[7.17] Fix Azure InputStream#read method (#96034) (#96045)

elastic · May 12, 2023 · eb9e452 · eb9e452
1 parent 724c7d1
commit eb9e452
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diff --git a/docs/changelog/96034.yaml b/docs/changelog/96034.yaml
@@ -0,0 +1,5 @@
+pr: 96034
+summary: Fix Azure `InputStream#read` method
+area: Snapshot/Restore
+type: bug
+issues: []
diff --git a/...lClusterTest/java/org/elasticsearch/repositories/azure/AzureBlobStoreRepositoryTests.java b/...lClusterTest/java/org/elasticsearch/repositories/azure/AzureBlobStoreRepositoryTests.java
@@ -16,6 +16,7 @@
 import com.sun.net.httpserver.HttpHandler;
 
 import org.elasticsearch.common.Randomness;
+import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.blobstore.BlobContainer;
 import org.elasticsearch.common.blobstore.BlobPath;
 import org.elasticsearch.common.blobstore.BlobStore;
@@ -30,7 +31,9 @@
 import org.elasticsearch.repositories.blobstore.ESMockAPIBasedRepositoryIntegTestCase;
 import org.elasticsearch.rest.RestStatus;
 
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
@@ -43,6 +46,7 @@
 
 import static org.hamcrest.Matchers.anEmptyMap;
 import static org.hamcrest.Matchers.containsString;
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
 
 @SuppressForbidden(reason = "this test uses a HttpServer to emulate an Azure endpoint")
@@ -267,4 +271,24 @@ public void testNotFoundErrorMessageContainsFullKey() throws Exception {
             assertThat(exception.getMessage(), containsString("nested/dir/blob] not found"));
         }
     }
+
+    public void testReadByteByByte() throws Exception {
+        try (BlobStore store = newBlobStore()) {
+            BlobContainer container = store.blobContainer(BlobPath.EMPTY.add(UUIDs.randomBase64UUID()));
+            byte[] data = randomBytes(randomIntBetween(128, 512));
+            String blobName = randomName();
+            container.writeBlob(blobName, new ByteArrayInputStream(data), data.length, true);
+
+            InputStream originalDataInputStream = new ByteArrayInputStream(data);
+            try (InputStream azureInputStream = container.readBlob(blobName)) {
+                for (int i = 0; i < data.length; i++) {
+                    assertThat(originalDataInputStream.read(), is(equalTo(azureInputStream.read())));
+                }
+
+                assertThat(azureInputStream.read(), is(equalTo(-1)));
+                assertThat(originalDataInputStream.read(), is(equalTo(-1)));
+            }
+            container.delete();
+        }
+    }
 }
diff --git a/...s/repository-azure/src/main/java/org/elasticsearch/repositories/azure/AzureBlobStore.java b/...s/repository-azure/src/main/java/org/elasticsearch/repositories/azure/AzureBlobStore.java
@@ -708,7 +708,19 @@ private ByteBuf copyBuffer(ByteBuffer buffer) {
         @Override
         public int read() throws IOException {
             byte[] b = new byte[1];
-            return read(b, 0, 1);
+            int bytesRead = read(b, 0, 1);
+
+            if (bytesRead > 1) {
+                throw new IOException("Stream returned more data than requested");
+            }
+
+            if (bytesRead == 1) {
+                return b[0] & 0xFF;
+            } else if (bytesRead == 0) {
+                throw new IOException("Stream returned unexpected number of bytes");
+            } else {
+                return -1;
+            }
         }
 
         @Override