katip-0.8.8.4: src/Katip/Core.hs
{-# LANGUAGE DeriveLift #-}
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE UndecidableInstances #-}
#if MIN_VERSION_base(4, 9, 0)
{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
#endif
-- | This module is not meant to be imported directly and may contain
-- internal mechanisms that will change without notice.
module Katip.Core where
-------------------------------------------------------------------------------
import Control.Applicative as A
import Control.AutoUpdate
import Control.Concurrent
import qualified Control.Concurrent.Async as Async
import Control.Concurrent.STM
import qualified Control.Concurrent.STM.TBQueue as BQ
import Control.Exception.Safe
import Control.Monad (unless, void, when)
import Control.Monad.Base
#if MIN_VERSION_base(4, 9, 0)
import qualified Control.Monad.Fail as MF
#endif
import Control.Monad.IO.Class
import Control.Monad.IO.Unlift
import Control.Monad.Trans.Class
import Control.Monad.Trans.Control
#if !MIN_VERSION_either(4, 5, 0)
import Control.Monad.Trans.Either
#endif
import Control.Monad.Trans.Except
import Control.Monad.Trans.Maybe
import Control.Monad.Trans.Reader
import Control.Monad.Trans.Resource (MonadResource, ResourceT,
transResourceT)
import Control.Monad.Trans.RWS.Lazy (RWST, mapRWST)
import qualified Control.Monad.Trans.RWS.Strict as Strict (RWST, mapRWST)
import Control.Monad.Trans.State.Lazy (StateT, mapStateT)
import qualified Control.Monad.Trans.State.Strict as Strict (StateT, mapStateT)
import Control.Monad.Trans.Writer.Lazy (WriterT, mapWriterT)
import qualified Control.Monad.Trans.Writer.Strict as Strict (WriterT,
mapWriterT)
import Data.Aeson (FromJSON (..), ToJSON (..),
object)
import qualified Data.Aeson as A
#if MIN_VERSION_aeson(2, 0, 0)
import qualified Data.Aeson.Key as K
import qualified Data.Aeson.KeyMap as KM
import Data.Bifunctor (Bifunctor (..))
#endif
import Data.Foldable as FT
#if !MIN_VERSION_aeson(2, 0, 0)
import qualified Data.HashMap.Strict as HM
#endif
import Data.List
import qualified Data.Map.Strict as M
import Data.Maybe (listToMaybe)
import Data.Semigroup as SG
import qualified Data.Set as Set
import Data.String
import Data.String.Conv
import Data.Text (Text)
import qualified Data.Text as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.Builder as B
import qualified Data.Text.Lazy.Builder.Int as B
import Data.Time
import GHC.Generics hiding (to)
#if MIN_VERSION_base(4, 8, 0)
#if !MIN_VERSION_base(4, 9, 0)
import GHC.SrcLoc
#endif
import GHC.Stack
#endif
import Language.Haskell.TH
import qualified Language.Haskell.TH.Syntax as TH
import Lens.Micro
import Lens.Micro.TH
import Network.HostName
#if mingw32_HOST_OS
import Katip.Compat
#else
import System.Posix
#endif
import GHC.Conc.Sync (labelThread)
#if MIN_VERSION_base(4, 19, 0)
import GHC.Conc.Sync (fromThreadId)
#else
import Data.Maybe (fromMaybe)
#endif
-------------------------------------------------------------------------------
readMay :: Read a => String -> Maybe a
readMay s = case [x | (x,t) <- reads s, ("","") <- lex t] of
[x] -> Just x
[] -> Nothing -- no parse
_ -> Nothing -- Ambiguous parse
{-# INLINE readMay #-}
decimalToText :: Integral a => a -> Text
decimalToText = TL.toStrict . B.toLazyText . B.decimal
-------------------------------------------------------------------------------
-- | Represents a heirarchy of namespaces going from general to
-- specific. For instance: ["processname", "subsystem"]. Note that
-- single-segment namespaces can be created using
-- IsString/OverloadedStrings, so "foo" will result in Namespace
-- ["foo"].
newtype Namespace = Namespace { unNamespace :: [Text] }
deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,SG.Semigroup,Monoid,TH.Lift)
instance IsString Namespace where
fromString s = Namespace [fromString s]
-------------------------------------------------------------------------------
-- | Ready namespace for emission with dots to join the segments.
intercalateNs :: Namespace -> [Text]
intercalateNs (Namespace xs) = intersperse "." xs
{-# INLINE intercalateNs #-}
-------------------------------------------------------------------------------
-- | Application environment, like @prod@, @devel@, @testing@.
newtype Environment = Environment { getEnvironment :: Text }
deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,IsString)
-------------------------------------------------------------------------------
data Severity
= DebugS -- ^ Debug messages
| InfoS -- ^ Information
| NoticeS -- ^ Normal runtime Conditions
| WarningS -- ^ General Warnings
| ErrorS -- ^ General Errors
| CriticalS -- ^ Severe situations
| AlertS -- ^ Take immediate action
| EmergencyS -- ^ System is unusable
deriving (Eq, Ord, Show, Read, Generic, Enum, Bounded, TH.Lift)
-------------------------------------------------------------------------------
-- | Verbosity controls the amount of information (columns) a 'Scribe'
-- emits during logging.
--
-- The convention is:
-- - 'V0' implies no additional payload information is included in message.
-- - 'V3' implies the maximum amount of payload information.
-- - Anything in between is left to the discretion of the developer.
data Verbosity = V0 | V1 | V2 | V3
deriving (Eq, Ord, Show, Read, Generic, Enum, Bounded, TH.Lift)
-------------------------------------------------------------------------------
{-# INLINE renderSeverity #-}
renderSeverity :: Severity -> Text
renderSeverity !s = case s of
DebugS -> "Debug"
InfoS -> "Info"
NoticeS -> "Notice"
WarningS -> "Warning"
ErrorS -> "Error"
CriticalS -> "Critical"
AlertS -> "Alert"
EmergencyS -> "Emergency"
-------------------------------------------------------------------------------
{-# INLINE textToSeverity #-}
textToSeverity :: Text -> Maybe Severity
textToSeverity = go . T.toLower
where
go "debug" = Just DebugS
go "info" = Just InfoS
go "notice" = Just NoticeS
go "warning" = Just WarningS
go "error" = Just ErrorS
go "critical" = Just CriticalS
go "alert" = Just AlertS
go "emergency" = Just EmergencyS
go _ = Nothing
instance ToJSON Severity where
toJSON s = A.String (renderSeverity s)
instance FromJSON Severity where
parseJSON = A.withText "Severity" parseSeverity
where
parseSeverity t = case textToSeverity t of
Just x -> return x
Nothing -> fail $ "Invalid Severity " ++ toS t
instance ToJSON Verbosity where
toJSON s = A.String $ case s of
V0 -> "V0"
V1 -> "V1"
V2 -> "V2"
V3 -> "V3"
instance FromJSON Verbosity where
parseJSON = A.withText "Verbosity" $ \s -> case s of
"V0" -> return V0
"V1" -> return V1
"V2" -> return V2
"V3" -> return V3
_ -> fail $ "Invalid Verbosity " ++ toS s
-------------------------------------------------------------------------------
-- | Log message with Builder underneath; use '<>' to concat in O(1).
newtype LogStr = LogStr { unLogStr :: B.Builder }
deriving (Generic, Show, Eq)
instance IsString LogStr where
fromString = LogStr . B.fromString
instance Semigroup LogStr where
(LogStr a) <> (LogStr b) = LogStr (a <> b)
{-# INLINE (<>) #-}
instance Monoid LogStr where
mappend = (<>)
mempty = LogStr mempty
{-# INLINE mempty #-}
instance FromJSON LogStr where
parseJSON = A.withText "LogStr" parseLogStr
where
parseLogStr = return . LogStr . B.fromText
-------------------------------------------------------------------------------
-- | Pack any string-like thing into a 'LogStr'. This will
-- automatically work on 'String', 'ByteString', 'Text' and any of the
-- lazy variants.
logStr :: StringConv a Text => a -> LogStr
logStr t = LogStr (B.fromText $ toS t)
{-# INLINE logStr #-}
-------------------------------------------------------------------------------
-- | Shorthand for 'logStr'
ls :: StringConv a Text => a -> LogStr
ls = logStr
{-# INLINE ls #-}
-------------------------------------------------------------------------------
-- | Convert any showable type into a 'LogStr'.
showLS :: Show a => a -> LogStr
showLS = ls . show
{-# INLINE showLS #-}
-------------------------------------------------------------------------------
newtype ThreadIdText = ThreadIdText {
getThreadIdText :: Text
} deriving (ToJSON, FromJSON, Show, Eq, Ord)
mkThreadIdText :: ThreadId -> ThreadIdText
#if MIN_VERSION_base(4, 19, 0)
mkThreadIdText = ThreadIdText . decimalToText . fromThreadId
#else
mkThreadIdText = ThreadIdText . stripPrefix' "ThreadId " . T.pack . show
where
stripPrefix' pfx t = fromMaybe t (T.stripPrefix pfx t)
#endif
{-# INLINE mkThreadIdText #-}
-------------------------------------------------------------------------------
-- | This has everything each log message will contain.
data Item a = Item {
_itemApp :: Namespace
, _itemEnv :: Environment
, _itemSeverity :: {-# UNPACK #-} !Severity
, _itemThread :: ThreadIdText
, _itemHost :: HostName
, _itemProcess :: ProcessID
, _itemPayload :: a
, _itemMessage :: LogStr
, _itemTime :: UTCTime
, _itemNamespace :: Namespace
, _itemLoc :: Maybe Loc
} deriving (Generic, Functor)
makeLenses ''Item
-- Manual instance because 'Loc' has no 'Eq' and 'Show' instances in old
-- versions of template-haskell (< 2.10)
instance Eq a => Eq (Item a) where
a == b = FT.and [ _itemApp a == _itemApp b
, _itemEnv a == _itemEnv b
, _itemSeverity a == _itemSeverity b
, _itemThread a == _itemThread b
, _itemHost a == _itemHost b
, _itemProcess a == _itemProcess b
, _itemPayload a == _itemPayload b
, _itemMessage a == _itemMessage b
, _itemTime a == _itemTime b
, _itemNamespace a == _itemNamespace b
, case (_itemLoc a, _itemLoc b) of
(Nothing, Nothing) -> True
(Just l1, Just l2) -> FT.and [ loc_filename l1 == loc_filename l2
, loc_package l1 == loc_package l2
, loc_module l1 == loc_module l2
, loc_start l1 == loc_start l2
, loc_end l1 == loc_end l2
]
_ -> False
]
instance Show a => Show (Item a) where
showsPrec d Item{..} = showParen (d >= 11) ( showString "Item {"
. field "_itemApp" _itemApp
. field "_itemEnv" _itemEnv
. field "_itemSeverity" _itemSeverity
. field "_itemThread" _itemThread
. field "_itemHost" _itemHost
. field "_itemProcess" _itemProcess
. field "_itemPayload" _itemPayload
. field "_itemMessage" _itemMessage
. field "_itemTime" _itemTime
. field "_itemNamespace" _itemNamespace
. showString "_itemLoc = " . shows (LocShow <$> _itemLoc)
. showChar '}'
)
where
field n v = showString n . showString " = " . shows v . showString ", "
newtype LocShow = LocShow Loc
instance Show LocShow where
showsPrec d (LocShow Loc{..}) = showParen (d >= 11) ( showString "Loc {"
. field "loc_filename" loc_filename
. field "loc_package" loc_package
. field "loc_module" loc_module
. field "loc_start" loc_start
. showString "loc_end = " . shows loc_end
. showChar '}'
)
where
field n v = showString n . showString " = " . shows v . showString ", "
instance ToJSON a => ToJSON (Item a) where
toJSON Item{..} = A.object
[ "app" A..= _itemApp
, "env" A..= _itemEnv
, "sev" A..= _itemSeverity
, "thread" A..= getThreadIdText _itemThread
, "host" A..= _itemHost
, "pid" A..= ProcessIDJs _itemProcess
, "data" A..= _itemPayload
, "msg" A..= (B.toLazyText $ unLogStr _itemMessage)
, "at" A..= _itemTime
, "ns" A..= _itemNamespace
, "loc" A..= fmap LocJs _itemLoc
]
newtype LocJs = LocJs { getLocJs :: Loc }
instance ToJSON LocJs where
toJSON (LocJs (Loc fn p m (l, c) _)) = A.object
[ "loc_fn" A..= fn
, "loc_pkg" A..= p
, "loc_mod" A..= m
, "loc_ln" A..= l
, "loc_col" A..= c
]
instance FromJSON LocJs where
parseJSON = A.withObject "LocJs" parseLocJs
where
parseLocJs o = do
fn <- o A..: "loc_fn"
p <- o A..: "loc_pkg"
m <- o A..: "loc_mod"
l <- o A..: "loc_ln"
c <- o A..: "loc_col"
return $ LocJs $ Loc fn p m (l, c) (l, c)
instance FromJSON a => FromJSON (Item a) where
parseJSON = A.withObject "Item" parseItem
where
parseItem o = Item
<$> o A..: "app"
<*> o A..: "env"
<*> o A..: "sev"
<*> o A..: "thread"
<*> o A..: "host"
<*> (getProcessIDJs <$> o A..: "pid")
<*> o A..: "data"
<*> o A..: "msg"
<*> o A..: "at"
<*> o A..: "ns"
<*> (fmap getLocJs <$> o A..: "loc")
processIDToText :: ProcessID -> Text
processIDToText = decimalToText
{-# INLINE processIDToText #-}
textToProcessID :: Text -> Maybe ProcessID
textToProcessID = readMay . toS
{-# INLINE textToProcessID #-}
newtype ProcessIDJs = ProcessIDJs {
getProcessIDJs :: ProcessID
}
instance ToJSON ProcessIDJs where
toJSON (ProcessIDJs p) = A.String (processIDToText p)
instance FromJSON ProcessIDJs where
parseJSON = A.withText "ProcessID" parseProcessID
where
parseProcessID t = case textToProcessID t of
Just p -> return $ ProcessIDJs p
Nothing -> fail $ "Invalid ProcessIDJs " ++ toS t
-------------------------------------------------------------------------------
-- | Field selector by verbosity within JSON payload.
data PayloadSelection
= AllKeys
| SomeKeys [Text]
deriving (Show, Eq)
instance Semigroup PayloadSelection where
AllKeys <> _ = AllKeys
_ <> AllKeys = AllKeys
SomeKeys as <> SomeKeys bs = SomeKeys (as <> bs)
instance Monoid PayloadSelection where
mempty = SomeKeys []
mappend = (<>)
-- | Compares two payload selections for equivalence. With SomeKeys, ordering
-- and duplicates are ignored.
equivalentPayloadSelection :: PayloadSelection -> PayloadSelection -> Bool
equivalentPayloadSelection AllKeys AllKeys = True
equivalentPayloadSelection (SomeKeys a) (SomeKeys b) = Set.fromList a == Set.fromList b
equivalentPayloadSelection _ _ = False
{-# INLINE equivalentPayloadSelection #-}
-------------------------------------------------------------------------------
-- | Katip requires JSON objects to be logged as context. This
-- typeclass provides a default instance which uses ToJSON and
-- produces an empty object if 'toJSON' results in any type other than
-- object. If you have a type you want to log that produces an Array
-- or Number for example, you'll want to write an explicit instance
-- here. You can trivially add a ToObject instance for something with
-- a ToJSON instance like:
--
-- > instance ToObject Foo
class ToObject a where
toObject :: a -> A.Object
default toObject :: ToJSON a => a -> A.Object
toObject v = case toJSON v of
A.Object o -> o
_ -> mempty
instance ToObject ()
instance ToObject A.Object
-------------------------------------------------------------------------------
-- | Payload objects need instances of this class. LogItem makes it so
-- that you can have very verbose items getting logged with lots of
-- extra fields but under normal circumstances, if your scribe is
-- configured for a lower verbosity level, it will only log a
-- selection of those keys. Furthermore, each 'Scribe' can be
-- configured with a different 'Verbosity' level. You could even use
-- 'registerScribe', 'unregisterScribe', and 'clearScribes' to at
-- runtime swap out your existing scribes for more verbose debugging
-- scribes if you wanted to.
--
-- When defining 'payloadKeys', don't redundantly declare the same
-- keys for higher levels of verbosity. Each level of verbosity
-- automatically and recursively contains all keys from the level
-- before it.
class ToObject a => LogItem a where
-- | List of keys in the JSON object that should be included in message.
payloadKeys :: Verbosity -> a -> PayloadSelection
instance LogItem () where payloadKeys _ _ = SomeKeys []
data AnyLogPayload = forall a. ToJSON a => AnyLogPayload a
newtype SimpleLogPayload = SimpleLogPayload {
unSimpleLogPayload :: [(Text, AnyLogPayload)]
}
-------------------------------------------------------------------------------
-- | A built-in convenience log payload that won't log anything on 'V0',
-- but will log everything in any other level of verbosity. Intended
-- for easy in-line usage without having to define new log types.
--
-- Construct using 'sl' and combine multiple tuples using '<>' from
-- 'Monoid'.
instance ToJSON SimpleLogPayload where
toJSON (SimpleLogPayload as) = object $ map go as'
where go (k, AnyLogPayload v) = k A..= v
as' = toKey <$> as
#if MIN_VERSION_aeson(2, 0, 0)
toKey :: (Text, c) -> (K.Key, c)
toKey = first K.fromText
#else
toKey :: a -> a
toKey = id
#endif
{-# INLINE toKey #-}
instance ToObject SimpleLogPayload
instance LogItem SimpleLogPayload where
payloadKeys V0 _ = SomeKeys []
payloadKeys _ _ = AllKeys
instance Semigroup SimpleLogPayload where
SimpleLogPayload a <> SimpleLogPayload b = SimpleLogPayload (a <> b)
instance Monoid SimpleLogPayload where
mempty = SimpleLogPayload []
mappend = (<>)
-------------------------------------------------------------------------------
-- | Construct a simple log from any JSON item.
sl :: ToJSON a => Text -> a -> SimpleLogPayload
sl a b = SimpleLogPayload [(a, AnyLogPayload b)]
{-# INLINE sl #-}
-------------------------------------------------------------------------------
-- | Constrain payload based on verbosity. Backends should use this to
-- automatically bubble higher verbosity levels to lower ones.
payloadObject :: LogItem a => Verbosity -> a -> A.Object
payloadObject verb a = case FT.foldMap (flip payloadKeys a) [(V0)..verb] of
AllKeys -> toObject a
SomeKeys ks -> filterElems ks $ toObject a
{-# INLINE payloadObject #-}
#if MIN_VERSION_aeson(2, 0, 0)
filterElems :: [Text] -> KM.KeyMap v -> KM.KeyMap v
filterElems ks = KM.filterWithKey (\ k _ -> K.toText k `FT.elem` ks)
#else
filterElems :: [Text] -> HM.HashMap Text v -> HM.HashMap Text v
filterElems ks = HM.filterWithKey (\ k _ -> k `FT.elem` ks)
#endif
{-# INLINE filterElems #-}
-------------------------------------------------------------------------------
-- | Convert log item to its JSON representation while trimming its
-- payload based on the desired verbosity. Backends that push JSON
-- messages should use this to obtain their payload.
itemJson :: LogItem a => Verbosity -> Item a -> A.Value
itemJson verb a = toJSON $ a & itemPayload %~ payloadObject verb
{-# INLINE itemJson #-}
-------------------------------------------------------------------------------
-- | Scribes are handlers of incoming items. Each registered scribe
-- knows how to push a log item somewhere.
--
-- = Guidelines for writing your own 'Scribe'
--
-- Scribes should always take a 'Severity' and 'Verbosity'.
--
-- Severity is used to __exclude log messages__ that are lower than
-- the provided Severity. For instance, if the user passes InfoS,
-- DebugS items should be ignored. Katip provides the 'permitItem'
-- utility for this. The user or the scribe may use 'permitAND' and
-- 'permitOR' to further customize this filtering, even dynamically if
-- they wish to.
--
-- Verbosity is used to select keys from the log item's payload. Each
-- 'LogItem' instance describes what keys should be retained for each
-- Verbosity level. Use the 'payloadObject' utility for extracting the keys
-- that should be written.
--
-- Scribes provide a finalizer IO action ('scribeFinalizer') that is
-- meant to synchronously flush any remaining writes and clean up any
-- resources acquired when the scribe was created. Internally, katip
-- keeps a buffer for each scribe's writes. When 'closeScribe' or
-- 'closeScribes' is called, that buffer stops accepting new log
-- messages and after the last item in its buffer is sent to 'liPush',
-- calls the finalizer. Thus, when the finalizer returns, katip can
-- assume that all resources are cleaned up and all log messages are
-- durably written.
--
-- While katip internally buffers messages per 'ScribeSettings', it
-- sends them one at a time to the scribe. Depending on the scribe
-- itself, it may make sense for that scribe to keep its own internal
-- buffer to batch-send logs if writing items one at a time is not
-- efficient. The scribe implementer must be sure that on
-- finalization, all writes are committed synchronously.
-- | Signature of a function passed to `Scribe` constructor and
-- mkScribe* functions that decides which messages to be
-- logged. Typically filters based on 'Severity', but can be
-- combined with other, custom logic with 'permitAND' and 'permitOR'
type PermitFunc = forall a. Item a -> IO Bool
-- | AND together 2 permit functions
permitAND :: PermitFunc -> PermitFunc -> PermitFunc
permitAND f1 f2 = \a -> liftA2 (&&) (f1 a) (f2 a)
{-# INLINE permitAND #-}
-- | OR together 2 permit functions
permitOR :: PermitFunc -> PermitFunc -> PermitFunc
permitOR f1 f2 = \a -> liftA2 (||) (f1 a) (f2 a)
{-# INLINE permitOR #-}
data Scribe = Scribe {
liPush :: forall a. LogItem a => Item a -> IO ()
-- ^ How do we write an item to the scribe's output?
, scribeFinalizer :: IO ()
-- ^ Provide a __blocking__ finalizer to call when your scribe is
-- removed. All pending writes should be flushed synchronously. If
-- this is not relevant to your scribe, return () is fine.
, scribePermitItem :: !PermitFunc
-- ^ Provide a filtering function to allow the item to be logged,
-- or not. It can check Severity or some string in item's
-- body. The initial value of this is usually created from
-- 'permitItem'. Scribes and users can customize this by ANDing
-- or ORing onto the default with 'permitAND' or 'permitOR'
}
whenM :: Monad m => m Bool -> m () -> m ()
whenM mbool = (>>=) mbool . flip when
{-# INLINE whenM #-}
-- | Combine two scribes. Publishes to the left scribe if the left
-- would permit the item and to the right scribe if the right would
-- permit the item. Finalizers are called in sequence from left to
-- right.
instance Semigroup Scribe where
(Scribe pushA finA permitA) <> (Scribe pushB finB permitB) =
Scribe (\item -> whenM (permitA item) (pushA item)
>> whenM (permitB item) (pushB item)
)
(finA `finally` finB)
(permitOR permitA permitB)
{-# INLINE (<>) #-}
instance Monoid Scribe where
mempty = Scribe (const (return ())) (return ()) (permitItem DebugS)
{-# INLINE mempty #-}
mappend = (<>)
-------------------------------------------------------------------------------
data ScribeHandle = ScribeHandle {
shScribe :: Scribe
, shChan :: BQ.TBQueue WorkerMessage
}
-------------------------------------------------------------------------------
data WorkerMessage where
NewItem :: LogItem a => Item a -> WorkerMessage
PoisonPill :: WorkerMessage
-------------------------------------------------------------------------------
-- | Should this item be logged given the user's maximum severity?
-- Most new scribes will use this as a base for their 'PermitFunc'
permitItem :: Monad m => Severity -> Item a -> m Bool
permitItem sev item = return (_itemSeverity item >= sev)
{-# INLINE permitItem #-}
-------------------------------------------------------------------------------
data LogEnv = LogEnv {
_logEnvHost :: HostName
, _logEnvPid :: ProcessID
, _logEnvApp :: Namespace
-- ^ Name of application. This will typically never change. This
-- field gets prepended to the namespace of your individual log
-- messages. For example, if your app is MyApp and you write a log
-- using "logItem" and the namespace "WebServer", the final
-- namespace will be "MyApp.WebServer"
, _logEnvEnv :: Environment
, _logEnvTimer :: IO UTCTime
-- ^ Action to fetch the timestamp. You can use something like
-- 'AutoUpdate' for high volume logs but note that this may cause
-- some output forms to display logs out of order. Alternatively,
-- you could just use 'getCurrentTime'.
, _logEnvScribes :: M.Map Text ScribeHandle
}
makeLenses ''LogEnv
-------------------------------------------------------------------------------
-- | Create a reasonable default InitLogEnv. Uses an 'AutoUpdate' which
-- updates the timer every 1ms. If you need even more timestamp
-- precision at the cost of performance, consider setting
-- '_logEnvTimer' with 'getCurrentTime'.
initLogEnv
:: Namespace
-- ^ A base namespace for this application
-> Environment
-- ^ Current run environment (e.g. @prod@ vs. @devel@)
-> IO LogEnv
initLogEnv an env = LogEnv
<$> getHostName
<*> getProcessID
<*> pure an
<*> pure env
<*> mkAutoUpdate defaultUpdateSettings { updateAction = getCurrentTime, updateFreq = 1000 }
<*> pure mempty
{-# INLINE initLogEnv#-}
-------------------------------------------------------------------------------
-- | Add a scribe to the list. All future log calls will go to this
-- scribe in addition to the others. Writes will be buffered per the
-- ScribeSettings to prevent slow scribes from slowing down
-- logging. Writes will be dropped if the buffer fills.
registerScribe
:: Text
-- ^ Name the scribe
-> Scribe
-> ScribeSettings
-> LogEnv
-> IO LogEnv
registerScribe nm scribe ScribeSettings {..} le = do
queue <- atomically (BQ.newTBQueue (fromIntegral _scribeBufferSize))
worker <- spawnScribeWorker scribe queue
let fin = do
atomically (BQ.writeTBQueue queue PoisonPill)
-- wait for our worker to finish final write
void (Async.waitCatch worker)
-- wait for scribe to finish final write
void (scribeFinalizer scribe)
let sh = ScribeHandle (scribe { scribeFinalizer = fin }) queue
return (le & logEnvScribes %~ M.insert nm sh)
{-# INLINE registerScribe#-}
-------------------------------------------------------------------------------
spawnScribeWorker :: Scribe -> BQ.TBQueue WorkerMessage -> IO (Async.Async ())
spawnScribeWorker (Scribe write _ _) queue = Async.async $ do
myThreadId >>= flip labelThread "Scribe worker (katip)"
go
where
go = do
newCmd <- atomically (BQ.readTBQueue queue)
case newCmd of
NewItem a -> do
-- Swallow any direct exceptions from the
-- scribe. safe-exceptions won't catch async exceptions.
void (tryAny (write a))
go
PoisonPill -> return ()
{-# INLINE spawnScribeWorker #-}
-------------------------------------------------------------------------------
data ScribeSettings = ScribeSettings {
_scribeBufferSize :: Int
}
deriving (Show, Eq)
makeLenses ''ScribeSettings
-- | Reasonable defaults for a scribe. Buffer
-- size of 4096.
defaultScribeSettings :: ScribeSettings
defaultScribeSettings = ScribeSettings 4096
-------------------------------------------------------------------------------
-- | Remove a scribe from the environment. This does __not__ finalize
-- the scribe. This mainly only makes sense to use with something like
-- MonadReader's @local@ function to temporarily disavow a single
-- logger for a block of code.
unregisterScribe
:: Text
-- ^ Name of the scribe
-> LogEnv
-> LogEnv
unregisterScribe nm = logEnvScribes %~ M.delete nm
-------------------------------------------------------------------------------
-- | Unregister __all__ scribes. Note that this is __not__ for closing or
-- finalizing scribes, use 'closeScribes' for that. This mainly only
-- makes sense to use with something like MonadReader's @local@
-- function to temporarily disavow any loggers for a block of code.
clearScribes
:: LogEnv
-> LogEnv
clearScribes = logEnvScribes .~ mempty
-------------------------------------------------------------------------------
-- | Finalize a scribe. The scribe is removed from the environment,
-- its finalizer is called so that it can never be written to again
-- and all pending writes are flushed. Note that this will throw any
-- exceptions yoru finalizer will throw, and that LogEnv is immutable,
-- so it will not be removed in that case.
closeScribe
:: Text
-- ^ Name of the scribe
-> LogEnv
-> IO LogEnv
closeScribe nm le = do
maybe (return ()) (scribeFinalizer . shScribe) (M.lookup nm (_logEnvScribes le))
return (le & logEnvScribes %~ M.delete nm)
-------------------------------------------------------------------------------
-- | Call this at the end of your program. This is a blocking call
-- that stop writing to a scribe's queue, waits for the queue to
-- empty, finalizes each scribe in the log environment and then
-- removes it. Finalizers are all run even if one of them throws, but
-- the exception will be re-thrown at the end.
closeScribes
:: LogEnv
-> IO LogEnv
closeScribes le = do
-- We want to run every finalizer here so we'll not save
-- intermediate logenvs and just clear scribes at the end.
let actions = [void (closeScribe k le) | k <- M.keys (_logEnvScribes le)]
FT.foldr finally (return ()) actions
return (le & logEnvScribes .~ mempty)
-------------------------------------------------------------------------------
-- | Monads where katip logging actions can be performed. Katip is the
-- most basic logging monad. You will typically use this directly if
-- you either don't want to use namespaces/contexts heavily or if you
-- want to pass in specific contexts and/or namespaces at each log site.
--
-- For something more powerful, look at the docs for 'KatipContext',
-- which keeps a namespace and merged context. You can write simple
-- functions that add additional namespacing and merges additional
-- context on the fly.
--
-- 'localLogEnv' was added to allow for lexically-scoped modifications
-- of the log env that are reverted when the supplied monad
-- completes. 'katipNoLogging', for example, uses this to temporarily
-- pause log outputs.
class MonadIO m => Katip m where
getLogEnv :: m LogEnv
localLogEnv :: (LogEnv -> LogEnv) -> m a -> m a
instance Katip m => Katip (ReaderT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapReaderT . localLogEnv
{-# INLINE localLogEnv #-}
#if !MIN_VERSION_either(4, 5, 0)
instance Katip m => Katip (EitherT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapEitherT . localLogEnv
{-# INLINE localLogEnv #-}
#endif
instance Katip m => Katip (ExceptT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapExceptT . localLogEnv
{-# INLINE localLogEnv #-}
instance Katip m => Katip (MaybeT m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapMaybeT . localLogEnv
{-# INLINE localLogEnv #-}
instance Katip m => Katip (StateT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapStateT . localLogEnv
{-# INLINE localLogEnv #-}
instance (Katip m, Monoid w) => Katip (RWST r w s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapRWST . localLogEnv
{-# INLINE localLogEnv #-}
instance (Katip m, Monoid w) => Katip (Strict.RWST r w s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = Strict.mapRWST . localLogEnv
{-# INLINE localLogEnv #-}
instance Katip m => Katip (Strict.StateT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = Strict.mapStateT . localLogEnv
{-# INLINE localLogEnv #-}
instance (Katip m, Monoid s) => Katip (WriterT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = mapWriterT . localLogEnv
{-# INLINE localLogEnv #-}
instance (Katip m, Monoid s) => Katip (Strict.WriterT s m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = Strict.mapWriterT . localLogEnv
{-# INLINE localLogEnv #-}
instance (Katip m) => Katip (ResourceT m) where
getLogEnv = lift getLogEnv
{-# INLINE getLogEnv #-}
localLogEnv = transResourceT . localLogEnv
{-# INLINE localLogEnv #-}
-------------------------------------------------------------------------------
-- | A concrete monad you can use to run logging actions. Use this if
-- you prefer an explicit monad transformer stack and adding layers as
-- opposed to implementing 'Katip' for your monad.
newtype KatipT m a = KatipT { unKatipT :: ReaderT LogEnv m a }
deriving ( Functor, Applicative, Monad, MonadIO
, MonadMask, MonadCatch, MonadThrow, MonadResource, MonadTrans
, MonadBase b)
instance MonadIO m => Katip (KatipT m) where
getLogEnv = KatipT ask
localLogEnv f (KatipT m) = KatipT $ local f m
instance MonadTransControl KatipT where
type StT (KatipT) a = a
liftWith f = KatipT $ ReaderT $ \le -> f $ \t -> runKatipT le t
restoreT = KatipT . ReaderT . const
{-# INLINABLE liftWith #-}
{-# INLINABLE restoreT #-}
instance (MonadBaseControl b m) => MonadBaseControl b (KatipT m) where
type StM ((KatipT) m) a = ComposeSt (KatipT) m a
liftBaseWith = defaultLiftBaseWith
restoreM = defaultRestoreM
instance MonadUnliftIO m => MonadUnliftIO (KatipT m) where
#if MIN_VERSION_unliftio_core(0, 2, 0)
withRunInIO inner = KatipT $ ReaderT $ \le -> withRunInIO $ \run ->
inner (run . runKatipT le)
#else
askUnliftIO = KatipT $
withUnliftIO $ \u ->
pure (UnliftIO (unliftIO u . unKatipT))
#endif
#if MIN_VERSION_base(4, 9, 0)
instance MF.MonadFail m => MF.MonadFail (KatipT m) where
fail msg = lift (MF.fail msg)
{-# INLINE fail #-}
#endif
-------------------------------------------------------------------------------
-- | Execute 'KatipT' on a log env.
runKatipT :: LogEnv -> KatipT m a -> m a
runKatipT le (KatipT f) = runReaderT f le
{-# INLINE runKatipT #-}
-------------------------------------------------------------------------------
-- | Disable all scribes for the given monadic action, then restore
-- them afterwards. Works in any Katip monad.
katipNoLogging
:: ( Katip m
)
=> m a
-> m a
katipNoLogging = localLogEnv (\le -> set logEnvScribes mempty le)
-------------------------------------------------------------------------------
-- | Log with everything, including a source code location. This is
-- very low level and you typically can use 'logT' in its place.
logItem
:: (A.Applicative m, LogItem a, Katip m)
=> a
-> Namespace
-> Maybe Loc
-> Severity
-> LogStr
-> m ()
logItem a ns loc sev msg = do
LogEnv{..} <- getLogEnv
logKatipItem =<< liftIO
(Item <$> pure _logEnvApp
<*> pure _logEnvEnv
<*> pure sev
<*> (mkThreadIdText <$> myThreadId)
<*> pure _logEnvHost
<*> pure _logEnvPid
<*> pure a
<*> pure msg
<*> _logEnvTimer
<*> pure (_logEnvApp <> ns)
<*> pure loc)
{-# INLINE logItem#-}
-- | Log already constructed 'Item'. This is the lowest level function that other log*
-- functions use.
-- It can be useful when implementing centralised logging services.
logKatipItem
:: (A.Applicative m, LogItem a, Katip m)
=> Item a
-> m ()
logKatipItem item = do
LogEnv{..} <- getLogEnv
liftIO $
FT.forM_ (M.elems _logEnvScribes) $ \ ScribeHandle {..} -> do
whenM (scribePermitItem shScribe item) $
void $ atomically (tryWriteTBQueue shChan (NewItem item))
{-# INLINE logKatipItem#-}
-------------------------------------------------------------------------------
tryWriteTBQueue
:: TBQueue a
-> a
-> STM Bool
-- ^ Did we write?
tryWriteTBQueue q a = do
full <- isFullTBQueue q
unless full (writeTBQueue q a)
return (not full)
{-# INLINE tryWriteTBQueue#-}
-------------------------------------------------------------------------------
-- | Log with full context, but without any code location.
logF
:: (Applicative m, LogItem a, Katip m)
=> a
-- ^ Contextual payload for the log
-> Namespace
-- ^ Specific namespace of the message.
-> Severity
-- ^ Severity of the message
-> LogStr
-- ^ The log message
-> m ()
logF a ns sev msg = logItem a ns Nothing sev msg
{-# INLINE logF#-}
-------------------------------------------------------------------------------
-- | Perform an action while logging any exceptions that may occur.
-- Inspired by 'onException`.
--
-- >>>> logException () mempty ErrorS (error "foo")
logException
:: (Katip m, LogItem a, MonadCatch m, Applicative m)
=> a -- ^ Log context
-> Namespace -- ^ Namespace
-> Severity -- ^ Severity
-> m b -- ^ Main action being run
-> m b
logException a ns sev action = action `catchAny` \e -> f e >> throwM e
where
f e = logF a ns sev (msg e)
msg e = ls (T.pack "An exception has occurred: ") <> showLS e
-------------------------------------------------------------------------------
-- | Log a message without any payload/context or code location.
logMsg
:: (Applicative m, Katip m)
=> Namespace
-> Severity
-> LogStr
-> m ()
logMsg ns sev msg = logF () ns sev msg
-- | Lift a location into an Exp.
liftLoc :: Loc -> Q Exp
liftLoc (Loc a b c (d1, d2) (e1, e2)) = [|Loc
$(TH.lift a)
$(TH.lift b)
$(TH.lift c)
($(TH.lift d1), $(TH.lift d2))
($(TH.lift e1), $(TH.lift e2))
|]
-------------------------------------------------------------------------------
-- | For use when you want to include location in your logs. This will
-- fill the 'Maybe Loc' gap in 'logF' of this module, and relies on implicit
-- callstacks when available (GHC > 7.8).
#if MIN_VERSION_base(4, 8, 0)
getLoc :: HasCallStack => Maybe Loc
getLoc = withFrozenCallStack $ toLoc <$> listToMaybe (getCallStack callStack)
where
toLoc :: (String, SrcLoc) -> Loc
toLoc (_, l) = Loc {
loc_filename = srcLocFile l
, loc_package = srcLocPackage l
, loc_module = srcLocModule l
, loc_start = (srcLocStartLine l, srcLocStartCol l)
, loc_end = (srcLocEndLine l, srcLocEndCol l)
}
#else
getLoc :: Maybe Loc
getLoc = Nothing
#endif
-------------------------------------------------------------------------------
-- Like `getLoc`, but uses template-haskell and works with older versions of
-- the compiler (GHC 7.8 or older).
getLocTH :: ExpQ
getLocTH = [| $(location >>= liftLoc) |]
-------------------------------------------------------------------------------
-- | 'Loc'-tagged logging when using template-haskell.
--
-- @$(logT) obj mempty InfoS "Hello world"@
logT :: ExpQ
logT = [| \ a ns sev msg -> logItem a ns (Just $(getLocTH)) sev msg |]
-------------------------------------------------------------------------------
-- | 'Loc'-tagged logging using 'GHC.Stack' when available.
--
-- This function does not require template-haskell as it
-- automatically uses <https://hackage.haskell.org/package/base-4.8.2.0/docs/GHC-Stack.html#v:getCallStack implicit-callstacks>
-- when the code is compiled using GHC > 7.8. Using an older version of the
-- compiler will result in the emission of a log line without any location information,
-- so be aware of it. Users using GHC <= 7.8 may want to use the template-haskell function
-- `logT` for maximum compatibility.
--
-- @logLoc obj mempty InfoS "Hello world"@
#if MIN_VERSION_base(4, 8, 0)
logLoc :: (Applicative m, LogItem a, Katip m, HasCallStack)
#else
logLoc :: (Applicative m, LogItem a, Katip m)
#endif
=> a
-> Namespace
-> Severity
-> LogStr
-> m ()
logLoc a ns = withFrozenCallStack $ logItem a ns getLoc
-- taken from the file-location package
-- turn the TH Loc loaction information into a human readable string
-- leaving out the loc_end parameter
locationToString :: Loc -> String
locationToString loc = (loc_package loc) ++ ':' : (loc_module loc) ++
' ' : (loc_filename loc) ++ ':' : (line loc) ++ ':' : (char loc)
where
line = show . fst . loc_start
char = show . snd . loc_start