I use PKL for most of my configuration needs these days. But PKL is only a format, it doesn't say where to store the config. Could I use Externalized Properties to e.g. fetch config from some random source but have it be PKL?
Definitely! There's no limit on what configuration formats Externalized Properties can support as you can implement custom `Resolver`s to retrieve from any source and format e.g.
public class PklResolver implements Resolver {
public Optional<String> resolve(InvocationContext context, String propertyName) {
return getFromPklConfig(propertyName);
}
}
// Register custom resolver when building ExternalizedProperties
ExternalizedProperties externalizedProperties = ExternalizedProperties.builder()
.resolvers(new PklResolver(...))
.build();
AppProperties appProperties = externalizedProperties.initialize(AppProperties.class);
// Resolves config from PklResolver
String myConfig = appProperties.myConfig();
By using ExternalizedProperties instead of direct System.getenv() you get other useful features such as automatic conversions, variable expansion, and processing (e.g. automatic decryption/automatic base64 decode, etc)