kowshik commented on a change in pull request #9001:
URL: https://github.com/apache/kafka/pull/9001#discussion_r498093400
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File path: core/src/main/scala/kafka/controller/KafkaController.scala
##########
@@ -1656,6 +1910,204 @@ class KafkaController(val config: KafkaConfig,
}
}
+ /**
+ * Returns the new FinalizedVersionRange for the feature, if there are no
feature
+ * incompatibilities seen with all known brokers for the provided feature
update.
+ * Otherwise returns an ApiError object containing Errors.INVALID_REQUEST.
+ *
+ * @param update the feature update to be processed (this can not be meant
to delete the feature)
+ *
+ * @return the new FinalizedVersionRange or error, as described
above.
+ */
+ private def newFinalizedVersionRangeOrIncompatibilityError(update:
UpdateFeaturesRequestData.FeatureUpdateKey): Either[FinalizedVersionRange,
ApiError] = {
+ if (UpdateFeaturesRequest.isDeleteRequest(update)) {
+ throw new IllegalArgumentException(s"Provided feature update can not be
meant to delete the feature: $update")
+ }
+
+ val supportedVersionRange =
brokerFeatures.supportedFeatures.get(update.feature)
+ if (supportedVersionRange == null) {
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ "Could not apply finalized feature update because the
provided feature" +
+ " is not supported."))
+ } else {
+ var newVersionRange: FinalizedVersionRange = null
+ try {
+ newVersionRange = new
FinalizedVersionRange(supportedVersionRange.firstActiveVersion,
update.maxVersionLevel)
+ } catch {
+ case _: IllegalArgumentException => {
+ // This exception means the provided maxVersionLevel is invalid. It
is handled below
+ // outside of this catch clause.
+ }
+ }
+ if (newVersionRange == null) {
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ "Could not apply finalized feature update because the provided" +
+ s" maxVersionLevel:${update.maxVersionLevel} is lower than the" +
+ s" first active
version:${supportedVersionRange.firstActiveVersion}."))
+ } else {
+ val newFinalizedFeature =
+ Features.finalizedFeatures(Utils.mkMap(Utils.mkEntry(update.feature,
newVersionRange)))
+ val numIncompatibleBrokers =
controllerContext.liveOrShuttingDownBrokers.count(broker => {
+ BrokerFeatures.hasIncompatibleFeatures(broker.features,
newFinalizedFeature)
+ })
+ if (numIncompatibleBrokers == 0) {
+ Left(newVersionRange)
+ } else {
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ "Could not apply finalized feature update
because" +
+ " brokers were found to have incompatible
versions for the feature."))
+ }
+ }
+ }
+ }
+
+ /**
+ * Validates a feature update on an existing FinalizedVersionRange.
+ * If the validation succeeds, then, the return value contains:
+ * 1. the new FinalizedVersionRange for the feature, if the feature update
was not meant to delete the feature.
+ * 2. Option.empty, if the feature update was meant to delete the feature.
+ *
+ * If the validation fails, then returned value contains a suitable ApiError.
+ *
+ * @param update the feature update to be processed.
+ * @param existingVersionRange the existing FinalizedVersionRange which
can be empty when no
+ * FinalizedVersionRange exists for the
associated feature
+ *
+ * @return the new FinalizedVersionRange to be updated
into ZK or error
+ * as described above.
+ */
+ private def validateFeatureUpdate(update:
UpdateFeaturesRequestData.FeatureUpdateKey,
+ existingVersionRange:
Option[FinalizedVersionRange]): Either[Option[FinalizedVersionRange], ApiError]
= {
+ def newVersionRangeOrError(update:
UpdateFeaturesRequestData.FeatureUpdateKey):
Either[Option[FinalizedVersionRange], ApiError] = {
+ newFinalizedVersionRangeOrIncompatibilityError(update)
+ .fold(versionRange => Left(Some(versionRange)), error => Right(error))
+ }
+
+ if (update.feature.isEmpty) {
+ // Check that the feature name is not empty.
+ Right(new ApiError(Errors.INVALID_REQUEST, "Feature name can not be
empty."))
+ } else {
+ // We handle deletion requests separately from non-deletion requests.
+ if (UpdateFeaturesRequest.isDeleteRequest(update)) {
+ if (existingVersionRange.isEmpty) {
+ // Disallow deletion of a non-existing finalized feature.
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ "Can not delete non-existing finalized feature."))
+ } else {
+ Left(Option.empty)
+ }
+ } else if (update.maxVersionLevel() < 1) {
+ // Disallow deletion of a finalized feature without allowDowngrade
flag set.
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ s"Can not provide maxVersionLevel:
${update.maxVersionLevel} less" +
+ s" than 1 without setting the allowDowngrade flag
to true in the request."))
+ } else {
+ existingVersionRange.map(existing =>
+ if (update.maxVersionLevel == existing.max) {
+ // Disallow a case where target maxVersionLevel matches existing
maxVersionLevel.
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ s"Can not ${if (update.allowDowngrade)
"downgrade" else "upgrade"}" +
+ s" a finalized feature from existing
maxVersionLevel:${existing.max}" +
+ " to the same value."))
+ } else if (update.maxVersionLevel < existing.max &&
!update.allowDowngrade) {
+ // Disallow downgrade of a finalized feature without the
allowDowngrade flag set.
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ s"Can not downgrade finalized feature from
existing" +
+ s" maxVersionLevel:${existing.max} to provided"
+
+ s" maxVersionLevel:${update.maxVersionLevel}
without setting the" +
+ " allowDowngrade flag in the request."))
+ } else if (update.allowDowngrade && update.maxVersionLevel >
existing.max) {
+ // Disallow a request that sets allowDowngrade flag without
specifying a
+ // maxVersionLevel that's lower than the existing maxVersionLevel.
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ s"When the allowDowngrade flag set in the
request, the provided" +
+ s" maxVersionLevel:${update.maxVersionLevel}
can not be greater than" +
+ s" existing maxVersionLevel:${existing.max}."))
+ } else if (update.maxVersionLevel < existing.min) {
+ // Disallow downgrade of a finalized feature below the existing
finalized
+ // minVersionLevel.
+ Right(new ApiError(Errors.INVALID_REQUEST,
+ s"Can not downgrade finalized feature to
maxVersionLevel:${update.maxVersionLevel}" +
+ s" because it's lower than the existing
minVersionLevel:${existing.min}."))
+ } else {
+ newVersionRangeOrError(update)
+ }
+ ).getOrElse(newVersionRangeOrError(update))
+ }
+ }
+ }
+
+ private def processFeatureUpdates(request: UpdateFeaturesRequest,
+ callback: UpdateFeaturesCallback): Unit = {
+ if (isActive) {
+ processFeatureUpdatesWithActiveController(request, callback)
+ } else {
+ callback(Left(new ApiError(Errors.NOT_CONTROLLER)))
+ }
+ }
+
+ private def processFeatureUpdatesWithActiveController(request:
UpdateFeaturesRequest,
+ callback:
UpdateFeaturesCallback): Unit = {
+ val updates = request.data.featureUpdates
+ val existingFeatures = featureCache.get
+ .map(featuresAndEpoch => featuresAndEpoch.features.features().asScala)
+ .getOrElse(Map[String, FinalizedVersionRange]())
+ // A map with key being feature name and value being FinalizedVersionRange.
+ // This contains the target features to be eventually written to
FeatureZNode.
+ val targetFeatures = scala.collection.mutable.Map[String,
FinalizedVersionRange]() ++ existingFeatures
+ // A map with key being feature name and value being error encountered
when the FeatureUpdate
+ // was applied.
+ val errors = scala.collection.mutable.Map[String, ApiError]()
+
+ // Below we process each FeatureUpdate using the following logic:
+ // - If a FeatureUpdate is found to be valid, then:
+ // - The corresponding entry in errors map would be updated to contain
Errors.NONE.
+ // - If the FeatureUpdate is an add or update request, then the
targetFeatures map is updated
+ // to contain the new FinalizedVersionRange for the feature.
+ // - Otherwise if the FeatureUpdate is a delete request, then the
feature is removed from the
+ // targetFeatures map.
+ // - Otherwise if a FeatureUpdate is found to be invalid, then:
+ // - The corresponding entry in errors map would be updated with the
appropriate ApiError.
+ // - The entry in targetFeatures map is left untouched.
+ updates.asScala.iterator.foreach { update =>
+ validateFeatureUpdate(update, existingFeatures.get(update.feature()))
match {
+ case Left(newVersionRangeOrNone) =>
+ newVersionRangeOrNone match {
+ case Some(newVersionRange) => targetFeatures += (update.feature()
-> newVersionRange)
+ case None => targetFeatures -= update.feature()
+ }
+ errors += (update.feature() -> new ApiError(Errors.NONE))
+ case Right(featureUpdateFailureReason) =>
+ errors += (update.feature() -> featureUpdateFailureReason)
+ }
+ }
+
+ // If the existing and target features are the same, then, we skip the
update to the
+ // FeatureZNode as no changes to the node are required. Otherwise, we
replace the contents
+ // of the FeatureZNode with the new features. This may result in partial
or full modification
+ // of the existing finalized features in ZK.
+ try {
+ if (!existingFeatures.equals(targetFeatures)) {
+ val newNode = new FeatureZNode(FeatureZNodeStatus.Enabled,
Features.finalizedFeatures(targetFeatures.asJava))
+ val newVersion = zkClient.updateFeatureZNode(newNode)
+ featureCache.waitUntilEpochOrThrow(newVersion,
request.data().timeoutMs().min(config.zkConnectionTimeoutMs))
+ }
+ } catch {
+ // For all features that correspond to valid FeatureUpdate (i.e. error
is Errors.NONE),
+ // we set the error as Errors.FEATURE_UPDATE_FAILED since the
FeatureZNode update has failed
+ // for these. For the rest, the existing error is left untouched.
+ case e: Exception =>
+ warn(s"Processing of feature updates: $request failed due to error:
$e")
+ errors.foreach { case (feature, apiError) =>
+ if (apiError.error() == Errors.NONE) {
+ errors(feature) = new ApiError(Errors.FEATURE_UPDATE_FAILED)
Review comment:
Would the default error message suffice?: `Unable to update finalized
features due to an unexpected server error.`
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