Armeria per-port VirtualHost and random port are incompatible

[davinkevin]

Hello 👋

I'd like to report a behavior. It might not be considered as a bug but it makes developer life a bit more complicated.

To summarize, if I use this kind of code:

fun main(){
    val server = Server.builder().apply {
        service("/foo") { ctx, req -> HttpResponse.of("Hello foo")}
    }
        .http(0)
        .build()

    server.closeOnJvmShutdown()
    server.start().join()
}

It works perfectly and reports a specific port used at startup, like this:

SLF4J(I): Connected with provider of type [ch.qos.logback.classic.spi.LogbackServiceProvider]
08:13:50.854 [armeria-boss-http-*:51313] INFO  -- Serving HTTP at /[0:0:0:0:0:0:0:0]:51313 - http://127.0.0.1:51313/

And if I use multiple ports:

SLF4J(I): Connected with provider of type [ch.qos.logback.classic.spi.LogbackServiceProvider]
08:18:39.446 [armeria-boss-http-*:51461] INFO  -- Serving HTTP at /[0:0:0:0:0:0:0:0]:51461 - http://127.0.0.1:51461/
08:18:39.448 [armeria-boss-http-*:51462] INFO  -- Serving HTTP at /[0:0:0:0:0:0:0:0]:51462 - http://127.0.0.1:51462/

This is very handy, especially in test setup when I want to avoid conflicting port usage in CI.

But, my business case led me to a situation where I have to consider per-port service. For that, we used the VirtualHost feature, but this one is incompatible with random port selection if set to 0.

See, the following code works:

val isRandomPort = System.getenv("IS_RANDOM_PORT").toBooleanStrict()

fun main(){
    val firstHost = if (isRandomPort) 0 else 8080
    val secondHost = if (isRandomPort) 0 else 8081
    val server = Server.builder().apply {

        http(firstHost)
        virtualHost(firstHost).apply {
            service("/foo") { ctx, req -> HttpResponse.of("Hello, foo!")}
        }

        http(secondHost)
        virtualHost(secondHost).apply {
            service("/bar") { ctx, req -> HttpResponse.of("Hello, bar!")}
        }
    }
        .build()

    server.closeOnJvmShutdown()
    server.start().join()
}

But I can't anymore use the random port feature. because they'll both be with 0 and the virtualHost mechanism won't work, with the following error:

> Task :server:run FAILED
SLF4J(I): Connected with provider of type [ch.qos.logback.classic.spi.LogbackServiceProvider]
Exception in thread "main" java.lang.IllegalArgumentException: port: 0 (expected: 1-65535)
        at com.linecorp.armeria.internal.shaded.guava.base.Preconditions.checkArgument(Preconditions.java:191)
        at com.linecorp.armeria.server.ServerBuilder.virtualHost(ServerBuilder.java:1734)
        at com.gitlab.davinkevin.experimentations.armeria.grpc.MainKt.main(Main.kt:15)
        at com.gitlab.davinkevin.experimentations.armeria.grpc.MainKt.main(Main.kt)

FAILURE: Build failed with an exception.

Is there a solution to still leverage the random port feature, almost crucial in CI and being compatible with virtualHost? Maybe something like virtualHost(ServerPort s) where s should be the exact same object provided to the port(…) method.

Thank you for your help,

[ikhoon]

Maybe something like virtualHost(ServerPort s) where s should be the exact same object provided to the port(…) method.

Sounds like a good idea.