kiran002 / kissconfig

Simple scala library for reading TypeSafe configuration directly into case classes

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KissConfig

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Intro

KissConfig (KISS + Config) is a pure scala library for reading TypeSafe configuration. modelled after the Keep it stupid simple principle.

Why?

Dealing with configurations is an every day task and it should be simple. KissConfig aims to make this a reality built on top of LightBend Config, Define a model (case class) for the properties you need and point KissConfig to your Configuration and let it take over the messy parts.

KissConfig is a pure scala library, meaning first class support to all scala types and no need interop with Java types.

How does it work?

KissConfig, just requires two inputs

  1. the configuration and
  2. the model you want to populate,

Using Scala reflection KissConfig inspects each field (type and name) in runtime, the field name is used the source of the configuration and type is used to determine how the configuration will be extracted.

Example

The following is a sample model for a Person,

case class Person(name:String,age:Int)

and this is how its corresponding configuration looks like

{
name = "John"
age = 34
}
Field Key Extraction method
name name getString
age age getInteger

Which types does KissConfig support?

The idea behind KissConfig is not to support every type available, but only the types types that are most used in configurations. KissConfig currently supports the following types,

  1. Primitive types + Strings
  2. Collections (Lists,Maps)
  3. Custom case classes
  4. Optional Types

if you have a valid suggestion for some other types, please create an issue with the proper usecase and we can discuss it.

Config examples

Configuration can be simple assignments with Integers, Strings, Booleans

myInt = 5
myString = "myString"
myBoolean = true

Configuration can be list of Strings, Integers, Booleans

lists = ["1", "2", "3"]

Configuration can be maps (key value pairs)

map = {
  "key1" = "val1"
  "key2" = "val2"
}

Configurations can be nested types and the fields are populated based on the fields of the custom types but config should contain config for all the fields, otherwise this would throw an exception in runtime the configuration below could correspond to the following case class

case class PrimaryTypes(myInt: Int, myString: String, myBoolean: Boolean)
pt = {
  myInt = 5
  myString = "myString"
  myBoolean = true
}

Configuration can also be custom types of Lists and Maps

lm = {
  lists = ["1", "2", "3"]
  map = {
    "key1" = "val1"
    "key2" = "val2"
  }
}

It is most often the case, that we want to follow different naming conventions in code and different naming conventions in Configuration. You should have the flexibility to chose the conventions that work the best for you, Using a resolution strategy you are able to define how a field name (in Scala) should be translated to its corresponding Key in the Configuration.

KissConfig provides two such conversions out of the box,

  1. camelCase to underscore

    underscore = {
      my_int = 5
      my_string = "myString"
      my_boolean = true
    }
    
  2. underscore to camelCase

    camelcase = {
      myInt = 5
      myString = "myString"
      myBoolean = true
    }
    

Usage

Kissconfig is currently available only for scala 2.12, but it is planned to add support for scala 2.11 and 2.13.

Import the dependency in your project

SBT

libraryDependencies += "com.github.kiran002" %% "kissconfig-core" % "1.0.2"

Gradle

for scala 2.11
implementation 'com.github.kiran002:kissconfig-core_2.11:1.0.2'

for scala 2.12
implementation 'com.github.kiran002:kissconfig-core_2.12:1.0.2'

for scala 2.13
implementation 'com.github.kiran002:kissconfig-core_2.13:1.0.2'

Maven

<dependency>
  <groupId>com.github.kiran002</groupId>
  <artifactId>kissconfig_<<scala_version>>/artifactId>
  <version>1.0.2</version>
</dependency>

License

This project is licensed under the Apache License, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0)

Contributing

If you find bugs while using KissConfig, please feel free to create an issue or a PR to patch the bug. If you would like to improve the software in any way (code, documentation, tests), please free to get in touch with mel