Contributed by Steve Loughran.
This moves the new API of HDFS-13616 into a interface which is implemented by
HDFS RPC filesystem client (not WebHDFS or any other connector)
This new interface, BatchListingOperations, is in hadoop-common,
so applications do not need to be compiled with HDFS on the classpath.
They must cast the FS into the interface.
instanceof can probe the client for having the new interface -the patch
also adds a new path capability to probe for this.
The FileSystem implementation is cut; tests updated as appropriate.
All new interfaces/classes/constants are marked as @unstable.
Change-Id: I5623c51f2c75804f58f915dd7e60cb2cffdac681
Contributed by Steve Loughran.
Not all stores do complete validation here; in particular the S3A
Connector does not: checking up the entire directory tree to see if a path matches
is a file significantly slows things down.
This check does take place in S3A mkdirs(), which walks backwards up the list of
parent paths until it finds a directory (success) or a file (failure).
In practice production applications invariably create destination directories
before writing 1+ file into them -restricting check purely to the mkdirs()
call deliver significant speed up while implicitly including the checks.
Change-Id: I2c9df748e92b5655232e7d888d896f1868806eb0
Contributed by Xiaoyu Yao.
Contains HDFS-14892. Close the output stream if createWrappedOutputStream() fails
Copying file through the FsShell command into an HDFS encryption zone where
the caller lacks permissions is leaks a temp ._COPYING file
and potentially a wrapped stream unclosed.
This is a convergence of a fix for S3 meeting an issue in HDFS.
S3: a HEAD against a file can cache a 404,
-you must not do any existence checks, including deleteOnExit(),
until the file is written.
Hence: HADOOP-16490, only register files for deletion the create worked
and the upload is not direct.
HDFS-14892. HDFS doesn't close wrapped streams when IOEs are raised on
create() failures. Which means that an entry is retained on the NN.
-you need to register a file with deleteOnExit() even if the file wasn't
created.
This patch:
* Moves the deleteOnExit to ensure the created file get deleted cleanly.
* Fixes HDFS to close the wrapped stream on failures.
Contributed by Steve Loughran.
This complements the StreamCapabilities Interface by allowing applications to probe for a specific path on a specific instance of a FileSystem client
to offer a specific capability.
This is intended to allow applications to determine
* Whether a method is implemented before calling it and dealing with UnsupportedOperationException.
* Whether a specific feature is believed to be available in the remote store.
As well as a common set of capabilities defined in CommonPathCapabilities,
file systems are free to add their own capabilities, prefixed with
fs. + schema + .
The plan is to identify and document more capabilities -and for file systems which add new features, for a declaration of the availability of the feature to always be available.
Note
* The remote store is not expected to be checked for the feature;
It is more a check of client API and the client's configuration/knowledge
of the state of the remote system.
* Permissions are not checked.
Change-Id: I80bfebe94f4a8bdad8f3ac055495735b824968f5
