do some small changes to allow more flexibility when tracking a download

src/main/java/io/bioimage/modelrunner/engine/installation/EngineInstall.java

@@ -34,13 +34,15 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.stream.Collectors;
 
 import io.bioimage.modelrunner.bioimageio.BioimageioRepo;
 import io.bioimage.modelrunner.bioimageio.description.ModelDescriptor;
 import io.bioimage.modelrunner.bioimageio.description.ModelDescriptorFactory;
 import io.bioimage.modelrunner.bioimageio.description.exceptions.ModelSpecsException;
 import io.bioimage.modelrunner.bioimageio.description.weights.WeightFormat;
+import io.bioimage.modelrunner.bioimageio.download.DownloadModel;
 import io.bioimage.modelrunner.bioimageio.download.DownloadTracker;
 import io.bioimage.modelrunner.bioimageio.download.DownloadTracker.TwoParameterConsumer;
 import io.bioimage.modelrunner.engine.EngineInfo;
@@ -69,6 +71,12 @@ public class EngineInstall {
 	 * Map containing which version should always be installed per framework
 	 */
 	public static LinkedHashMap<String, String> ENGINES_VERSIONS = new LinkedHashMap<String, String>();
+	/**
+	 * Suffix in the download progress tracker consumer that indicates that the value is total size of
+	 * bytes to be downloaded. On the other hand, if the suffix is not present, it will represent the 
+	 * percentage of bytes that is being downloaded currently
+	 */
+	public static final String NBYTES_SUFFIX = "_SIZE";
 
 	static {
 		ENGINES_VERSIONS.put(EngineInfo.getTensorflowKey() + "_2", "2.7.0");
@@ -542,13 +550,11 @@ private void installMissingBasicEngines() {
 			checkEnginesInstalled();
 		if (missingEngineFolders.entrySet().size() == 0)
 			return;
+		getBasicDownloadTotalSize();
 		missingEngineFolders = missingEngineFolders.entrySet().stream()
 				.filter(v -> {
-					TwoParameterConsumer<String, Double> consumer = DownloadTracker.createConsumerProgress();
-					if (this.consumersMap != null && this.consumersMap.get(v.getValue()) != null)
-						consumer = this.consumersMap.get(v.getValue());
 					try {
-						return!installEngineByCompleteName(v.getValue(), consumer);
+						return!installEngineByCompleteName(v.getValue(), consumersMap.get(v.getValue()));
 					} catch (IOException | InterruptedException e) {
 						return true;
 					}
@@ -557,6 +563,34 @@ private void installMissingBasicEngines() {
 						(u, v) -> u, LinkedHashMap::new));
 	}
 
+	/**
+	 * 
+	 * @return the total numebr of bytes to be downloaded in the basic installation. This also prepares the 
+	 * download tracker by setting the number of bytes per file
+	 */
+	public long getBasicDownloadTotalSize() {
+		if (this.consumersMap == null)
+			getBasicEnginesProgress();
+		long totalSize = 0;
+		for (Entry<String, String> ee : missingEngineFolders.entrySet()) {
+			try {
+				long engineSize = 0;
+				DeepLearningVersion dlVersion = DeepLearningVersion.fromFile(new File(ee.getValue()));
+				for (String link : dlVersion.getJars()) {
+					String key = DownloadModel.getFileNameFromURLString(link) + NBYTES_SUFFIX;
+					long val = DownloadModel.getFileSize(new URL(link));
+					this.consumersMap.get(ee.getValue()).accept(key, (double) val);
+					engineSize += val;
+				}
+				this.consumersMap.get(ee.getValue()).accept("total" + NBYTES_SUFFIX, (double) engineSize);
+				totalSize += engineSize;
+			} catch (IllegalStateException | IOException e) {
+				continue;
+			}
+		}
+		return totalSize;
+	}
+
 	/**
 	 * Install the engine that should be located in the engine dir specified
 	 * @param engineDir
@@ -1139,7 +1173,7 @@ public static boolean installEngineInDir(DeepLearningVersion engine, String engi
 	 * @param engineDir
 	 * 	directory where the files will be downloaded
 	 */
-	private static void downloadEngineFiles(DeepLearningVersion engine, String engineDir) {
+	public static void downloadEngineFiles(DeepLearningVersion engine, String engineDir) {
 		for (String jar : engine.getJars()) {
 			try {
 				URL website = new URL(jar);