module LaunchDarkly.Server.Events where
import Data.Aeson (ToJSON, Value(..), toJSON, object)
import Data.Text (Text)
import GHC.Natural (Natural)
import GHC.Generics (Generic)
import Data.Generics.Product (HasField', getField, field, setField)
import qualified Data.Text as T
import Control.Concurrent.MVar (MVar, putMVar, swapMVar, newEmptyMVar, newMVar, tryTakeMVar, modifyMVar_)
import qualified Data.HashMap.Strict as HM
import Data.HashMap.Strict (HashMap)
import Data.Time.Clock.POSIX (getPOSIXTime)
import Control.Lens ((&), (%~))
import Data.Maybe (fromMaybe)
import Data.Cache.LRU (LRU, newLRU)
import Control.Monad (when)
import qualified Data.Cache.LRU as LRU
import LaunchDarkly.Server.Config.Internal (ConfigI, shouldSendEvents)
import LaunchDarkly.Server.User.Internal (UserI, userSerializeRedacted)
import LaunchDarkly.Server.Details (EvaluationReason(..))
import LaunchDarkly.Server.Features (Flag)
data ContextKind = ContextKindUser | ContextKindAnonymousUser
deriving (Eq, Show)
instance ToJSON ContextKind where
toJSON contextKind = String $ case contextKind of
ContextKindUser -> "user"
ContextKindAnonymousUser -> "anonymousUser"
userGetContextKind :: UserI -> ContextKind
userGetContextKind user = if (getField @"anonymous" user)
then ContextKindAnonymousUser else ContextKindUser
data EvalEvent = EvalEvent
{ key :: !Text
, variation :: !(Maybe Natural)
, value :: !Value
, defaultValue :: !(Maybe Value)
, version :: !(Maybe Natural)
, prereqOf :: !(Maybe Text)
, reason :: !EvaluationReason
, trackEvents :: !Bool
, forceIncludeReason :: !Bool
, debug :: !Bool
, debugEventsUntilDate :: !(Maybe Natural)
} deriving (Generic, Eq, Show)
data EventState = EventState
{ events :: !(MVar [EventType])
, flush :: !(MVar ())
, summary :: !(MVar (HashMap Text (FlagSummaryContext (HashMap Text CounterContext))))
, startDate :: !(MVar Natural)
, userKeyLRU :: !(MVar (LRU Text ()))
} deriving (Generic)
makeEventState :: ConfigI -> IO EventState
makeEventState config = do
events <- newMVar []
flush <- newEmptyMVar
summary <- newMVar mempty
startDate <- newEmptyMVar
userKeyLRU <- newMVar $ newLRU $ pure $ fromIntegral $ getField @"userKeyLRUCapacity" config
pure EventState{..}
convertFeatures :: HashMap Text (FlagSummaryContext (HashMap Text CounterContext))
-> HashMap Text (FlagSummaryContext [CounterContext])
convertFeatures summary = (flip HM.map) summary $ \context -> context & field @"counters" %~ HM.elems
queueEvent :: ConfigI -> EventState -> EventType -> IO ()
queueEvent config state event = if not (shouldSendEvents config) then pure () else
modifyMVar_ (getField @"events" state) $ \events ->
if length events < fromIntegral (getField @"eventsCapacity" config) then pure (event : events) else pure events
unixMilliseconds :: IO Natural
unixMilliseconds = (round . (* 1000)) <$> getPOSIXTime
makeBaseEvent :: a -> IO (BaseEvent a)
makeBaseEvent child = unixMilliseconds >>= \now -> pure $ BaseEvent { creationDate = now, event = child }
processSummary :: ConfigI -> EventState -> IO ()
processSummary config state = tryTakeMVar (getField @"startDate" state) >>= \case
Nothing -> pure ()
(Just startDate) -> do
endDate <- unixMilliseconds
features <- convertFeatures <$> swapMVar (getField @"summary" state) mempty
makeBaseEvent SummaryEvent {..} >>= queueEvent config state . EventTypeSummary
class EventKind a where
eventKind :: a -> Text
data SummaryEvent = SummaryEvent
{ startDate :: !Natural
, endDate :: !Natural
, features :: !(HashMap Text (FlagSummaryContext [CounterContext]))
} deriving (Generic, Show, ToJSON)
instance EventKind SummaryEvent where
eventKind _ = "summary"
data FlagSummaryContext a = FlagSummaryContext
{ defaultValue :: Maybe Value
, counters :: a
} deriving (Generic, Show)
instance ToJSON a => ToJSON (FlagSummaryContext a) where
toJSON ctx = object $ filter ((/=) Null . snd)
[ ("default", toJSON $ getField @"defaultValue" ctx)
, ("counters", toJSON $ getField @"counters" ctx)
]
data CounterContext = CounterContext
{ count :: !Natural
, version :: !(Maybe Natural)
, variation :: !(Maybe Natural)
, value :: !Value
, unknown :: !Bool
} deriving (Generic, Show, ToJSON)
data IdentifyEvent = IdentifyEvent
{ key :: !Text
, user :: !Value
} deriving (Generic, ToJSON, Show)
instance EventKind IdentifyEvent where
eventKind _ = "identify"
data IndexEvent = IndexEvent { user :: Value } deriving (Generic, ToJSON, Show)
instance EventKind IndexEvent where
eventKind _ = "index"
data FeatureEvent = FeatureEvent
{ key :: !Text
, user :: !(Maybe Value)
, userKey :: !(Maybe Text)
, value :: !Value
, defaultValue :: !(Maybe Value)
, version :: !(Maybe Natural)
, variation :: !(Maybe Natural)
, reason :: !(Maybe EvaluationReason)
, contextKind :: !ContextKind
} deriving (Generic, Show)
instance ToJSON FeatureEvent where
toJSON event = object $ filter ((/=) Null . snd)
[ ("key", toJSON $ getField @"key" event)
, ("user", toJSON $ getField @"user" event)
, ("userKey", toJSON $ getField @"userKey" event)
, ("value", toJSON $ getField @"value" event)
, ("default", toJSON $ getField @"defaultValue" event)
, ("version", toJSON $ getField @"version" event)
, ("variation", toJSON $ getField @"variation" event)
, ("reason", toJSON $ getField @"reason" event)
, ("contextKind", let c = (getField @"contextKind" event) in
if c == ContextKindUser then Null else toJSON c)
]
instance EventKind FeatureEvent where
eventKind _ = "feature"
newtype DebugEvent = DebugEvent FeatureEvent
instance EventKind DebugEvent where
eventKind _ = "debug"
instance ToJSON DebugEvent where
toJSON (DebugEvent x) = toJSON x
addUserToEvent :: (HasField' "user" r (Maybe Value), HasField' "userKey" r (Maybe Text)) => ConfigI -> UserI -> r -> r
addUserToEvent config user event = if getField @"inlineUsersInEvents" config
then setField @"user" (pure $ userSerializeRedacted config user) event
else setField @"userKey" (pure $ getField @"key" user) event
makeFeatureEvent :: ConfigI -> UserI -> Bool -> EvalEvent -> FeatureEvent
makeFeatureEvent config user includeReason event = addUserToEvent config user $ FeatureEvent
{ key = getField @"key" event
, user = Nothing
, userKey = Nothing
, value = getField @"value" event
, defaultValue = getField @"defaultValue" event
, version = getField @"version" event
, variation = getField @"variation" event
, reason = if includeReason || getField @"forceIncludeReason" event
then pure $ getField @"reason" event else Nothing
, contextKind = userGetContextKind user
}
data CustomEvent = CustomEvent
{ key :: !Text
, user :: !(Maybe Value)
, userKey :: !(Maybe Text)
, metricValue :: !(Maybe Double)
, value :: !(Maybe Value)
, contextKind :: !ContextKind
} deriving (Generic, Show)
instance ToJSON CustomEvent where
toJSON ctx = object $ filter ((/=) Null . snd)
[ ("key", toJSON $ getField @"key" ctx)
, ("user", toJSON $ getField @"user" ctx)
, ("userKey", toJSON $ getField @"userKey" ctx)
, ("metricValue", toJSON $ getField @"metricValue" ctx)
, ("data", toJSON $ getField @"value" ctx)
, ("contextKind", let c = (getField @"contextKind" ctx) in
if c == ContextKindUser then Null else toJSON c)
]
instance EventKind CustomEvent where
eventKind _ = "custom"
data AliasEvent = AliasEvent
{ key :: !Text
, contextKind :: !ContextKind
, previousKey :: !Text
, previousContextKind :: !ContextKind
}
deriving (Generic, Show)
instance ToJSON AliasEvent where
toJSON ctx = object $ filter ((/=) Null . snd)
[ ("key", toJSON $ getField @"key" ctx)
, ("contextKind", toJSON $ getField @"contextKind" ctx)
, ("previousKey", toJSON $ getField @"previousKey" ctx)
, ("previousContextKind", toJSON $ getField @"previousContextKind" ctx)
]
instance EventKind AliasEvent where
eventKind _ = "alias"
data BaseEvent event = BaseEvent
{ creationDate :: Natural
, event :: event
} deriving (Generic, Show)
fromObject :: Value -> HashMap Text Value
fromObject x = case x of (Object o) -> o; _ -> error "expected object"
instance (EventKind sub, ToJSON sub) => ToJSON (BaseEvent sub) where
toJSON event = Object $ HM.union (fromObject $ toJSON $ getField @"event" event) $ HM.fromList
[ ("creationDate", toJSON $ getField @"creationDate" event)
, ("kind", String $ eventKind $ getField @"event" event)
]
data EventType =
EventTypeIdentify !(BaseEvent IdentifyEvent)
| EventTypeFeature !(BaseEvent FeatureEvent)
| EventTypeSummary !(BaseEvent SummaryEvent)
| EventTypeCustom !(BaseEvent CustomEvent)
| EventTypeIndex !(BaseEvent IndexEvent)
| EventTypeDebug !(BaseEvent DebugEvent)
| EventTypeAlias !(BaseEvent AliasEvent)
instance ToJSON EventType where
toJSON event = case event of
EventTypeIdentify x -> toJSON x
EventTypeFeature x -> toJSON x
EventTypeSummary x -> toJSON x
EventTypeCustom x -> toJSON x
EventTypeIndex x -> toJSON x
EventTypeDebug x -> toJSON x
EventTypeAlias x -> toJSON x
newUnknownFlagEvent :: Text -> Value -> EvaluationReason -> EvalEvent
newUnknownFlagEvent key defaultValue reason = EvalEvent
{ key = key
, variation = Nothing
, value = defaultValue
, defaultValue = pure defaultValue
, version = Nothing
, prereqOf = Nothing
, reason = reason
, trackEvents = False
, forceIncludeReason = False
, debug = False
, debugEventsUntilDate = Nothing
}
newSuccessfulEvalEvent :: Flag -> Maybe Natural -> Value -> Maybe Value -> EvaluationReason -> Maybe Text -> EvalEvent
newSuccessfulEvalEvent flag variation value defaultValue reason prereqOf = EvalEvent
{ key = getField @"key" flag
, variation = variation
, value = value
, defaultValue = defaultValue
, version = Just $ getField @"version" flag
, prereqOf = prereqOf
, reason = reason
, trackEvents = getField @"trackEvents" flag || shouldForceReason
, forceIncludeReason = shouldForceReason
, debug = False
, debugEventsUntilDate = getField @"debugEventsUntilDate" flag
}
where
shouldForceReason = case reason of
(EvaluationReasonFallthrough inExperiment) ->
inExperiment || getField @"trackEventsFallthrough" flag
(EvaluationReasonRuleMatch idx _ inExperiment) ->
inExperiment || getField @"trackEvents" (getField @"rules" flag !! fromIntegral idx)
_ -> False
makeSummaryKey :: EvalEvent -> Text
makeSummaryKey event = T.intercalate "-"
[ fromMaybe "" $ fmap (T.pack . show) $ getField @"version" event
, fromMaybe "" $ fmap (T.pack . show) $ getField @"variation" event
]
summarizeEvent :: (HashMap Text (FlagSummaryContext (HashMap Text CounterContext)))
-> EvalEvent -> Bool -> (HashMap Text (FlagSummaryContext (HashMap Text CounterContext)))
summarizeEvent context event unknown = result where
key = makeSummaryKey event
root = case HM.lookup (getField @"key" event) context of
(Just x) -> x; Nothing -> FlagSummaryContext (getField @"defaultValue" event) mempty
leaf = case HM.lookup key (getField @"counters" root) of
(Just x) -> x & field @"count" %~ (1 +)
Nothing -> CounterContext
{ count = 1
, version = getField @"version" event
, variation = getField @"variation" event
, value = getField @"value" event
, unknown = unknown
}
result = flip (HM.insert $ getField @"key" event) context $
root & field @"counters" %~ HM.insert key leaf
putIfEmptyMVar :: MVar a -> a -> IO ()
putIfEmptyMVar mvar value = tryTakeMVar mvar >>= \case Just x -> putMVar mvar x; Nothing -> putMVar mvar value;
runSummary :: Natural -> EventState -> EvalEvent -> Bool -> IO ()
runSummary now state event unknown = putIfEmptyMVar (getField @"startDate" state) now >>
modifyMVar_ (getField @"summary" state) (\summary -> pure $ summarizeEvent summary event unknown)
processEvalEvent :: Natural -> ConfigI -> EventState -> UserI -> Bool -> Bool -> EvalEvent -> IO ()
processEvalEvent now config state user includeReason unknown event = do
let featureEvent = makeFeatureEvent config user includeReason event
when (getField @"trackEvents" event) $
queueEvent config state $ EventTypeFeature $ BaseEvent now $ featureEvent
when (now < fromMaybe 0 (getField @"debugEventsUntilDate" event)) $
queueEvent config state $ EventTypeDebug $ BaseEvent now $ DebugEvent featureEvent
runSummary now state event unknown
maybeIndexUser now config user state
processEvalEvents :: ConfigI -> EventState -> UserI -> Bool -> [EvalEvent] -> Bool -> IO ()
processEvalEvents config state user includeReason events unknown = unixMilliseconds >>= \now ->
mapM_ (processEvalEvent now config state user includeReason unknown) events
maybeIndexUser :: Natural -> ConfigI -> UserI -> EventState -> IO ()
maybeIndexUser now config user state = modifyMVar_ (getField @"userKeyLRU" state) $ \cache ->
let key = getField @"key" user in case LRU.lookup key cache of
(cache', Just _) -> pure cache'
(cache', Nothing) -> do
queueEvent config state (EventTypeIndex $ BaseEvent now $ IndexEvent { user = userSerializeRedacted config user })
pure $ LRU.insert key () cache'