[ML] Add debug logging for tests failing with empty model download

muted-tests.yml

@@ -142,9 +142,6 @@ tests:
 - class: org.elasticsearch.xpack.remotecluster.RemoteClusterSecurityWithApmTracingRestIT
   method: testTracingCrossCluster
   issue: https://github.com/elastic/elasticsearch/issues/112731
-- class: org.elasticsearch.xpack.inference.DefaultEndPointsIT
-  method: testInferDeploysDefaultElser
-  issue: https://github.com/elastic/elasticsearch/issues/114913
 - class: org.elasticsearch.xpack.test.rest.XPackRestIT
   method: test {p0=esql/60_usage/Basic ESQL usage output (telemetry)}
   issue: https://github.com/elastic/elasticsearch/issues/115231

x-pack/plugin/inference/qa/inference-service-tests/src/javaRestTest/java/org/elasticsearch/xpack/inference/DefaultEndPointsIT.java

@@ -7,6 +7,7 @@
 
 package org.elasticsearch.xpack.inference;
 
+import org.elasticsearch.client.Request;
 import org.elasticsearch.inference.TaskType;
 import org.elasticsearch.threadpool.TestThreadPool;
 import org.elasticsearch.xpack.inference.services.elasticsearch.ElasticsearchInternalService;
@@ -27,8 +28,15 @@ public class DefaultEndPointsIT extends InferenceBaseRestTest {
     private TestThreadPool threadPool;
 
     @Before
-    public void createThreadPool() {
+    public void setupTest() throws IOException {
         threadPool = new TestThreadPool(DefaultEndPointsIT.class.getSimpleName());
+
+        Request loggingSettings = new Request("PUT", "_cluster/settings");
+        loggingSettings.setJsonEntity("""
+            {"persistent" : {
+                    "logger.org.elasticsearch.xpack.ml.packageloader" : "DEBUG"
+                }}""");
+        client().performRequest(loggingSettings);
     }
 
     @After
@@ -64,7 +72,7 @@ private static void assertDefaultElserConfig(Map<String, Object> modelConfig) {
         assertThat(
             modelConfig.toString(),
             adaptiveAllocations,
-            Matchers.is(Map.of("enabled", true, "min_number_of_allocations", 0, "max_number_of_allocations", 8))
+            Matchers.is(Map.of("enabled", true, "min_number_of_allocations", 0, "max_number_of_allocations", 32))
         );
     }
 
@@ -99,7 +107,7 @@ private static void assertDefaultE5Config(Map<String, Object> modelConfig) {
         assertThat(
             modelConfig.toString(),
             adaptiveAllocations,
-            Matchers.is(Map.of("enabled", true, "min_number_of_allocations", 0, "max_number_of_allocations", 8))
+            Matchers.is(Map.of("enabled", true, "min_number_of_allocations", 0, "max_number_of_allocations", 32))
         );
     }
 }

x-pack/plugin/ml-package-loader/src/main/java/org/elasticsearch/xpack/ml/packageloader/action/ModelLoaderUtils.java

@@ -7,6 +7,8 @@
 
 package org.elasticsearch.xpack.ml.packageloader.action;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ElasticsearchStatusException;
 import org.elasticsearch.ResourceNotFoundException;
@@ -56,10 +58,12 @@
  */
 final class ModelLoaderUtils {
 
+    private static final Logger logger = LogManager.getLogger(ModelLoaderUtils.class);
+
     public static String METADATA_FILE_EXTENSION = ".metadata.json";
     public static String MODEL_FILE_EXTENSION = ".pt";
 
-    private static ByteSizeValue VOCABULARY_SIZE_LIMIT = new ByteSizeValue(20, ByteSizeUnit.MB);
+    private static final ByteSizeValue VOCABULARY_SIZE_LIMIT = new ByteSizeValue(20, ByteSizeUnit.MB);
     private static final String VOCABULARY = "vocabulary";
     private static final String MERGES = "merges";
     private static final String SCORES = "scores";
@@ -83,6 +87,7 @@ record BytesAndPartIndex(BytesArray bytes, int partIndex) {}
         private final AtomicInteger currentPart;
         private final int lastPartNumber;
         private final byte[] buf;
+        private final RequestRange range;  // TODO debug only
 
         HttpStreamChunker(URI uri, RequestRange range, int chunkSize) {
             var inputStream = getHttpOrHttpsInputStream(uri, range);
@@ -91,6 +96,7 @@ record BytesAndPartIndex(BytesArray bytes, int partIndex) {}
             this.lastPartNumber = range.startPart() + range.numParts();
             this.currentPart = new AtomicInteger(range.startPart());
             this.buf = new byte[chunkSize];
+            this.range = range;
         }
 
         // This ctor exists for testing purposes only.
@@ -100,6 +106,7 @@ record BytesAndPartIndex(BytesArray bytes, int partIndex) {}
             this.lastPartNumber = range.startPart() + range.numParts();
             this.currentPart = new AtomicInteger(range.startPart());
             this.buf = new byte[chunkSize];
+            this.range = range;
         }
 
         public boolean hasNext() {
@@ -113,6 +120,7 @@ public BytesAndPartIndex next() throws IOException {
                 int read = inputStream.read(buf, bytesRead, chunkSize - bytesRead);
                 // EOF??
                 if (read == -1) {
+                    logger.debug("end of stream, " + bytesRead + " bytes read");
                     break;
                 }
                 bytesRead += read;
@@ -122,6 +130,7 @@ public BytesAndPartIndex next() throws IOException {
                 totalBytesRead.addAndGet(bytesRead);
                 return new BytesAndPartIndex(new BytesArray(buf, 0, bytesRead), currentPart.getAndIncrement());
             } else {
+                logger.warn("Empty part in range " + range + ", current part=" + currentPart.get() + ", last part=" + lastPartNumber);
                 return new BytesAndPartIndex(BytesArray.EMPTY, currentPart.get());
             }
         }