Safe Haskell	Safe-Inferred
Language	GHC2021

Conftrack.Source

Synopsis

class ConfigSource s where
- type SourceState s
- fetchValue :: Key -> s -> StateT (SourceState s) IO (Either ConfigError (Value, Text))
- leftovers :: s -> StateT (SourceState s) IO (Maybe [Key])
data SomeSource = forall source.ConfigSource source => SomeSource (source, SourceState source)

Documentation

class ConfigSource s where Source #

An abstraction over "config sources". This might mean file formats, environment variables, or any other kind of format that can be seen as a key-value store.

Associated Types

type SourceState s Source #

Some sources require state, e.g. to keep track of which values were already read.

Methods

fetchValue :: Key -> s -> StateT (SourceState s) IO (Either ConfigError (Value, Text)) Source #

read a single value from the source.

leftovers :: s -> StateT (SourceState s) IO (Maybe [Key]) Source #

given s, determine if any keys are "left over" and were not used. This is used to produce warnings for unknown configuration options; since not all sources can support this, this function's return type includes Maybe and sources are free to return Nothing if they cannot determine if any unknown keys are present.

Instances

Instances details

ConfigSource JsonSource Source #
Instance details Defined in Conftrack.Source.Aeson Associated Types type SourceState JsonSource Source # Methods fetchValue :: Key -> JsonSource -> StateT (SourceState JsonSource) IO (Either ConfigError (Value, Text)) Source # leftovers :: JsonSource -> StateT (SourceState JsonSource) IO (Maybe [Key]) Source #
ConfigSource EnvSource Source #
Instance details Defined in Conftrack.Source.Env Associated Types type SourceState EnvSource Source # Methods fetchValue :: Key -> EnvSource -> StateT (SourceState EnvSource) IO (Either ConfigError (Value, Text)) Source # leftovers :: EnvSource -> StateT (SourceState EnvSource) IO (Maybe [Key]) Source #
ConfigSource Trivial Source #
Instance details Defined in Conftrack.Source.Trivial Associated Types type SourceState Trivial Source # Methods fetchValue :: Key -> Trivial -> StateT (SourceState Trivial) IO (Either ConfigError (Value, Text)) Source # leftovers :: Trivial -> StateT (SourceState Trivial) IO (Maybe [Key]) Source #
ConfigSource YamlSource Source #
Instance details Defined in Conftrack.Source.Yaml Associated Types type SourceState YamlSource Source # Methods fetchValue :: Key -> YamlSource -> StateT (SourceState YamlSource) IO (Either ConfigError (Value, Text)) Source # leftovers :: YamlSource -> StateT (SourceState YamlSource) IO (Maybe [Key]) Source #

data SomeSource Source #

An opaque type for any kind of config sources. Values of this type can be acquired from they Conftrack.Source.* modules, or by implementing the ConfigSource type class.

Constructors

forall source.ConfigSource source => SomeSource (source, SourceState source)