org.apache.flink.runtime.state.CheckpointStorageCoordinatorView Maven / Gradle / Ivy
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
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*/
package org.apache.flink.runtime.state;
import javax.annotation.Nullable;
import java.io.IOException;
/**
* This interface creates a {@link CheckpointStorageLocation} to which
* an individual checkpoint or savepoint is stored.
*
* Methods of this interface act as an administration role in checkpoint coordinator.
*/
public interface CheckpointStorageCoordinatorView {
/**
* Checks whether this backend supports highly available storage of data.
*
*
Some state backends may not support highly-available durable storage, with default settings,
* which makes them suitable for zero-config prototyping, but not for actual production setups.
*/
boolean supportsHighlyAvailableStorage();
/**
* Checks whether the storage has a default savepoint location configured.
*/
boolean hasDefaultSavepointLocation();
/**
* Resolves the given pointer to a checkpoint/savepoint into a checkpoint location. The location
* supports reading the checkpoint metadata, or disposing the checkpoint storage location.
*
*
If the state backend cannot understand the format of the pointer (for example because it
* was created by a different state backend) this method should throw an {@code IOException}.
*
* @param externalPointer The external checkpoint pointer to resolve.
* @return The checkpoint location handle.
*
* @throws IOException Thrown, if the state backend does not understand the pointer, or if
* the pointer could not be resolved due to an I/O error.
*/
CompletedCheckpointStorageLocation resolveCheckpoint(String externalPointer) throws IOException;
/**
* Initializes the necessary prerequisites for storage locations of checkpoints/savepoints.
*
*
For file-based checkpoint storage, this method would initialize essential base checkpoint directories
* on checkpoint coordinator side and should be executed before calling {@link #initializeLocationForCheckpoint(long)}
* and {@link #initializeLocationForSavepoint(long, String)}.
*
* @throws IOException Thrown, if these base storage locations cannot be initialized due to an I/O exception.
*/
void initializeBaseLocations() throws IOException;
/**
* Initializes a storage location for new checkpoint with the given ID.
*
*
The returned storage location can be used to write the checkpoint data and metadata
* to and to obtain the pointers for the location(s) where the actual checkpoint data should be
* stored.
*
* @param checkpointId The ID (logical timestamp) of the checkpoint that should be persisted.
* @return A storage location for the data and metadata of the given checkpoint.
*
* @throws IOException Thrown if the storage location cannot be initialized due to an I/O exception.
*/
CheckpointStorageLocation initializeLocationForCheckpoint(long checkpointId) throws IOException;
/**
* Initializes a storage location for new savepoint with the given ID.
*
*
If an external location pointer is passed, the savepoint storage location
* will be initialized at the location of that pointer. If the external location pointer is null,
* the default savepoint location will be used. If no default savepoint location is configured,
* this will throw an exception. Whether a default savepoint location is configured can be
* checked via {@link #hasDefaultSavepointLocation()}.
*
* @param checkpointId The ID (logical timestamp) of the savepoint's checkpoint.
* @param externalLocationPointer Optionally, a pointer to the location where the savepoint should
* be stored. May be null.
*
* @return A storage location for the data and metadata of the savepoint.
*
* @throws IOException Thrown if the storage location cannot be initialized due to an I/O exception.
*/
CheckpointStorageLocation initializeLocationForSavepoint(
long checkpointId,
@Nullable String externalLocationPointer) throws IOException;
/**
* Resolves the given pointer to a checkpoint/savepoint into the latest completed checkpoint location.
* The location supports reading the checkpoint metadata, or disposing the checkpoint storage location.
*
*
If the state backend cannot understand the format of the pointer (for example because it
* was created by a different state backend) this method should throw an {@code IOException}.
*
* @param externalPointer The external checkpoint pointer to resolve.
* @return The latest completed checkpoint location handle.
*
* @throws IOException Thrown, if the state backend does not understand the pointer, or if
* the pointer could not be resolved due to an I/O error.
*/
CompletedCheckpointStorageLocation resolveLatestCheckpoint(String externalPointer) throws IOException;
}