@@ -1,8 +1,11 @@
2+{-# LANGUAGE DefaultSignatures #-}
1{-# LANGUAGE DeriveFunctor #-}
3{-# LANGUAGE DeriveFunctor #-}
2{-# LANGUAGE DeriveGeneric #-}
4{-# LANGUAGE DeriveGeneric #-}
3{-# LANGUAGE ExistentialQuantification #-}
5{-# LANGUAGE ExistentialQuantification #-}
4{-# LANGUAGE FlexibleContexts #-}
6{-# LANGUAGE FlexibleContexts #-}
5{-# LANGUAGE FlexibleInstances #-}
7{-# LANGUAGE FlexibleInstances #-}
6{-# LANGUAGE GeneralizedNewtypeDeriving #-}
9{-# LANGUAGE GeneralizedNewtypeDeriving #-}
7{-# LANGUAGE MultiParamTypeClasses #-}
10{-# LANGUAGE MultiParamTypeClasses #-}
8{-# LANGUAGE OverloadedStrings #-}
11{-# LANGUAGE OverloadedStrings #-}
@@ -11,50 +14,96 @@
11{-# LANGUAGE TemplateHaskell #-}
14{-# LANGUAGE TemplateHaskell #-}
12{-# LANGUAGE TypeFamilies #-}
15{-# LANGUAGE TypeFamilies #-}
13{-# LANGUAGE UndecidableInstances #-}
16{-# LANGUAGE UndecidableInstances #-}
17+#if MIN_VERSION_base(4, 9, 0)
18+{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
20+-- | This module is not meant to be imported directly and may contain
21+-- internal mechanisms that will change without notice.
14module Katip.Core where
22module Katip.Core where
16-------------------------------------------------------------------------------
24-------------------------------------------------------------------------------
17−import Control.Applicative as A
25+import Control.Applicative as A
18import Control.AutoUpdate
26import Control.AutoUpdate
19import Control.Concurrent
27import Control.Concurrent
20−import Control.Lens
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
21−import Control.Monad
32+import Control.Monad (unless, void, when)
22import Control.Monad.Base
33import Control.Monad.Base
34+#if MIN_VERSION_base(4, 9, 0)
23−import Control.Monad.Catch
35+import qualified Control.Monad.Fail as MF
24import Control.Monad.IO.Class
37import Control.Monad.IO.Class
38+import Control.Monad.IO.Unlift
25import Control.Monad.Trans.Class
39import Control.Monad.Trans.Class
26import Control.Monad.Trans.Control
40import Control.Monad.Trans.Control
41+#if !MIN_VERSION_either(4, 5, 0)
27import Control.Monad.Trans.Either
42import Control.Monad.Trans.Either
44+import Control.Monad.Trans.Except
28import Control.Monad.Trans.Maybe
45import Control.Monad.Trans.Maybe
29import Control.Monad.Trans.Reader
46import Control.Monad.Trans.Reader
30−import Control.Monad.Trans.Resource
47+import Control.Monad.Trans.Resource (MonadResource, ResourceT,
31−import Control.Monad.Trans.State
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)
32−import Control.Monad.Trans.Writer
53+import Control.Monad.Trans.Writer.Lazy (WriterT, mapWriterT)
54+import qualified Control.Monad.Trans.Writer.Strict as Strict (WriterT,
33−import Data.Aeson (FromJSON (..), ToJSON (..),
56+import Data.Aeson (FromJSON (..), ToJSON (..),
35−import qualified Data.Aeson as A
58+import qualified Data.Aeson as A
36−import Data.Foldable as FT
59+import Data.Foldable as FT
37−import qualified Data.HashMap.Strict as HM
60+import qualified Data.HashMap.Strict as HM
38import Data.List
61import Data.List
39−import qualified Data.Map.Strict as M
62+import qualified Data.Map.Strict as M
40−import Data.Monoid
63+import Data.Maybe (fromMaybe)
64+import Data.Semigroup as SG
41import Data.String
65import Data.String
42import Data.String.Conv
66import Data.String.Conv
43−import Data.Text (Text)
67+import Data.Text (Text)
44−import qualified Data.Text as T
68+import qualified Data.Text as T
45−import qualified Data.Text.Lazy.Builder as B
69+import qualified Data.Text.Lazy.Builder as B
46import Data.Time
70import Data.Time
47−import GHC.Generics hiding (to)
71+import GHC.Generics hiding (to)
72+#if MIN_VERSION_base(4, 8, 0)
73+#if !MIN_VERSION_base(4, 9, 0)
48import Language.Haskell.TH
78import Language.Haskell.TH
49−import qualified Language.Haskell.TH.Syntax as TH
79+import qualified Language.Haskell.TH.Syntax as TH
50import Network.HostName
82import Network.HostName
51import System.Posix
86import System.Posix
52-------------------------------------------------------------------------------
89-------------------------------------------------------------------------------
92+readMay :: Read a => String -> Maybe a
93+readMay s = case [x | (x,t) <- reads s, ("","") <- lex t] of
95+ [] -> Nothing -- no parse
96+ _ -> Nothing -- Ambiguous parse
55-------------------------------------------------------------------------------
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
56newtype Namespace = Namespace { unNamespace :: [Text] }
105newtype Namespace = Namespace { unNamespace :: [Text] }
57− deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,Monoid)
106+ deriving (Eq,Show,Read,Ord,Generic,ToJSON,FromJSON,SG.Semigroup,Monoid)
59instance IsString Namespace where
108instance IsString Namespace where
60 fromString s = Namespace [fromString s]
109 fromString s = Namespace [fromString s]
@@ -94,60 +143,81 @@ data Severity
94-- - 'V3' implies the maximum amount of payload information.
143-- - 'V3' implies the maximum amount of payload information.
95-- - Anything in between is left to the discretion of the developer.
144-- - Anything in between is left to the discretion of the developer.
96data Verbosity = V0 | V1 | V2 | V3
145data Verbosity = V0 | V1 | V2 | V3
97− deriving (Eq, Ord, Show, Read, Generic, Enum)
146+ deriving (Eq, Ord, Show, Read, Generic, Enum, Bounded)
100-------------------------------------------------------------------------------
149-------------------------------------------------------------------------------
101renderSeverity :: Severity -> Text
150renderSeverity :: Severity -> Text
102renderSeverity s = case s of
151renderSeverity s = case s of
103− DebugS -> "Debug"
152+ DebugS -> "Debug"
104− InfoS -> "Info"
153+ InfoS -> "Info"
105− NoticeS -> "Notice"
154+ NoticeS -> "Notice"
106− WarningS -> "Warning"
155+ WarningS -> "Warning"
107− ErrorS -> "Error"
156+ ErrorS -> "Error"
108− CriticalS -> "Critical"
157+ CriticalS -> "Critical"
109− AlertS -> "Alert"
158+ AlertS -> "Alert"
110 EmergencyS -> "Emergency"
159 EmergencyS -> "Emergency"
113-------------------------------------------------------------------------------
162-------------------------------------------------------------------------------
114−severityText :: Prism' Text Severity
163+textToSeverity :: Text -> Maybe Severity
115−severityText = prism renderSeverity toSev
164+textToSeverity = go . T.toLower
117− toSev "Debug" = Right DebugS
166+ go "debug" = Just DebugS
118− toSev "Info" = Right InfoS
167+ go "info" = Just InfoS
119− toSev "Notice" = Right NoticeS
168+ go "notice" = Just NoticeS
120− toSev "Warning" = Right WarningS
169+ go "warning" = Just WarningS
121− toSev "Error" = Right ErrorS
170+ go "error" = Just ErrorS
122− toSev "Critical" = Right CriticalS
171+ go "critical" = Just CriticalS
123− toSev "Alert" = Right AlertS
172+ go "alert" = Just AlertS
124− toSev "Emergency" = Right EmergencyS
173+ go "emergency" = Just EmergencyS
125− toSev x = Left x
174+ go _ = Nothing
127−instance ToJSON Severity where
128− toJSON s = A.String (s ^. re severityText)
177+instance ToJSON Severity where
178+ toJSON s = A.String (renderSeverity s)
131instance FromJSON Severity where
180instance FromJSON Severity where
132 parseJSON = A.withText "Severity" parseSeverity
181 parseJSON = A.withText "Severity" parseSeverity
134− parseSeverity t = case t ^? severityText of
183+ parseSeverity t = case textToSeverity t of
135− Just x -> return x
184+ Just x -> return x
136 Nothing -> fail $ "Invalid Severity " ++ toS t
185 Nothing -> fail $ "Invalid Severity " ++ toS t
187+instance ToJSON Verbosity where
188+ toJSON s = A.String $ case s of
194+instance FromJSON Verbosity where
195+ parseJSON = A.withText "Verbosity" $ \s -> case s of
200+ _ -> fail $ "Invalid Verbosity " ++ toS s
139-------------------------------------------------------------------------------
203-------------------------------------------------------------------------------
140−-- | Log message with Builder unerneath; use '<>' to concat in O(1).
204+-- | Log message with Builder underneath; use '<>' to concat in O(1).
141newtype LogStr = LogStr { unLogStr :: B.Builder }
205newtype LogStr = LogStr { unLogStr :: B.Builder }
142− deriving (Generic, Show)
206+ deriving (Generic, Show, Eq)
144instance IsString LogStr where
208instance IsString LogStr where
145 fromString = LogStr . B.fromString
209 fromString = LogStr . B.fromString
212+instance Semigroup LogStr where
213+ (LogStr a) <> (LogStr b) = LogStr (a <> b)
147instance Monoid LogStr where
216instance Monoid LogStr where
148− mappend (LogStr a) (LogStr b) = LogStr (a `mappend` b)
217+ mappend = (<>)
149 mempty = LogStr mempty
218 mempty = LogStr mempty
151instance FromJSON LogStr where
221instance FromJSON LogStr where
152 parseJSON = A.withText "LogStr" parseLogStr
222 parseJSON = A.withText "LogStr" parseLogStr
@@ -155,19 +225,20 @@ instance FromJSON LogStr where
156-------------------------------------------------------------------------------
226-------------------------------------------------------------------------------
157-- | Pack any string-like thing into a 'LogStr'. This will
227-- | Pack any string-like thing into a 'LogStr'. This will
158−-- automatically work on 'String', 'ByteString, 'Text' and any of the
228+-- automatically work on 'String', 'ByteString', 'Text' and any of the
159-- lazy variants.
229-- lazy variants.
160logStr :: StringConv a Text => a -> LogStr
230logStr :: StringConv a Text => a -> LogStr
161logStr t = LogStr (B.fromText $ toS t)
231logStr t = LogStr (B.fromText $ toS t)
164-------------------------------------------------------------------------------
234-------------------------------------------------------------------------------
165−-- | Shorthand for 'logMsg'
235+-- | Shorthand for 'logStr'
166ls :: StringConv a Text => a -> LogStr
236ls :: StringConv a Text => a -> LogStr
167ls = logStr
237ls = logStr
170-------------------------------------------------------------------------------
240-------------------------------------------------------------------------------
241+-- | Convert any showable type into a 'LogStr'.
171showLS :: Show a => a -> LogStr
242showLS :: Show a => a -> LogStr
172showLS = ls . show
243showLS = ls . show
@@ -179,7 +250,10 @@ newtype ThreadIdText = ThreadIdText {
181mkThreadIdText :: ThreadId -> ThreadIdText
252mkThreadIdText :: ThreadId -> ThreadIdText
182−mkThreadIdText = ThreadIdText . T.pack . show
253+mkThreadIdText = ThreadIdText . stripPrefix' "ThreadId " . T.pack . show
255+ stripPrefix' pfx t = fromMaybe t (T.stripPrefix pfx t)
184-------------------------------------------------------------------------------
258-------------------------------------------------------------------------------
185-- | This has everything each log message will contain.
259-- | This has everything each log message will contain.
@@ -198,31 +272,62 @@ data Item a = Item {
198 } deriving (Generic, Functor)
272 } deriving (Generic, Functor)
199makeLenses ''Item
273makeLenses ''Item
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
202instance Show a => Show (Item a) where
299instance Show a => Show (Item a) where
203− show Item{..} = "Item {_itemApp = " ++ show _itemApp ++ ", " ++
300+ showsPrec d Item{..} = showParen (d >= 11) ( showString "Item {"
204− "_itemEnv = " ++ show _itemEnv ++ ", " ++
301+ . field "_itemApp" _itemApp
302+ . field "_itemEnv" _itemEnv
205− "_itemSeverity = " ++ show _itemSeverity ++ ", " ++
303+ . field "_itemSeverity" _itemSeverity
206− "_itemThread = " ++ show _itemThread ++ ", " ++
304+ . field "_itemThread" _itemThread
207− "_itemHost = " ++ show _itemHost ++ ", " ++
305+ . field "_itemHost" _itemHost
208− "_itemProcess = " ++ show _itemProcess ++ ", " ++
306+ . field "_itemProcess" _itemProcess
209− "_itemPayload = " ++ show _itemPayload ++ ", " ++
307+ . field "_itemPayload" _itemPayload
210− "_itemMessage = " ++ show _itemMessage ++ ", " ++
308+ . field "_itemMessage" _itemMessage
211− "_itemTime = " ++ show _itemTime ++ ", " ++
309+ . field "_itemTime" _itemTime
212− "_itemNamespace = " ++ show _itemNamespace ++ ", " ++
310+ . field "_itemNamespace" _itemNamespace
213− "_itemLoc = " ++ show (LocShow <$> _itemLoc) ++ "}"
311+ . showString "_itemLoc = " . shows (LocShow <$> _itemLoc)
315+ field n v = showString n . showString " = " . shows v . showString ", "
216newtype LocShow = LocShow Loc
317newtype LocShow = LocShow Loc
219instance Show LocShow where
320instance Show LocShow where
220− show (LocShow Loc{..}) =
321+ showsPrec d (LocShow Loc{..}) = showParen (d >= 11) ( showString "Loc {"
221− "Loc {loc_filename = " ++ show loc_filename ++ ", " ++
322+ . field "loc_filename" loc_filename
222− "loc_package = " ++ show loc_package ++ ", " ++
323+ . field "loc_package" loc_package
223− "loc_module = " ++ show loc_module ++ ", " ++
324+ . field "loc_module" loc_module
224− "loc_start = " ++ show loc_start ++ ", " ++
325+ . field "loc_start" loc_start
225− "loc_end = " ++ show loc_end ++ "}"
326+ . showString "loc_end = " . shows loc_end
330+ field n v = showString n . showString " = " . shows v . showString ", "
228instance ToJSON a => ToJSON (Item a) where
333instance ToJSON a => ToJSON (Item a) where
@@ -282,13 +387,12 @@ instance FromJSON a => FromJSON (Item a) where
282 <*> (fmap getLocJs <$> o A..: "loc")
387 <*> (fmap getLocJs <$> o A..: "loc")
285−processIDText :: Prism' Text ProcessID
390+processIDToText :: ProcessID -> Text
286−processIDText = prism fromProcessID toProcessID
391+processIDToText = toS . show
288− fromProcessID = toS . show
393+
289− toProcessID t = case toS t ^? _Show of
394+textToProcessID :: Text -> Maybe ProcessID
290− Just i -> Right i
395+textToProcessID = readMay . toS
294newtype ProcessIDJs = ProcessIDJs {
398newtype ProcessIDJs = ProcessIDJs {
@@ -297,14 +401,14 @@ newtype ProcessIDJs = ProcessIDJs {
299instance ToJSON ProcessIDJs where
403instance ToJSON ProcessIDJs where
300− toJSON (ProcessIDJs p) = A.String (p ^. re processIDText)
404+ toJSON (ProcessIDJs p) = A.String (processIDToText p)
303instance FromJSON ProcessIDJs where
407instance FromJSON ProcessIDJs where
304 parseJSON = A.withText "ProcessID" parseProcessID
408 parseJSON = A.withText "ProcessID" parseProcessID
306− parseProcessID t = case t ^? processIDText of
410+ parseProcessID t = case textToProcessID t of
307− Just p -> return $ ProcessIDJs p
411+ Just p -> return $ ProcessIDJs p
308 Nothing -> fail $ "Invalid ProcessIDJs " ++ toS t
412 Nothing -> fail $ "Invalid ProcessIDJs " ++ toS t
@@ -313,12 +417,17 @@ instance FromJSON ProcessIDJs where
313data PayloadSelection
417data PayloadSelection
314 = AllKeys
418 = AllKeys
315 | SomeKeys [Text]
419 | SomeKeys [Text]
422+instance Semigroup PayloadSelection where
423+ AllKeys <> _ = AllKeys
424+ _ <> AllKeys = AllKeys
425+ SomeKeys as <> SomeKeys bs = SomeKeys (as <> bs)
317instance Monoid PayloadSelection where
428instance Monoid PayloadSelection where
318 mempty = SomeKeys []
429 mempty = SomeKeys []
319− mappend AllKeys _ = AllKeys
430+ mappend = (<>)
320− mappend _ AllKeys = AllKeys
321− mappend (SomeKeys as) (SomeKeys bs) = SomeKeys (as++bs)
324-------------------------------------------------------------------------------
433-------------------------------------------------------------------------------
@@ -331,17 +440,26 @@ instance Monoid PayloadSelection where
331-- a ToJSON instance like:
440-- a ToJSON instance like:
333-- > instance ToObject Foo
442-- > instance ToObject Foo
334−class ToJSON a => ToObject a where
443+class ToObject a where
335 toObject :: a -> A.Object
444 toObject :: a -> A.Object
445+ default toObject :: ToJSON a => a -> A.Object
336 toObject v = case toJSON v of
446 toObject v = case toJSON v of
337 A.Object o -> o
447 A.Object o -> o
338− _ -> mempty
448+ _ -> mempty
340instance ToObject ()
450instance ToObject ()
341instance ToObject A.Object
451instance ToObject A.Object
343-------------------------------------------------------------------------------
453-------------------------------------------------------------------------------
344−-- | Payload objects need instances of this class.
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.
346-- When defining 'payloadKeys', don't redundantly declare the same
464-- When defining 'payloadKeys', don't redundantly declare the same
347-- keys for higher levels of verbosity. Each level of verbosity
465-- keys for higher levels of verbosity. Each level of verbosity
@@ -373,15 +491,22 @@ instance ToJSON SimpleLogPayload where
373 toJSON (SimpleLogPayload as) = object $ map go as
491 toJSON (SimpleLogPayload as) = object $ map go as
374 where go (k, AnyLogPayload v) = k A..= v
492 where go (k, AnyLogPayload v) = k A..= v
376instance ToObject SimpleLogPayload
495instance ToObject SimpleLogPayload
378instance LogItem SimpleLogPayload where
498instance LogItem SimpleLogPayload where
379 payloadKeys V0 _ = SomeKeys []
499 payloadKeys V0 _ = SomeKeys []
380− payloadKeys _ _ = AllKeys
500+ payloadKeys _ _ = AllKeys
503+instance Semigroup SimpleLogPayload where
504+ SimpleLogPayload a <> SimpleLogPayload b = SimpleLogPayload (a <> b)
382instance Monoid SimpleLogPayload where
507instance Monoid SimpleLogPayload where
383 mempty = SimpleLogPayload []
508 mempty = SimpleLogPayload []
384− SimpleLogPayload a `mappend` SimpleLogPayload b = SimpleLogPayload (a `mappend` b)
509+ mappend = (<>)
387-------------------------------------------------------------------------------
512-------------------------------------------------------------------------------
@@ -395,8 +520,8 @@ sl a b = SimpleLogPayload [(a, AnyLogPayload b)]
395-- automatically bubble higher verbosity levels to lower ones.
520-- automatically bubble higher verbosity levels to lower ones.
396payloadObject :: LogItem a => Verbosity -> a -> A.Object
521payloadObject :: LogItem a => Verbosity -> a -> A.Object
397payloadObject verb a = case FT.foldMap (flip payloadKeys a) [(V0)..verb] of
522payloadObject verb a = case FT.foldMap (flip payloadKeys a) [(V0)..verb] of
398− AllKeys -> toObject a
523+ AllKeys -> toObject a
399− SomeKeys ks -> HM.filterWithKey (\ k _ -> k `elem` ks) $ toObject a
524+ SomeKeys ks -> HM.filterWithKey (\ k _ -> k `FT.elem` ks) $ toObject a
402-------------------------------------------------------------------------------
527-------------------------------------------------------------------------------
@@ -410,37 +535,140 @@ itemJson verb a = toJSON $ a & itemPayload %~ payloadObject verb
410-------------------------------------------------------------------------------
535-------------------------------------------------------------------------------
411-- | Scribes are handlers of incoming items. Each registered scribe
536-- | Scribes are handlers of incoming items. Each registered scribe
412-- knows how to push a log item somewhere.
537-- knows how to push a log item somewhere.
539+-- = Guidelines for writing your own 'Scribe'
541+-- Scribes should always take a 'Severity' and 'Verbosity'.
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
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.
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
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.
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
579+-- | AND together 2 permit functions
580+permitAND :: PermitFunc -> PermitFunc -> PermitFunc
581+permitAND f1 f2 = \a -> liftA2 (&&) (f1 a) (f2 a)
583+-- | OR together 2 permit functions
584+permitOR :: PermitFunc -> PermitFunc -> PermitFunc
585+permitOR f1 f2 = \a -> liftA2 (||) (f1 a) (f2 a)
413data Scribe = Scribe {
588data Scribe = Scribe {
414− lhPush :: forall a. LogItem a => Item a -> IO ()
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'
604+whenM :: Monad m => m Bool -> m () -> m ()
605+whenM mbool = (>>=) mbool . flip when
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
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)
617+ (finA `finally` finB)
618+ (permitOR permitA permitB)
418instance Monoid Scribe where
621instance Monoid Scribe where
419− mempty = Scribe $ const $ return ()
622+ mempty = Scribe (const (return ())) (return ()) (permitItem DebugS)
420− mappend (Scribe a) (Scribe b) = Scribe $ \ item -> do
623+ mappend = (<>)
626+-------------------------------------------------------------------------------
627+data ScribeHandle = ScribeHandle {
629+ , shChan :: BQ.TBQueue WorkerMessage
633+-------------------------------------------------------------------------------
634+data WorkerMessage where
635+ NewItem :: LogItem a => Item a -> WorkerMessage
636+ PoisonPill :: WorkerMessage
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)
424-------------------------------------------------------------------------------
646-------------------------------------------------------------------------------
425data LogEnv = LogEnv {
647data LogEnv = LogEnv {
426 _logEnvHost :: HostName
648 _logEnvHost :: HostName
427 , _logEnvPid :: ProcessID
649 , _logEnvPid :: ProcessID
428− , _logEnvNs :: Namespace
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"
429 , _logEnvEnv :: Environment
656 , _logEnvEnv :: Environment
430 , _logEnvTimer :: IO UTCTime
657 , _logEnvTimer :: IO UTCTime
431 -- ^ Action to fetch the timestamp. You can use something like
658 -- ^ Action to fetch the timestamp. You can use something like
432 -- 'AutoUpdate' for high volume logs but note that this may cause
659 -- 'AutoUpdate' for high volume logs but note that this may cause
433− -- some output forms to display logs out of order.
660+ -- some output forms to display logs out of order. Alternatively,
661+ -- you could just use 'getCurrentTime'.
434− , _logEnvScribes :: M.Map Text Scribe
662+ , _logEnvScribes :: M.Map Text ScribeHandle
436makeLenses ''LogEnv
664makeLenses ''LogEnv
439-------------------------------------------------------------------------------
667-------------------------------------------------------------------------------
440−-- | Create a reasonable default InitLogEnv. Uses an 'AutoUdate' with
668+-- | Create a reasonable default InitLogEnv. Uses an 'AutoUpdate' which
441−-- the default settings as the timer. If you are concerned about
669+-- updates the timer every 1ms. If you need even more timestamp
442−-- timestamp precision or event ordering in log outputs like
670+-- precision at the cost of performance, consider setting
443−-- ElasticSearch, you should replace the timer with 'getCurrentTime'
671+-- '_logEnvTimer' with 'getCurrentTime'.
444initLogEnv
672initLogEnv
445 :: Namespace
673 :: Namespace
446 -- ^ A base namespace for this application
674 -- ^ A base namespace for this application
@@ -452,36 +680,84 @@ initLogEnv an env = LogEnv
452 <*> getProcessID
680 <*> getProcessID
453 <*> pure an
681 <*> pure an
454 <*> pure env
682 <*> pure env
455− <*> mkAutoUpdate defaultUpdateSettings { updateAction = getCurrentTime }
683+ <*> mkAutoUpdate defaultUpdateSettings { updateAction = getCurrentTime, updateFreq = 1000 }
456 <*> pure mempty
684 <*> pure mempty
459-------------------------------------------------------------------------------
687-------------------------------------------------------------------------------
460-- | Add a scribe to the list. All future log calls will go to this
688-- | Add a scribe to the list. All future log calls will go to this
461−-- 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.
462registerScribe
692registerScribe
464 -- ^ Name the scribe
694 -- ^ Name the scribe
465 -> Scribe
695 -> Scribe
466 -> LogEnv
697 -> LogEnv
467− -> LogEnv
698+ -> IO LogEnv
468−registerScribe nm h = logEnvScribes . at nm .~ Just h
699+registerScribe nm scribe ScribeSettings {..} le = do
700+ queue <- atomically (BQ.newTBQueue (fromIntegral _scribeBufferSize))
701+ worker <- spawnScribeWorker scribe queue
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)
709+ let sh = ScribeHandle (scribe { scribeFinalizer = fin }) queue
710+ return (le & logEnvScribes %~ M.insert nm sh)
713+-------------------------------------------------------------------------------
714+spawnScribeWorker :: Scribe -> BQ.TBQueue WorkerMessage -> IO (Async.Async ())
715+spawnScribeWorker (Scribe write _ _) queue = Async.async go
718+ newCmd <- atomically (BQ.readTBQueue queue)
721+ -- Swallow any direct exceptions from the
722+ -- scribe. safe-exceptions won't catch async exceptions.
723+ void (tryAny (write a))
725+ PoisonPill -> return ()
728+-------------------------------------------------------------------------------
729+data ScribeSettings = ScribeSettings {
730+ _scribeBufferSize :: Int
734+makeLenses ''ScribeSettings
737+-- | Reasonable defaults for a scribe. Buffer
739+defaultScribeSettings :: ScribeSettings
740+defaultScribeSettings = ScribeSettings 4096
471-------------------------------------------------------------------------------
743-------------------------------------------------------------------------------
472−-- | Remove a scribe from the list. All future log calls will no
744+-- | Remove a scribe from the environment. This does __not__ finalize
473−-- longer use this scribe. If the given scribe doesn't exist, its a no-op.
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.
474unregisterScribe
748unregisterScribe
476 -- ^ Name of the scribe
750 -- ^ Name of the scribe
477 -> LogEnv
751 -> LogEnv
478 -> LogEnv
752 -> LogEnv
479−unregisterScribe nm = logEnvScribes . at nm .~ Nothing
753+unregisterScribe nm = logEnvScribes %~ M.delete nm
482-------------------------------------------------------------------------------
756-------------------------------------------------------------------------------
483−-- | Unregister *all* scribes. Logs will go off into space from this
757+-- | Unregister __all__ scribes. Note that this is __not__ for closing or
484−-- point onward until new scribes are added.
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.
485clearScribes
761clearScribes
486 :: LogEnv
762 :: LogEnv
487 -> LogEnv
763 -> LogEnv
@@ -489,43 +765,128 @@ clearScribes = logEnvScribes .~ mempty
491-------------------------------------------------------------------------------
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.
775+ -- ^ Name of the scribe
778+closeScribe nm le = do
779+ maybe (return ()) (scribeFinalizer . shScribe) (M.lookup nm (_logEnvScribes le))
780+ return (le & logEnvScribes %~ M.delete nm)
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.
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)
800+-------------------------------------------------------------------------------
492−-- | Monads where katip logging actions can be performed
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.
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.
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.
493−class MonadIO m => Katip m where
815+class MonadIO m => Katip m where
494 getLogEnv :: m LogEnv
816 getLogEnv :: m LogEnv
817+ localLogEnv :: (LogEnv -> LogEnv) -> m a -> m a
497instance Katip m => Katip (ReaderT s m) where
820instance Katip m => Katip (ReaderT s m) where
498 getLogEnv = lift getLogEnv
821 getLogEnv = lift getLogEnv
822+ localLogEnv = mapReaderT . localLogEnv
825+#if !MIN_VERSION_either(4, 5, 0)
501instance Katip m => Katip (EitherT s m) where
826instance Katip m => Katip (EitherT s m) where
502 getLogEnv = lift getLogEnv
827 getLogEnv = lift getLogEnv
828+ localLogEnv = mapEitherT . localLogEnv
832+instance Katip m => Katip (ExceptT s m) where
833+ getLogEnv = lift getLogEnv
834+ localLogEnv = mapExceptT . localLogEnv
505instance Katip m => Katip (MaybeT m) where
837instance Katip m => Katip (MaybeT m) where
506 getLogEnv = lift getLogEnv
838 getLogEnv = lift getLogEnv
839+ localLogEnv = mapMaybeT . localLogEnv
509instance Katip m => Katip (StateT s m) where
842instance Katip m => Katip (StateT s m) where
510 getLogEnv = lift getLogEnv
843 getLogEnv = lift getLogEnv
844+ localLogEnv = mapStateT . localLogEnv
847+instance (Katip m, Monoid w) => Katip (RWST r w s m) where
848+ getLogEnv = lift getLogEnv
849+ localLogEnv = mapRWST . localLogEnv
852+instance (Katip m, Monoid w) => Katip (Strict.RWST r w s m) where
853+ getLogEnv = lift getLogEnv
854+ localLogEnv = Strict.mapRWST . localLogEnv
857+instance Katip m => Katip (Strict.StateT s m) where
858+ getLogEnv = lift getLogEnv
859+ localLogEnv = Strict.mapStateT . localLogEnv
513instance (Katip m, Monoid s) => Katip (WriterT s m) where
862instance (Katip m, Monoid s) => Katip (WriterT s m) where
514 getLogEnv = lift getLogEnv
863 getLogEnv = lift getLogEnv
864+ localLogEnv = mapWriterT . localLogEnv
867+instance (Katip m, Monoid s) => Katip (Strict.WriterT s m) where
868+ getLogEnv = lift getLogEnv
869+ localLogEnv = Strict.mapWriterT . localLogEnv
516instance (Katip m) => Katip (ResourceT m) where
872instance (Katip m) => Katip (ResourceT m) where
517 getLogEnv = lift getLogEnv
873 getLogEnv = lift getLogEnv
874+ localLogEnv = transResourceT . localLogEnv
520-------------------------------------------------------------------------------
877-------------------------------------------------------------------------------
521−-- | 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.
522newtype KatipT m a = KatipT { unKatipT :: ReaderT LogEnv m a }
881newtype KatipT m a = KatipT { unKatipT :: ReaderT LogEnv m a }
523 deriving ( Functor, Applicative, Monad, MonadIO
882 deriving ( Functor, Applicative, Monad, MonadIO
524− , MonadMask, MonadCatch, MonadThrow, MonadTrans, MonadBase b)
883+ , MonadMask, MonadCatch, MonadThrow, MonadResource, MonadTrans
527instance MonadIO m => Katip (KatipT m) where
887instance MonadIO m => Katip (KatipT m) where
528 getLogEnv = KatipT ask
888 getLogEnv = KatipT ask
889+ localLogEnv f (KatipT m) = KatipT $ local f m
531instance MonadTransControl KatipT where
892instance MonadTransControl KatipT where
@@ -541,6 +902,21 @@ instance (MonadBaseControl b m) => MonadBaseControl b (KatipT m) where
541 liftBaseWith = defaultLiftBaseWith
902 liftBaseWith = defaultLiftBaseWith
542 restoreM = defaultRestoreM
903 restoreM = defaultRestoreM
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)
910+ askUnliftIO = KatipT $
911+ withUnliftIO $ \u ->
912+ pure (UnliftIO (unliftIO u . unKatipT))
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)
545-------------------------------------------------------------------------------
921-------------------------------------------------------------------------------
546-- | Execute 'KatipT' on a log env.
922-- | Execute 'KatipT' on a log env.
@@ -548,6 +924,17 @@ runKatipT :: LogEnv -> KatipT m a -> m a
548runKatipT le (KatipT f) = runReaderT f le
924runKatipT le (KatipT f) = runReaderT f le
927+-------------------------------------------------------------------------------
928+-- | Disable all scribes for the given monadic action, then restore
929+-- them afterwards. Works in any Katip monad.
935+katipNoLogging = localLogEnv (\le -> set logEnvScribes mempty le)
551-------------------------------------------------------------------------------
938-------------------------------------------------------------------------------
552-- | Log with everything, including a source code location. This is
939-- | Log with everything, including a source code location. This is
553-- very low level and you typically can use 'logT' in its place.
940-- very low level and you typically can use 'logT' in its place.
@@ -561,19 +948,43 @@ logItem
562logItem a ns loc sev msg = do
949logItem a ns loc sev msg = do
563 LogEnv{..} <- getLogEnv
950 LogEnv{..} <- getLogEnv
564− item <- Item
951+ logKatipItem =<< liftIO
565− <$> pure _logEnvNs
952+ (Item <$> pure _logEnvApp
566− <*> pure _logEnvEnv
953+ <*> pure _logEnvEnv
567− <*> pure sev
954+ <*> pure sev
568− <*> liftIO (mkThreadIdText <$> myThreadId)
955+ <*> (mkThreadIdText <$> myThreadId)
569− <*> pure _logEnvHost
956+ <*> pure _logEnvHost
570− <*> pure _logEnvPid
957+ <*> pure _logEnvPid
571− <*> pure a
958+ <*> pure a
572− <*> pure msg
959+ <*> pure msg
573− <*> liftIO _logEnvTimer
960+ <*> _logEnvTimer
574− <*> pure (_logEnvNs <> ns)
961+ <*> pure (_logEnvApp <> ns)
575− <*> pure loc
962+ <*> pure loc)
964+-- | Log already constructed 'Item'. This is the lowest level function that other log*
966+-- It can be useful when implementing centralised logging services.
968+ :: (A.Applicative m, LogItem a, Katip m)
971+logKatipItem item = do
972+ LogEnv{..} <- getLogEnv
576− liftIO $ forM_ (M.elems _logEnvScribes) $ \ (Scribe h) -> h item
974+ FT.forM_ (M.elems _logEnvScribes) $ \ ScribeHandle {..} -> do
975+ whenM (scribePermitItem shScribe item) $
976+ void $ atomically (tryWriteTBQueue shChan (NewItem item))
978+-------------------------------------------------------------------------------
984+tryWriteTBQueue q a = do
985+ full <- isFullTBQueue q
986+ unless full (writeTBQueue q a)
579-------------------------------------------------------------------------------
990-------------------------------------------------------------------------------
@@ -605,10 +1016,10 @@ logException
605 -> Severity -- ^ Severity
1016 -> Severity -- ^ Severity
606 -> m b -- ^ Main action being run
1017 -> m b -- ^ Main action being run
608−logException a ns sev action = action `catchAll` \e -> f e >> throwM e
1019+logException a ns sev action = action `catchAny` \e -> f e >> throwM e
610 f e = logF a ns sev (msg e)
1021 f e = logF a ns sev (msg e)
611− msg e = ls (T.pack "An exception has occured: ") <> showLS e
1022+ msg e = ls (T.pack "An exception has occurred: ") <> showLS e
614-------------------------------------------------------------------------------
1025-------------------------------------------------------------------------------
@@ -636,14 +1047,14 @@ instance TH.Lift Verbosity where
638instance TH.Lift Severity where
1049instance TH.Lift Severity where
639− lift DebugS = [| DebugS |]
1050+ lift DebugS = [| DebugS |]
640− lift InfoS = [| InfoS |]
1051+ lift InfoS = [| InfoS |]
641− lift NoticeS = [| NoticeS |]
1052+ lift NoticeS = [| NoticeS |]
642− lift WarningS = [| WarningS |]
1053+ lift WarningS = [| WarningS |]
643− lift ErrorS = [| ErrorS |]
1054+ lift ErrorS = [| ErrorS |]
644 lift CriticalS = [| CriticalS |]
1055 lift CriticalS = [| CriticalS |]
645− lift AlertS = [| AlertS |]
1056+ lift AlertS = [| AlertS |]
646− lift EmergencyS = [| EmergencyS |]
1057+ lift EmergencyS = [| EmergencyS |]
649-- | Lift a location into an Exp.
1060-- | Lift a location into an Exp.
@@ -659,17 +1070,69 @@ liftLoc (Loc a b c (d1, d2) (e1, e2)) = [|Loc
660-------------------------------------------------------------------------------
1071-------------------------------------------------------------------------------
661-- | For use when you want to include location in your logs. This will
1072-- | For use when you want to include location in your logs. This will
662−-- fill the 'Maybe Loc' gap in 'logF' of this module.
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
1079+ xs -> Just . toLoc . head $ filter filterKatip xs
1081+ filterKatip :: (String, SrcLoc) -> Bool
1082+ filterKatip (_, srcloc) = not $
1083+ "katip-" `isPrefixOf` srcLocPackage srcloc
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)
663−getLoc :: Q Exp
1094+getLoc :: Maybe Loc
1099+-------------------------------------------------------------------------------
1100+-- Like `getLoc`, but uses template-haskell and works with older versions of
1101+-- the compiler (GHC 7.8 or older).
664−getLoc = [| $(location >>= liftLoc) |]
1103+getLocTH = [| $(location >>= liftLoc) |]
667-------------------------------------------------------------------------------
1106-------------------------------------------------------------------------------
668−-- | 'Loc'-tagged logging when using template-haskell is OK.
1107+-- | 'Loc'-tagged logging when using template-haskell.
670-- @$(logT) obj mempty InfoS "Hello world"@
1109-- @$(logT) obj mempty InfoS "Hello world"@
671logT :: ExpQ
1110logT :: ExpQ
672−logT = [| \ a ns sev msg -> logItem a ns (Just $(getLoc)) sev msg |]
1111+logT = [| \ a ns sev msg -> logItem a ns (Just $(getLocTH)) sev msg |]
1114+-------------------------------------------------------------------------------
1115+-- | 'Loc'-tagged logging using 'GHC.Stack' when available.
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.
1124+-- @logLoc obj mempty InfoS "Hello world"@
1125+#if MIN_VERSION_base(4, 8, 0)
1126+logLoc :: (Applicative m, LogItem a, Katip m, HasCallStack)
1128+logLoc :: (Applicative m, LogItem a, Katip m)
1135+logLoc a ns = logItem a ns getLoc
675-- taken from the file-location package
1138-- taken from the file-location package