configs

configs is Scala wrapper for Typesafe config.

Usage

Add the following line to your build file:

libraryDependencies += "com.github.kxbmap" %% "configs" % "0.6.1"

Quick Start

import com.typesafe.config.ConfigFactory
import configs.ConfigReader

Result type of get a value from config is configs.Result. If get successfully, returns configs.Result.Success, if not configs.Result.Failure:

val config = ConfigFactory.parseString("foo = 42")

val foo = ConfigReader[Int].read(config, "foo")
// foo: configs.Result[Int] = Success(value = 42)

foo.valueOrElse(0)
// res0: Int = 42

val missing = ConfigReader[Int].read(config, "missing")
// missing: configs.Result[Int] = Failure(
//   error = ConfigError(
//     head = Exceptional(
//       throwable = com.typesafe.config.ConfigException$Missing: String: 1: No configuration setting found for key 'missing',
//       paths = List("missing")
//     ),
//     tail = Vector()
//   )
// )

missing.valueOrElse(0)
// res1: Int = 0

Import configs.syntax._ provides extension methods for Config:

import configs.syntax._

config.get[Int]("foo")
// res2: configs.Result[Int] = Success(value = 42)

get[Option[A]] will return success with value None if path is not exists:

config.get[Option[Int]]("missing")
// res3: configs.Result[Option[Int]] = Success(value = None)

config.getOrElse("missing", 0) // Alias for config.get[Option[Int]]("missing").map(_.getOrElse(0))
// res4: configs.Result[Int] = Success(value = 0)

You can get a case class value out of the box:

import scala.concurrent.duration.FiniteDuration

case class MyConfig(foo: String, bar: Int, baz: List[FiniteDuration])

val config = ConfigFactory.parseString("""
  my-config {
    foo = My config value
    bar = 123456
    baz = [1h, 2m, 3s]
  }
  """)

config.get[MyConfig]("my-config")
// res5: configs.Result[MyConfig] = Success(
//   value = MyConfig(
//     foo = "My config value",
//     bar = 123456,
//     baz = List(1 hour, 2 minutes, 3 seconds)
//   )
// )

If failed, Result accumulates error messages:

val config = ConfigFactory.parseString("""
  my-config {
    bar = 2147483648
    baz = [aaa, bbb, ccc]
  }
  """)

val result = config.get[MyConfig]("my-config")
// result: configs.Result[MyConfig] = Failure(
//   error = ConfigError(
//     head = Exceptional(
//       throwable = com.typesafe.config.ConfigException$Missing: String: 2: No configuration setting found for key 'foo',
//       paths = List("my-config", "foo")
//     ),
//     tail = Vector(
//       Exceptional(
//         throwable = com.typesafe.config.ConfigException$WrongType: String: 2: bar has type out-of-range value 2147483648 rather than int (32-bit integer),
//         paths = List("my-config", "bar")
//       ),
//       Exceptional(
//         throwable = com.typesafe.config.ConfigException$BadValue: String: 4: Invalid value at '0': No number in duration value 'aaa',
//         paths = List("my-config", "baz", "0")
//       ),
//       Exceptional(
//         throwable = com.typesafe.config.ConfigException$BadValue: String: 4: Invalid value at '1': No number in duration value 'bbb',
//         paths = List("my-config", "baz", "1")
//       ),
//       Exceptional(
//         throwable = com.typesafe.config.ConfigException$BadValue: String: 4: Invalid value at '2': No number in duration value 'ccc',
//         paths = List("my-config", "baz", "2")
//       )
//     )
//   )
// )

result.failed.foreach { error =>
  error.messages.foreach(println)
}
// [my-config.foo] String: 2: No configuration setting found for key 'foo'
// [my-config.bar] String: 2: bar has type out-of-range value 2147483648 rather than int (32-bit integer)
// [my-config.baz.0] String: 4: Invalid value at '0': No number in duration value 'aaa'
// [my-config.baz.1] String: 4: Invalid value at '1': No number in duration value 'bbb'
// [my-config.baz.2] String: 4: Invalid value at '2': No number in duration value 'ccc'

You can get a value without key using extract:

val config = ConfigFactory.parseString("""
  foo = My config value
  bar = 123456
  baz = [1h, 2m, 3s]
  """)

config.extract[MyConfig]
// res7: configs.Result[MyConfig] = Success(
//   value = MyConfig(
//     foo = "My config value",
//     bar = 123456,
//     baz = List(1 hour, 2 minutes, 3 seconds)
//   )
// )

You may use the ~ operator to combine multiple results and apply a function with the results passed as arguments, this is useful when you want to construct a complex case class from several config extractors.

case class ServiceConfig(name: String, port: Int, hosts: List[String])

val config = ConfigFactory.parseString(
  """
    |name = "foo"
    |port = 9876
    |hosts = ["localhost", "foo.com"]
  """.stripMargin)

(
  config.get[String]("name") ~
  config.get[Int]("port") ~
  config.get[List[String]]("hosts")
)(ServiceConfig) // Alternatively (name, port, hosts) => ServerConfig(name, port, posts)
// res8: configs.Result[ServiceConfig] = Success(
//   value = ServiceConfig(
//     name = "foo",
//     port = 9876,
//     hosts = List("localhost", "foo.com")
//   )
// )

Supported types

configs can get many type values from config. It is provided by type class ConfigReader.

There are a number of built-in ConfigReader instances:

Primitive/Wrapper types
- Long, Int, Short, Byte, Double, Float, Char, Boolean
- java.lang.{Long, Integer, Short, Byte, Double, Float, Character, Boolean}
Big number types
- BigInt, BigDecimal
- java.math.{BigInteger, BigDecimal}
String representation types
- String
- Symbol, java.util.{UUID, Locale}
- java.io.File, java.nio.file.Path
- java.net.{URI, InetAddress}
Duration types
- java.time.Duration
- scala.concurrent.duration.{Duration, FiniteDuration}
Config types
- com.typesafe.config.{Config, ConfigValue, ConfigList, ConfigObject, ConfigMemorySize}
- configs.Bytes
Enum types
- Java enum types
- Scala Enumeration types
Collection types
- F[A] (using CanBuildFrom[Nothing, A, F[A]], e.g. List[String], Seq[Int])
- M[S, A] (using CanBuildFrom[Nothing, (S, A), M[S, A]], e.g. Map[String, Int], TreeMap[UUID, Config])
- java.util.{List[A], Map[S, A], Set[A], Collection[A]}, java.lang.Iterable[A]
- java.util.Properties
Optional types
- Option[A]
- java.util.{Optional[A], OptionalLong, OptionalInt, OptionalDouble}
case classes
ADTs (sealed trait + classes/objects). See ADTs support
Java Beans. See Java Beans support

In this list, A means any type that is ConfigReader instance. And S means any type that is StringConverter instance.

ADTs support

If there is such an ADT:

sealed trait Tree
case class Branch(value: Int, left: Tree, right: Tree) extends Tree
case object Leaf extends Tree

You can get an ADT value from config:

val config = ConfigFactory.parseString("""
  tree = {
    value = 42
    left = Leaf
    right {
      value = 123
      left = Leaf
      right = Leaf
    }
  }
  """)

config.get[Tree]("tree")
// res9: configs.Result[Tree] = Success(
//   value = Branch(
//     value = 42,
//     left = Leaf,
//     right = Branch(value = 123, left = Leaf, right = Leaf)
//   )
// )

Java Beans support

If there is Java Beans class like the follows:

package com.example;

@lombok.Data
public class MyBean {
    private int intValue;
    private java.util.List<String> stringList;
    private java.util.Map<java.util.Locale, java.time.Duration> localeToDuration;
}

Then you define ConfigReader instance using deriveBean macro:

import com.example.MyBean

implicit val myBeanConfigReader: ConfigReader[MyBean] =
  ConfigReader.deriveBean[MyBean]

And then you can get Java Beans value:

val config = ConfigFactory.parseString("""
  int-value = 42
  string-list = [foo, bar, baz]
  locale-to-duration {
    ja_JP = 42ms
    en_US = 123s
  }
  """)

config.extract[MyBean]
// res11: configs.Result[MyBean] = Success(
//   value = MyBean(intValue=42, stringList=[foo, bar, baz], localeToDuration={en_US=PT2M3S, ja_JP=PT0.042S})
// )

License

Apache License, Version 2.0

kxbmap/configs

kxbmap

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