HttpLoggingInterceptor not logging with retrofit 2

Instead of

val okHttpClient = OkHttpClient.Builder()
    .addNetworkInterceptor(interceptor)
    ...

you should have something like:

val okHttpClient = OkHttpClient.Builder()
    .addInterceptor(interceptor)
    ...

as the addNetworkInterceptor() plays with interceptors that observe a single network request and response, while addInterceptor() adds interceptor that observes the full span of each call: from the connection is established (if any) until after the response source is selected (either the origin server, cache, or both).

EDIT

Errors doing requests on Main Thread are not showing by the logger, so be careful

Doing networking on main thread is not an "ordinary" error. It will result in your app being killed by the system with NetworkOnMainThreadException and this will happen before interceptor would be given any chance to run.

private val interceptor = run {
    val httpLoggingInterceptor = HttpLoggingInterceptor()
    httpLoggingInterceptor.apply {
        httpLoggingInterceptor.level = HttpLoggingInterceptor.Level.BODY
    }
}


private val okHttpClient = OkHttpClient.Builder()
    .addNetworkInterceptor(interceptor) // same for .addInterceptor(...)
    .connectTimeout(30, TimeUnit.SECONDS) //Backend is really slow
    .writeTimeout(30, TimeUnit.SECONDS)
    .readTimeout(30, TimeUnit.SECONDS)
    .build()