Provide a way to automatically delete multipart temporary files

benchmarks/jmh/src/jmh/java/com/linecorp/armeria/server/RoutersBenchmark.java

@@ -67,19 +67,23 @@ public class RoutersBenchmark {
  SERVICE, defaultLogName, defaultServiceName, defaultServiceNaming, 0, 0,
  false, AccessLogWriter.disabled(), CommonPools.blockingTaskExecutor(),
  SuccessFunction.always(), 0, multipartUploadsLocation,
+ MultipartRemovalStrategy.ON_RESPONSE_COMPLETION,
  CommonPools.workerGroup(), ImmutableList.of(), HttpHeaders.of(),
  ctx -> RequestId.random(), serviceErrorHandler, NOOP_CONTEXT_HOOK),
  new ServiceConfig(route2, route2,
  SERVICE, defaultLogName, defaultServiceName, defaultServiceNaming, 0, 0,
  false, AccessLogWriter.disabled(), CommonPools.blockingTaskExecutor(),
  SuccessFunction.always(), 0, multipartUploadsLocation,
+ MultipartRemovalStrategy.ON_RESPONSE_COMPLETION,
  CommonPools.workerGroup(), ImmutableList.of(), HttpHeaders.of(),
  ctx -> RequestId.random(), serviceErrorHandler, NOOP_CONTEXT_HOOK));
  FALLBACK_SERVICE = new ServiceConfig(Route.ofCatchAll(), Route.ofCatchAll(), SERVICE,
  defaultLogName, defaultServiceName,
  defaultServiceNaming, 0, 0, false, AccessLogWriter.disabled(),
  CommonPools.blockingTaskExecutor(), SuccessFunction.always(), 0,
- multipartUploadsLocation, CommonPools.workerGroup(),
+ multipartUploadsLocation,
+ MultipartRemovalStrategy.ON_RESPONSE_COMPLETION,
+ CommonPools.workerGroup(),
  ImmutableList.of(), HttpHeaders.of(), ctx -> RequestId.random(),
  serviceErrorHandler, NOOP_CONTEXT_HOOK);
  HOST = new VirtualHost(

core/src/main/java/com/linecorp/armeria/common/DefaultFlagsProvider.java

@@ -29,6 +29,7 @@
 import com.linecorp.armeria.common.util.Sampler;
 import com.linecorp.armeria.common.util.TlsEngineType;
 import com.linecorp.armeria.common.util.TransportType;
+import com.linecorp.armeria.server.MultipartRemovalStrategy;
 import com.linecorp.armeria.server.TransientServiceOption;
 
 import io.micrometer.core.instrument.MeterRegistry;
@@ -460,6 +461,11 @@ public Path defaultMultipartUploadsLocation() {
  File.separatorChar + "multipart-uploads");
  }
 
+ @Override
+ public MultipartRemovalStrategy defaultMultipartRemovalStrategy() {
+ return MultipartRemovalStrategy.ON_RESPONSE_COMPLETION;
+ }
+
  @Override
  public Sampler<? super RequestContext> requestContextLeakDetectionSampler() {
  return Sampler.never();

core/src/main/java/com/linecorp/armeria/common/Flags.java

@@ -58,6 +58,7 @@
 import com.linecorp.armeria.internal.common.FlagsLoaded;
 import com.linecorp.armeria.internal.common.util.SslContextUtil;
 import com.linecorp.armeria.server.HttpService;
+import com.linecorp.armeria.server.MultipartRemovalStrategy;
 import com.linecorp.armeria.server.ServerBuilder;
 import com.linecorp.armeria.server.ServerErrorHandler;
 import com.linecorp.armeria.server.Service;
@@ -399,6 +400,9 @@ private static boolean validateTransportType(TransportType transportType, String
  private static final Path DEFAULT_MULTIPART_UPLOADS_LOCATION =
  getValue(FlagsProvider::defaultMultipartUploadsLocation, "defaultMultipartUploadsLocation");
 
+ private static final MultipartRemovalStrategy DEFAULT_MULTIPART_REMOVAL_STRATEGY =
+ getValue(FlagsProvider::defaultMultipartRemovalStrategy, "defaultMultipartRemovalStrategy");
+
  private static final Sampler<? super RequestContext> REQUEST_CONTEXT_LEAK_DETECTION_SAMPLER =
  getValue(FlagsProvider::requestContextLeakDetectionSampler, "requestContextLeakDetectionSampler");
 
@@ -1442,6 +1446,15 @@ public static Path defaultMultipartUploadsLocation() {
  return DEFAULT_MULTIPART_UPLOADS_LOCATION;
  }
 
+ /**
+ * Returns the {@link MultipartRemovalStrategy} that is used to determine how to remove the uploaded files
+ * from {@code multipart/form-data}.
+ */
+ @UnstableApi
+ public static MultipartRemovalStrategy defaultMultipartRemovalStrategy() {
+ return DEFAULT_MULTIPART_REMOVAL_STRATEGY;
+ }
+
  /**
  * Returns whether to allow double dots ({@code ..}) in a request path query string.
  *

core/src/main/java/com/linecorp/armeria/common/FlagsProvider.java

@@ -45,6 +45,7 @@
 import com.linecorp.armeria.common.util.TlsEngineType;
 import com.linecorp.armeria.common.util.TransportType;
 import com.linecorp.armeria.server.HttpService;
+import com.linecorp.armeria.server.MultipartRemovalStrategy;
 import com.linecorp.armeria.server.ServerBuilder;
 import com.linecorp.armeria.server.Service;
 import com.linecorp.armeria.server.ServiceRequestContext;
@@ -1095,6 +1096,15 @@ default Path defaultMultipartUploadsLocation() {
  return null;
  }
 
+ /**
+ * Returns the {@link MultipartRemovalStrategy} that is used to determine how to remove the uploaded files
+ * from {@code multipart/form-data}.
+ */
+ @Nullable
+ default MultipartRemovalStrategy defaultMultipartRemovalStrategy() {
+ return null;
+ }
+
  /**
  * Returns the {@link Sampler} that determines whether to trace the stack trace of request contexts leaks
  * and how frequently to keeps stack trace. A sampled exception will have the stack trace while the others

core/src/main/java/com/linecorp/armeria/common/SystemPropertyFlagsProvider.java

@@ -41,6 +41,7 @@
 import com.linecorp.armeria.common.util.Sampler;
 import com.linecorp.armeria.common.util.TlsEngineType;
 import com.linecorp.armeria.common.util.TransportType;
+import com.linecorp.armeria.server.MultipartRemovalStrategy;
 import com.linecorp.armeria.server.TransientServiceOption;
 
 /**
@@ -473,6 +474,24 @@ public Path defaultMultipartUploadsLocation() {
  return getAndParse("defaultMultipartUploadsLocation", Paths::get);
  }
 
+ @Nullable
+ @Override
+ public MultipartRemovalStrategy defaultMultipartRemovalStrategy() {
+ final String multipartRemovalStrategy = getNormalized("defaultMultipartRemovalStrategy");
+ if (multipartRemovalStrategy == null) {
+ return null;
+ }
+ switch (multipartRemovalStrategy) {
+ case "never":
+ return MultipartRemovalStrategy.NEVER;
+ case "on_response_completion":
+ return MultipartRemovalStrategy.ON_RESPONSE_COMPLETION;
+ default:
+ throw new IllegalArgumentException(
+ multipartRemovalStrategy + " isn't MultipartRemovalStrategy");
+ }
+ }
+
  @Override
  public Sampler<? super RequestContext> requestContextLeakDetectionSampler() {
  final String spec = getNormalized("requestContextLeakDetectionSampler");

core/src/main/java/com/linecorp/armeria/internal/server/FileAggregatedMultipart.java

@@ -26,6 +26,9 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ScheduledExecutorService;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Maps;
@@ -39,6 +42,8 @@
 import io.netty.channel.EventLoop;
 
 public final class FileAggregatedMultipart {
+ private static final Logger logger = LoggerFactory.getLogger(FileAggregatedMultipart.class);
+
  private final ListMultimap<String, String> params;
  private final ListMultimap<String, MultipartFile> files;
 
@@ -72,7 +77,7 @@ public static CompletableFuture<FileAggregatedMultipart> aggregateMultipart(Serv
  return resolveTmpFile(incompleteDir, filename, executor).thenCompose(path -> {
  return bodyPart.writeTo(path, eventLoop, executor).thenCompose(ignore -> {
  final Path completeDir = destination.resolve("complete");
- return moveFile(path, completeDir, executor);
+ return moveFile(path, completeDir, executor, ctx);
  }).thenApply(completePath -> MultipartFile.of(name, filename, completePath.toFile(),
  bodyPart.headers()));
  });
@@ -102,19 +107,40 @@ public static CompletableFuture<FileAggregatedMultipart> aggregateMultipart(Serv
  }
 
  private static CompletableFuture<Path> moveFile(Path file, Path targetDirectory,
- ExecutorService blockingExecutorService) {
+ ExecutorService blockingExecutorService,
+ ServiceRequestContext ctx) {
  return CompletableFuture.supplyAsync(() -> {
  try {
  Files.createDirectories(targetDirectory);
  // Avoid name duplication, create new file at target place and replace it.
- return Files.move(file, Files.createTempFile(targetDirectory, null, ".multipart"),
-   StandardCopyOption.REPLACE_EXISTING);
+ final Path tempFile = createRemovableTempFile(targetDirectory, blockingExecutorService, ctx);
+ return Files.move(file, tempFile, StandardCopyOption.REPLACE_EXISTING);
  } catch (IOException e) {
  throw new UncheckedIOException(e);
  }
  }, blockingExecutorService);
  }
 
+ private static Path createRemovableTempFile(Path targetDirectory,
+ ExecutorService blockingExecutorService,
+ ServiceRequestContext ctx) throws IOException {
+ final Path tempFile = Files.createTempFile(targetDirectory, null, ".multipart");
+ switch (ctx.config().multipartRemovalStrategy()) {
+ case NEVER:
+ break;
+ case ON_RESPONSE_COMPLETION:
+ ctx.log().whenComplete().thenAcceptAsync(unused -> {
+ try {
+ Files.deleteIfExists(tempFile);
+ } catch (IOException e) {
+ logger.warn("Failed to delete a temporary file: {}", tempFile, e);
+ }
+ }, blockingExecutorService);
+ break;
+ }
+ return tempFile;
+ }
+
  private static CompletableFuture<Path> resolveTmpFile(Path directory,
  String filename,
  ExecutorService blockingExecutorService) {

core/src/main/java/com/linecorp/armeria/server/AbstractAnnotatedServiceConfigSetters.java

@@ -282,6 +282,14 @@ public AbstractAnnotatedServiceConfigSetters multipartUploadsLocation(Path multi
  return this;
  }
 
+ @UnstableApi
+ @Override
+ public AbstractAnnotatedServiceConfigSetters multipartRemovalStrategy(
+ MultipartRemovalStrategy removalStrategy) {
+ defaultServiceConfigSetters.multipartRemovalStrategy(removalStrategy);
+ return this;
+ }
+
  @Override
  public ServiceConfigSetters serviceWorkerGroup(EventLoopGroup serviceWorkerGroup, boolean shutdownOnStop) {
  defaultServiceConfigSetters.serviceWorkerGroup(serviceWorkerGroup, shutdownOnStop);

core/src/main/java/com/linecorp/armeria/server/AbstractServiceBindingBuilder.java

@@ -177,6 +177,12 @@ public AbstractServiceBindingBuilder multipartUploadsLocation(Path multipartUplo
  return this;
  }
 
+ @Override
+ public AbstractServiceBindingBuilder multipartRemovalStrategy(MultipartRemovalStrategy removalStrategy) {
+ defaultServiceConfigSetters.multipartRemovalStrategy(removalStrategy);
+ return this;
+ }
+
  @Override
  public AbstractServiceBindingBuilder serviceWorkerGroup(EventLoopGroup serviceWorkerGroup,
  boolean shutdownOnStop) {

core/src/main/java/com/linecorp/armeria/server/AnnotatedServiceBindingBuilder.java

@@ -224,6 +224,11 @@ public AnnotatedServiceBindingBuilder multipartUploadsLocation(Path multipartUpl
  return (AnnotatedServiceBindingBuilder) super.multipartUploadsLocation(multipartUploadsLocation);
  }
 
+ @Override
+ public AnnotatedServiceBindingBuilder multipartRemovalStrategy(MultipartRemovalStrategy removalStrategy) {
+ return (AnnotatedServiceBindingBuilder) super.multipartRemovalStrategy(removalStrategy);
+ }
+
  @Override
  public AnnotatedServiceBindingBuilder requestIdGenerator(
  Function<? super RoutingContext, ? extends RequestId> requestIdGenerator) {

core/src/main/java/com/linecorp/armeria/server/ContextPathAnnotatedServiceConfigSetters.java

@@ -250,6 +250,12 @@ public ContextPathAnnotatedServiceConfigSetters multipartUploadsLocation(
  super.multipartUploadsLocation(multipartUploadsLocation);
  }
 
+ @Override
+ public ContextPathAnnotatedServiceConfigSetters multipartRemovalStrategy(
+ MultipartRemovalStrategy removalStrategy) {
+ return (ContextPathAnnotatedServiceConfigSetters) super.multipartRemovalStrategy(removalStrategy);
+ }
+
  @Override
  public ContextPathAnnotatedServiceConfigSetters requestIdGenerator(
  Function<? super RoutingContext, ? extends RequestId> requestIdGenerator) {

core/src/main/java/com/linecorp/armeria/server/ContextPathServiceBindingBuilder.java

@@ -161,17 +161,20 @@ public ContextPathServiceBindingBuilder requestAutoAbortDelay(Duration delay) {
  }
 
  @Override
- public ContextPathServiceBindingBuilder requestAutoAbortDelayMillis(
- long delayMillis) {
+ public ContextPathServiceBindingBuilder requestAutoAbortDelayMillis(long delayMillis) {
  return (ContextPathServiceBindingBuilder) super.requestAutoAbortDelayMillis(delayMillis);
  }
 
  @Override
- public ContextPathServiceBindingBuilder multipartUploadsLocation(
- Path multipartUploadsLocation) {
+ public ContextPathServiceBindingBuilder multipartUploadsLocation(Path multipartUploadsLocation) {
  return (ContextPathServiceBindingBuilder) super.multipartUploadsLocation(multipartUploadsLocation);
  }
 
+ @Override
+ public ContextPathServiceBindingBuilder multipartRemovalStrategy(MultipartRemovalStrategy removalStrategy) {
+ return (ContextPathServiceBindingBuilder) super.multipartRemovalStrategy(removalStrategy);
+ }
+
  @Override
  public ContextPathServiceBindingBuilder serviceWorkerGroup(EventLoopGroup serviceWorkerGroup,
  boolean shutdownOnStop) {

core/src/main/java/com/linecorp/armeria/server/DefaultServiceConfigSetters.java

@@ -79,6 +79,8 @@ final class DefaultServiceConfigSetters implements ServiceConfigSetters {
  @Nullable
  private Path multipartUploadsLocation;
  @Nullable
+ private MultipartRemovalStrategy multipartRemovalStrategy;
+ @Nullable
  private EventLoopGroup serviceWorkerGroup;
  @Nullable
  private ServiceErrorHandler serviceErrorHandler;
@@ -237,6 +239,12 @@ public ServiceConfigSetters multipartUploadsLocation(Path multipartUploadsLocati
  return this;
  }
 
+ @Override
+ public ServiceConfigSetters multipartRemovalStrategy(MultipartRemovalStrategy removalStrategy) {
+ this.multipartRemovalStrategy = requireNonNull(removalStrategy, "removalStrategy");
+ return this;
+ }
+
  @Override
  public ServiceConfigSetters serviceWorkerGroup(EventLoopGroup serviceWorkerGroup,
  boolean shutdownOnStop) {
@@ -377,6 +385,9 @@ ServiceConfigBuilder toServiceConfigBuilder(Route route, String contextPath, Htt
  if (multipartUploadsLocation != null) {
  serviceConfigBuilder.multipartUploadsLocation(multipartUploadsLocation);
  }
+ if (multipartRemovalStrategy != null) {
+ serviceConfigBuilder.multipartRemovalStrategy(multipartRemovalStrategy);
+ }
  if (serviceWorkerGroup != null) {
  serviceConfigBuilder.serviceWorkerGroup(serviceWorkerGroup, false);
  // Set the serviceWorkerGroup as false because it's shut down in ShutdownSupport.

core/src/main/java/com/linecorp/armeria/server/MultipartRemovalStrategy.java

@@ -0,0 +1,37 @@
+/*
+ * 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;
+
+import com.linecorp.armeria.common.annotation.UnstableApi;
+
+/**
+ * Specifies when to remove the temporary files created for multipart requests.
+ */
+@UnstableApi
+public enum MultipartRemovalStrategy {
+ /**
+ * Never remove the temporary files.
+ *
+ * <p><strong>Warning:</strong> This option may cause a disk space leak if the temporary files are not
+ * removed manually.
+ */
+ NEVER,
+ /**
+ * Remove the temporary files after the response is fully sent.
+ */
+ ON_RESPONSE_COMPLETION
+}

core/src/main/java/com/linecorp/armeria/server/ServerBuilder.java

@@ -255,6 +255,7 @@ public final class ServerBuilder implements TlsSetters, ServiceConfigsBuilder {
  virtualHostTemplate.successFunction(SuccessFunction.ofDefault());
  virtualHostTemplate.requestAutoAbortDelayMillis(0);
  virtualHostTemplate.multipartUploadsLocation(Flags.defaultMultipartUploadsLocation());
+ virtualHostTemplate.multipartRemovalStrategy(Flags.defaultMultipartRemovalStrategy());
  virtualHostTemplate.requestIdGenerator(routingContext -> RequestId.random());
  }
 
@@ -953,6 +954,18 @@ public ServerBuilder multipartUploadsLocation(Path path) {
  return this;
  }
 
+ /**
+ * Sets the {@link MultipartRemovalStrategy} that determines when to remove temporary files created
+ * for multipart requests.
+ * If not set, {@link MultipartRemovalStrategy#ON_RESPONSE_COMPLETION} is used by default.
+ */
+ @UnstableApi
+ public ServerBuilder multipartRemovalStrategy(MultipartRemovalStrategy removalStrategy) {
+ requireNonNull(removalStrategy, "removalStrategy");
+ virtualHostTemplate.multipartRemovalStrategy(removalStrategy);
+ return this;
+ }
+
  /**
  * Sets the {@link ScheduledExecutorService} dedicated to the execution of blocking tasks or invocations.
  * If not set, {@linkplain CommonPools#blockingTaskExecutor() the common pool} is used.

core/src/main/java/com/linecorp/armeria/server/ServiceBindingBuilder.java

@@ -293,6 +293,11 @@ public ServiceBindingBuilder multipartUploadsLocation(Path multipartUploadsLocat
  return (ServiceBindingBuilder) super.multipartUploadsLocation(multipartUploadsLocation);
  }
 
+ @Override
+ public ServiceBindingBuilder multipartRemovalStrategy(MultipartRemovalStrategy removalStrategy) {
+ return (ServiceBindingBuilder) super.multipartRemovalStrategy(removalStrategy);
+ }
+
  @Override
  public ServiceBindingBuilder serviceWorkerGroup(EventLoopGroup serviceWorkerGroup,
  boolean shutdownOnStop) {