[GitHub] [flink] zentol commented on a change in pull request #11536: [FLINK-16807][e2e] Improve reporting for instantiation errors

[GitBox <gi...@apache.org>]

zentol commented on a change in pull request #11536: [FLINK-16807][e2e] Improve reporting for instantiation errors 
URL: https://github.com/apache/flink/pull/11536#discussion_r399539228
 
 

 ##########
 File path: flink-end-to-end-tests/flink-end-to-end-tests-common/src/main/java/org/apache/flink/tests/util/util/FactoryUtils.java
 ##########
 @@ -43,24 +45,43 @@
 	 * @throws RuntimeException if no or multiple resources could be instantiated
 	 * @return created instance
 	 */
-	public static <R, F> R loadAndInvokeFactory(final Class<F> factoryInterface, final Function<F, Optional<R>> factoryInvoker, final Supplier<F> defaultProvider) {
+	public static <R, F> R loadAndInvokeFactory(final Class<F> factoryInterface, final FactoryInvoker<F, R> factoryInvoker, final Supplier<F> defaultProvider) {
 		final ServiceLoader<F> factories = ServiceLoader.load(factoryInterface);
 
-		final List<R> resources = StreamSupport.stream(factories.spliterator(), false)
-			.map(factoryInvoker)
-			.filter(Optional::isPresent)
-			.map(Optional::get)
-			.collect(Collectors.toList());
+		final List<R> instantiatedResources = new ArrayList<>();
+		final List<Exception> errorsDuringInitialization = new ArrayList<>();
+		for (F factory : factories) {
+			try {
+				R resource = factoryInvoker.invoke(factory);
+				instantiatedResources.add(resource);
+				LOG.info("Instantiated {}.", resource.getClass().getSimpleName());
+			} catch (Exception e) {
+				LOG.debug("Factory {} could not instantiate instance.", factory.getClass().getSimpleName(), e);
+				errorsDuringInitialization.add(e);
+			}
+		}
 
-		if (resources.size() == 1) {
-			return resources.get(0);
+		if (instantiatedResources.size() == 1) {
+			return instantiatedResources.get(0);
 		}
 
-		if (resources.isEmpty()) {
-			return factoryInvoker.apply(defaultProvider.get())
-				.orElseThrow(() -> new RuntimeException("Could not instantiate instance using default factory."));
+		if (instantiatedResources.isEmpty()) {
+			try {
+				return factoryInvoker.invoke(defaultProvider.get());
+			} catch (Exception e) {
+				final RuntimeException exception = new RuntimeException("Could not instantiate instance.");
 
 Review comment:
   So, generally speaking it shouldn't be necessary to include `e` as a cause, the reason being that the default provider is usually included in the set of factories returned by `ServiceLoader.load`. This also implies that the error is already being logged.
   There is only one exception to this which is the `LolCache`, which generally speaking should never fail (technically it could if it can't create a TemporaryDirectory, but then you likely have bigger problems).
   
   Handling at the call-size doesn't really give us a lot; we can't handle the error but only slightly enhance the error message which shouldn't be necessary in the first place. For some reason the stack trace is being trimmed to ridiculous degrees; which may also cause the suppressed exception to not be shown.
   
   I will investigate why this happens; I did try it with the `FlinkResoure` without `distDir` being set (the original original cause for this PR), and it displayed the right exception. But IIRC I did that in the IDE, so maybe maven/surefire is getting in the way here.

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services