Fix handling of artifact range requests

Artifact range requests in HawkBit were impossible to do efficiently, as the
underlying mechanism had no choice but to read the start byte and discard
content both before and after.

To address this situation, we need to introduce a new method to DbArtifact:
getFileInputStream(long, long), which maps to the semantics of a range request.

The next step is to adjust FileStreamingUtil to use it for both simple range
and multi-part requests.

Signed-off-by: Zygmunt Krynicki <[email protected]>

hawkbit-artifact-repository-filesystem/src/main/java/org/eclipse/hawkbit/artifact/repository/ArtifactFilesystem.java

@@ -11,13 +11,19 @@
 
 import java.io.BufferedInputStream;
 import java.io.File;
+import java.io.RandomAccessFile;
+import java.nio.channels.Channels;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
+import java.io.IOException;
 import java.io.InputStream;
 import java.util.Objects;
 
 import javax.validation.constraints.NotNull;
 
+import com.google.common.io.ByteStreams;
+import org.apache.commons.io.input.RandomAccessFileInputStream;
+
 import org.eclipse.hawkbit.artifact.repository.model.AbstractDbArtifact;
 import org.eclipse.hawkbit.artifact.repository.model.DbArtifactHash;
 
@@ -47,4 +53,19 @@ public InputStream getFileInputStream() {
             throw new ArtifactFileNotFoundException(e);
         }
     }
+
+    @Override
+    // suppress warning, this InputStream needs to be closed by the caller, this
+    // cannot be closed in this method
+    @SuppressWarnings("squid:S2095")
+    public InputStream getFileInputStream(long start, long end) {
+        try {
+            var f = new RandomAccessFile(file, "r");
+            var ch = f.getChannel();
+            ch.position(start);
+            return ByteStreams.limit(Channels.newInputStream(ch), end - start + 1);
+        } catch (final IOException e) {
+            throw new ArtifactFileNotFoundException(e);
+        }
+    }
 }

hawkbit-core/src/main/java/org/eclipse/hawkbit/artifact/repository/model/DbArtifact.java

@@ -43,4 +43,13 @@ public interface DbArtifact {
      * @return {@link InputStream} to read from artifact.
      */
     InputStream getFileInputStream();
+
+    /**
+     * Creates an {@link InputStream} on a single range of this artifact.
+     * The caller has to take care of closing the stream.
+     * Repeatable calls open a new {@link InputStream}.
+     *
+     * @return {@link InputStream} to read from artifact.
+     */
+    InputStream getFileInputStream(long start, long end);
 }

hawkbit-repository/hawkbit-repository-jpa/src/main/java/org/eclipse/hawkbit/repository/jpa/EncryptionAwareDbArtifact.java

@@ -63,4 +63,9 @@ public String getContentType() {
     public InputStream getFileInputStream() {
         return decryptionFunction.apply(encryptedDbArtifact.getFileInputStream());
     }
+
+    @Override
+    public InputStream getFileInputStream(long start, long end) {
+        return decryptionFunction.apply(encryptedDbArtifact.getFileInputStream(start, end));
+    }
 }

hawkbit-rest/hawkbit-rest-core/src/main/java/org/eclipse/hawkbit/rest/util/FileStreamingUtil.java

@@ -285,8 +285,8 @@ private static ResponseEntity<InputStream> handleMultipartRangeRequest(final DbA
             final ServletOutputStream to = response.getOutputStream();
 
             for (final ByteRange r : ranges) {
-                try (final InputStream from = artifact.getFileInputStream()) {
 
+                try (final InputStream from = artifact.getFileInputStream(r.getStart(), r.getEnd())) {
                     // Add multipart boundary and header fields for every range.
                     to.println();
                     to.println("--" + ByteRange.MULTIPART_BOUNDARY);
@@ -316,7 +316,7 @@ private static ResponseEntity<InputStream> handleStandardRangeRequest(final DbAr
         response.setContentLengthLong(r.getLength());
         response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
 
-        try (final InputStream from = artifact.getFileInputStream()) {
+        try (final InputStream from = artifact.getFileInputStream(r.getStart(), r.getEnd())) {
             final ServletOutputStream to = response.getOutputStream();
             copyStreams(from, to, progressListener, r.getStart(), r.getLength(), filename);
         } catch (final IOException e) {
@@ -340,8 +340,6 @@ private static long copyStreams(final InputStream from, final OutputStream to,
         long total = 0;
         int progressPercent = 1;
 
-        ByteStreams.skipFully(from, start);
-
         long toRead = length;
         boolean toContinue = true;
         long shippedSinceLastEvent = 0;

hawkbit-rest/hawkbit-rest-core/src/test/java/org/eclipse/hawkbit/rest/util/FileStreamingUtilTest.java

@@ -69,6 +69,11 @@ public String getContentType() {
         public InputStream getFileInputStream() {
             return new ByteArrayInputStream(CONTENT_BYTES);
         }
+
+        @Override
+        public InputStream getFileInputStream(long start, long end) {
+            return new ByteArrayInputStream(CONTENT_BYTES, (int)start, (int)(end-start));
+        }
     };
 
     @Test