com.rpl.rama.backup

Interface BackupProvider

public interface BackupProvider

This interface defines the functionality required in order to create, store and manage Rama cluster backups. The primary requirements for a backup store are supporting storing objects by key and range queries. The ProgressListener is used by Rama to detected stalled backups. Most backup providers will want to implement progress reporting in putObject and getObject, using the ProgressListener nested interface on the object passed to setProgressListener.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	BackupProvider.KeysPage
static interface	BackupProvider.ProgressListener

Method Summary

Modifier and Type	Method and Description
java.util.concurrent.CompletableFuture<java.lang.Void>	deleteObject(java.lang.String key) Delete the object at the given key in the backup provider.
<T extends java.io.InputStream> java.util.concurrent.CompletableFuture<T>	getObject(java.lang.String key) Get the contents of the key stored in the backup provider.
java.util.concurrent.CompletableFuture<java.lang.Boolean>	hasKey(java.lang.String key) Predicate for key existing in the provider.
java.util.concurrent.CompletableFuture<BackupProvider.KeysPage>	listKeys(java.lang.String prefix, java.lang.Boolean recursive, java.lang.Object paginationKey) List all keys with the given prefix.
java.util.concurrent.CompletableFuture<java.lang.Void>	putObject(java.lang.String key, java.io.InputStream contents, java.lang.Long contentLength) Put the contents of path to the backup provider at the given key.
void	setProgressListener(BackupProvider.ProgressListener listener) Set the progress listener.

Method Detail

setProgressListener

void setProgressListener(BackupProvider.ProgressListener listener)

Set the progress listener.

Parameters:

listener - a ProgressListener instance. The progress listener should be called by the non-blocking implementations of the methods, e.g. putObject, that interact with the backup provider, to show that they are still running. The listener should be called as frequently as possible.

getObject

<T extends java.io.InputStream> java.util.concurrent.CompletableFuture<T> getObject(java.lang.String key)

Get the contents of the key stored in the backup provider. The contents are written to path.

Parameters:

key - the path at which to recover the contents.

Returns:

CompletableFuture that is completed with an input stream for the contents.. The implementation MUST be non-blocking.

putObject

java.util.concurrent.CompletableFuture<java.lang.Void> putObject(java.lang.String key,
                                                                 java.io.InputStream contents,
                                                                 java.lang.Long contentLength)

Put the contents of path to the backup provider at the given key. If the path already exists, this should be a no-op.

Parameters:

key - the path at which to recover the contents.

contents - an input-stream which provides the contents to upload.

contentLength - the number of bytes in the contents input stream.

Returns:

CompletableFuture that is completed with an InputStream providing the contents. The implementation MUST be non-blocking. The provider should handle cancellation of the futures it returns by stopping uploads.

hasKey

java.util.concurrent.CompletableFuture<java.lang.Boolean> hasKey(java.lang.String key)

Predicate for key existing in the provider.

Parameters:

key - path to check for existence.

Returns:

CompletableFuture completed with existence status.

listKeys

java.util.concurrent.CompletableFuture<BackupProvider.KeysPage> listKeys(java.lang.String prefix,
                                                                         java.lang.Boolean recursive,
                                                                         java.lang.Object paginationKey)

List all keys with the given prefix. If the prefix ends in "/", then the contents of the path are returned, otherwise the prefix is treated as an object name. The recursive flag determines whether contents of sub-folders are returned. If recursive is true, the filenames are returned relative to the root. If recursive is false, the filenames are returned relative to the prefix.

Parameters:

prefix - the path to start listing keys.

recursive - a Boolean flag for listing paths recursively.

paginationKey - token controlling pagination.

Returns:

CompletableFuture that is delivered with a KeysPage instance. paginationKey should be be null on the initial call. On subsequent calls, pass the nextPageMarker returned by the previous call.

deleteObject

java.util.concurrent.CompletableFuture<java.lang.Void> deleteObject(java.lang.String key)

Delete the object at the given key in the backup provider.

Parameters:

key - the path of the object to delete.

Returns:

CompletableFuture that is delivered when the delete completes. The implementation MUST be non-blocking.