@@ -7,7 +7,6 @@
77{-# LANGUAGE FlexibleInstances #-}
88{-# LANGUAGE GADTs #-}
99{-# LANGUAGE GeneralizedNewtypeDeriving #-}
10−{-# LANGUAGE ImplicitParams #-}
1110{-# LANGUAGE MultiParamTypeClasses #-}
1211{-# LANGUAGE OverloadedStrings #-}
1312{-# LANGUAGE RankNTypes #-}
@@ -23,40 +22,53 @@
2322module Katip.Core where
2423
2524-------------------------------------------------------------------------------
26−import Control.Applicative as A
25+import Control.Applicative as A
2726import Control.AutoUpdate
2827import Control.Concurrent
29−import qualified Control.Concurrent.Async as Async
28+import qualified Control.Concurrent.Async as Async
3029import Control.Concurrent.STM
31−import qualified Control.Concurrent.STM.TBQueue as BQ
30+import qualified Control.Concurrent.STM.TBQueue as BQ
3231import Control.Exception.Safe
33−import Control.Monad (unless, void)
32+import Control.Monad (unless, void, when)
3433import Control.Monad.Base
34+#if MIN_VERSION_base(4, 9, 0)
35+import qualified Control.Monad.Fail as MF
36+#endif
3537import Control.Monad.IO.Class
38+import Control.Monad.IO.Unlift
3639import Control.Monad.Trans.Class
3740import Control.Monad.Trans.Control
41+#if !MIN_VERSION_either(4, 5, 0)
3842import Control.Monad.Trans.Either
43+#endif
3944import Control.Monad.Trans.Except
4045import Control.Monad.Trans.Maybe
4146import Control.Monad.Trans.Reader
42−import Control.Monad.Trans.Resource (ResourceT)
43−import Control.Monad.Trans.State
44−import Control.Monad.Trans.Writer
45−import Data.Aeson (FromJSON (..),
46− ToJSON (..), object)
47−import qualified Data.Aeson as A
48−import Data.Foldable as FT
49−import qualified Data.HashMap.Strict as HM
47+import Control.Monad.Trans.Resource (MonadResource, ResourceT,
48+ transResourceT)
49+import Control.Monad.Trans.RWS.Lazy (RWST, mapRWST)
50+import qualified Control.Monad.Trans.RWS.Strict as Strict (RWST, mapRWST)
51+import Control.Monad.Trans.State.Lazy (StateT, mapStateT)
52+import qualified Control.Monad.Trans.State.Strict as Strict (StateT, mapStateT)
53+import Control.Monad.Trans.Writer.Lazy (WriterT, mapWriterT)
54+import qualified Control.Monad.Trans.Writer.Strict as Strict (WriterT,
55+ mapWriterT)
56+import Data.Aeson (FromJSON (..), ToJSON (..),
57+ object)
58+import qualified Data.Aeson as A
59+import Data.Foldable as FT
60+import qualified Data.HashMap.Strict as HM
5061import Data.List
51−import qualified Data.Map.Strict as M
52−import Data.Semigroup
62+import qualified Data.Map.Strict as M
63+import Data.Maybe (fromMaybe)
64+import Data.Semigroup as SG
5365import Data.String
5466import Data.String.Conv
55−import Data.Text (Text)
56−import qualified Data.Text as T
57−import qualified Data.Text.Lazy.Builder as B
67+import Data.Text (Text)
68+import qualified Data.Text as T
69+import qualified Data.Text.Lazy.Builder as B
5870import Data.Time
59−import GHC.Generics hiding (to)
71+import GHC.Generics hiding (to)
6072#if MIN_VERSION_base(4, 8, 0)
6173#if !MIN_VERSION_base(4, 9, 0)
6274import GHC.SrcLoc
@@ -64,7 +76,7 @@ import GHC.SrcLoc
6476import GHC.Stack
6577#endif
6678import Language.Haskell.TH
67−import qualified Language.Haskell.TH.Syntax as TH
79+import qualified Language.Haskell.TH.Syntax as TH
6880import Lens.Micro
6981import Lens.Micro.TH
7082import Network.HostName
@@ -91,7 +103,7 @@ readMay s = case [x | (x,t) <- reads s, ("","") <- lex t] of
91103-- IsString/OverloadedStrings, so "foo" will result in Namespace
92104-- ["foo"].
93105newtype Namespace = Namespace { unNamespace :: [Text] }
94− deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,Semigroup,Monoid)
106+ deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,SG.Semigroup,Monoid)
95107
96108instance IsString Namespace where
97109 fromString s = Namespace [fromString s]
@@ -131,7 +143,7 @@ data Severity
131143-- - 'V3' implies the maximum amount of payload information.
132144-- - Anything in between is left to the discretion of the developer.
133145data Verbosity = V0 | V1 | V2 | V3
134− deriving (Eq, Ord, Show, Read, Generic, Enum)
146+ deriving (Eq, Ord, Show, Read, Generic, Enum, Bounded)
135147
136148
137149-------------------------------------------------------------------------------
@@ -172,11 +184,26 @@ instance FromJSON Severity where
172184 Just x -> return x
173185 Nothing -> fail $ "Invalid Severity " ++ toS t
174186
187+instance ToJSON Verbosity where
188+ toJSON s = A.String $ case s of
189+ V0 -> "V0"
190+ V1 -> "V1"
191+ V2 -> "V2"
192+ V3 -> "V3"
193+
194+instance FromJSON Verbosity where
195+ parseJSON = A.withText "Verbosity" $ \s -> case s of
196+ "V0" -> return V0
197+ "V1" -> return V1
198+ "V2" -> return V2
199+ "V3" -> return V3
200+ _ -> fail $ "Invalid Verbosity " ++ toS s
201+
175202
176203-------------------------------------------------------------------------------
177−-- | Log message with Builder unerneath; use '<>' to concat in O(1).
204+-- | Log message with Builder underneath; use '<>' to concat in O(1).
178205newtype LogStr = LogStr { unLogStr :: B.Builder }
179− deriving (Generic, Show)
206+ deriving (Generic, Show, Eq)
180207
181208instance IsString LogStr where
182209 fromString = LogStr . B.fromString
@@ -198,7 +225,7 @@ instance FromJSON LogStr where
198225
199226-------------------------------------------------------------------------------
200227-- | Pack any string-like thing into a 'LogStr'. This will
201−-- automatically work on 'String', 'ByteString, 'Text' and any of the
228+-- automatically work on 'String', 'ByteString', 'Text' and any of the
202229-- lazy variants.
203230logStr :: StringConv a Text => a -> LogStr
204231logStr t = LogStr (B.fromText $ toS t)
@@ -223,7 +250,9 @@ newtype ThreadIdText = ThreadIdText {
223250
224251
225252mkThreadIdText :: ThreadId -> ThreadIdText
226−mkThreadIdText = ThreadIdText . T.pack . show
253+mkThreadIdText = ThreadIdText . stripPrefix' "ThreadId " . T.pack . show
254+ where
255+ stripPrefix' pfx t = fromMaybe t (T.stripPrefix pfx t)
227256
228257
229258-------------------------------------------------------------------------------
@@ -243,31 +272,62 @@ data Item a = Item {
243272 } deriving (Generic, Functor)
244273makeLenses ''Item
245274
275+-- Manual instance because 'Loc' has no 'Eq' and 'Show' instances in old
276+-- versions of template-haskell (< 2.10)
277+instance Eq a => Eq (Item a) where
278+ a == b = FT.and [ _itemApp a == _itemApp b
279+ , _itemEnv a == _itemEnv b
280+ , _itemSeverity a == _itemSeverity b
281+ , _itemThread a == _itemThread b
282+ , _itemHost a == _itemHost b
283+ , _itemProcess a == _itemProcess b
284+ , _itemPayload a == _itemPayload b
285+ , _itemMessage a == _itemMessage b
286+ , _itemTime a == _itemTime b
287+ , _itemNamespace a == _itemNamespace b
288+ , case (_itemLoc a, _itemLoc b) of
289+ (Nothing, Nothing) -> True
290+ (Just l1, Just l2) -> FT.and [ loc_filename l1 == loc_filename l2
291+ , loc_package l1 == loc_package l2
292+ , loc_module l1 == loc_module l2
293+ , loc_start l1 == loc_start l2
294+ , loc_end l1 == loc_end l2
295+ ]
296+ _ -> False
297+ ]
246298
247299instance Show a => Show (Item a) where
248− show Item{..} = "Item {_itemApp = " ++ show _itemApp ++ ", " ++
249− "_itemEnv = " ++ show _itemEnv ++ ", " ++
250− "_itemSeverity = " ++ show _itemSeverity ++ ", " ++
251− "_itemThread = " ++ show _itemThread ++ ", " ++
252− "_itemHost = " ++ show _itemHost ++ ", " ++
253− "_itemProcess = " ++ show _itemProcess ++ ", " ++
254− "_itemPayload = " ++ show _itemPayload ++ ", " ++
255− "_itemMessage = " ++ show _itemMessage ++ ", " ++
256− "_itemTime = " ++ show _itemTime ++ ", " ++
257− "_itemNamespace = " ++ show _itemNamespace ++ ", " ++
258− "_itemLoc = " ++ show (LocShow <$> _itemLoc) ++ "}"
259−
300+ showsPrec d Item{..} = showParen (d >= 11) ( showString "Item {"
301+ . field "_itemApp" _itemApp
302+ . field "_itemEnv" _itemEnv
303+ . field "_itemSeverity" _itemSeverity
304+ . field "_itemThread" _itemThread
305+ . field "_itemHost" _itemHost
306+ . field "_itemProcess" _itemProcess
307+ . field "_itemPayload" _itemPayload
308+ . field "_itemMessage" _itemMessage
309+ . field "_itemTime" _itemTime
310+ . field "_itemNamespace" _itemNamespace
311+ . showString "_itemLoc = " . shows (LocShow <$> _itemLoc)
312+ . showChar '}'
313+ )
314+ where
315+ field n v = showString n . showString " = " . shows v . showString ", "
260316
261317newtype LocShow = LocShow Loc
262318
263319
264320instance Show LocShow where
265− show (LocShow Loc{..}) =
266− "Loc {loc_filename = " ++ show loc_filename ++ ", " ++
267− "loc_package = " ++ show loc_package ++ ", " ++
268− "loc_module = " ++ show loc_module ++ ", " ++
269− "loc_start = " ++ show loc_start ++ ", " ++
270− "loc_end = " ++ show loc_end ++ "}"
321+ showsPrec d (LocShow Loc{..}) = showParen (d >= 11) ( showString "Loc {"
322+ . field "loc_filename" loc_filename
323+ . field "loc_package" loc_package
324+ . field "loc_module" loc_module
325+ . field "loc_start" loc_start
326+ . showString "loc_end = " . shows loc_end
327+ . showChar '}'
328+ )
329+ where
330+ field n v = showString n . showString " = " . shows v . showString ", "
271331
272332
273333instance ToJSON a => ToJSON (Item a) where
@@ -480,52 +540,93 @@ itemJson verb a = toJSON $ a & itemPayload %~ payloadObject verb
480540--
481541-- Scribes should always take a 'Severity' and 'Verbosity'.
482542--
483−-- Severity is used to *exclude log messages* that are < the provided
484−-- Severity. For instance, if the user passes InfoS, DebugS items
485−-- should be ignored. Katip provides the 'permitItem' utility for this.
543+-- Severity is used to __exclude log messages__ that are lower than
544+-- the provided Severity. For instance, if the user passes InfoS,
545+-- DebugS items should be ignored. Katip provides the 'permitItem'
546+-- utility for this. The user or the scribe may use 'permitAND' and
547+-- 'permitOR' to further customize this filtering, even dynamically if
548+-- they wish to.
486549--
487550-- Verbosity is used to select keys from the log item's payload. Each
488551-- 'LogItem' instance describes what keys should be retained for each
489552-- Verbosity level. Use the 'payloadObject' utility for extracting the keys
490−-- that should be permitted.
553+-- that should be written.
491554--
492−-- There is no built-in mechanism in katip for telling a scribe that
493−-- its time to shut down. 'unregisterScribe' merely drops it from the
494−-- 'LogEnv'. This means there are 2 ways to handle resources as a scribe:
555+-- Scribes provide a finalizer IO action ('scribeFinalizer') that is
556+-- meant to synchronously flush any remaining writes and clean up any
557+-- resources acquired when the scribe was created. Internally, katip
558+-- keeps a buffer for each scribe's writes. When 'closeScribe' or
559+-- 'closeScribes' is called, that buffer stops accepting new log
560+-- messages and after the last item in its buffer is sent to 'liPush',
561+-- calls the finalizer. Thus, when the finalizer returns, katip can
562+-- assume that all resources are cleaned up and all log messages are
563+-- durably written.
495564--
496−-- 1. Pass in the resource when the scribe is created. Handle
497−-- allocation and release of the resource elsewhere. This is what the
498−-- Handle scribe does.
499−--
500−-- 2. Return a finalizing function that tells the scribe to shut
501−-- down. @katip-elasticsearch@'s @mkEsScribe@ returns a @IO (Scribe,
502−-- IO ())@. The finalizer will flush any queued log messages and shut
503−-- down gracefully before returning. This can be hooked into your
504−-- application's shutdown routine to ensure you never miss any log
505−-- messages on shutdown.
565+-- While katip internally buffers messages per 'ScribeSettings', it
566+-- sends them one at a time to the scribe. Depending on the scribe
567+-- itself, it may make sense for that scribe to keep its own internal
568+-- buffer to batch-send logs if writing items one at a time is not
569+-- efficient. The scribe implementer must be sure that on
570+-- finalization, all writes are committed synchronously.
571+
572+-- | Signature of a function passed to `Scribe` constructor and
573+-- mkScribe* functions that decides which messages to be
574+-- logged. Typically filters based on 'Severity', but can be
575+-- combined with other, custom logic with 'permitAND' and 'permitOR'
576+type PermitFunc = forall a. Item a -> IO Bool
577+
578+
579+-- | AND together 2 permit functions
580+permitAND :: PermitFunc -> PermitFunc -> PermitFunc
581+permitAND f1 f2 = \a -> liftA2 (&&) (f1 a) (f2 a)
582+
583+-- | OR together 2 permit functions
584+permitOR :: PermitFunc -> PermitFunc -> PermitFunc
585+permitOR f1 f2 = \a -> liftA2 (||) (f1 a) (f2 a)
586+
587+
506588data Scribe = Scribe {
507− liPush :: forall a. LogItem a => Item a -> IO ()
508− , scribeFinalizer :: IO ()
509− -- ^ Provide a *blocking* finalizer to call when your scribe is
510− -- removed. If this is not relevant to your scribe, return () is
511− -- fine.
589+ liPush :: forall a. LogItem a => Item a -> IO ()
590+ -- ^ How do we write an item to the scribe's output?
591+ , scribeFinalizer :: IO ()
592+ -- ^ Provide a __blocking__ finalizer to call when your scribe is
593+ -- removed. All pending writes should be flushed synchronously. If
594+ -- this is not relevant to your scribe, return () is fine.
595+ , scribePermitItem :: PermitFunc
596+ -- ^ Provide a filtering function to allow the item to be logged,
597+ -- or not. It can check Severity or some string in item's
598+ -- body. The initial value of this is usually created from
599+ -- 'permitItem'. Scribes and users can customize this by ANDing
600+ -- or ORing onto the default with 'permitAND' or 'permitOR'
512601 }
513602
514603
604+whenM :: Monad m => m Bool -> m () -> m ()
605+whenM mbool = (>>=) mbool . flip when
606+
607+
608+-- | Combine two scribes. Publishes to the left scribe if the left
609+-- would permit the item and to the right scribe if the right would
610+-- permit the item. Finalizers are called in sequence from left to
611+-- right.
515612instance Semigroup Scribe where
516− (Scribe pushA finA) <> (Scribe pushB finB) =
517− Scribe (\item -> pushA item >> pushB item) (finA `finally` finB)
613+ (Scribe pushA finA permitA) <> (Scribe pushB finB permitB) =
614+ Scribe (\item -> whenM (permitA item) (pushA item)
615+ >> whenM (permitB item) (pushB item)
616+ )
617+ (finA `finally` finB)
618+ (permitOR permitA permitB)
518619
519620
520621instance Monoid Scribe where
521− mempty = Scribe (const (return ())) (return ())
622+ mempty = Scribe (const (return ())) (return ()) (permitItem DebugS)
522623 mappend = (<>)
523624
524625
525626-------------------------------------------------------------------------------
526627data ScribeHandle = ScribeHandle {
527628 shScribe :: Scribe
528− , shChan :: BQ.TBQueue WorkerMessage
629+ , shChan :: BQ.TBQueue WorkerMessage
529630 }
530631
531632
@@ -537,8 +638,9 @@ data WorkerMessage where
537638
538639-------------------------------------------------------------------------------
539640-- | Should this item be logged given the user's maximum severity?
540−permitItem :: Severity -> Item a -> Bool
541−permitItem sev i = _itemSeverity i >= sev
641+-- Most new scribes will use this as a base for their 'PermitFunc'
642+permitItem :: Monad m => Severity -> Item a -> m Bool
643+permitItem sev item = return (_itemSeverity item >= sev)
542644
543645
544646-------------------------------------------------------------------------------
@@ -563,10 +665,10 @@ makeLenses ''LogEnv
563665
564666
565667-------------------------------------------------------------------------------
566−-- | Create a reasonable default InitLogEnv. Uses an 'AutoUdate' with
567−-- the default settings as the timer. If you are concerned about
568−-- timestamp precision or event ordering in log outputs like
569−-- ElasticSearch, you should replace the timer with 'getCurrentTime'
668+-- | Create a reasonable default InitLogEnv. Uses an 'AutoUpdate' which
669+-- updates the timer every 1ms. If you need even more timestamp
670+-- precision at the cost of performance, consider setting
671+-- '_logEnvTimer' with 'getCurrentTime'.
570672initLogEnv
571673 :: Namespace
572674 -- ^ A base namespace for this application
@@ -578,13 +680,15 @@ initLogEnv an env = LogEnv
578680 <*> getProcessID
579681 <*> pure an
580682 <*> pure env
581− <*> mkAutoUpdate defaultUpdateSettings { updateAction = getCurrentTime }
683+ <*> mkAutoUpdate defaultUpdateSettings { updateAction = getCurrentTime, updateFreq = 1000 }
582684 <*> pure mempty
583685
584686
585687-------------------------------------------------------------------------------
586688-- | Add a scribe to the list. All future log calls will go to this
587−-- scribe in addition to the others.
689+-- scribe in addition to the others. Writes will be buffered per the
690+-- ScribeSettings to prevent slow scribes from slowing down
691+-- logging. Writes will be dropped if the buffer fills.
588692registerScribe
589693 :: Text
590694 -- ^ Name the scribe
@@ -593,14 +697,14 @@ registerScribe
593697 -> LogEnv
594698 -> IO LogEnv
595699registerScribe nm scribe ScribeSettings {..} le = do
596− queue <- atomically (BQ.newTBQueue _scribeBufferSize)
700+ queue <- atomically (BQ.newTBQueue (fromIntegral _scribeBufferSize))
597701 worker <- spawnScribeWorker scribe queue
598702 let fin = do
599703 atomically (BQ.writeTBQueue queue PoisonPill)
600704 -- wait for our worker to finish final write
601705 void (Async.waitCatch worker)
602706 -- wait for scribe to finish final write
603− void (tryAny (scribeFinalizer scribe))
707+ void (scribeFinalizer scribe)
604708
605709 let sh = ScribeHandle (scribe { scribeFinalizer = fin }) queue
606710 return (le & logEnvScribes %~ M.insert nm sh)
@@ -608,7 +712,7 @@ registerScribe nm scribe ScribeSettings {..} le = do
608712
609713-------------------------------------------------------------------------------
610714spawnScribeWorker :: Scribe -> BQ.TBQueue WorkerMessage -> IO (Async.Async ())
611−spawnScribeWorker (Scribe write _) queue = Async.async go
715+spawnScribeWorker (Scribe write _ _) queue = Async.async go
612716 where
613717 go = do
614718 newCmd <- atomically (BQ.readTBQueue queue)
@@ -625,6 +729,7 @@ spawnScribeWorker (Scribe write _) queue = Async.async go
625729data ScribeSettings = ScribeSettings {
626730 _scribeBufferSize :: Int
627731 }
732+ deriving (Show, Eq)
628733
629734makeLenses ''ScribeSettings
630735
@@ -636,7 +741,7 @@ defaultScribeSettings = ScribeSettings 4096
636741
637742
638743-------------------------------------------------------------------------------
639−-- | Remove a scribe from the environment. This does *not* finalize
744+-- | Remove a scribe from the environment. This does __not__ finalize
640745-- the scribe. This mainly only makes sense to use with something like
641746-- MonadReader's @local@ function to temporarily disavow a single
642747-- logger for a block of code.
@@ -649,7 +754,7 @@ unregisterScribe nm = logEnvScribes %~ M.delete nm
649754
650755
651756-------------------------------------------------------------------------------
652−-- | Unregister *all* scribes. Note that this is *not* for closing or
757+-- | Unregister __all__ scribes. Note that this is __not__ for closing or
653758-- finalizing scribes, use 'closeScribes' for that. This mainly only
654759-- makes sense to use with something like MonadReader's @local@
655760-- function to temporarily disavow any loggers for a block of code.
@@ -661,7 +766,10 @@ clearScribes = logEnvScribes .~ mempty
661766
662767-------------------------------------------------------------------------------
663768-- | Finalize a scribe. The scribe is removed from the environment,
664−-- its finalizer is called and it can never be written to again.
769+-- its finalizer is called so that it can never be written to again
770+-- and all pending writes are flushed. Note that this will throw any
771+-- exceptions yoru finalizer will throw, and that LogEnv is immutable,
772+-- so it will not be removed in that case.
665773closeScribe
666774 :: Text
667775 -- ^ Name of the scribe
@@ -676,12 +784,17 @@ closeScribe nm le = do
676784-- | Call this at the end of your program. This is a blocking call
677785-- that stop writing to a scribe's queue, waits for the queue to
678786-- empty, finalizes each scribe in the log environment and then
679−-- removes it.
787+-- removes it. Finalizers are all run even if one of them throws, but
788+-- the exception will be re-thrown at the end.
680789closeScribes
681790 :: LogEnv
682791 -> IO LogEnv
683−closeScribes le =
684− foldrM closeScribe le (M.keys (_logEnvScribes le))
792+closeScribes le = do
793+ -- We want to run every finalizer here so we'll not save
794+ -- intermediate logenvs and just clear scribes at the end.
795+ let actions = [void (closeScribe k le) | k <- M.keys (_logEnvScribes le)]
796+ FT.foldr finally (return ()) actions
797+ return (le & logEnvScribes .~ mempty)
685798
686799
687800-------------------------------------------------------------------------------
@@ -694,44 +807,86 @@ closeScribes le =
694807-- which keeps a namespace and merged context. You can write simple
695808-- functions that add additional namespacing and merges additional
696809-- context on the fly.
810+--
811+-- 'localLogEnv' was added to allow for lexically-scoped modifications
812+-- of the log env that are reverted when the supplied monad
813+-- completes. 'katipNoLogging', for example, uses this to temporarily
814+-- pause log outputs.
697815class MonadIO m => Katip m where
698816 getLogEnv :: m LogEnv
817+ localLogEnv :: (LogEnv -> LogEnv) -> m a -> m a
699818
700819
701820instance Katip m => Katip (ReaderT s m) where
702821 getLogEnv = lift getLogEnv
822+ localLogEnv = mapReaderT . localLogEnv
703823
704824
825+#if !MIN_VERSION_either(4, 5, 0)
705826instance Katip m => Katip (EitherT s m) where
706827 getLogEnv = lift getLogEnv
828+ localLogEnv = mapEitherT . localLogEnv
829+#endif
830+
707831
708832instance Katip m => Katip (ExceptT s m) where
709833 getLogEnv = lift getLogEnv
834+ localLogEnv = mapExceptT . localLogEnv
835+
710836
711837instance Katip m => Katip (MaybeT m) where
712838 getLogEnv = lift getLogEnv
839+ localLogEnv = mapMaybeT . localLogEnv
713840
714841
715842instance Katip m => Katip (StateT s m) where
716843 getLogEnv = lift getLogEnv
844+ localLogEnv = mapStateT . localLogEnv
845+
846+
847+instance (Katip m, Monoid w) => Katip (RWST r w s m) where
848+ getLogEnv = lift getLogEnv
849+ localLogEnv = mapRWST . localLogEnv
850+
851+
852+instance (Katip m, Monoid w) => Katip (Strict.RWST r w s m) where
853+ getLogEnv = lift getLogEnv
854+ localLogEnv = Strict.mapRWST . localLogEnv
855+
856+
857+instance Katip m => Katip (Strict.StateT s m) where
858+ getLogEnv = lift getLogEnv
859+ localLogEnv = Strict.mapStateT . localLogEnv
717860
718861
719862instance (Katip m, Monoid s) => Katip (WriterT s m) where
720863 getLogEnv = lift getLogEnv
864+ localLogEnv = mapWriterT . localLogEnv
865+
866+
867+instance (Katip m, Monoid s) => Katip (Strict.WriterT s m) where
868+ getLogEnv = lift getLogEnv
869+ localLogEnv = Strict.mapWriterT . localLogEnv
870+
721871
722872instance (Katip m) => Katip (ResourceT m) where
723873 getLogEnv = lift getLogEnv
874+ localLogEnv = transResourceT . localLogEnv
724875
725876
726877-------------------------------------------------------------------------------
727−-- | A concrete monad you can use to run logging actions.
878+-- | A concrete monad you can use to run logging actions. Use this if
879+-- you prefer an explicit monad transformer stack and adding layers as
880+-- opposed to implementing 'Katip' for your monad.
728881newtype KatipT m a = KatipT { unKatipT :: ReaderT LogEnv m a }
729882 deriving ( Functor, Applicative, Monad, MonadIO
730− , MonadMask, MonadCatch, MonadThrow, MonadTrans, MonadBase b)
883+ , MonadMask, MonadCatch, MonadThrow, MonadResource, MonadTrans
884+ , MonadBase b)
731885
732886
733887instance MonadIO m => Katip (KatipT m) where
734888 getLogEnv = KatipT ask
889+ localLogEnv f (KatipT m) = KatipT $ local f m
735890
736891
737892instance MonadTransControl KatipT where
@@ -747,6 +902,21 @@ instance (MonadBaseControl b m) => MonadBaseControl b (KatipT m) where
747902 liftBaseWith = defaultLiftBaseWith
748903 restoreM = defaultRestoreM
749904
905+instance MonadUnliftIO m => MonadUnliftIO (KatipT m) where
906+#if MIN_VERSION_unliftio_core(0, 2, 0)
907+ withRunInIO inner = KatipT $ ReaderT $ \le -> withRunInIO $ \run ->
908+ inner (run . runKatipT le)
909+#else
910+ askUnliftIO = KatipT $
911+ withUnliftIO $ \u ->
912+ pure (UnliftIO (unliftIO u . unKatipT))
913+#endif
914+
915+#if MIN_VERSION_base(4, 9, 0)
916+instance MF.MonadFail m => MF.MonadFail (KatipT m) where
917+ fail msg = lift (MF.fail msg)
918+ {-# INLINE fail #-}
919+#endif
750920
751921-------------------------------------------------------------------------------
752922-- | Execute 'KatipT' on a log env.
@@ -754,6 +924,17 @@ runKatipT :: LogEnv -> KatipT m a -> m a
754924runKatipT le (KatipT f) = runReaderT f le
755925
756926
927+-------------------------------------------------------------------------------
928+-- | Disable all scribes for the given monadic action, then restore
929+-- them afterwards. Works in any Katip monad.
930+katipNoLogging
931+ :: ( Katip m
932+ )
933+ => m a
934+ -> m a
935+katipNoLogging = localLogEnv (\le -> set logEnvScribes mempty le)
936+
937+
757938-------------------------------------------------------------------------------
758939-- | Log with everything, including a source code location. This is
759940-- very low level and you typically can use 'logT' in its place.
@@ -767,22 +948,32 @@ logItem
767948 -> m ()
768949logItem a ns loc sev msg = do
769950 LogEnv{..} <- getLogEnv
770− liftIO $ do
771− item <- Item
772− <$> pure _logEnvApp
773− <*> pure _logEnvEnv
774− <*> pure sev
775− <*> (mkThreadIdText <$> myThreadId)
776− <*> pure _logEnvHost
777− <*> pure _logEnvPid
778− <*> pure a
779− <*> pure msg
780− <*> _logEnvTimer
781− <*> pure (_logEnvApp <> ns)
782− <*> pure loc
783− FT.forM_ (M.elems _logEnvScribes) $ \ ScribeHandle {..} -> atomically (tryWriteTBQueue shChan (NewItem item))
784− --TODO: if we use tbqueue, write an atomic tryWriteTBQueue
785−
951+ logKatipItem =<< liftIO
952+ (Item <$> pure _logEnvApp
953+ <*> pure _logEnvEnv
954+ <*> pure sev
955+ <*> (mkThreadIdText <$> myThreadId)
956+ <*> pure _logEnvHost
957+ <*> pure _logEnvPid
958+ <*> pure a
959+ <*> pure msg
960+ <*> _logEnvTimer
961+ <*> pure (_logEnvApp <> ns)
962+ <*> pure loc)
963+
964+-- | Log already constructed 'Item'. This is the lowest level function that other log*
965+-- functions use.
966+-- It can be useful when implementing centralised logging services.
967+logKatipItem
968+ :: (A.Applicative m, LogItem a, Katip m)
969+ => Item a
970+ -> m ()
971+logKatipItem item = do
972+ LogEnv{..} <- getLogEnv
973+ liftIO $
974+ FT.forM_ (M.elems _logEnvScribes) $ \ ScribeHandle {..} -> do
975+ whenM (scribePermitItem shScribe item) $
976+ void $ atomically (tryWriteTBQueue shChan (NewItem item))
786977
787978-------------------------------------------------------------------------------
788979tryWriteTBQueue
@@ -795,6 +986,7 @@ tryWriteTBQueue q a = do
795986 unless full (writeTBQueue q a)
796987 return (not full)
797988
989+
798990-------------------------------------------------------------------------------
799991-- | Log with full context, but without any code location.
800992logF
@@ -827,7 +1019,7 @@ logException
8271019logException a ns sev action = action `catchAny` \e -> f e >> throwM e
8281020 where
8291021 f e = logF a ns sev (msg e)
830− msg e = ls (T.pack "An exception has occured: ") <> showLS e
1022+ msg e = ls (T.pack "An exception has occurred: ") <> showLS e
8311023
8321024
8331025-------------------------------------------------------------------------------
@@ -881,11 +1073,15 @@ liftLoc (Loc a b c (d1, d2) (e1, e2)) = [|Loc
8811073-- fill the 'Maybe Loc' gap in 'logF' of this module, and relies on implicit
8821074-- callstacks when available (GHC > 7.8).
8831075#if MIN_VERSION_base(4, 8, 0)
884−getLoc :: (?loc :: CallStack) => Maybe Loc
885−getLoc = case getCallStack ?loc of
1076+getLoc :: HasCallStack => Maybe Loc
1077+getLoc = case getCallStack callStack of
8861078 [] -> Nothing
887− xs -> Just . toLoc . last $ xs
1079+ xs -> Just . toLoc . head $ filter filterKatip xs
8881080 where
1081+ filterKatip :: (String, SrcLoc) -> Bool
1082+ filterKatip (_, srcloc) = not $
1083+ "katip-" `isPrefixOf` srcLocPackage srcloc
1084+
8891085 toLoc :: (String, SrcLoc) -> Loc
8901086 toLoc (_, l) = Loc {
8911087 loc_filename = srcLocFile l
@@ -916,7 +1112,7 @@ logT = [| \ a ns sev msg -> logItem a ns (Just $(getLocTH)) sev msg |]
9161112
9171113
9181114-------------------------------------------------------------------------------
919−-- | 'Loc'-tagged logging using implicit-callstacks when available.
1115+-- | 'Loc'-tagged logging using 'GHC.Stack' when available.
9201116--
9211117-- This function does not require template-haskell as it
9221118-- automatically uses <https://hackage.haskell.org/package/base-4.8.2.0/docs/GHC-Stack.html#v:getCallStack implicit-callstacks>
@@ -927,7 +1123,7 @@ logT = [| \ a ns sev msg -> logItem a ns (Just $(getLocTH)) sev msg |]
9271123--
9281124-- @logLoc obj mempty InfoS "Hello world"@
9291125#if MIN_VERSION_base(4, 8, 0)
930−logLoc :: (Applicative m, LogItem a, Katip m, ?loc :: CallStack)
1126+logLoc :: (Applicative m, LogItem a, Katip m, HasCallStack)
9311127#else
9321128logLoc :: (Applicative m, LogItem a, Katip m)
9331129#endif