Hi all, I'm learning Kotlin + Ktor + Graphql by following this <tutorial>. However, when I run the ...

# getting-started

[Ryan Zidago]

Hi all,

I'm learning Kotlin + Ktor + Graphql by following this tutorial.
However, when I run the server and visit http://localhost:8080/graphql I do not see the graphql playground 🤔

Here's what I did so far:
• created the project using the project builder on ktor.io
• added the kgraphql_version in gradle.properties
• updated the build.gradle.kts with the line mentioned in the tutorial
• in the tutorial src/Application.kt is mentioned but my automatically generated Application.kt file is under src/main/kotlin/com.ryanzidago/Application.kt 🤔
Here's the content of my Application.kt

package com.ryanzidago

import io.ktor.server.engine.*
import io.ktor.server.netty.*
import com.ryanzidago.plugins.*

import io.ktor.application.Application
import io.ktor.application.install
import com.apurebase.kgraphql.GraphQL

fun main() {
    embeddedServer(Netty, port = 8080, host = "0.0.0.0") {
        configureRouting()
    }.start(wait = true)
}
fun Application.module(testing: Boolean = false) {
    install(GraphQL) {
        playground = true
        schema {
            query("hello") {
                resolver { -> "World" }
            }
        }
    }
}

Intellij tells me that there is a problem with the install (Not enough information to infer type variable B) and playground (Variable expected) but I cannot figure out what is wrong 🤔

When I type gradle --version in my project root I get the following output:

ariviv 
❯ gradle --version

------------------------------------------------------------
Gradle 7.3.3
------------------------------------------------------------

Build time:   2021-12-22 12:37:54 UTC
Revision:     6f556c80f945dc54b50e0be633da6c62dbe8dc71

Kotlin:       1.5.31
Groovy:       3.0.9
Ant:          Apache Ant(TM) version 1.10.11 compiled on July 10 2021
JVM:          17.0.1 (Oracle Corporation 17.0.1+12-39)
OS:           Linux 5.4.0-94-generic amd64

Any tips?

[Dariusz Kuc]

Does the app start? In general /graphql would be used to accept queries (through POST or GET). Unsure how kgraphql does the routing but I've often seen (and we do it in graphql-kotlin) the specific /playground routes (or /graphiql , /voyager etc) for the tooling.

[Ryan Zidago]

Yes the app starts:

[Ryan Zidago]

Here, the author specifically mentioned http://localhost:8080/graphql as the endpoint to use in order to see the playground 🤔

[Vampire]

Regarding the errors in IntelliJ, try to refresh the Gradle project. This shows that you have unsynced changes:

[Vampire]

So you probably just don't have the graph ql library in IntelliJ which is why it cannot import and then also not use it

[Dariusz Kuc]

this ⬆️

[Ryan Zidago]

Alright, I did it and it seems that now, the error is gone.

However, I still can't visit the endpoint 🤔

[Ryan Zidago]

(I've restarted the server in the meantime)

[Dariusz Kuc]

not familiar with that lib so won't be much help

based on https://github.com/aPureBase/KGraphQL/blob/main/kgraphql-ktor/src/main/kotlin/com/apurebase/kgraphql/KtorFeature.kt#L66 it does use same /graphql endpoint for surfacing playground using GET requests (which does not follow best practices defined in https://graphql.org/learn/serving-over-http/)

[Vampire]

Yeah, that didn't change anything but what IntelliJ sees when displaying to you.
Application.module color-wise looks unused, should that be called somewhere?

[Vampire]

I have no idea though about ktor or kgraphql

[Dariusz Kuc]

we (I am one of the maintainers of graphql-kotlin) don't have a tutorial for ktor (there is one for Spring) but there is an example app -> https://github.com/ExpediaGroup/graphql-kotlin/tree/master/examples/server/ktor-server

maybe that can be of some help

[Vampire]

The tutorial says add lines to module, but I guess this just does not fit the generated template anymore, also because the path is differently and that you simply added the whole function

[Ryan Zidago]

Thanks @Dariusz Kuc I'll definitely look into it.

[Ryan Zidago]

@Vampire yeah the tuto does not fit the generated template anymore; but I'm a bit at loss as to how to configure kgraphql with Ktor 🤔

[Vampire]

Ask them?
Especially to update the outdated tutorial?

[Ryan Zidago]

I need to get this done for a take home task 🤷
I guess by the time they'll update the docs it might be too late 😅

[Vampire]

But they might answer faster than they update the docs.
It seems here you will not get help as noone (at least active right now) knows what that is about.

[Ryan Zidago]

Alright thank you very much for your time 🙏

[Ryan Zidago]

Okay so apparently, I needed to not get rid of the configureRouting() call in my Application.module function. Now it works!

[Ryan Zidago]

Hopefully, this will prevent someone in the future to have to spent many hours like I did on this issue 😅