@@ -1,1146 +0,0 @@
1−{-# LANGUAGE CPP #-}
2−{-# LANGUAGE DefaultSignatures #-}
3−{-# LANGUAGE DeriveFunctor #-}
4−{-# LANGUAGE DeriveGeneric #-}
5−{-# LANGUAGE ExistentialQuantification #-}
6−{-# LANGUAGE FlexibleContexts #-}
7−{-# LANGUAGE FlexibleInstances #-}
8−{-# LANGUAGE GADTs #-}
9−{-# LANGUAGE GeneralizedNewtypeDeriving #-}
10−{-# LANGUAGE MultiParamTypeClasses #-}
11−{-# LANGUAGE OverloadedStrings #-}
12−{-# LANGUAGE RankNTypes #-}
13−{-# LANGUAGE RecordWildCards #-}
14−{-# LANGUAGE TemplateHaskell #-}
15−{-# LANGUAGE TypeFamilies #-}
16−{-# LANGUAGE UndecidableInstances #-}
17−#if MIN_VERSION_base(4, 9, 0)
18−{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
19−#endif
20−-- | This module is not meant to be imported directly and may contain
21−-- internal mechanisms that will change without notice.
22−module Katip.Core where
23−
24−-------------------------------------------------------------------------------
25−import Control.Applicative as A
26−import Control.AutoUpdate
27−import Control.Concurrent
28−import qualified Control.Concurrent.Async as Async
29−import Control.Concurrent.STM
30−import qualified Control.Concurrent.STM.TBQueue as BQ
31−import Control.Exception.Safe
32−import Control.Monad (unless, void, when)
33−import Control.Monad.Base
34−#if MIN_VERSION_base(4, 9, 0)
35−import qualified Control.Monad.Fail as MF
36−#endif
37−import Control.Monad.IO.Class
38−import Control.Monad.IO.Unlift
39−import Control.Monad.Trans.Class
40−import Control.Monad.Trans.Control
41−#if !MIN_VERSION_either(4, 5, 0)
42−import Control.Monad.Trans.Either
43−#endif
44−import Control.Monad.Trans.Except
45−import Control.Monad.Trans.Maybe
46−import Control.Monad.Trans.Reader
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
61−import Data.List
62−import qualified Data.Map.Strict as M
63−import Data.Maybe (fromMaybe)
64−import Data.Semigroup as SG
65−import Data.String
66−import Data.String.Conv
67−import Data.Text (Text)
68−import qualified Data.Text as T
69−import qualified Data.Text.Lazy.Builder as B
70−import Data.Time
71−import GHC.Generics hiding (to)
72−#if MIN_VERSION_base(4, 8, 0)
73−#if !MIN_VERSION_base(4, 9, 0)
74−import GHC.SrcLoc
75−#endif
76−import GHC.Stack
77−#endif
78−import Language.Haskell.TH
79−import qualified Language.Haskell.TH.Syntax as TH
80−import Lens.Micro
81−import Lens.Micro.TH
82−import Network.HostName
83−#if mingw32_HOST_OS
84−import Katip.Compat
85−#else
86−import System.Posix
87−#endif
88−
89−-------------------------------------------------------------------------------
90−
91−
92−readMay :: Read a => String -> Maybe a
93−readMay s = case [x | (x,t) <- reads s, ("","") <- lex t] of
94− [x] -> Just x
95− [] -> Nothing -- no parse
96− _ -> Nothing -- Ambiguous parse
97−
98−
99−-------------------------------------------------------------------------------
100−-- | Represents a heirarchy of namespaces going from general to
101−-- specific. For instance: ["processname", "subsystem"]. Note that
102−-- single-segment namespaces can be created using
103−-- IsString/OverloadedStrings, so "foo" will result in Namespace
104−-- ["foo"].
105−newtype Namespace = Namespace { unNamespace :: [Text] }
106− deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,SG.Semigroup,Monoid)
107−
108−instance IsString Namespace where
109− fromString s = Namespace [fromString s]
110−
111−
112−-------------------------------------------------------------------------------
113−-- | Ready namespace for emission with dots to join the segments.
114−intercalateNs :: Namespace -> [Text]
115−intercalateNs (Namespace xs) = intersperse "." xs
116−
117−
118−-------------------------------------------------------------------------------
119−-- | Application environment, like @prod@, @devel@, @testing@.
120−newtype Environment = Environment { getEnvironment :: Text }
121− deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,IsString)
122−
123−
124−-------------------------------------------------------------------------------
125−data Severity
126− = DebugS -- ^ Debug messages
127− | InfoS -- ^ Information
128− | NoticeS -- ^ Normal runtime Conditions
129− | WarningS -- ^ General Warnings
130− | ErrorS -- ^ General Errors
131− | CriticalS -- ^ Severe situations
132− | AlertS -- ^ Take immediate action
133− | EmergencyS -- ^ System is unusable
134− deriving (Eq, Ord, Show, Read, Generic, Enum, Bounded)
135−
136−
137−-------------------------------------------------------------------------------
138−-- | Verbosity controls the amount of information (columns) a 'Scribe'
139−-- emits during logging.
140−--
141−-- The convention is:
142−-- - 'V0' implies no additional payload information is included in message.
143−-- - 'V3' implies the maximum amount of payload information.
144−-- - Anything in between is left to the discretion of the developer.
145−data Verbosity = V0 | V1 | V2 | V3
146− deriving (Eq, Ord, Show, Read, Generic, Enum, Bounded)
147−
148−
149−-------------------------------------------------------------------------------
150−renderSeverity :: Severity -> Text
151−renderSeverity s = case s of
152− DebugS -> "Debug"
153− InfoS -> "Info"
154− NoticeS -> "Notice"
155− WarningS -> "Warning"
156− ErrorS -> "Error"
157− CriticalS -> "Critical"
158− AlertS -> "Alert"
159− EmergencyS -> "Emergency"
160−
161−
162−-------------------------------------------------------------------------------
163−textToSeverity :: Text -> Maybe Severity
164−textToSeverity = go . T.toLower
165− where
166− go "debug" = Just DebugS
167− go "info" = Just InfoS
168− go "notice" = Just NoticeS
169− go "warning" = Just WarningS
170− go "error" = Just ErrorS
171− go "critical" = Just CriticalS
172− go "alert" = Just AlertS
173− go "emergency" = Just EmergencyS
174− go _ = Nothing
175−
176−
177−instance ToJSON Severity where
178− toJSON s = A.String (renderSeverity s)
179−
180−instance FromJSON Severity where
181− parseJSON = A.withText "Severity" parseSeverity
182− where
183− parseSeverity t = case textToSeverity t of
184− Just x -> return x
185− Nothing -> fail $ "Invalid Severity " ++ toS t
186−
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−
202−
203−-------------------------------------------------------------------------------
204−-- | Log message with Builder underneath; use '<>' to concat in O(1).
205−newtype LogStr = LogStr { unLogStr :: B.Builder }
206− deriving (Generic, Show, Eq)
207−
208−instance IsString LogStr where
209− fromString = LogStr . B.fromString
210−
211−
212−instance Semigroup LogStr where
213− (LogStr a) <> (LogStr b) = LogStr (a <> b)
214−
215−
216−instance Monoid LogStr where
217− mappend = (<>)
218− mempty = LogStr mempty
219−
220−
221−instance FromJSON LogStr where
222− parseJSON = A.withText "LogStr" parseLogStr
223− where
224− parseLogStr = return . LogStr . B.fromText
225−
226−-------------------------------------------------------------------------------
227−-- | Pack any string-like thing into a 'LogStr'. This will
228−-- automatically work on 'String', 'ByteString', 'Text' and any of the
229−-- lazy variants.
230−logStr :: StringConv a Text => a -> LogStr
231−logStr t = LogStr (B.fromText $ toS t)
232−
233−
234−-------------------------------------------------------------------------------
235−-- | Shorthand for 'logStr'
236−ls :: StringConv a Text => a -> LogStr
237−ls = logStr
238−
239−
240−-------------------------------------------------------------------------------
241−-- | Convert any showable type into a 'LogStr'.
242−showLS :: Show a => a -> LogStr
243−showLS = ls . show
244−
245−
246−-------------------------------------------------------------------------------
247−newtype ThreadIdText = ThreadIdText {
248− getThreadIdText :: Text
249− } deriving (ToJSON, FromJSON, Show, Eq, Ord)
250−
251−
252−mkThreadIdText :: ThreadId -> ThreadIdText
253−mkThreadIdText = ThreadIdText . stripPrefix' "ThreadId " . T.pack . show
254− where
255− stripPrefix' pfx t = fromMaybe t (T.stripPrefix pfx t)
256−
257−
258−-------------------------------------------------------------------------------
259−-- | This has everything each log message will contain.
260−data Item a = Item {
261− _itemApp :: Namespace
262− , _itemEnv :: Environment
263− , _itemSeverity :: Severity
264− , _itemThread :: ThreadIdText
265− , _itemHost :: HostName
266− , _itemProcess :: ProcessID
267− , _itemPayload :: a
268− , _itemMessage :: LogStr
269− , _itemTime :: UTCTime
270− , _itemNamespace :: Namespace
271− , _itemLoc :: Maybe Loc
272− } deriving (Generic, Functor)
273−makeLenses ''Item
274−
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− ]
298−
299−instance Show a => Show (Item a) where
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 ", "
316−
317−newtype LocShow = LocShow Loc
318−
319−
320−instance Show LocShow where
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 ", "
331−
332−
333−instance ToJSON a => ToJSON (Item a) where
334− toJSON Item{..} = A.object
335− [ "app" A..= _itemApp
336− , "env" A..= _itemEnv
337− , "sev" A..= _itemSeverity
338− , "thread" A..= getThreadIdText _itemThread
339− , "host" A..= _itemHost
340− , "pid" A..= ProcessIDJs _itemProcess
341− , "data" A..= _itemPayload
342− , "msg" A..= (B.toLazyText $ unLogStr _itemMessage)
343− , "at" A..= _itemTime
344− , "ns" A..= _itemNamespace
345− , "loc" A..= fmap LocJs _itemLoc
346− ]
347−
348−newtype LocJs = LocJs { getLocJs :: Loc }
349−
350−
351−instance ToJSON LocJs where
352− toJSON (LocJs (Loc fn p m (l, c) _)) = A.object
353− [ "loc_fn" A..= fn
354− , "loc_pkg" A..= p
355− , "loc_mod" A..= m
356− , "loc_ln" A..= l
357− , "loc_col" A..= c
358− ]
359−
360−
361−instance FromJSON LocJs where
362− parseJSON = A.withObject "LocJs" parseLocJs
363− where
364− parseLocJs o = do
365− fn <- o A..: "loc_fn"
366− p <- o A..: "loc_pkg"
367− m <- o A..: "loc_mod"
368− l <- o A..: "loc_ln"
369− c <- o A..: "loc_col"
370− return $ LocJs $ Loc fn p m (l, c) (l, c)
371−
372−
373−instance FromJSON a => FromJSON (Item a) where
374− parseJSON = A.withObject "Item" parseItem
375− where
376− parseItem o = Item
377− <$> o A..: "app"
378− <*> o A..: "env"
379− <*> o A..: "sev"
380− <*> o A..: "thread"
381− <*> o A..: "host"
382− <*> (getProcessIDJs <$> o A..: "pid")
383− <*> o A..: "data"
384− <*> o A..: "msg"
385− <*> o A..: "at"
386− <*> o A..: "ns"
387− <*> (fmap getLocJs <$> o A..: "loc")
388−
389−
390−processIDToText :: ProcessID -> Text
391−processIDToText = toS . show
392−
393−
394−textToProcessID :: Text -> Maybe ProcessID
395−textToProcessID = readMay . toS
396−
397−
398−newtype ProcessIDJs = ProcessIDJs {
399− getProcessIDJs :: ProcessID
400− }
401−
402−
403−instance ToJSON ProcessIDJs where
404− toJSON (ProcessIDJs p) = A.String (processIDToText p)
405−
406−
407−instance FromJSON ProcessIDJs where
408− parseJSON = A.withText "ProcessID" parseProcessID
409− where
410− parseProcessID t = case textToProcessID t of
411− Just p -> return $ ProcessIDJs p
412− Nothing -> fail $ "Invalid ProcessIDJs " ++ toS t
413−
414−
415−-------------------------------------------------------------------------------
416−-- | Field selector by verbosity within JSON payload.
417−data PayloadSelection
418− = AllKeys
419− | SomeKeys [Text]
420− deriving (Show, Eq)
421−
422−instance Semigroup PayloadSelection where
423− AllKeys <> _ = AllKeys
424− _ <> AllKeys = AllKeys
425− SomeKeys as <> SomeKeys bs = SomeKeys (as <> bs)
426−
427−
428−instance Monoid PayloadSelection where
429− mempty = SomeKeys []
430− mappend = (<>)
431−
432−
433−-------------------------------------------------------------------------------
434−-- | Katip requires JSON objects to be logged as context. This
435−-- typeclass provides a default instance which uses ToJSON and
436−-- produces an empty object if 'toJSON' results in any type other than
437−-- object. If you have a type you want to log that produces an Array
438−-- or Number for example, you'll want to write an explicit instance
439−-- here. You can trivially add a ToObject instance for something with
440−-- a ToJSON instance like:
441−--
442−-- > instance ToObject Foo
443−class ToObject a where
444− toObject :: a -> A.Object
445− default toObject :: ToJSON a => a -> A.Object
446− toObject v = case toJSON v of
447− A.Object o -> o
448− _ -> mempty
449−
450−instance ToObject ()
451−instance ToObject A.Object
452−
453−-------------------------------------------------------------------------------
454−-- | Payload objects need instances of this class. LogItem makes it so
455−-- that you can have very verbose items getting logged with lots of
456−-- extra fields but under normal circumstances, if your scribe is
457−-- configured for a lower verbosity level, it will only log a
458−-- selection of those keys. Furthermore, each 'Scribe' can be
459−-- configured with a different 'Verbosity' level. You could even use
460−-- 'registerScribe', 'unregisterScribe', and 'clearScribes' to at
461−-- runtime swap out your existing scribes for more verbose debugging
462−-- scribes if you wanted to.
463−--
464−-- When defining 'payloadKeys', don't redundantly declare the same
465−-- keys for higher levels of verbosity. Each level of verbosity
466−-- automatically and recursively contains all keys from the level
467−-- before it.
468−class ToObject a => LogItem a where
469−
470− -- | List of keys in the JSON object that should be included in message.
471− payloadKeys :: Verbosity -> a -> PayloadSelection
472−
473−
474−instance LogItem () where payloadKeys _ _ = SomeKeys []
475−
476−
477−data AnyLogPayload = forall a. ToJSON a => AnyLogPayload a
478−
479−newtype SimpleLogPayload = SimpleLogPayload {
480− unSimpleLogPayload :: [(Text, AnyLogPayload)]
481− }
482−
483−-------------------------------------------------------------------------------
484−-- | A built-in convenience log payload that won't log anything on 'V0',
485−-- but will log everything in any other level of verbosity. Intended
486−-- for easy in-line usage without having to define new log types.
487−--
488−-- Construct using 'sl' and combine multiple tuples using '<>' from
489−-- 'Monoid'.
490−instance ToJSON SimpleLogPayload where
491− toJSON (SimpleLogPayload as) = object $ map go as
492− where go (k, AnyLogPayload v) = k A..= v
493−
494−
495−instance ToObject SimpleLogPayload
496−
497−
498−instance LogItem SimpleLogPayload where
499− payloadKeys V0 _ = SomeKeys []
500− payloadKeys _ _ = AllKeys
501−
502−
503−instance Semigroup SimpleLogPayload where
504− SimpleLogPayload a <> SimpleLogPayload b = SimpleLogPayload (a <> b)
505−
506−
507−instance Monoid SimpleLogPayload where
508− mempty = SimpleLogPayload []
509− mappend = (<>)
510−
511−
512−-------------------------------------------------------------------------------
513−-- | Construct a simple log from any JSON item.
514−sl :: ToJSON a => Text -> a -> SimpleLogPayload
515−sl a b = SimpleLogPayload [(a, AnyLogPayload b)]
516−
517−
518−-------------------------------------------------------------------------------
519−-- | Constrain payload based on verbosity. Backends should use this to
520−-- automatically bubble higher verbosity levels to lower ones.
521−payloadObject :: LogItem a => Verbosity -> a -> A.Object
522−payloadObject verb a = case FT.foldMap (flip payloadKeys a) [(V0)..verb] of
523− AllKeys -> toObject a
524− SomeKeys ks -> HM.filterWithKey (\ k _ -> k `FT.elem` ks) $ toObject a
525−
526−
527−-------------------------------------------------------------------------------
528−-- | Convert log item to its JSON representation while trimming its
529−-- payload based on the desired verbosity. Backends that push JSON
530−-- messages should use this to obtain their payload.
531−itemJson :: LogItem a => Verbosity -> Item a -> A.Value
532−itemJson verb a = toJSON $ a & itemPayload %~ payloadObject verb
533−
534−
535−-------------------------------------------------------------------------------
536−-- | Scribes are handlers of incoming items. Each registered scribe
537−-- knows how to push a log item somewhere.
538−--
539−-- = Guidelines for writing your own 'Scribe'
540−--
541−-- Scribes should always take a 'Severity' and 'Verbosity'.
542−--
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.
549−--
550−-- Verbosity is used to select keys from the log item's payload. Each
551−-- 'LogItem' instance describes what keys should be retained for each
552−-- Verbosity level. Use the 'payloadObject' utility for extracting the keys
553−-- that should be written.
554−--
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.
564−--
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−
588−data Scribe = Scribe {
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'
601− }
602−
603−
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.
612−instance Semigroup Scribe where
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)
619−
620−
621−instance Monoid Scribe where
622− mempty = Scribe (const (return ())) (return ()) (permitItem DebugS)
623− mappend = (<>)
624−
625−
626−-------------------------------------------------------------------------------
627−data ScribeHandle = ScribeHandle {
628− shScribe :: Scribe
629− , shChan :: BQ.TBQueue WorkerMessage
630− }
631−
632−
633−-------------------------------------------------------------------------------
634−data WorkerMessage where
635− NewItem :: LogItem a => Item a -> WorkerMessage
636− PoisonPill :: WorkerMessage
637−
638−
639−-------------------------------------------------------------------------------
640−-- | Should this item be logged given the user's maximum severity?
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)
644−
645−
646−-------------------------------------------------------------------------------
647−data LogEnv = LogEnv {
648− _logEnvHost :: HostName
649− , _logEnvPid :: ProcessID
650− , _logEnvApp :: Namespace
651− -- ^ Name of application. This will typically never change. This
652− -- field gets prepended to the namespace of your individual log
653− -- messages. For example, if your app is MyApp and you write a log
654− -- using "logItem" and the namespace "WebServer", the final
655− -- namespace will be "MyApp.WebServer"
656− , _logEnvEnv :: Environment
657− , _logEnvTimer :: IO UTCTime
658− -- ^ Action to fetch the timestamp. You can use something like
659− -- 'AutoUpdate' for high volume logs but note that this may cause
660− -- some output forms to display logs out of order. Alternatively,
661− -- you could just use 'getCurrentTime'.
662− , _logEnvScribes :: M.Map Text ScribeHandle
663− }
664−makeLenses ''LogEnv
665−
666−
667−-------------------------------------------------------------------------------
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'.
672−initLogEnv
673− :: Namespace
674− -- ^ A base namespace for this application
675− -> Environment
676− -- ^ Current run environment (e.g. @prod@ vs. @devel@)
677− -> IO LogEnv
678−initLogEnv an env = LogEnv
679− <$> getHostName
680− <*> getProcessID
681− <*> pure an
682− <*> pure env
683− <*> mkAutoUpdate defaultUpdateSettings { updateAction = getCurrentTime, updateFreq = 1000 }
684− <*> pure mempty
685−
686−
687−-------------------------------------------------------------------------------
688−-- | Add a scribe to the list. All future log calls will go to this
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.
692−registerScribe
693− :: Text
694− -- ^ Name the scribe
695− -> Scribe
696− -> ScribeSettings
697− -> LogEnv
698− -> IO LogEnv
699−registerScribe nm scribe ScribeSettings {..} le = do
700− queue <- atomically (BQ.newTBQueue (fromIntegral _scribeBufferSize))
701− worker <- spawnScribeWorker scribe queue
702− let fin = do
703− atomically (BQ.writeTBQueue queue PoisonPill)
704− -- wait for our worker to finish final write
705− void (Async.waitCatch worker)
706− -- wait for scribe to finish final write
707− void (scribeFinalizer scribe)
708−
709− let sh = ScribeHandle (scribe { scribeFinalizer = fin }) queue
710− return (le & logEnvScribes %~ M.insert nm sh)
711−
712−
713−-------------------------------------------------------------------------------
714−spawnScribeWorker :: Scribe -> BQ.TBQueue WorkerMessage -> IO (Async.Async ())
715−spawnScribeWorker (Scribe write _ _) queue = Async.async go
716− where
717− go = do
718− newCmd <- atomically (BQ.readTBQueue queue)
719− case newCmd of
720− NewItem a -> do
721− -- Swallow any direct exceptions from the
722− -- scribe. safe-exceptions won't catch async exceptions.
723− void (tryAny (write a))
724− go
725− PoisonPill -> return ()
726−
727−
728−-------------------------------------------------------------------------------
729−data ScribeSettings = ScribeSettings {
730− _scribeBufferSize :: Int
731− }
732− deriving (Show, Eq)
733−
734−makeLenses ''ScribeSettings
735−
736−
737−-- | Reasonable defaults for a scribe. Buffer
738−-- size of 4096.
739−defaultScribeSettings :: ScribeSettings
740−defaultScribeSettings = ScribeSettings 4096
741−
742−
743−-------------------------------------------------------------------------------
744−-- | Remove a scribe from the environment. This does __not__ finalize
745−-- the scribe. This mainly only makes sense to use with something like
746−-- MonadReader's @local@ function to temporarily disavow a single
747−-- logger for a block of code.
748−unregisterScribe
749− :: Text
750− -- ^ Name of the scribe
751− -> LogEnv
752− -> LogEnv
753−unregisterScribe nm = logEnvScribes %~ M.delete nm
754−
755−
756−-------------------------------------------------------------------------------
757−-- | Unregister __all__ scribes. Note that this is __not__ for closing or
758−-- finalizing scribes, use 'closeScribes' for that. This mainly only
759−-- makes sense to use with something like MonadReader's @local@
760−-- function to temporarily disavow any loggers for a block of code.
761−clearScribes
762− :: LogEnv
763− -> LogEnv
764−clearScribes = logEnvScribes .~ mempty
765−
766−
767−-------------------------------------------------------------------------------
768−-- | Finalize a scribe. The scribe is removed from the environment,
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.
773−closeScribe
774− :: Text
775− -- ^ Name of the scribe
776− -> LogEnv
777− -> IO LogEnv
778−closeScribe nm le = do
779− maybe (return ()) (scribeFinalizer . shScribe) (M.lookup nm (_logEnvScribes le))
780− return (le & logEnvScribes %~ M.delete nm)
781−
782−
783−-------------------------------------------------------------------------------
784−-- | Call this at the end of your program. This is a blocking call
785−-- that stop writing to a scribe's queue, waits for the queue to
786−-- empty, finalizes each scribe in the log environment and then
787−-- removes it. Finalizers are all run even if one of them throws, but
788−-- the exception will be re-thrown at the end.
789−closeScribes
790− :: LogEnv
791− -> IO LogEnv
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)
798−
799−
800−-------------------------------------------------------------------------------
801−-- | Monads where katip logging actions can be performed. Katip is the
802−-- most basic logging monad. You will typically use this directly if
803−-- you either don't want to use namespaces/contexts heavily or if you
804−-- want to pass in specific contexts and/or namespaces at each log site.
805−--
806−-- For something more powerful, look at the docs for 'KatipContext',
807−-- which keeps a namespace and merged context. You can write simple
808−-- functions that add additional namespacing and merges additional
809−-- 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.
815−class MonadIO m => Katip m where
816− getLogEnv :: m LogEnv
817− localLogEnv :: (LogEnv -> LogEnv) -> m a -> m a
818−
819−
820−instance Katip m => Katip (ReaderT s m) where
821− getLogEnv = lift getLogEnv
822− localLogEnv = mapReaderT . localLogEnv
823−
824−
825−#if !MIN_VERSION_either(4, 5, 0)
826−instance Katip m => Katip (EitherT s m) where
827− getLogEnv = lift getLogEnv
828− localLogEnv = mapEitherT . localLogEnv
829−#endif
830−
831−
832−instance Katip m => Katip (ExceptT s m) where
833− getLogEnv = lift getLogEnv
834− localLogEnv = mapExceptT . localLogEnv
835−
836−
837−instance Katip m => Katip (MaybeT m) where
838− getLogEnv = lift getLogEnv
839− localLogEnv = mapMaybeT . localLogEnv
840−
841−
842−instance Katip m => Katip (StateT s m) where
843− 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
860−
861−
862−instance (Katip m, Monoid s) => Katip (WriterT s m) where
863− 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−
871−
872−instance (Katip m) => Katip (ResourceT m) where
873− getLogEnv = lift getLogEnv
874− localLogEnv = transResourceT . localLogEnv
875−
876−
877−-------------------------------------------------------------------------------
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.
881−newtype KatipT m a = KatipT { unKatipT :: ReaderT LogEnv m a }
882− deriving ( Functor, Applicative, Monad, MonadIO
883− , MonadMask, MonadCatch, MonadThrow, MonadResource, MonadTrans
884− , MonadBase b)
885−
886−
887−instance MonadIO m => Katip (KatipT m) where
888− getLogEnv = KatipT ask
889− localLogEnv f (KatipT m) = KatipT $ local f m
890−
891−
892−instance MonadTransControl KatipT where
893− type StT (KatipT) a = a
894− liftWith f = KatipT $ ReaderT $ \le -> f $ \t -> runKatipT le t
895− restoreT = KatipT . ReaderT . const
896− {-# INLINABLE liftWith #-}
897− {-# INLINABLE restoreT #-}
898−
899−
900−instance (MonadBaseControl b m) => MonadBaseControl b (KatipT m) where
901− type StM ((KatipT) m) a = ComposeSt (KatipT) m a
902− liftBaseWith = defaultLiftBaseWith
903− restoreM = defaultRestoreM
904−
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
920−
921−-------------------------------------------------------------------------------
922−-- | Execute 'KatipT' on a log env.
923−runKatipT :: LogEnv -> KatipT m a -> m a
924−runKatipT le (KatipT f) = runReaderT f le
925−
926−
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−
938−-------------------------------------------------------------------------------
939−-- | Log with everything, including a source code location. This is
940−-- very low level and you typically can use 'logT' in its place.
941−logItem
942− :: (A.Applicative m, LogItem a, Katip m)
943− => a
944− -> Namespace
945− -> Maybe Loc
946− -> Severity
947− -> LogStr
948− -> m ()
949−logItem a ns loc sev msg = do
950− LogEnv{..} <- getLogEnv
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))
977−
978−-------------------------------------------------------------------------------
979−tryWriteTBQueue
980− :: TBQueue a
981− -> a
982− -> STM Bool
983− -- ^ Did we write?
984−tryWriteTBQueue q a = do
985− full <- isFullTBQueue q
986− unless full (writeTBQueue q a)
987− return (not full)
988−
989−
990−-------------------------------------------------------------------------------
991−-- | Log with full context, but without any code location.
992−logF
993− :: (Applicative m, LogItem a, Katip m)
994− => a
995− -- ^ Contextual payload for the log
996− -> Namespace
997− -- ^ Specific namespace of the message.
998− -> Severity
999− -- ^ Severity of the message
1000− -> LogStr
1001− -- ^ The log message
1002− -> m ()
1003−logF a ns sev msg = logItem a ns Nothing sev msg
1004−
1005−
1006−
1007−-------------------------------------------------------------------------------
1008−-- | Perform an action while logging any exceptions that may occur.
1009−-- Inspired by 'onException`.
1010−--
1011−-- >>>> logException () mempty ErrorS (error "foo")
1012−logException
1013− :: (Katip m, LogItem a, MonadCatch m, Applicative m)
1014− => a -- ^ Log context
1015− -> Namespace -- ^ Namespace
1016− -> Severity -- ^ Severity
1017− -> m b -- ^ Main action being run
1018− -> m b
1019−logException a ns sev action = action `catchAny` \e -> f e >> throwM e
1020− where
1021− f e = logF a ns sev (msg e)
1022− msg e = ls (T.pack "An exception has occurred: ") <> showLS e
1023−
1024−
1025−-------------------------------------------------------------------------------
1026−-- | Log a message without any payload/context or code location.
1027−logMsg
1028− :: (Applicative m, Katip m)
1029− => Namespace
1030− -> Severity
1031− -> LogStr
1032− -> m ()
1033−logMsg ns sev msg = logF () ns sev msg
1034−
1035−
1036−instance TH.Lift Namespace where
1037− lift (Namespace xs) =
1038− let xs' = map T.unpack xs
1039− in [| Namespace (map T.pack xs') |]
1040−
1041−
1042−instance TH.Lift Verbosity where
1043− lift V0 = [| V0 |]
1044− lift V1 = [| V1 |]
1045− lift V2 = [| V2 |]
1046− lift V3 = [| V3 |]
1047−
1048−
1049−instance TH.Lift Severity where
1050− lift DebugS = [| DebugS |]
1051− lift InfoS = [| InfoS |]
1052− lift NoticeS = [| NoticeS |]
1053− lift WarningS = [| WarningS |]
1054− lift ErrorS = [| ErrorS |]
1055− lift CriticalS = [| CriticalS |]
1056− lift AlertS = [| AlertS |]
1057− lift EmergencyS = [| EmergencyS |]
1058−
1059−
1060−-- | Lift a location into an Exp.
1061−liftLoc :: Loc -> Q Exp
1062−liftLoc (Loc a b c (d1, d2) (e1, e2)) = [|Loc
1063− $(TH.lift a)
1064− $(TH.lift b)
1065− $(TH.lift c)
1066− ($(TH.lift d1), $(TH.lift d2))
1067− ($(TH.lift e1), $(TH.lift e2))
1068− |]
1069−
1070−
1071−-------------------------------------------------------------------------------
1072−-- | For use when you want to include location in your logs. This will
1073−-- fill the 'Maybe Loc' gap in 'logF' of this module, and relies on implicit
1074−-- callstacks when available (GHC > 7.8).
1075−#if MIN_VERSION_base(4, 8, 0)
1076−getLoc :: HasCallStack => Maybe Loc
1077−getLoc = case getCallStack callStack of
1078− [] -> Nothing
1079− xs -> Just . toLoc . head $ filter filterKatip xs
1080− where
1081− filterKatip :: (String, SrcLoc) -> Bool
1082− filterKatip (_, srcloc) = not $
1083− "katip-" `isPrefixOf` srcLocPackage srcloc
1084−
1085− toLoc :: (String, SrcLoc) -> Loc
1086− toLoc (_, l) = Loc {
1087− loc_filename = srcLocFile l
1088− , loc_package = srcLocPackage l
1089− , loc_module = srcLocModule l
1090− , loc_start = (srcLocStartLine l, srcLocStartCol l)
1091− , loc_end = (srcLocEndLine l, srcLocEndCol l)
1092− }
1093−#else
1094−getLoc :: Maybe Loc
1095−getLoc = Nothing
1096−#endif
1097−
1098−
1099−-------------------------------------------------------------------------------
1100−-- Like `getLoc`, but uses template-haskell and works with older versions of
1101−-- the compiler (GHC 7.8 or older).
1102−getLocTH :: ExpQ
1103−getLocTH = [| $(location >>= liftLoc) |]
1104−
1105−
1106−-------------------------------------------------------------------------------
1107−-- | 'Loc'-tagged logging when using template-haskell.
1108−--
1109−-- @$(logT) obj mempty InfoS "Hello world"@
1110−logT :: ExpQ
1111−logT = [| \ a ns sev msg -> logItem a ns (Just $(getLocTH)) sev msg |]
1112−
1113−
1114−-------------------------------------------------------------------------------
1115−-- | 'Loc'-tagged logging using 'GHC.Stack' when available.
1116−--
1117−-- This function does not require template-haskell as it
1118−-- automatically uses <https://hackage.haskell.org/package/base-4.8.2.0/docs/GHC-Stack.html#v:getCallStack implicit-callstacks>
1119−-- when the code is compiled using GHC > 7.8. Using an older version of the
1120−-- compiler will result in the emission of a log line without any location information,
1121−-- so be aware of it. Users using GHC <= 7.8 may want to use the template-haskell function
1122−-- `logT` for maximum compatibility.
1123−--
1124−-- @logLoc obj mempty InfoS "Hello world"@
1125−#if MIN_VERSION_base(4, 8, 0)
1126−logLoc :: (Applicative m, LogItem a, Katip m, HasCallStack)
1127−#else
1128−logLoc :: (Applicative m, LogItem a, Katip m)
1129−#endif
1130− => a
1131− -> Namespace
1132− -> Severity
1133− -> LogStr
1134− -> m ()
1135−logLoc a ns = logItem a ns getLoc
1136−
1137−
1138−-- taken from the file-location package
1139−-- turn the TH Loc loaction information into a human readable string
1140−-- leaving out the loc_end parameter
1141−locationToString :: Loc -> String
1142−locationToString loc = (loc_package loc) ++ ':' : (loc_module loc) ++
1143− ' ' : (loc_filename loc) ++ ':' : (line loc) ++ ':' : (char loc)
1144− where
1145− line = show . fst . loc_start
1146− char = show . snd . loc_start