adrianfilip / zio-properties   1.0

Usage:

"com.adrianfilip" %% "zio-properties" % "1.0"

Property resolution order:

• command line arguments
• system properties
• environment variables
• HOCON file
  • Looks for an application.conf if hoconFile and profile properties are not present in any previous source and application.conf in present in the classpath
  • if the hoconFile property is present the mentioned file will be used (and profile is ignored for HOCON file resolution). Fails if file not found in classpath.
  • if hoconFile is not present and profile is not present application.conf file will be used if present (does not fail if file not found in classpath)
  • if profile is present
    • and has a value that when lowercased equals "prod" or is empty string then application.conf file will be used if present (does not fail if file not found in classpath) otherwise
    • the application-${lowercase.profile}.conf file will be used if present (does not fail if file not found in classpath) otherwise
• properties file
  • Looks for an application.properties if propertiesFile and profile properties are not present in any previous source and application.properties in present in the classpath
  • if the propertiesFile property is present the mentioned file will be used (and profile is ignored for properties file resolution). Fails if file not found in classpath.
  • if propertiesFile is not present and profile is not present application.properties file will be used if present (does not fail if file not found in classpath)
  • if profile is present
    • and has a value that when lowercased equals "prod" or is empty string then application.properties file will be used if present (does not fail if file not found in classpath) otherwise
    • the application-${lowercase.profile}.properties file will be used if present (does not fail if file not found in classpath) otherwise

How the properties must be provided for each source:

1. command line arguments => keyDelimiter="." , valueDelimiter=","

-db.port=3306

-aliases=alias1,alias2,alias3

2. system properties => keyDelimiter="_" , valueDelimiter=","

db_port=3306

aliases=alias1,alias2,alias3

3. environment properties => keyDelimiter="_" , valueDelimiter=","

db_port=3306

aliases=alias1,alias2,alias3

4. HOCON file

db {

port=3306

}

aliases=["alias1","alias2","alias3"]

5. properties file => keyDelimiter="." , valueDelimiter=","

db.port=3306

aliases=alias1,alias2,alias3

Example usage:

(You can see the full example in ZioPropertiesExample.scala)

def run(args: List[String]): ZIO[ZEnv, Nothing, Int] = {
  //create the descriptor for your AppProperties
  val desc = descriptor[AppProperties]

  val p = for {
    //provide the arguments from main method and the descriptor to create the Layer
    layer <- ZioProperties.createPropertiesLayer(args, desc)
    props <- myProgram.provideCustomLayer(layer)
  } yield props

  ...
}


/**
 * Effects that require AppProperties can retrieve it from the Layer
*/
val myProgram: ZIO[Config[AppProperties] with Console, Nothing, AppProperties] =
  for {
    myProps <- config[AppProperties]
    _       <- putStrLn(myProps.toString())
  } yield myProps