fix(yogurt): repair Linux shutdown (#33)

* fix(yogurt): use platform specific shutdown on Linux

* fix(yogurt): use `posix.signal` on Linux

Author: Wesley-Young

yogurt/build.gradle.kts

@@ -8,6 +8,7 @@ plugins {
     id("buildsrc.convention.kotlin-multiplatform")
     alias(libs.plugins.kotlin.serialization)
     alias(libs.plugins.build.konfig)
+    alias(libs.plugins.kotlinx.atomicfu)
 }
 
 version = "0.1.0"

yogurt/src/commonMain/kotlin/org/ntqqrev/yogurt/Main.kt

@@ -2,13 +2,17 @@
 
 package org.ntqqrev.yogurt
 
-import io.ktor.server.engine.*
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.runBlocking
 import kotlin.jvm.JvmName
 
 fun main() {
     val server = YogurtApp.createServer()
-    server.addShutdownHook {
+    server.start(wait = false)
+    server.onSigint {
         server.stop(gracePeriodMillis = 2000L, timeoutMillis = 5000L)
     }
-    server.start(wait = true)
+    runBlocking {
+        delay(Long.MAX_VALUE)
+    }
 }

yogurt/src/commonMain/kotlin/org/ntqqrev/yogurt/Shutdown.kt

@@ -0,0 +1,5 @@
+package org.ntqqrev.yogurt
+
+import io.ktor.server.engine.EmbeddedServer
+
+expect fun EmbeddedServer<*, *>.onSigint(hook: () -> Unit)

yogurt/src/jvmMain/kotlin/org/ntqqrev/yogurt/Shutdown.jvm.kt

@@ -0,0 +1,7 @@
+package org.ntqqrev.yogurt
+
+import io.ktor.server.engine.*
+
+actual fun EmbeddedServer<*, *>.onSigint(hook: () -> Unit) {
+    addShutdownHook(hook)
+}

yogurt/src/linuxMain/kotlin/org/ntqqrev/yogurt/Shutdown.linux.kt

@@ -0,0 +1,31 @@
+package org.ntqqrev.yogurt
+
+import io.ktor.server.engine.*
+import io.ktor.server.plugins.di.dependencies
+import kotlinx.atomicfu.atomic
+import kotlinx.cinterop.ExperimentalForeignApi
+import kotlinx.cinterop.staticCFunction
+import kotlinx.coroutines.runBlocking
+import org.ntqqrev.acidify.AbstractBot
+import org.ntqqrev.acidify.offline
+import platform.posix.SIGINT
+import platform.posix.exit
+import platform.posix.signal
+
+val botRef = atomic<AbstractBot?>(null)
+
+@OptIn(ExperimentalForeignApi::class)
+actual fun EmbeddedServer<*, *>.onSigint(hook: () -> Unit) {
+    botRef.value = runBlocking { application.dependencies.resolve<AbstractBot>() }
+    // On Linux targets, the shutdown hook gets unexpectedly overridden by Ktor's internal shutdown hook;
+    // and `server.stop()` blocks forever on Linux,
+    // so we have to use a `exit(0)` to force the process to exit immediately after the shutdown hook is executed.
+    // See KTOR-9308 and KTOR-9309 for more details.
+    signal(SIGINT, staticCFunction { _ ->
+        println("Received SIGINT, shutting down...")
+        runBlocking {
+            botRef.value?.offline()
+        }
+        exit(0)
+    })
+}

yogurt/src/macosMain/kotlin/org/ntqqrev/yogurt/Shutdown.macos.kt

@@ -0,0 +1,7 @@
+package org.ntqqrev.yogurt
+
+import io.ktor.server.engine.*
+
+actual fun EmbeddedServer<*, *>.onSigint(hook: () -> Unit) {
+    addShutdownHook(hook)
+}

yogurt/src/mingwMain/kotlin/org/ntqqrev/yogurt/Shutdown.mingw.kt

@@ -0,0 +1,7 @@
+package org.ntqqrev.yogurt
+
+import io.ktor.server.engine.*
+
+actual fun EmbeddedServer<*, *>.onSigint(hook: () -> Unit) {
+    addShutdownHook(hook)
+}