCheckMap :: CheckMap

initBackgroundCheck :: SpaceCounters -> Manager -> Tracer IO (Track CheckSummary) -> (Host, Port) -> IO (BackgroundVal CheckSummary)

terminateBackgroundCheck :: BackgroundVal CheckSummary -> IO ()

data Space

Constructors

Space

Fields

• spacehttpManager :: Manager
• backgroundChecks :: IORef CheckMap
• requestCheck :: (Host, Port) -> IO (BackgroundVal CheckSummary)
• cancelCheck :: (Host, Port) -> IO ()

clearSpace :: Space -> IO ()

data Counters

Constructors

Counters

Fields

• healthcheck_added :: !(Vector Text Counter)
• healthcheck_removed :: !(Vector Text Counter)
• healthcheck_count :: !(Vector Text Counter)

newCounters :: IO Counters

type WithSpaceCounter = (Counter -> IO ()) -> IO ()

data SpaceCounters

Constructors

SpaceCounters

Fields

• ns_healthcheck_added :: WithSpaceCounter
• ns_healthcheck_removed :: WithSpaceCounter
• ns_healthcheck_count :: WithSpaceCounter

namespaceCounters :: Namespace -> Counters -> SpaceCounters

initSpace :: SpaceCounters -> Manager -> Tracer IO Track -> IO Space

setChecks :: Space -> [(Host, Port)] -> IO ()

cancelDeadChecks :: Space -> IO ()

setChecksFromDNSDiscovery :: Space -> DNSTrack [(Host, Port)] -> IO ()

Helper to build a Tracer to update hosts to check based on DNS-discovered answers. Note that the DNSTrack only gives Host, so you need to fmap the port.

addChecksFromDNSDiscovery :: Space -> DNSTrack [(Host, Port)] -> IO ()

Same as setChecksFromDNSDiscovery but only adding new checks. You should clear checks of permanently invalid backends.

type SummaryMap = Map (Host, Port) CheckSummary

readCheckMap :: CheckMap -> IO SummaryMap

readBackgroundChecks :: Space -> IO SummaryMap

healthyKeys :: SummaryMap -> [(Host, Port)]

Returns the set of (Host,Port) that are healthy in a given SummaryMap.

Healthiness consists in having the latest healthcheck as healthy.

deadKeys :: SummaryMap -> [(Host, Port)]

Returns the set of (Host,Port) that have no recent successful activity provided there is enough health-checking history.

safeHead :: [a] -> Maybe a

type Namespace = Text

type Namespaced a = (Namespace, a)

data Runtime

Constructors

Runtime

Fields

• counters :: Counters
• httpManager :: Manager
• tracer :: Tracer IO (Namespaced Track)
• spaces :: IORef (Map Namespace Space)

initRuntime :: Tracer IO (Namespaced Track) -> IO Runtime

readSpaces :: Runtime -> IO (Map Namespace SummaryMap)

registerSpace :: Runtime -> Namespace -> IO Space

withSpace :: Runtime -> Namespace -> (Space -> IO a) -> IO a

initRuntimeSpace :: Runtime -> Namespace -> IO Space

Only create a space (no registration).