Colog.Core.Severity

This module introduces Severity data type for expressing how severe the message is. Also, it contains useful functions and patterns for work with Severity.

Severity	Pattern	Meaning	Example
Debug	D	Information useful for debug purposes	Internal function call logs
Info	I	Normal operational information	Finish file uploading
Warning	W	General warnings, non-critical failures	Image load error
Error	E	General errors/severe errors	Could not connect to the DB

Documentation

data Severity

Severity for the log messages.

Constructors

Debug

Information useful for debug purposes.

E.g. output of the function that is important for the internal development, not for users. Like, the result of SQL query.

Info

Normal operational information.

E.g. describing general steps: starting application, finished downloading.

Warning

General warnings, non-critical failures.

E.g. couldn't download icon from some service to display.

Error

General errors/severe errors.

E.g. exceptional situations: couldn't syncronize accounts.

Instances

Bounded Severity

Defined in Colog.Core.Severity

Methods

minBound :: Severity

maxBound :: Severity

Enum Severity

Defined in Colog.Core.Severity

Methods

succ :: Severity -> Severity

pred :: Severity -> Severity

toEnum :: Int -> Severity

fromEnum :: Severity -> Int

enumFrom :: Severity -> [Severity]

enumFromThen :: Severity -> Severity -> [Severity]

enumFromTo :: Severity -> Severity -> [Severity]

enumFromThenTo :: Severity -> Severity -> Severity -> [Severity]

Ix Severity

Defined in Colog.Core.Severity

Methods

range :: (Severity, Severity) -> [Severity]

index :: (Severity, Severity) -> Severity -> Int

unsafeIndex :: (Severity, Severity) -> Severity -> Int

inRange :: (Severity, Severity) -> Severity -> Bool

rangeSize :: (Severity, Severity) -> Int

unsafeRangeSize :: (Severity, Severity) -> Int

Read Severity

Defined in Colog.Core.Severity

Methods

readsPrec :: Int -> ReadS Severity

readList :: ReadS [Severity]

readPrec :: ReadPrec Severity

readListPrec :: ReadPrec [Severity]

Show Severity

Defined in Colog.Core.Severity

Methods

showsPrec :: Int -> Severity -> ShowS

show :: Severity -> String

showList :: [Severity] -> ShowS

Eq Severity

Defined in Colog.Core.Severity

Methods

(==) :: Severity -> Severity -> Bool

(/=) :: Severity -> Severity -> Bool

Ord Severity

Defined in Colog.Core.Severity

Methods

compare :: Severity -> Severity -> Ordering

(<) :: Severity -> Severity -> Bool

(<=) :: Severity -> Severity -> Bool

(>) :: Severity -> Severity -> Bool

(>=) :: Severity -> Severity -> Bool

max :: Severity -> Severity -> Severity

min :: Severity -> Severity -> Severity

Patterns

Instead of using full names of the constructors you can instead use one-letter patterns. To do so you can import and use the pattern:

import Colog (pattern D)

example :: WithLog env Message m => m ()
example = log D "I'm using severity pattern"

Moreover, you could use patterns when pattern-matching on severity

errorToStderr :: Severity -> IO ()
errorToStderr E = hputStrLn stderr "Error severity"
errorToStderr _ = putStrLn "Something else"

pattern D :: Severity

pattern I :: Severity

pattern W :: Severity

pattern E :: Severity

filterBySeverity :: Applicative m => Severity -> (a -> Severity) -> LogAction m a -> LogAction m a

Filters messages by the given Severity.

data WithSeverity msg

A message tagged with a Severity.

It is common to want to log various types of messages tagged with a severity. WithSeverity provides a standard way to do so while allowing the messages to be processed independently of the severity.

It is easy to cmap over a 'LogAction m (WithSeverity a)', or to filter based on the severity.

logSomething :: LogAction m (WithSeverity String) -> m ()
logSomething logger = logger <& "hello" `WithSeverity` Info

cmap' :: (b -> a) -> LogAction m (WithSeverity a) -> LogAction m (WithSeverity b)
cmap' f action = cmap (fmap f) action

filterBySeverity' :: (Applicative m) => Severity -> LogAction m (WithSeverity a) -> LogAction m (WithSeverity a)
filterBySeverity' threshold action = filterBySeverity threshold getSeverity action

Since: 0.3.1.0

Constructors

WithSeverity

Fields

• getMsg :: msg
• getSeverity :: Severity

Instances

Foldable WithSeverity

Defined in Colog.Core.Severity

Methods

fold :: Monoid m => WithSeverity m -> m

foldMap :: Monoid m => (a -> m) -> WithSeverity a -> m

foldMap' :: Monoid m => (a -> m) -> WithSeverity a -> m

foldr :: (a -> b -> b) -> b -> WithSeverity a -> b

foldr' :: (a -> b -> b) -> b -> WithSeverity a -> b

foldl :: (b -> a -> b) -> b -> WithSeverity a -> b

foldl' :: (b -> a -> b) -> b -> WithSeverity a -> b

foldr1 :: (a -> a -> a) -> WithSeverity a -> a

foldl1 :: (a -> a -> a) -> WithSeverity a -> a

toList :: WithSeverity a -> [a]

null :: WithSeverity a -> Bool

length :: WithSeverity a -> Int

elem :: Eq a => a -> WithSeverity a -> Bool

maximum :: Ord a => WithSeverity a -> a

minimum :: Ord a => WithSeverity a -> a

sum :: Num a => WithSeverity a -> a

product :: Num a => WithSeverity a -> a

Traversable WithSeverity

Defined in Colog.Core.Severity

Methods

traverse :: Applicative f => (a -> f b) -> WithSeverity a -> f (WithSeverity b)

sequenceA :: Applicative f => WithSeverity (f a) -> f (WithSeverity a)

mapM :: Monad m => (a -> m b) -> WithSeverity a -> m (WithSeverity b)

sequence :: Monad m => WithSeverity (m a) -> m (WithSeverity a)

Functor WithSeverity

Defined in Colog.Core.Severity

Methods

fmap :: (a -> b) -> WithSeverity a -> WithSeverity b

(<$) :: a -> WithSeverity b -> WithSeverity a

Show msg => Show (WithSeverity msg)

Defined in Colog.Core.Severity

Methods

showsPrec :: Int -> WithSeverity msg -> ShowS

show :: WithSeverity msg -> String

showList :: [WithSeverity msg] -> ShowS

Eq msg => Eq (WithSeverity msg)

Defined in Colog.Core.Severity

Methods

(==) :: WithSeverity msg -> WithSeverity msg -> Bool

(/=) :: WithSeverity msg -> WithSeverity msg -> Bool

Ord msg => Ord (WithSeverity msg)

Defined in Colog.Core.Severity

Methods

compare :: WithSeverity msg -> WithSeverity msg -> Ordering

(<) :: WithSeverity msg -> WithSeverity msg -> Bool

(<=) :: WithSeverity msg -> WithSeverity msg -> Bool

(>) :: WithSeverity msg -> WithSeverity msg -> Bool

(>=) :: WithSeverity msg -> WithSeverity msg -> Bool

max :: WithSeverity msg -> WithSeverity msg -> WithSeverity msg

min :: WithSeverity msg -> WithSeverity msg -> WithSeverity msg

mapSeverity :: (Severity -> Severity) -> WithSeverity msg -> WithSeverity msg

Map the given function over the severity of a WithSeverity.

This can be useful to operate generically over the severity, for example:

suppressErrors :: LogAction m (WithSeverity msg) -> LogAction m (WithSeverity msg)
suppressErrors = cmap (mapSeverity (s -> if s == Error then Warning else s))

Since: 0.3.1.0