Module org.elasticsearch.server
Package org.elasticsearch.common.blobstore

Interface BlobContainer

All Known Implementing Classes:
AbstractBlobContainer, FilterBlobContainer, FsBlobContainer
public interface BlobContainer
An interface for managing a repository of blob entries, where each blob entry is just a named group of bytes.

  • Method Details

    • path

      BlobPath path()
      Gets the BlobPath that defines the implementation specific paths to where the blobs are contained.
      Returns:
      the BlobPath where the blobs are contained

    • blobExists

      boolean blobExists(OperationPurpose purpose, String blobName) throws IOException
      Tests whether a blob with the given blob name exists in the container.
      Parameters:
      purpose - The purpose of the operation
      blobName - The name of the blob whose existence is to be determined.
      Returns:
      true if a blob exists in the BlobContainer with the given name, and false otherwise.
      Throws:
      IOException

    • readBlob

      InputStream readBlob(OperationPurpose purpose, String blobName) throws IOException
      Creates a new InputStream for the given blob name.
      Parameters:
      purpose - The purpose of the operation
      blobName - The name of the blob to get an InputStream for.
      Returns:
      The InputStream to read the blob.
      Throws:
      NoSuchFileException - if the blob does not exist
      IOException - if the blob can not be read.

    • readBlob

      InputStream readBlob(OperationPurpose purpose, String blobName, long position, long length) throws IOException
      Creates a new InputStream that can be used to read the given blob starting from a specific position in the blob. The length is an indication of the number of bytes that are expected to be read from the InputStream.
      Parameters:
      purpose - The purpose of the operation
      blobName - The name of the blob to get an InputStream for.
      position - The position in the blob where the next byte will be read.
      length - An indication of the number of bytes to be read.
      Returns:
      The InputStream to read the blob.
      Throws:
      NoSuchFileException - if the blob does not exist
      IOException - if the blob can not be read.

    • readBlobPreferredLength

      default long readBlobPreferredLength()
      Provides a hint to clients for a suitable length to use with readBlob(OperationPurpose, String, long, long). Some blob containers have nontrivial costs attached to each readBlob call, so it is a good idea for consumers to speculatively request more data than they need right now and to re-use this stream for future needs if possible. Also, some blob containers return streams that are expensive to close before the stream has been fully consumed, and the cost may depend on the length of the data that was left unconsumed. For these containers it's best to bound the cost of a partial read by bounding the length of the data requested.
      Returns:
      a hint to consumers regarding the length of data to request if there is a good chance that future reads can be satisfied from the same stream.

    • writeBlob

      void writeBlob(OperationPurpose purpose, String blobName, InputStream inputStream, long blobSize, boolean failIfAlreadyExists) throws IOException
      Reads blob content from the input stream and writes it to the container in a new blob with the given name. This method assumes the container does not already contain a blob of the same blobName. If a blob by the same name already exists, the operation will fail and an IOException will be thrown.
      Parameters:
      purpose - The purpose of the operation
      blobName - The name of the blob to write the contents of the input stream to.
      inputStream - The input stream from which to retrieve the bytes to write to the blob.
      blobSize - The size of the blob to be written, in bytes. It is implementation dependent whether this value is used in writing the blob to the repository.
      failIfAlreadyExists - whether to throw a FileAlreadyExistsException if the given blob already exists
      Throws:
      FileAlreadyExistsException - if failIfAlreadyExists is true and a blob by the same name already exists
      IOException - if the input stream could not be read, or the target blob could not be written to.

    • writeBlob

      default void writeBlob(OperationPurpose purpose, String blobName, BytesReference bytes, boolean failIfAlreadyExists) throws IOException
      Reads blob content from a BytesReference and writes it to the container in a new blob with the given name.
      Parameters:
      purpose - The purpose of the operation
      blobName - The name of the blob to write the contents of the input stream to.
      bytes - The bytes to write
      failIfAlreadyExists - whether to throw a FileAlreadyExistsException if the given blob already exists
      Throws:
      FileAlreadyExistsException - if failIfAlreadyExists is true and a blob by the same name already exists
      IOException - if the input stream could not be read, or the target blob could not be written to.

    • writeMetadataBlob

      void writeMetadataBlob(OperationPurpose purpose, String blobName, boolean failIfAlreadyExists, boolean atomic, CheckedConsumer<OutputStream,IOException> writer) throws IOException
      Write a blob by providing a consumer that will write its contents to an output stream. This method allows serializing a blob's contents directly to the blob store without having to materialize the serialized version in full before writing. This method is only used for streaming serialization of repository metadata that is known to be of limited size at any point in time and across all concurrent invocations of this method.
      Parameters:
      purpose - The purpose of the operation
      blobName - the name of the blob to write
      failIfAlreadyExists - whether to throw a FileAlreadyExistsException if the given blob already exists
      atomic - whether the write should be atomic in case the implementation supports it
      writer - consumer for an output stream that will write the blob contents to the stream
      Throws:
      IOException

    • writeBlobAtomic

      void writeBlobAtomic(OperationPurpose purpose, String blobName, BytesReference bytes, boolean failIfAlreadyExists) throws IOException
      Reads blob content from a BytesReference and writes it to the container in a new blob with the given name, using an atomic write operation if the implementation supports it.
      Parameters:
      purpose - The purpose of the operation
      blobName - The name of the blob to write the contents of the input stream to.
      bytes - The bytes to write
      failIfAlreadyExists - whether to throw a FileAlreadyExistsException if the given blob already exists
      Throws:
      FileAlreadyExistsException - if failIfAlreadyExists is true and a blob by the same name already exists
      IOException - if the input stream could not be read, or the target blob could not be written to.

    • delete

      DeleteResult delete(OperationPurpose purpose) throws IOException
      Deletes this container and all its contents from the repository.
      Parameters:
      purpose - The purpose of the operation
      Returns:
      delete result
      Throws:
      IOException - on failure

    • deleteBlobsIgnoringIfNotExists

      void deleteBlobsIgnoringIfNotExists(OperationPurpose purpose, Iterator<String> blobNames) throws IOException
      Deletes the blobs with given names. This method will not throw an exception when one or multiple of the given blobs don't exist and simply ignore this case.
      Parameters:
      purpose - The purpose of the operation
      blobNames - the names of the blobs to delete
      Throws:
      IOException - if a subset of blob exists but could not be deleted.

    • listBlobs

      Map<String,BlobMetadata> listBlobs(OperationPurpose purpose) throws IOException
      Lists all blobs in the container.
      Returns:
      A map of all the blobs in the container. The keys in the map are the names of the blobs and the values are BlobMetadata, containing basic information about each blob.
      Throws:
      IOException - if there were any failures in reading from the blob container.

    • children

      Map<String,BlobContainer> children(OperationPurpose purpose) throws IOException
      Lists all child containers under this container. A child container is defined as a container whose path() method returns a path that has this containers path() return as its prefix and has one more path element than the current container's path.
      Parameters:
      purpose - The purpose of the operation
      Returns:
      Map of name of the child container to child container
      Throws:
      IOException - on failure to list child containers

    • listBlobsByPrefix

      Map<String,BlobMetadata> listBlobsByPrefix(OperationPurpose purpose, String blobNamePrefix) throws IOException
      Lists all blobs in the container that match the specified prefix.
      Parameters:
      purpose - The purpose of the operation
      blobNamePrefix - The prefix to match against blob names in the container.
      Returns:
      A map of the matching blobs in the container. The keys in the map are the names of the blobs and the values are BlobMetadata, containing basic information about each blob.
      Throws:
      IOException - if there were any failures in reading from the blob container.

    • compareAndExchangeRegister

      void compareAndExchangeRegister(OperationPurpose purpose, String key, BytesReference expected, BytesReference updated, ActionListener<OptionalBytesReference> listener)
      Atomically sets the value stored at the given key to updated if the current value == expected. Keys not yet used start at initial value 0. Returns the current value (before it was updated).
      Parameters:
      purpose - The purpose of the operation
      key - key of the value to update
      expected - the expected value
      updated - the new value
      listener - a listener, completed with the value read from the register (before it was updated) or OptionalBytesReference.MISSING if the value could not be read due to concurrent activity.

    • compareAndSetRegister

      default void compareAndSetRegister(OperationPurpose purpose, String key, BytesReference expected, BytesReference updated, ActionListener<Boolean> listener)
      Atomically sets the value stored at the given key to updated if the current value == expected. Keys not yet used start at initial value 0.
      Parameters:
      purpose -
      key - key of the value to update
      expected - the expected value
      updated - the new value
      listener - a listener which is completed with Boolean.TRUE if successful, Boolean.FALSE if the expected value did not match the updated value or the value could not be read due to concurrent activity

    • getRegister

      default void getRegister(OperationPurpose purpose, String key, ActionListener<OptionalBytesReference> listener)
      Gets the value set by compareAndSetRegister(org.elasticsearch.common.blobstore.OperationPurpose, java.lang.String, org.elasticsearch.common.bytes.BytesReference, org.elasticsearch.common.bytes.BytesReference, org.elasticsearch.action.ActionListener<java.lang.Boolean>) or compareAndExchangeRegister(org.elasticsearch.common.blobstore.OperationPurpose, java.lang.String, org.elasticsearch.common.bytes.BytesReference, org.elasticsearch.common.bytes.BytesReference, org.elasticsearch.action.ActionListener<org.elasticsearch.common.blobstore.OptionalBytesReference>) for a given key. If a key has not yet been used, the initial value is an empty BytesReference.
      Parameters:
      purpose - The purpose of the operation
      key - key of the value to get
      listener - a listener, completed with the value read from the register or OptionalBytesReference#MISSING if the value could not be read due to concurrent activity.

    • assertPurposeConsistency

      static boolean assertPurposeConsistency(OperationPurpose purpose, String blobName)
      Verify that the OperationPurpose is (somewhat) suitable for the name of the blob to which it applies: