Quick Start
To use PureConfig in an existing SBT project with Scala 2.11 or a later version, add the following dependency to your
build.sbt
:
libraryDependencies += "com.github.pureconfig" %% "pureconfig" % "0.12.0"
For a full example of build.sbt
you can have a look at this build.sbt.
Earlier versions of Scala had bugs which can cause subtle compile-time problems in PureConfig. As a result we recommend only using the latest Scala versions within the minor series.
In your code, import pureconfig.generic.auto
and define data types and a case class to hold the configuration:
import pureconfig._
import pureconfig.generic.auto._
sealed trait MyAdt
case class AdtA(a: String) extends MyAdt
case class AdtB(b: Int) extends MyAdt
final case class Port(value: Int) extends AnyVal
case class MyClass(
boolean: Boolean,
port: Port,
adt: MyAdt,
list: List[Double],
map: Map[String, String],
option: Option[String])
Second, define an application.conf
file like
this and add it as a
resource file of your application (with SBT, they are usually placed in src/main/resources
).
Finally, load the configuration:
ConfigSource.default.load[MyClass]
// res0: pureconfig.ConfigReader.Result[MyClass] = Right(MyClass(true,Port(8080),AdtB(1),List(1.0, 0.2),Map(key -> value),None))
ConfigReader.Result[MyClass]
is just an alias for Either[ConfigReaderFailures, MyClass]
, so you can handle it just like you
would handle an Either
value.
ConfigSource.default
defers to Typesafe Config’s
ConfigFactory
to
select where to load the config files from. Typesafe Config has well-documented rules for configuration
loading which we’ll not repeat. Please see Typesafe
Config’s documentation for a full telling of the subtleties and see Loading a Config for
alternative sources for configuration files.
Because PureConfig uses Typesafe Config to load configurations, it supports reading files in HOCON, JSON, and Java .properties
formats. HOCON is a delightful superset of both JSON and .properties
that is highly recommended. As an added bonus it supports advanced features like variable substitution and file sourcing.