I'm trying to run a simple program that makes an H...

# coroutines

[arekolek]

I'm trying to run a simple program that makes an HTTP call using retrofit but for some reason it is still running even after the call is finished and I can't figure out why

It finishes after about a minute, but the call is done after a few seconds

fun main() = runBlocking {
    val service = createFooService()
    val response = withContext(<http://Dispatchers.IO|Dispatchers.IO>) {
        service.foo()
    }
    println(response)
}

interface FooService {
    @POST("foo")
    suspend fun foo(): FooResponse
}

dependencies {
    implementation("com.jakewharton.retrofit:retrofit2-kotlinx-serialization-converter:0.8.0")
    implementation("com.squareup.okhttp3:okhttp:4.10.0")
    implementation("com.squareup.retrofit2:retrofit:2.9.0")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core-jvm:1.6.4")
    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.4.1")
}

[streetsofboston]

Did you have a typo in your example.
Should it be suspend fun main() ?

[streetsofboston]

Also, no need to switch to IO dispatcher just before callin suspend fun foo() since it is already suspending, not blocking.

[arekolek]

this is my last iteration I'm just trying different things

if I do it like you say:

suspend fun main() = runBlocking {
    val response = service.foo()
    println(response)
}

it's still the same thing

I run it using ./gradlew run if that changes anything

[Riccardo Lippolis]

sounds like maybe some connection keepalive / resources that aren't being closed, keeping the application alive? I know that OkHttp uses its own thread pool, that should be closed for proper application shutdown

[Riccardo Lippolis]

https://square.github.io/okhttp/4.x/okhttp/okhttp3/-ok-http-client/#shutdown-isnt-necessary

would explain why it shuts down after a minute, maybe a default connection keepalive of 60 seconds, after which the connection is terminated -> resources released -> application shutdown

[streetsofboston]

Yeah... it could be a non-daemon thread by OkHttp kept alive (too long).

[Riccardo Lippolis]

see also: https://github.com/square/retrofit/issues/3144

[arekolek]

ok so now I have:

suspend fun main() {
    val client = okHttpClient()
    val service = createFooService(client)
    val response = service.foo()
    println(response)
    client.dispatcher.executorService.shutdown()
    client.connectionPool.evictAll()
}

and it seems to work like expected! thanks for the help