KTOR-1854 "ApplicationEngineEnvironment was not started" when accessi…

…ng application before server is started (#2546)
ktorio · Jul 9, 2021 · 1f8fabd · 1f8fabd
1 parent 4c40b10
commit 1f8fabd
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Showing 3 changed files with 77 additions and 2 deletions.
diff --git a/ktor-server/ktor-server-host-common/build.gradle.kts b/ktor-server/ktor-server-host-common/build.gradle.kts
@@ -7,4 +7,10 @@ kotlin.sourceSets {
             api(project(":ktor-http:ktor-http-cio"))
         }
     }
+
+    val jvmTest by getting {
+        dependencies {
+            implementation(project(":ktor-server:ktor-server-test-host"))
+        }
+    }
 }
diff --git a/...server-host-common/jvm/src/io/ktor/server/engine/ApplicationEngineEnvironmentReloading.kt b/...server-host-common/jvm/src/io/ktor/server/engine/ApplicationEngineEnvironmentReloading.kt
@@ -54,7 +54,8 @@ public class ApplicationEngineEnvironmentReloading(
         parentCoroutineContext, rootPath, developmentMode = true
     )
 
-    private var _applicationInstance: Application? = null
+    private var _applicationInstance: Application? = Application(this)
+    private var recreateInstance: Boolean = false
     private var _applicationClassLoader: ClassLoader? = null
     private val applicationInstanceLock = ReentrantReadWriteLock()
     private var packageWatchKeys = emptyList<WatchKey>()
@@ -289,7 +290,13 @@ public class ApplicationEngineEnvironmentReloading(
     }
 
     private fun instantiateAndConfigureApplication(currentClassLoader: ClassLoader): Application {
-        val newInstance = Application(this)
+        val newInstance = if (recreateInstance || _applicationInstance == null) {
+            Application(this)
+        } else {
+            recreateInstance = true
+            _applicationInstance!!
+        }
+
         safeRiseEvent(ApplicationStarting, newInstance)
 
         avoidingDoubleStartup {

diff --git a/...er-host-common/jvm/test/io/ktor/tests/hosts/ApplicationEngineEnvironmentReloadingTests.kt b/...er-host-common/jvm/test/io/ktor/tests/hosts/ApplicationEngineEnvironmentReloadingTests.kt
@@ -7,8 +7,14 @@ package io.ktor.tests.hosts
 import com.typesafe.config.*
 import io.ktor.application.*
 import io.ktor.config.*
+import io.ktor.http.*
+import io.ktor.response.*
+import io.ktor.routing.*
 import io.ktor.server.engine.*
+import io.ktor.server.testing.*
 import io.ktor.util.*
+import kotlinx.coroutines.*
+import org.slf4j.helpers.*
 import kotlin.reflect.*
 import kotlin.reflect.jvm.*
 import kotlin.test.*
@@ -459,6 +465,62 @@ class ApplicationEngineEnvironmentReloadingTests {
             attributes.put(TestKey, "functionWithDefaultArg")
         }
     }
+
+    @Test
+    fun `application is available before environment start`() {
+        val env = dummyEnv()
+        val app = env.application
+        env.start()
+        assertEquals(app, env.application)
+    }
+
+    @Test
+    fun `completion handler is invoked when attached before environment start`() {
+        val env = dummyEnv()
+
+        var invoked = false
+        env.application.coroutineContext[Job]?.invokeOnCompletion {
+            invoked = true
+        }
+
+        env.start()
+        env.stop()
+
+        assertTrue(invoked, "On completion handler wasn't invoked")
+    }
+
+    @Test
+    fun `interceptor is invoked when added before environment start`() {
+        val engine = TestApplicationEngine(createTestEnvironment())
+        engine.application.intercept(ApplicationCallPipeline.Features) {
+            call.response.header("Custom", "Value")
+        }
+        engine.start()
+
+        try {
+            engine.apply {
+                application.routing {
+                    get("/") {
+                        call.respondText { "Hello" }
+                    }
+                }
+
+                assertEquals("Value", handleRequest(HttpMethod.Get, "/").response.headers["Custom"])
+            }
+        } catch (cause: Throwable) {
+            fail("Failed with an exception: ${cause.message}")
+        } finally {
+            engine.stop(0L, 0L)
+        }
+    }
+
+    private fun dummyEnv() = ApplicationEngineEnvironmentReloading(
+        classLoader = this::class.java.classLoader,
+        log = NOPLogger.NOP_LOGGER,
+        config = MapApplicationConfig(),
+        connectors = emptyList(),
+        modules = emptyList()
+    )
 }
 
 fun Application.topLevelExtensionFunction() {