Conftrack.Source

Documentation

class ConfigSource s where

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

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))

read a single value from the source.

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

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

ConfigSource JsonSource

Defined in Conftrack.Source.Aeson

Associated Types

type SourceState JsonSource

Methods

fetchValue :: Key -> JsonSource -> StateT (SourceState JsonSource) IO (Either ConfigError (Value, Text))

leftovers :: JsonSource -> StateT (SourceState JsonSource) IO (Maybe [Key])

ConfigSource EnvSource

Defined in Conftrack.Source.Env

Associated Types

type SourceState EnvSource

Methods

fetchValue :: Key -> EnvSource -> StateT (SourceState EnvSource) IO (Either ConfigError (Value, Text))

leftovers :: EnvSource -> StateT (SourceState EnvSource) IO (Maybe [Key])

ConfigSource Trivial

Defined in Conftrack.Source.Trivial

Associated Types

type SourceState Trivial

Methods

fetchValue :: Key -> Trivial -> StateT (SourceState Trivial) IO (Either ConfigError (Value, Text))

leftovers :: Trivial -> StateT (SourceState Trivial) IO (Maybe [Key])

ConfigSource YamlSource

Defined in Conftrack.Source.Yaml

Associated Types

type SourceState YamlSource

Methods

fetchValue :: Key -> YamlSource -> StateT (SourceState YamlSource) IO (Either ConfigError (Value, Text))

leftovers :: YamlSource -> StateT (SourceState YamlSource) IO (Maybe [Key])

data SomeSource

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)