remote: Proactively close the ZstdInputStream in ZstdDecompressingOutputStream.

ZstdInputStream hangs onto some native memory, which should be released as soon as ZstdDecompressingOutputStream is done being used rather than when the finalizer runs.

Closes bazelbuild#15061.

PiperOrigin-RevId: 438521302

Author: benjaminp

src/main/java/com/google/devtools/build/lib/remote/BUILD

@@ -97,7 +97,6 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//src/main/java/com/google/devtools/common/options",
         "//src/main/protobuf:failure_details_java_proto",
-        "//third_party:apache_commons_compress",
         "//third_party:auth",
         "//third_party:caffeine",
         "//third_party:flogger",

src/main/java/com/google/devtools/build/lib/remote/GrpcCacheClient.java

@@ -37,6 +37,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.common.flogger.GoogleLogger;
+import com.google.common.io.CountingOutputStream;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
@@ -67,10 +68,8 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Supplier;
 import javax.annotation.Nullable;
-import org.apache.commons.compress.utils.CountingOutputStream;
 
 /** A RemoteActionCache implementation that uses gRPC calls to a remote cache server. */
 @ThreadSafe
@@ -303,7 +302,7 @@ public ListenableFuture<Void> uploadActionResult(
   public ListenableFuture<Void> downloadBlob(
       RemoteActionExecutionContext context, Digest digest, OutputStream out) {
     if (digest.getSizeBytes() == 0) {
-      return Futures.immediateFuture(null);
+      return Futures.immediateVoidFuture();
     }
 
     @Nullable Supplier<Digest> digestSupplier = null;
@@ -313,26 +312,14 @@ public ListenableFuture<Void> downloadBlob(
       out = digestOut;
     }
 
-    CountingOutputStream outputStream;
-    if (options.cacheCompression) {
-      try {
-        outputStream = new ZstdDecompressingOutputStream(out);
-      } catch (IOException e) {
-        return Futures.immediateFailedFuture(e);
-      }
-    } else {
-      outputStream = new CountingOutputStream(out);
-    }
-
-    return downloadBlob(context, digest, outputStream, digestSupplier);
+    return downloadBlob(context, digest, new CountingOutputStream(out), digestSupplier);
   }
 
   private ListenableFuture<Void> downloadBlob(
       RemoteActionExecutionContext context,
       Digest digest,
       CountingOutputStream out,
       @Nullable Supplier<Digest> digestSupplier) {
-    AtomicLong offset = new AtomicLong(0);
     ProgressiveBackoff progressiveBackoff = new ProgressiveBackoff(retrier::newBackoff);
     ListenableFuture<Long> downloadFuture =
         Utils.refreshIfUnauthenticatedAsync(
@@ -343,7 +330,6 @@ private ListenableFuture<Void> downloadBlob(
                             channel ->
                                 requestRead(
                                     context,
-                                    offset,
                                     progressiveBackoff,
                                     digest,
                                     out,
@@ -370,20 +356,25 @@ public static String getResourceName(String instanceName, Digest digest, boolean
 
   private ListenableFuture<Long> requestRead(
       RemoteActionExecutionContext context,
-      AtomicLong offset,
       ProgressiveBackoff progressiveBackoff,
       Digest digest,
-      CountingOutputStream out,
+      CountingOutputStream rawOut,
       @Nullable Supplier<Digest> digestSupplier,
       Channel channel) {
     String resourceName =
         getResourceName(options.remoteInstanceName, digest, options.cacheCompression);
     SettableFuture<Long> future = SettableFuture.create();
+    OutputStream out;
+    try {
+      out = options.cacheCompression ? new ZstdDecompressingOutputStream(rawOut) : rawOut;
+    } catch (IOException e) {
+      return Futures.immediateFailedFuture(e);
+    }
     bsAsyncStub(context, channel)
         .read(
             ReadRequest.newBuilder()
                 .setResourceName(resourceName)
-                .setReadOffset(offset.get())
+                .setReadOffset(rawOut.getCount())
                 .build(),
             new StreamObserver<ReadResponse>() {
 
@@ -392,7 +383,6 @@ public void onNext(ReadResponse readResponse) {
                 ByteString data = readResponse.getData();
                 try {
                   data.writeTo(out);
-                  offset.set(out.getBytesWritten());
                 } catch (IOException e) {
                   // Cancel the call.
                   throw new RuntimeException(e);
@@ -403,14 +393,15 @@ public void onNext(ReadResponse readResponse) {
 
               @Override
               public void onError(Throwable t) {
-                if (offset.get() == digest.getSizeBytes()) {
+                if (rawOut.getCount() == digest.getSizeBytes()) {
                   // If the file was fully downloaded, it doesn't matter if there was an error at
                   // the end of the stream.
                   logger.atInfo().withCause(t).log(
                       "ignoring error because file was fully received");
                   onCompleted();
                   return;
                 }
+                releaseOut();
                 Status status = Status.fromThrowable(t);
                 if (status.getCode() == Status.Code.NOT_FOUND) {
                   future.setException(new CacheNotFoundException(digest));
@@ -426,12 +417,24 @@ public void onCompleted() {
                     Utils.verifyBlobContents(digest, digestSupplier.get());
                   }
                   out.flush();
-                  future.set(offset.get());
+                  future.set(rawOut.getCount());
                 } catch (IOException e) {
                   future.setException(e);
                 } catch (RuntimeException e) {
                   logger.atWarning().withCause(e).log("Unexpected exception");
                   future.setException(e);
+                } finally {
+                  releaseOut();
+                }
+              }
+
+              private void releaseOut() {
+                if (out instanceof ZstdDecompressingOutputStream) {
+                  try {
+                    ((ZstdDecompressingOutputStream) out).closeShallow();
+                  } catch (IOException e) {
+                    logger.atWarning().withCause(e).log("failed to cleanly close output stream");
+                  }
                 }
               }
             });

src/main/java/com/google/devtools/build/lib/remote/zstd/BUILD

@@ -16,7 +16,6 @@ java_library(
     name = "zstd",
     srcs = glob(["*.java"]),
     deps = [
-        "//third_party:apache_commons_compress",
         "//third_party:guava",
         "//third_party/protobuf:protobuf_java",
         "@zstd-jni",

src/main/java/com/google/devtools/build/lib/remote/zstd/ZstdDecompressingOutputStream.java

@@ -13,35 +13,35 @@
 // limitations under the License.
 package com.google.devtools.build.lib.remote.zstd;
 
-import com.github.luben.zstd.ZstdInputStream;
+import com.github.luben.zstd.ZstdInputStreamNoFinalizer;
 import com.google.protobuf.ByteString;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import org.apache.commons.compress.utils.CountingOutputStream;
 
-/** A {@link CountingOutputStream} that use zstd to decompress the content. */
-public class ZstdDecompressingOutputStream extends CountingOutputStream {
+/** An {@link OutputStream} that use zstd to decompress the content. */
+public final class ZstdDecompressingOutputStream extends OutputStream {
+  private final OutputStream out;
   private ByteArrayInputStream inner;
-  private final ZstdInputStream zis;
+  private final ZstdInputStreamNoFinalizer zis;
 
   public ZstdDecompressingOutputStream(OutputStream out) throws IOException {
-    super(out);
+    this.out = out;
     zis =
-        new ZstdInputStream(
-            new InputStream() {
-              @Override
-              public int read() {
-                return inner.read();
-              }
-
-              @Override
-              public int read(byte[] b, int off, int len) {
-                return inner.read(b, off, len);
-              }
-            });
-    zis.setContinuous(true);
+        new ZstdInputStreamNoFinalizer(
+                new InputStream() {
+                  @Override
+                  public int read() {
+                    return inner.read();
+                  }
+
+                  @Override
+                  public int read(byte[] b, int off, int len) {
+                    return inner.read(b, off, len);
+                  }
+                })
+            .setContinuous(true);
   }
 
   @Override
@@ -58,6 +58,19 @@ public void write(byte[] b) throws IOException {
   public void write(byte[] b, int off, int len) throws IOException {
     inner = new ByteArrayInputStream(b, off, len);
     byte[] data = ByteString.readFrom(zis).toByteArray();
-    super.write(data, 0, data.length);
+    out.write(data, 0, data.length);
+  }
+
+  @Override
+  public void close() throws IOException {
+    closeShallow();
+    out.close();
+  }
+
+  /**
+   * Free resources related to decompression without closing the underlying {@link OutputStream}.
+   */
+  public void closeShallow() throws IOException {
+    zis.close();
   }
 }

src/test/java/com/google/devtools/build/lib/remote/GrpcCacheClientTestExtra.java

@@ -15,14 +15,12 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static java.nio.charset.StandardCharsets.UTF_8;
-import static org.mockito.ArgumentMatchers.any;
 
 import build.bazel.remote.execution.v2.Digest;
 import com.github.luben.zstd.Zstd;
 import com.google.bytestream.ByteStreamGrpc.ByteStreamImplBase;
 import com.google.bytestream.ByteStreamProto.ReadRequest;
 import com.google.bytestream.ByteStreamProto.ReadResponse;
-import com.google.devtools.build.lib.remote.Retrier.Backoff;
 import com.google.devtools.build.lib.remote.options.RemoteOptions;
 import com.google.devtools.common.options.Options;
 import com.google.protobuf.ByteString;
@@ -31,38 +29,50 @@
 import java.io.IOException;
 import java.util.Arrays;
 import org.junit.Test;
-import org.mockito.Mockito;
 
 /** Extra tests for {@link GrpcCacheClient} that are not tested internally. */
 public class GrpcCacheClientTestExtra extends GrpcCacheClientTest {
 
   @Test
   public void compressedDownloadBlobIsRetriedWithProgress()
       throws IOException, InterruptedException {
-    Backoff mockBackoff = Mockito.mock(Backoff.class);
     RemoteOptions options = Options.getDefaults(RemoteOptions.class);
     options.cacheCompression = true;
-    final GrpcCacheClient client = newClient(options, () -> mockBackoff);
+    final GrpcCacheClient client = newClient(options);
     final Digest digest = DIGEST_UTIL.computeAsUtf8("abcdefg");
-    ByteString blob = ByteString.copyFrom(Zstd.compress("abcdefg".getBytes(UTF_8)));
+    ByteString chunk1 = ByteString.copyFrom(Zstd.compress("abc".getBytes(UTF_8)));
+    ByteString chunk2 = ByteString.copyFrom(Zstd.compress("def".getBytes(UTF_8)));
+    ByteString chunk3 = ByteString.copyFrom(Zstd.compress("g".getBytes(UTF_8)));
     serviceRegistry.addService(
         new ByteStreamImplBase() {
+          private boolean first = true;
+
           @Override
           public void read(ReadRequest request, StreamObserver<ReadResponse> responseObserver) {
             assertThat(request.getResourceName().contains(digest.getHash())).isTrue();
-            int off = (int) request.getReadOffset();
-            // Zstd header size is 9 bytes
-            ByteString data = off == 0 ? blob.substring(0, 9 + 1) : blob.substring(9 + off);
-            responseObserver.onNext(ReadResponse.newBuilder().setData(data).build());
-            if (off == 0) {
+            if (first) {
+              first = false;
               responseObserver.onError(Status.DEADLINE_EXCEEDED.asException());
-            } else {
-              responseObserver.onCompleted();
+              return;
+            }
+            switch (Math.toIntExact(request.getReadOffset())) {
+              case 0:
+                responseObserver.onNext(ReadResponse.newBuilder().setData(chunk1).build());
+                break;
+              case 3:
+                responseObserver.onNext(ReadResponse.newBuilder().setData(chunk2).build());
+                break;
+              case 6:
+                responseObserver.onNext(ReadResponse.newBuilder().setData(chunk3).build());
+                responseObserver.onCompleted();
+                return;
+              default:
+                throw new IllegalStateException("unexpected offset " + request.getReadOffset());
             }
+            responseObserver.onError(Status.DEADLINE_EXCEEDED.asException());
           }
         });
     assertThat(new String(downloadBlob(context, client, digest), UTF_8)).isEqualTo("abcdefg");
-    Mockito.verify(mockBackoff, Mockito.never()).nextDelayMillis(any(Exception.class));
   }
 
   @Test

src/test/java/com/google/devtools/build/lib/remote/zstd/ZstdDecompressingOutputStreamTestExtra.java

@@ -63,7 +63,6 @@ public void bytesWrittenMatchesDecompressedBytes() throws IOException {
     for (byte b : compressed.toByteArray()) {
       zdos.write(b);
       zdos.flush();
-      assertThat(zdos.getBytesWritten()).isEqualTo(decompressed.toByteArray().length);
     }
     assertThat(decompressed.toByteArray()).isEqualTo(data);
   }