Package com.microsoft.azure.eventprocessorhost

Interface ICheckpointManager

  • All Known Implementing Classes:
    InMemoryCheckpointManager
    public interface ICheckpointManager
    If you wish to have EventProcessorHost store checkpoints somewhere other than Azure Storage, you can write your own checkpoint manager using this interface. The Azure Storage managers use the same storage for both lease and checkpoints, so both interfaces are implemented by the same class. You are free to do the same thing if you have a unified store for both types of data. This interface does not specify initialization methods because we have no way of knowing what information your implementation will require. If your implementation needs initialization, you will have to initialize the instance before passing it to the EventProcessorHost constructor.

    • Method Detail

      • checkpointStoreExists

        CompletableFuture<Boolean> checkpointStoreExists()
        Does the checkpoint store exist? The returned CompletableFuture completes with true if the checkpoint store exists or false if it does not. It completes exceptionally on error.
        Returns:
        CompletableFuture -> true if it exists, false if not

      • createCheckpointStoreIfNotExists

        CompletableFuture<Void> createCheckpointStoreIfNotExists()
        Create the checkpoint store if it doesn't exist. Do nothing if it does exist.
        Returns:
        CompletableFuture -> null on success, completes exceptionally on error.

      • deleteCheckpointStore

        CompletableFuture<Void> deleteCheckpointStore()
        Deletes the checkpoint store.
        Returns:
        CompletableFuture -> null on success, completes exceptionally on error.

      • getCheckpoint

        CompletableFuture<Checkpoint> getCheckpoint​(String partitionId)
        Get the checkpoint data associated with the given partition. Could return null if no checkpoint has been created for that partition.
        Parameters:
        partitionId - Id of partition to get checkpoint info for.
        Returns:
        CompletableFuture -> checkpoint info, or null. Completes exceptionally on error.

      • createAllCheckpointsIfNotExists

        CompletableFuture<Void> createAllCheckpointsIfNotExists​(List<String> partitionIds)
        Creates the checkpoint HOLDERs for the given partitions. Does nothing for any checkpoint HOLDERs that already exist. The semantics of this are complicated because it is possible to use the same store for both leases and checkpoints (the Azure Storage implementation does so) and it is required to have a lease for every partition but it is not required to have a checkpoint for a partition. It is a valid scenario to never use checkpoints at all, so it is important for the store to distinguish between creating the structure(s) that will hold a checkpoint and actually creating a checkpoint (storing an offset/sequence number pair in the structure).
        Parameters:
        partitionIds - List of partitions to create checkpoint HOLDERs for.
        Returns:
        CompletableFuture -> null on success, completes exceptionally on error.

      • updateCheckpoint

        CompletableFuture<Void> updateCheckpoint​(CompleteLease lease,
                                         Checkpoint checkpoint)
        Update the checkpoint in the store with the offset/sequenceNumber in the provided checkpoint. The lease argument is necessary to make the Azure Storage implementation work correctly: the Azure Storage implementation stores the checkpoint as part of the lease and we cannot completely hide the connection between the two. If your implementation does not have this limitation, you are free to ignore the lease argument.
        Parameters:
        lease - lease for the partition to be checkpointed.
        checkpoint - offset/sequenceNumber and partition id to update the store with.
        Returns:
        CompletableFuture -> null on success. Completes exceptionally on error.

      • deleteCheckpoint

        CompletableFuture<Void> deleteCheckpoint​(String partitionId)
        Delete the stored checkpoint data for the given partition. If there is no stored checkpoint for the given partition, that is treated as success. Deleting the checkpoint HOLDER is allowed but not required; your implementation is free to do whichever is more convenient.
        Parameters:
        partitionId - id of partition to delete checkpoint from store
        Returns:
        CompletableFuture -> null on success. Completes exceptionally on error.