org.apache.flink.runtime.blob

Interface PermanentBlobService

All Superinterfaces:

AutoCloseable, Closeable

All Known Subinterfaces:

JobPermanentBlobService

All Known Implementing Classes:

BlobServer, PermanentBlobCache

public interface PermanentBlobService
extends Closeable

A service to retrieve permanent binary large objects (BLOBs).

These may include per-job BLOBs that are covered by high-availability (HA) mode, e.g. a job's JAR files or (parts of) an off-loaded TaskDeploymentDescriptor or files in the DistributedCache.

Method Summary

Modifier and Type	Method and Description
File	getFile(JobID jobId, PermanentBlobKey key) Returns the path to a local copy of the file associated with the provided job ID and blob key.
default byte[]	readFile(JobID jobId, PermanentBlobKey key) Returns the content of the file for the BLOB with the provided job ID the blob key.

Methods inherited from interface java.io.Closeable

close

Method Detail

getFile

File getFile(JobID jobId,
             PermanentBlobKey key)
      throws IOException

Returns the path to a local copy of the file associated with the provided job ID and blob key.

Parameters:

jobId - ID of the job this blob belongs to

key - BLOB key associated with the requested file

Returns:

The path to the file.

Throws:

FileNotFoundException - if the BLOB does not exist;

IOException - if any other error occurs when retrieving the file

readFile

default byte[] readFile(JobID jobId,
                        PermanentBlobKey key)
                 throws IOException

Returns the content of the file for the BLOB with the provided job ID the blob key.

Compared to getFile, readFile will attempt to read the entire file after retrieving it. If file reading and file retrieving is done in the same WRITE lock, it can avoid the scenario that the path to the file is deleted concurrently by other threads when the file is retrieved but not read yet.

Parameters:

jobId - ID of the job this blob belongs to

key - BLOB key associated with the requested file

Returns:

The content of the BLOB.

Throws:

FileNotFoundException - if the BLOB does not exist;

IOException - if any other error occurs when retrieving the file.