Add CoroutineHttpService for handle request within Coroutine suspend (#…

…5603)

Motivation:
- Closes #5442

Modifications:
- Add CoroutineHttpService implements HttpService

Result:
- Closes #5442.
- You can now use `CoroutineHttpService` that runs your service in a coroutine scope.
Co-authored-by: minwoox <songmw725@gmail.com>

kotlin/src/main/kotlin/com/linecorp/armeria/server/kotlin/CoroutineHttpService.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2024 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package com.linecorp.armeria.server.kotlin
+
+import com.linecorp.armeria.common.HttpRequest
+import com.linecorp.armeria.common.HttpResponse
+import com.linecorp.armeria.common.kotlin.CoroutineContexts
+import com.linecorp.armeria.common.kotlin.asCoroutineContext
+import com.linecorp.armeria.server.HttpService
+import com.linecorp.armeria.server.ServiceRequestContext
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.future.future
+import kotlin.coroutines.EmptyCoroutineContext
+
+/**
+ * A Coroutine-based [HttpService]
+ */
+fun interface CoroutineHttpService : HttpService {
+    /**
+     * Calls [suspendedServe] in a [CoroutineScope] and returns the result as an [HttpResponse].
+     */
+    override fun serve(
+        ctx: ServiceRequestContext,
+        req: HttpRequest,
+    ): HttpResponse {
+        val userContext = CoroutineContexts.get(ctx) ?: EmptyCoroutineContext
+        return HttpResponse.of(
+            CoroutineScope(
+                ctx.asCoroutineContext() + userContext,
+            ).future {
+                suspendedServe(ctx, req)
+            },
+        )
+    }
+
+    /**
+     * Serves an incoming [HttpRequest] in a [CoroutineScope].
+     */
+    suspend fun suspendedServe(
+        ctx: ServiceRequestContext,
+        req: HttpRequest,
+    ): HttpResponse
+}

kotlin/src/test/kotlin/com/linecorp/armeria/server/kotlin/CoroutineHttpServiceTest.kt

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2024 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package com.linecorp.armeria.server.kotlin
+
+import com.linecorp.armeria.common.HttpResponse
+import com.linecorp.armeria.common.HttpStatus
+import com.linecorp.armeria.server.ServerBuilder
+import com.linecorp.armeria.server.ServiceRequestContext
+import com.linecorp.armeria.testing.junit5.server.ServerExtension
+import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.currentCoroutineContext
+import kotlinx.coroutines.test.runTest
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.RegisterExtension
+
+class CoroutineHttpServiceTest {
+    companion object {
+        @JvmField
+        @RegisterExtension
+        val server =
+            object : ServerExtension() {
+                override fun configure(sb: ServerBuilder) {
+                    sb.service(
+                        "/hello",
+                        CoroutineHttpService { ctx, req ->
+                            assertContextPropagation()
+                            HttpResponse.of("hello world")
+                        },
+                    ).decorator(
+                        CoroutineContextService.newDecorator { ctx ->
+                            CoroutineName("my-coroutine-name")
+                        },
+                    )
+                }
+            }
+
+        private suspend fun assertContextPropagation() {
+            assertThat(ServiceRequestContext.currentOrNull()).isNotNull()
+            assertThat(currentCoroutineContext()[CoroutineName]?.name).isEqualTo("my-coroutine-name")
+        }
+    }
+
+    @Test
+    fun `Should return hello world when call hello coroutine service`() =
+        runTest {
+            val response = server.blockingWebClient().get("/hello")
+            assertThat(response.status()).isEqualTo(HttpStatus.OK)
+            assertThat(response.contentUtf8()).isEqualTo("hello world")
+        }
+}