module LaunchDarkly.Server.Events where
import Control.Concurrent.MVar (MVar, modifyMVar, modifyMVar_, newEmptyMVar, newMVar, putMVar, readMVar, swapMVar, tryTakeMVar)
import Control.Lens ((%~), (&))
import Control.Monad (when)
import Data.Aeson (ToJSON, Value (..), object, toJSON, (.=))
import Data.Cache.LRU (LRU, newLRU)
import qualified Data.Cache.LRU as LRU
import Data.Generics.Product (field, getField)
import qualified Data.HashSet as HS
import Data.Maybe (fromMaybe)
import Data.Text (Text)
import qualified Data.Text as T
import Data.Time.Clock.POSIX (getPOSIXTime)
import GHC.Exts (fromList)
import GHC.Generics (Generic)
import GHC.Natural (Natural, naturalFromInteger)
import LaunchDarkly.AesonCompat (KeyMap, insertKey, keyMapUnion, lookupKey, objectValues)
import LaunchDarkly.Server.Config.Internal (Config, shouldSendEvents)
import LaunchDarkly.Server.Context (Context)
import LaunchDarkly.Server.Context.Internal (Context (Invalid), getCanonicalKey, getKinds, optionallyRedactAnonymous, redactContext, redactContextRedactAnonymous)
import LaunchDarkly.Server.Details (EvaluationReason (..))
import LaunchDarkly.Server.Features (Flag)
data EvalEvent = EvalEvent
{ key :: !Text
, context :: !Context
, variation :: !(Maybe Integer)
, 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])
, lastKnownServerTime :: !(MVar Integer)
, flush :: !(MVar ())
, summary :: !(MVar (KeyMap FlagSummaryContext))
, startDate :: !(MVar Natural)
, contextKeyLRU :: !(MVar (LRU Text ()))
}
deriving (Generic)
makeEventState :: Config -> IO EventState
makeEventState config = do
events <- newMVar []
lastKnownServerTime <- newMVar 0
flush <- newEmptyMVar
summary <- newMVar mempty
startDate <- newEmptyMVar
contextKeyLRU <- newMVar $ newLRU $ pure $ fromIntegral $ getField @"contextKeyLRUCapacity" config
pure EventState {..}
queueEvent :: Config -> EventState -> EventType -> IO ()
queueEvent config state event =
if not (shouldSendEvents config)
then pure ()
else modifyMVar_ (getField @"events" state) $ \events ->
pure $ case event of
EventTypeSummary _ -> event : events
_ | length events < fromIntegral (getField @"eventsCapacity" config) -> event : events
_ -> events
unixMilliseconds :: IO Natural
unixMilliseconds = round . (* 1000) <$> getPOSIXTime
makeBaseEvent :: a -> IO (BaseEvent a)
makeBaseEvent child = unixMilliseconds >>= \now -> pure $ BaseEvent {creationDate = now, event = child}
processSummary :: Config -> EventState -> IO ()
processSummary config state =
tryTakeMVar (getField @"startDate" state) >>= \case
Nothing -> pure ()
(Just startDate) -> do
endDate <- unixMilliseconds
features <- swapMVar (getField @"summary" state) mempty
queueEvent config state $ EventTypeSummary $ SummaryEvent {..}
class EventKind a where
eventKind :: a -> Text
data SummaryEvent = SummaryEvent
{ startDate :: !Natural
, endDate :: !Natural
, features :: !(KeyMap FlagSummaryContext)
}
deriving (Generic, Show, ToJSON)
instance EventKind SummaryEvent where
eventKind _ = "summary"
data FlagSummaryContext = FlagSummaryContext
{ defaultValue :: Maybe Value
, counters :: KeyMap CounterContext
, contextKinds :: HS.HashSet Text
}
deriving (Generic, Show)
instance ToJSON FlagSummaryContext where
toJSON ctx =
object $
filter
((/=) Null . snd)
[ ("default", toJSON $ getField @"defaultValue" ctx)
, ("counters", toJSON $ objectValues $ getField @"counters" ctx)
, ("contextKinds", toJSON $ getField @"contextKinds" ctx)
]
data CounterContext = CounterContext
{ count :: !Natural
, version :: !(Maybe Natural)
, variation :: !(Maybe Integer)
, value :: !Value
, unknown :: !Bool
}
deriving (Generic, Show)
instance ToJSON CounterContext where
toJSON context =
object $
[ "count" .= getField @"count" context
, "value" .= getField @"value" context
]
<> filter
((/=) Null . snd)
[ "version" .= getField @"version" context
, "variation" .= getField @"variation" context
, "unknown" .= if getField @"unknown" context then Just True else Nothing
]
data IdentifyEvent = IdentifyEvent
{ key :: !Text
, context :: !Value
}
deriving (Generic, ToJSON, Show)
instance EventKind IdentifyEvent where
eventKind _ = "identify"
data IndexEvent = IndexEvent {context :: Value} deriving (Generic, ToJSON, Show)
instance EventKind IndexEvent where
eventKind _ = "index"
data FeatureEvent = FeatureEvent
{ key :: !Text
, context :: !Value
, value :: !Value
, defaultValue :: !(Maybe Value)
, version :: !(Maybe Natural)
, prereqOf :: !(Maybe Text)
, variation :: !(Maybe Integer)
, reason :: !(Maybe EvaluationReason)
}
deriving (Generic, Show)
instance ToJSON FeatureEvent where
toJSON event =
object $
filter
((/=) Null . snd)
[ ("key", toJSON $ getField @"key" event)
, ("context", toJSON $ getField @"context" event)
, ("value", toJSON $ getField @"value" event)
, ("default", toJSON $ getField @"defaultValue" event)
, ("version", toJSON $ getField @"version" event)
, ("prereqOf", toJSON $ getField @"prereqOf" event)
, ("variation", toJSON $ getField @"variation" event)
, ("reason", toJSON $ getField @"reason" event)
]
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
makeDebugEvent :: Config -> Context -> Bool -> EvalEvent -> DebugEvent
makeDebugEvent config context includeReason event =
DebugEvent $ makeFeatureEventWithContextPayload (redactContext config context) includeReason event
makeFeatureEvent :: Config -> Context -> Bool -> EvalEvent -> FeatureEvent
makeFeatureEvent config context includeReason event =
makeFeatureEventWithContextPayload (redactContextRedactAnonymous config context) includeReason event
makeFeatureEventWithContextPayload :: Value -> Bool -> EvalEvent -> FeatureEvent
makeFeatureEventWithContextPayload context includeReason event =
FeatureEvent
{ key = getField @"key" event
, context = context
, value = getField @"value" event
, defaultValue = getField @"defaultValue" event
, version = getField @"version" event
, prereqOf = getField @"prereqOf" event
, variation = getField @"variation" event
, reason =
if includeReason || getField @"forceIncludeReason" event
then pure $ getField @"reason" event
else Nothing
}
data CustomEvent = CustomEvent
{ key :: !Text
, contextKeys :: !(KeyMap Text)
, metricValue :: !(Maybe Double)
, value :: !(Maybe Value)
}
deriving (Generic, Show)
instance ToJSON CustomEvent where
toJSON ctx =
object $
filter
((/=) Null . snd)
[ ("key", toJSON $ getField @"key" ctx)
, ("contextKeys", toJSON $ getField @"contextKeys" ctx)
, ("metricValue", toJSON $ getField @"metricValue" ctx)
, ("data", toJSON $ getField @"value" ctx)
]
instance EventKind CustomEvent where
eventKind _ = "custom"
data BaseEvent event = BaseEvent
{ creationDate :: Natural
, event :: event
}
deriving (Generic, Show)
fromObject :: Value -> KeyMap Value
fromObject x = case x of (Object o) -> o; _ -> error "expected object"
instance (EventKind sub, ToJSON sub) => ToJSON (BaseEvent sub) where
toJSON event =
Object $
keyMapUnion (fromObject $ toJSON $ getField @"event" event) $
fromList
[ ("creationDate", toJSON $ getField @"creationDate" event)
, ("kind", String $ eventKind $ getField @"event" event)
]
data EventType
= EventTypeIdentify !(BaseEvent IdentifyEvent)
| EventTypeFeature !(BaseEvent FeatureEvent)
| EventTypeSummary !SummaryEvent
| EventTypeCustom !(BaseEvent CustomEvent)
| EventTypeIndex !(BaseEvent IndexEvent)
| EventTypeDebug !(BaseEvent DebugEvent)
instance ToJSON EventType where
toJSON event = case event of
EventTypeIdentify x -> toJSON x
EventTypeFeature x -> toJSON x
EventTypeSummary x -> Object $ insertKey "kind" (String "summary") (fromObject $ toJSON x)
EventTypeCustom x -> toJSON x
EventTypeIndex x -> toJSON x
EventTypeDebug x -> toJSON x
newUnknownFlagEvent :: Text -> Value -> EvaluationReason -> Context -> EvalEvent
newUnknownFlagEvent key defaultValue reason context =
EvalEvent
{ key = key
, context = context
, variation = Nothing
, value = defaultValue
, defaultValue = pure defaultValue
, version = Nothing
, prereqOf = Nothing
, reason = reason
, trackEvents = False
, forceIncludeReason = False
, debug = False
, debugEventsUntilDate = Nothing
}
newSuccessfulEvalEvent :: Flag -> Maybe Integer -> Value -> Maybe Value -> EvaluationReason -> Maybe Text -> Context -> EvalEvent
newSuccessfulEvalEvent flag variation value defaultValue reason prereqOf context =
EvalEvent
{ key = getField @"key" flag
, context = context
, 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 :: KeyMap FlagSummaryContext -> EvalEvent -> Bool -> KeyMap FlagSummaryContext
summarizeEvent summaryContext event unknown = result
where
key = makeSummaryKey event
contextKinds = HS.fromList $ getKinds $ getField @"context" event
root = case lookupKey (getField @"key" event) summaryContext of
(Just x) -> x
Nothing ->
FlagSummaryContext
{ defaultValue = (getField @"defaultValue" event)
, counters = mempty
, contextKinds = mempty
}
leaf = case lookupKey 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 (insertKey $ getField @"key" event) summaryContext $ (root & field @"counters" %~ (insertKey key leaf) & field @"contextKinds" %~ (HS.union contextKinds))
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 -> Config -> EventState -> Context -> Bool -> Bool -> EvalEvent -> IO ()
processEvalEvent now config state context includeReason unknown event = do
let featureEvent = makeFeatureEvent config context includeReason event
trackEvents = getField @"trackEvents" event
debugEventsUntilDate = fromMaybe 0 (getField @"debugEventsUntilDate" event)
lastKnownServerTime <- naturalFromInteger <$> (* 1000) <$> readMVar (getField @"lastKnownServerTime" state)
when trackEvents $
queueEvent config state $
EventTypeFeature $
BaseEvent now featureEvent
when (now < debugEventsUntilDate && lastKnownServerTime < debugEventsUntilDate) $
queueEvent config state $
EventTypeDebug $
BaseEvent now $
makeDebugEvent config context includeReason event
runSummary now state event unknown
maybeIndexContext now config context state
processEvalEvents :: Config -> EventState -> Context -> Bool -> [EvalEvent] -> Bool -> IO ()
processEvalEvents config state context includeReason events unknown =
unixMilliseconds >>= \now -> mapM_ (processEvalEvent now config state context includeReason unknown) events
maybeIndexContext :: Natural -> Config -> Context -> EventState -> IO ()
maybeIndexContext now config context state = do
case optionallyRedactAnonymous config context of
(Invalid _) -> pure ()
ctx -> do
noticedContext <- noticeContext state ctx
when noticedContext $
queueEvent config state (EventTypeIndex $ BaseEvent now $ IndexEvent {context = redactContext config ctx})
noticeContext :: EventState -> Context -> IO Bool
noticeContext state context = modifyMVar (getField @"contextKeyLRU" state) $ \cache -> do
let key = getCanonicalKey context
case LRU.lookup key cache of
(cache', Just _) -> pure (cache', False)
(cache', Nothing) -> pure (LRU.insert key () cache', True)