Salak

Configuration Loader for Production in Haskell.

How to use this library

| This library define a universal procedure to load configurations and parse properties, also supports reload configuration files.

We can load configurations from command line, environment, configuration files such as yaml or toml etc, and we may want to have our own strategies to load configurations from multi sources and overwrite properties by orders of these sources.

PropConfig defines a common loading strategy:

1. loadCommandLine
2. loadEnvironment
3. loadConfFiles
4. load file from folder `salak.conf.dir` if defined
5. load file from current folder if enabled
6. load file from home folder if enabled
7. file extension matching, support yaml or toml or any other loader.

Load earlier has higher priority, priorities cannot be changed.

Usage:

Environment:

export TEST_CONFIG_NAME=daniel

Current Directory: salak.yaml

test.config:
  name: noop
  dir: ls

Current Directory: salak.toml

[test.config]
ext=2

data Config = Config
  { name :: Text
  , dir  :: Maybe Text
  , ext  :: Int
  } deriving (Eq, Show)

instance FromProp Config where
  fromProp = Config
    <$> "user" ? pattern "[a-z]{5,16}"
    <*> "pwd"
    <*> "ext" .?= 1

main = runSalak def { configName = Just "salak", loadExt = loadByExt $ YAML :|: TOML } $ do
  c :: Config <- require "test.config"
  lift $ print c

GHCi play

λ> import Salak
λ> import Salak.Load.YAML
λ> import Salak.Load.TOML
λ> :set -XTypeApplications
λ> instance FromProp Config where fromProp = Config <$> "user" <*> "dir" <*> "ext" .?= 1
λ> f = runSalak def { configName = Just "salak", loadExt = loadByExt $ YAML :|: TOML }
λ> f (require "") >>= print @Config
Config {name = "daniel", dir = Just "ls", ext = 2}

Salak

loadAndRunSalak

Arguments

:: Monad m

=> SourcePackT m ()

Load properties monad.

-> ReaderT SourcePack m a

Fetch properties monad.

-> m a

Load and run salak SourcePack and fetch properties.

runSalak :: MonadIO m => PropConfig -> ReaderT SourcePack m a -> m a

Default load salak. All these configuration sources has orders, from highest priority to lowest priority:

1. loadCommandLine
2. loadEnvironment
3. loadConfFiles
4. load file from folder `salak.conf.dir` if defined
5. load file from current folder if enabled
6. load file from home folder if enabled
7. file extension matching, support yaml or toml or any other loader.

data PropConfig

Prop load configuration

Constructors

PropConfig

Fields

• configName :: Maybe String

  Config name

• configDirKey :: Text

  Specify config dir

• searchCurrent :: Bool

  Search current directory, default true

• searchHome :: Bool

  Search home directory, default false.

• commandLine :: ParseCommandLine

  How to parse commandline

• loadExt :: FilePath -> SourcePackT IO ()

Instances

Default PropConfig

Defined in Salak

Methods

def :: PropConfig

Static Get Properties

class Monad m => HasSourcePack m where

Methods

askSourcePack :: m SourcePack

Instances

Monad m => HasSourcePack (ReaderT SourcePack m)

Defined in Salak

Methods

askSourcePack :: ReaderT SourcePack m SourcePack

Monad m => HasSourcePack (StateT SourcePack m)

Defined in Salak

Methods

askSourcePack :: StateT SourcePack m SourcePack

fetch

Arguments

:: (HasSourcePack m, FromProp a)

=> Text

Properties key

-> m (Either String a)

Try fetch properties from SourcePack

require

Arguments

:: (HasSourcePack m, FromProp a)

=> Text

Properties key

-> m a

Fetch properties from SourcePack, or throw fail

Dynamic Get Properties

data ReloadableSourcePack

Reloadable SourcePack

type ReloadableSourcePackT = StateT ReloadableSourcePack

data ReloadResult

Constructors

ReloadResult

Fields

• isError :: Bool
• msg :: [String]

Instances

Eq ReloadResult

Defined in Salak.Load.Dynamic

Methods

(==) :: ReloadResult -> ReloadResult -> Bool

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

Show ReloadResult

Defined in Salak.Load.Dynamic

Methods

showsPrec :: Int -> ReloadResult -> ShowS

show :: ReloadResult -> String

showList :: [ReloadResult] -> ShowS

reloadable :: (MonadIO m, HasSourcePack m) => ReloadableSourcePackT m a -> m a

Lift to reloadable environment for dynamic properties.

reloadAction :: Monad m => ReloadableSourcePackT m (IO ReloadResult)

fetchD

Arguments

:: (MonadIO m, FromProp a)

=> Text

Properties key

-> ReloadableSourcePackT m (Either String (IO a))

Try fetch dynamic properties from SourcePack

requireD

Arguments

:: (MonadIO m, FromProp a)

=> Text

Properties key

-> ReloadableSourcePackT m (IO a)

Fetch dynamic properties from SourcePack, or throw fail

Prop Parser

type Prop = PropT PResult

class FromProp a where

Minimal complete definition

Nothing

Methods

fromProp :: Prop a

fromProp :: (Generic a, GFromProp (Rep a)) => Prop a

Instances

FromProp Bool

Defined in Salak.Prop

Methods

fromProp :: Prop Bool

FromProp Double

Defined in Salak.Prop

Methods

fromProp :: Prop Double

FromProp Float

Defined in Salak.Prop

Methods

fromProp :: Prop Float

FromProp Int

Defined in Salak.Prop

Methods

fromProp :: Prop Int

FromProp Int8

Defined in Salak.Prop

Methods

fromProp :: Prop Int8

FromProp Int16

Defined in Salak.Prop

Methods

fromProp :: Prop Int16

FromProp Int32

Defined in Salak.Prop

Methods

fromProp :: Prop Int32

FromProp Int64

Defined in Salak.Prop

Methods

fromProp :: Prop Int64

FromProp Word

Defined in Salak.Prop

Methods

fromProp :: Prop Word

FromProp Word8

Defined in Salak.Prop

Methods

fromProp :: Prop Word8

FromProp Word16

Defined in Salak.Prop

Methods

fromProp :: Prop Word16

FromProp Word32

Defined in Salak.Prop

Methods

fromProp :: Prop Word32

FromProp Word64

Defined in Salak.Prop

Methods

fromProp :: Prop Word64

FromEnumProp a => FromProp a

Defined in Salak.Prop

Methods

fromProp :: Prop a

FromProp Text

Defined in Salak.Prop

Methods

fromProp :: Prop Text

FromProp Text

Defined in Salak.Prop

Methods

fromProp :: Prop Text

FromProp String

Defined in Salak.Prop

Methods

fromProp :: Prop String

FromProp Scientific

Defined in Salak.Prop

Methods

fromProp :: Prop Scientific

FromProp a => FromProp [a]

Defined in Salak.Prop

Methods

fromProp :: Prop [a]

FromProp a => FromProp (Maybe a)

Defined in Salak.Prop

Methods

fromProp :: Prop (Maybe a)

class FromEnumProp a where

Methods

fromEnumProp :: Text -> Either String a

(.?=) :: Alternative f => f a -> a -> f a infixl 5

Optional value.

(.?:) :: (Alternative f, Default b) => f a -> (b -> a) -> f a infixl 5

Default value.

SourcePack

data SourcePack

Instances

Show SourcePack

Defined in Salak.Types

Methods

showsPrec :: Int -> SourcePack -> ShowS

show :: SourcePack -> String

showList :: [SourcePack] -> ShowS

MonadReader SourcePack Prop

Defined in Salak.Prop

Methods

ask :: Prop SourcePack

local :: (SourcePack -> SourcePack) -> Prop a -> Prop a

reader :: (SourcePack -> a) -> Prop a

Monad m => HasSourcePack (ReaderT SourcePack m)

Defined in Salak

Methods

askSourcePack :: ReaderT SourcePack m SourcePack

Monad m => HasSourcePack (StateT SourcePack m)

Defined in Salak

Methods

askSourcePack :: StateT SourcePack m SourcePack

type SourcePackT = StateT SourcePack

Load configurations

loadCommandLine :: MonadIO m => ParseCommandLine -> SourcePackT m ()

loadEnv :: MonadIO m => SourcePackT m ()

loadMock :: Monad m => [(Text, Text)] -> SourcePackT m ()

Load By Extension

type ExtLoad = (String, FilePath -> SourcePackT IO ())

Load file by extension

loadByExt :: (HasLoad a, MonadIO m) => a -> FilePath -> SourcePackT m ()

class HasLoad a where

Methods

loaders :: a -> [ExtLoad]

Instances

(HasLoad a, HasLoad b) => HasLoad (a :|: b)

Defined in Salak

Methods

loaders :: (a :|: b) -> [ExtLoad]

data a :|: b infixr 3

Constructors

a :|: b infixr 3

Instances

(HasLoad a, HasLoad b) => HasLoad (a :|: b)

Defined in Salak

Methods

loaders :: (a :|: b) -> [ExtLoad]

Other

type ParseCommandLine = [String] -> IO [(Text, Priority -> Value)]

defaultParseCommandLine :: ParseCommandLine

type Priority = Int

data Value

Constructors

VStr !Priority !Text

VNum !Priority !Scientific

VBool !Priority !Bool

VZTime !Priority !TimeZone !LocalTime

VLTime !Priority !LocalTime

VDay !Priority !Day

VHour !Priority !TimeOfDay

Instances

Eq Value

Defined in Salak.Types.Value

Methods

(==) :: Value -> Value -> Bool

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

Ord Value

Defined in Salak.Types.Value

Methods

compare :: Value -> Value -> Ordering

(<) :: Value -> Value -> Bool

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

(>) :: Value -> Value -> Bool

(>=) :: Value -> Value -> Bool

max :: Value -> Value -> Value

min :: Value -> Value -> Value

Show Value

Defined in Salak.Types.Value

Methods

showsPrec :: Int -> Value -> ShowS

show :: Value -> String

showList :: [Value] -> ShowS

Show Source

Defined in Salak.Types.Source

Methods

showsPrec :: Int -> Source -> ShowS

show :: Source -> String

showList :: [Source] -> ShowS

defaultLoadSalak :: MonadIO m => PropConfig -> ReaderT SourcePack m a -> m a

Deprecated: use runSalak instead