BlockStatusListener

== [[BlockStatusListener]] BlockStatusListener Spark Listener

BlockStatusListener is a SparkListener.md[]s that tracks storage:BlockManager.md[BlockManagers] and the blocks for spark-webui-storage.md[Storage tab] in web UI.

.BlockStatusListener Registries [cols="1,2",options="header",width="100%"] |=== | Registry | Description | [[blockManagers]] blockManagers | The lookup table for a collection of storage:BlockId.md[] and BlockUIData per storage:BlockManagerId.md[] |===

CAUTION: FIXME When are the events posted?

.BlockStatusListener Event Handlers [cols="1,2",options="header",width="100%"] |=== | Event Handler | Description

| onBlockManagerAdded | Registers a BlockManager in <> internal registry (with no blocks).

| onBlockManagerRemoved | Removes a BlockManager from <> internal registry.

| onBlockUpdated | Puts an updated BlockUIData for BlockId for BlockManagerId in <> internal registry.

Ignores updates for unregistered BlockManagers or non-StreamBlockIds.

For invalid storage:StorageLevel.md[StorageLevel]s (i.e. they do not use a memory or a disk or no replication) the block is removed. |===