add ktor server plugin module

[dariuszkuc]

📝 Description

Creates Ktor GraphQL Plugin with similar functionality as the existing SpringBoot auto-configuration module.

fun Application.graphQLModule() {
    install(GraphQL) {
        schema {
            packages = listOf("com.example")
            queries = listOf(HelloWorldQuery())
        }
    }
}

🔗 Related Issues

Resolves: #1471

[dariuszkuc]

I started with the same configuration properties as used by Spring. This config contains some properties that can be set through configuration files (i.e. same as spring) and others that can only be set programmatically.

I'm not a big fan of how this is all structured at the moment so most likely structure of this file will change.

In general there are 3 areas of configuration:

• schema - everything related to schema generation (e.g. which queries to include)
• engine - everything related to GraphQL Java engine configuration
• server - Ktor server custom config (e.g. context factory)

I'm thinking I will move the existing properties (which were matching spring config) under those three sections, e.g. when configuring schema I think it would make sense to specify target packages in the same place

[dariuszkuc]

One drawback of reorganizing the properties would be the change in property file mapping - currently properties match the path from the root graphql prefix, e.g. graphql.packages is a top level packages property. If we move those around then we either have to use different properties than in Spring (not ideal but I guess it should be fine?) or have a mismatch between paths and variables, e.g.

• graphql.packages would become graphql.schema.packages
• graphql.introspection.enabled would become graphql.engine.introspection.enabled