Merge pull request #227 from armanbilge/issue/226

Close the output writer in JVM lambda runtime

Author: armanbilge

lambda/jvm/src/main/scala/feral/lambda/IOLambdaPlatform.scala

@@ -53,6 +53,7 @@ private[lambda] abstract class IOLambdaPlatform[Event, Result]
               val json = result.asJson
               val writer = new OutputStreamWriter(output)
               Printer.noSpaces.unsafePrintToAppendable(json, writer)
+              writer.close()
             }
           }
         } yield ()

lambda/jvm/src/test/scala/feral/lambda/IOLambdaJvmSuite.scala

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2021 Typelevel
+ *
+ * Licensed 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
+ *
+ *     http://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 feral.lambda
+
+import cats.effect.IO
+import cats.effect.kernel.Resource
+import com.amazonaws.services.lambda.runtime
+import io.circe.Json
+import io.circe.jawn
+import io.circe.literal._
+import munit.FunSuite
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+
+class IOLambdaJvmSuite extends FunSuite {
+
+  test("reads input and writes output") {
+
+    val input = json"""{ "foo": "bar" }"""
+    val output = json"""{ "woozle": "heffalump" }"""
+
+    val lambda = new IOLambda[Json, Json] {
+      def handler = Resource.pure(_ => IO(Some(output)))
+    }
+
+    val os = new ByteArrayOutputStream
+
+    lambda.handleRequest(
+      new ByteArrayInputStream(input.toString.getBytes()),
+      os,
+      DummyContext
+    )
+
+    assertEquals(
+      jawn.parseByteArray(os.toByteArray()),
+      Right(output),
+      new String(os.toByteArray())
+    )
+  }
+
+  object DummyContext extends runtime.Context {
+    override def getAwsRequestId(): String = ""
+    override def getLogGroupName(): String = ""
+    override def getLogStreamName(): String = ""
+    override def getFunctionName(): String = ""
+    override def getFunctionVersion(): String = ""
+    override def getInvokedFunctionArn(): String = ""
+    override def getIdentity(): runtime.CognitoIdentity = null
+    override def getClientContext(): runtime.ClientContext = null
+    override def getRemainingTimeInMillis(): Int = 0
+    override def getMemoryLimitInMB(): Int = 0
+    override def getLogger(): runtime.LambdaLogger = null
+  }
+
+}