Package com.yahoo.vespa.curator.api

Interface VespaCurator

All Known Implementing Classes:
CuratorWrapper
public interface VespaCurator
A client for a ZooKeeper cluster running inside Vespa. Applications that want to use ZooKeeper can inject this in their code.
Author:
mpolden, jonmv

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static final record 
    VespaCurator.Data
    Data of a ZK node, including content (possibly empty, never null) and metadata.
    static final record 
    VespaCurator.Meta
    Metadata for a ZK node.
    static interface 
    VespaCurator.SingletonWorker
    Callback interface for processes of which only a single instance should be active at any time, across all containers in the cluster, and across all component generations.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    delete(com.yahoo.path.Path path)
    Deletes the node at the given path.
    boolean
    delete(com.yahoo.path.Path path, int expectedVersion)
    Atomically compares the version in the stat of the node at the given path, with the expected version, and then: if they are equal, attempts the delete operation (see delete(Path)), and returns true; otherwise, returns false.
    void
    deleteAll(com.yahoo.path.Path path)
    Recursively deletes any node at the given path, and any children it may have.
    boolean
    isActive(String singletonId)
    Whether this container currently holds the exclusive lease for activation of singletons with this ID.
    List<String>
    list(com.yahoo.path.Path path)
    Lists the children of the node at the given path, or throws if there is no node at that path.
    AutoCloseable
    lock(com.yahoo.path.Path path, Duration timeout)
    Creates and acquires a re-entrant lock with the given path.
    Optional<VespaCurator.Data>
    read(com.yahoo.path.Path path)
    Returns the content and stat for the node at the given path, or empty if no node exists at that path.
    void
    register(VespaCurator.SingletonWorker singleton, Duration timeout)
    Register the singleton with the framework, so it may become active.
    Optional<VespaCurator.Meta>
    stat(com.yahoo.path.Path path)
    Returns the stat for the node at the given path, or empty if no node exists at that path.
    void
    unregister(VespaCurator.SingletonWorker singleton, Duration timeout)
    Unregister with the framework, so this singleton may no longer be active, and returns
    VespaCurator.Meta
    write(com.yahoo.path.Path path, byte[] data)
    Writes the given data to a node at the given path, creating it and its parents as needed, and returns the stat of the modified node.
    Optional<VespaCurator.Meta>
    write(com.yahoo.path.Path path, byte[] data, int expectedVersion)
    Atomically compares the version in the stat of the node at the given path, with the expected version, and then: if they are equal, attempts the write operation (see write(Path, byte[])); otherwise, return empty.

  • Method Details

    • stat

      Optional<VespaCurator.Meta> stat(com.yahoo.path.Path path)
      Returns the stat for the node at the given path, or empty if no node exists at that path.

    • read

      Optional<VespaCurator.Data> read(com.yahoo.path.Path path)
      Returns the content and stat for the node at the given path, or empty if no node exists at that path.

    • write

      VespaCurator.Meta write(com.yahoo.path.Path path, byte[] data)
      Writes the given data to a node at the given path, creating it and its parents as needed, and returns the stat of the modified node. Failure to write, due to connection loss, is retried a limited number of times.

    • write

      Optional<VespaCurator.Meta> write(com.yahoo.path.Path path, byte[] data, int expectedVersion)
      Atomically compares the version in the stat of the node at the given path, with the expected version, and then: if they are equal, attempts the write operation (see write(Path, byte[])); otherwise, return empty.

    • deleteAll

      void deleteAll(com.yahoo.path.Path path)
      Recursively deletes any node at the given path, and any children it may have.

    • delete

      void delete(com.yahoo.path.Path path)
      Deletes the node at the given path. Failres due to connection loss are retried a limited number of times.

    • delete

      boolean delete(com.yahoo.path.Path path, int expectedVersion)
      Atomically compares the version in the stat of the node at the given path, with the expected version, and then: if they are equal, attempts the delete operation (see delete(Path)), and returns true; otherwise, returns false.

    • list

      List<String> list(com.yahoo.path.Path path)
      Lists the children of the node at the given path, or throws if there is no node at that path.

    • lock

      AutoCloseable lock(com.yahoo.path.Path path, Duration timeout) throws com.yahoo.concurrent.UncheckedTimeoutException
      Creates and acquires a re-entrant lock with the given path. This blocks until the lock is acquired or timeout elapses.
      Throws:
      com.yahoo.concurrent.UncheckedTimeoutException

    • register

      void register(VespaCurator.SingletonWorker singleton, Duration timeout)
      Register the singleton with the framework, so it may become active.

      Call this after construction of the singleton, typically during component construction!

      • If this activates the singleton, this happens synchronously, and any errors are propagated here.
      • If this replaces an already active singleton, its deactivation is also called, prior to activation of this.
      • If (de)activation is not complete within the given timeout, a timeout exception is thrown.
      • If an error occurs (due to failed activation), unregistration is automatically attempted, with the same timeout.

    • unregister

      void unregister(VespaCurator.SingletonWorker singleton, Duration timeout)
      Unregister with the framework, so this singleton may no longer be active, and returns

      Call this before deconstruction of the singleton, typically during component deconstruction!

      • If this singleton is active, deactivation will be called synchronously, and errors propagated here.
      • If this also triggers activation of a new singleton, its activation is called after deactivation of this.
      • If (de)activation is not complete within the given timeout, a timeout exception is thrown.

    • isActive

      boolean isActive(String singletonId)
      Whether this container currently holds the exclusive lease for activation of singletons with this ID.