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This module contains code to support integration with Amazon Web Services.
It also declares the dependencies needed to work with AWS services.
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.fs.s3a.s3guard;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.s3a.Retries;
import org.apache.hadoop.fs.s3a.S3AFileStatus;
import org.apache.hadoop.fs.s3a.S3AInstrumentation;
import org.apache.hadoop.fs.s3a.Tristate;
import org.apache.hadoop.util.ReflectionUtils;
import static org.apache.hadoop.fs.s3a.Constants.S3_METADATA_STORE_IMPL;
import static org.apache.hadoop.fs.s3a.Statistic.S3GUARD_METADATASTORE_PUT_PATH_LATENCY;
import static org.apache.hadoop.fs.s3a.Statistic.S3GUARD_METADATASTORE_PUT_PATH_REQUEST;
import static org.apache.hadoop.fs.s3a.S3AUtils.createUploadFileStatus;
/**
* Logic for integrating MetadataStore with S3A.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public final class S3Guard {
private static final Logger LOG = LoggerFactory.getLogger(S3Guard.class);
@InterfaceAudience.Private
@InterfaceStability.Unstable
@VisibleForTesting
public static final String S3GUARD_DDB_CLIENT_FACTORY_IMPL =
"fs.s3a.s3guard.ddb.client.factory.impl";
static final Class
S3GUARD_DDB_CLIENT_FACTORY_IMPL_DEFAULT =
DynamoDBClientFactory.DefaultDynamoDBClientFactory.class;
private static final FileStatus[] EMPTY_LISTING = new FileStatus[0];
// Utility class. All static functions.
private S3Guard() { }
/* Utility functions. */
/**
* Create a new instance of the configured MetadataStore.
* The returned MetadataStore will have been initialized via
* {@link MetadataStore#initialize(FileSystem)} by this function before
* returning it. Callers must clean up by calling
* {@link MetadataStore#close()} when done using the MetadataStore.
*
* @param fs FileSystem whose Configuration specifies which
* implementation to use.
* @return Reference to new MetadataStore.
* @throws IOException if the metadata store cannot be instantiated
*/
@Retries.OnceTranslated
public static MetadataStore getMetadataStore(FileSystem fs)
throws IOException {
Preconditions.checkNotNull(fs);
Configuration conf = fs.getConf();
Preconditions.checkNotNull(conf);
MetadataStore msInstance;
try {
Class msClass = getMetadataStoreClass(conf);
msInstance = ReflectionUtils.newInstance(msClass, conf);
LOG.debug("Using {} metadata store for {} filesystem",
msClass.getSimpleName(), fs.getScheme());
msInstance.initialize(fs);
return msInstance;
} catch (FileNotFoundException e) {
// Don't log this exception as it means the table doesn't exist yet;
// rely on callers to catch and treat specially
throw e;
} catch (RuntimeException | IOException e) {
String message = "Failed to instantiate metadata store " +
conf.get(S3_METADATA_STORE_IMPL)
+ " defined in " + S3_METADATA_STORE_IMPL
+ ": " + e;
LOG.error(message, e);
if (e instanceof IOException) {
throw e;
} else {
throw new IOException(message, e);
}
}
}
static Class getMetadataStoreClass(
Configuration conf) {
if (conf == null) {
return NullMetadataStore.class;
}
if (conf.get(S3_METADATA_STORE_IMPL) != null && LOG.isDebugEnabled()) {
LOG.debug("Metastore option source {}",
conf.getPropertySources(S3_METADATA_STORE_IMPL));
}
Class aClass = conf.getClass(
S3_METADATA_STORE_IMPL, NullMetadataStore.class,
MetadataStore.class);
return aClass;
}
/**
* Helper function which puts a given S3AFileStatus into the MetadataStore and
* returns the same S3AFileStatus. Instrumentation monitors the put operation.
* @param ms MetadataStore to {@code put()} into.
* @param status status to store
* @param instrumentation instrumentation of the s3a file system
* @return The same status as passed in
* @throws IOException if metadata store update failed
*/
public static S3AFileStatus putAndReturn(MetadataStore ms,
S3AFileStatus status,
S3AInstrumentation instrumentation) throws IOException {
long startTimeNano = System.nanoTime();
ms.put(new PathMetadata(status));
instrumentation.addValueToQuantiles(S3GUARD_METADATASTORE_PUT_PATH_LATENCY,
(System.nanoTime() - startTimeNano));
instrumentation.incrementCounter(S3GUARD_METADATASTORE_PUT_PATH_REQUEST, 1);
return status;
}
/**
* Convert the data of a directory listing to an array of {@link FileStatus}
* entries. Tombstones are filtered out at this point. If the listing is null
* an empty array is returned.
* @param dirMeta directory listing -may be null
* @return a possibly-empty array of file status entries
*/
public static FileStatus[] dirMetaToStatuses(DirListingMetadata dirMeta) {
if (dirMeta == null) {
return EMPTY_LISTING;
}
Collection listing = dirMeta.getListing();
List statuses = new ArrayList<>();
for (PathMetadata pm : listing) {
if (!pm.isDeleted()) {
statuses.add(pm.getFileStatus());
}
}
return statuses.toArray(new FileStatus[0]);
}
/**
* Given directory listing metadata from both the backing store and the
* MetadataStore, merge the two sources of truth to create a consistent
* view of the current directory contents, which can be returned to clients.
*
* Also update the MetadataStore to reflect the resulting directory listing.
*
* @param ms MetadataStore to use.
* @param path path to directory
* @param backingStatuses Directory listing from the backing store.
* @param dirMeta Directory listing from MetadataStore. May be null.
* @param isAuthoritative State of authoritative mode
* @return Final result of directory listing.
* @throws IOException if metadata store update failed
*/
public static FileStatus[] dirListingUnion(MetadataStore ms, Path path,
List backingStatuses, DirListingMetadata dirMeta,
boolean isAuthoritative) throws IOException {
// Fast-path for NullMetadataStore
if (isNullMetadataStore(ms)) {
return backingStatuses.toArray(new FileStatus[backingStatuses.size()]);
}
assertQualified(path);
if (dirMeta == null) {
// The metadataStore had zero state for this directory
dirMeta = new DirListingMetadata(path, DirListingMetadata.EMPTY_DIR,
false);
}
Set deleted = dirMeta.listTombstones();
// Since we treat the MetadataStore as a "fresher" or "consistent" view
// of metadata, we always use its metadata first.
// Since the authoritative case is already handled outside this function,
// we will basically start with the set of directory entries in the
// DirListingMetadata, and add any that only exist in the backingStatuses.
boolean changed = false;
for (FileStatus s : backingStatuses) {
if (deleted.contains(s.getPath())) {
continue;
}
// Minor race condition here. Multiple threads could add to this
// mutable DirListingMetadata. Since it is backed by a
// ConcurrentHashMap, the last put() wins.
// More concerning is two threads racing on listStatus() and delete().
// Any FileSystem has similar race conditions, but we could persist
// a stale entry longer. We could expose an atomic
// DirListingMetadata#putIfNotPresent()
boolean updated = dirMeta.put(s);
changed = changed || updated;
}
// If dirMeta is not authoritative, but isAuthoritative is true the
// directory metadata should be updated. Treat it as a change.
changed = changed || (!dirMeta.isAuthoritative() && isAuthoritative);
if (changed && isAuthoritative) {
dirMeta.setAuthoritative(true); // This is the full directory contents
ms.put(dirMeta);
}
return dirMetaToStatuses(dirMeta);
}
/**
* Although NullMetadataStore does nothing, callers may wish to avoid work
* (fast path) when the NullMetadataStore is in use.
* @param ms The MetadataStore to test
* @return true iff the MetadataStore is the null, or no-op, implementation.
*/
public static boolean isNullMetadataStore(MetadataStore ms) {
return (ms instanceof NullMetadataStore);
}
/**
* Update MetadataStore to reflect creation of the given directories.
*
* If an IOException is raised while trying to update the entry, this
* operation catches the exception, swallows it and returns.
*
* @deprecated this is no longer called by {@code S3AFilesystem.innerMkDirs}.
* See: HADOOP-15079 (January 2018).
* It is currently retained because of its discussion in the method on
* atomicity and in case we need to reinstate it or adapt the current
* process of directory marker creation.
* But it is not being tested and so may age with time...consider
* deleting it in future if it's clear there's no need for it.
* @param ms MetadataStore to update.
* @param dirs null, or an ordered list of directories from leaf to root.
* E.g. if /a/ exists, and mkdirs(/a/b/c/d) is called, this
* list will contain [/a/b/c/d, /a/b/c, /a/b]. /a/b/c/d is
* an empty, dir, and the other dirs only contain their child
* dir.
* @param owner Hadoop user name.
* @param authoritative Whether to mark new directories as authoritative.
*/
@Deprecated
@Retries.OnceExceptionsSwallowed
public static void makeDirsOrdered(MetadataStore ms, List dirs,
String owner, boolean authoritative) {
if (dirs == null) {
return;
}
/* We discussed atomicity of this implementation.
* The concern is that multiple clients could race to write different
* cached directories to the MetadataStore. Two solutions are proposed:
* 1. Move mkdirs() into MetadataStore interface and let implementations
* ensure they are atomic.
* 2. Specify that the semantics of MetadataStore#putListStatus() is
* always additive, That is, if MetadataStore has listStatus() state
* for /a/b that contains [/a/b/file0, /a/b/file1], and we then call
* putListStatus(/a/b -> [/a/b/file2, /a/b/file3], isAuthoritative=true),
* then we will end up with final state of
* [/a/b/file0, /a/b/file1, /a/b/file2, /a/b/file3], isAuthoritative =
* true
*/
FileStatus prevStatus = null;
// Use new batched put to reduce round trips.
List pathMetas = new ArrayList<>(dirs.size());
try {
// Iterate from leaf to root
for (int i = 0; i < dirs.size(); i++) {
boolean isLeaf = (prevStatus == null);
Path f = dirs.get(i);
assertQualified(f);
FileStatus status =
createUploadFileStatus(f, true, 0, 0, owner);
// We only need to put a DirListingMetadata if we are setting
// authoritative bit
DirListingMetadata dirMeta = null;
if (authoritative) {
Collection children;
if (isLeaf) {
children = DirListingMetadata.EMPTY_DIR;
} else {
children = new ArrayList<>(1);
children.add(new PathMetadata(prevStatus));
}
dirMeta = new DirListingMetadata(f, children, authoritative);
ms.put(dirMeta);
}
pathMetas.add(new PathMetadata(status));
prevStatus = status;
}
// Batched put
ms.put(pathMetas);
} catch (IOException ioe) {
LOG.error("MetadataStore#put() failure:", ioe);
}
}
/**
* Helper function that records the move of directory paths, adding
* resulting metadata to the supplied lists.
* Does not store in MetadataStore.
* @param ms MetadataStore, used to make this a no-op, when it is
* NullMetadataStore.
* @param srcPaths stores the source path here
* @param dstMetas stores destination metadata here
* @param srcPath source path to store
* @param dstPath destination path to store
* @param owner file owner to use in created records
*/
public static void addMoveDir(MetadataStore ms, Collection srcPaths,
Collection dstMetas, Path srcPath, Path dstPath,
String owner) {
if (isNullMetadataStore(ms)) {
return;
}
assertQualified(srcPath, dstPath);
FileStatus dstStatus = createUploadFileStatus(dstPath, true, 0, 0, owner);
addMoveStatus(srcPaths, dstMetas, srcPath, dstStatus);
}
/**
* Like {@link #addMoveDir(MetadataStore, Collection, Collection, Path,
* Path, String)} (), but for files.
* @param ms MetadataStore, used to make this a no-op, when it is
* NullMetadataStore.
* @param srcPaths stores the source path here
* @param dstMetas stores destination metadata here
* @param srcPath source path to store
* @param dstPath destination path to store
* @param size length of file moved
* @param blockSize blocksize to associate with destination file
* @param owner file owner to use in created records
*/
public static void addMoveFile(MetadataStore ms, Collection srcPaths,
Collection dstMetas, Path srcPath, Path dstPath,
long size, long blockSize, String owner) {
if (isNullMetadataStore(ms)) {
return;
}
assertQualified(srcPath, dstPath);
FileStatus dstStatus = createUploadFileStatus(dstPath, false,
size, blockSize, owner);
addMoveStatus(srcPaths, dstMetas, srcPath, dstStatus);
}
/**
* Helper method that records the move of all ancestors of a path.
*
* In S3A, an optimization is to delete unnecessary fake directory objects if
* the directory is non-empty. In that case, for a nested child to move, S3A
* is not listing and thus moving all its ancestors (up to source root). So we
* take care of those inferred directories of this path explicitly.
*
* As {@link #addMoveFile} and {@link #addMoveDir}, this method adds resulting
* metadata to the supplied lists. It does not store in MetadataStore.
*
* @param ms MetadataStore, no-op if it is NullMetadataStore
* @param srcPaths stores the source path here
* @param dstMetas stores destination metadata here
* @param srcRoot source root up to which (exclusive) should we add ancestors
* @param srcPath source path of the child to add ancestors
* @param dstPath destination path of the child to add ancestors
* @param owner Hadoop user name
*/
public static void addMoveAncestors(MetadataStore ms,
Collection srcPaths, Collection dstMetas,
Path srcRoot, Path srcPath, Path dstPath, String owner) {
if (isNullMetadataStore(ms)) {
return;
}
assertQualified(srcRoot, srcPath, dstPath);
if (srcPath.equals(srcRoot)) {
LOG.debug("Skip moving ancestors of source root directory {}", srcRoot);
return;
}
Path parentSrc = srcPath.getParent();
Path parentDst = dstPath.getParent();
while (parentSrc != null
&& !parentSrc.isRoot()
&& !parentSrc.equals(srcRoot)
&& !srcPaths.contains(parentSrc)) {
LOG.debug("Renaming non-listed parent {} to {}", parentSrc, parentDst);
S3Guard.addMoveDir(ms, srcPaths, dstMetas, parentSrc, parentDst, owner);
parentSrc = parentSrc.getParent();
parentDst = parentDst.getParent();
}
}
public static void addAncestors(MetadataStore metadataStore,
Path qualifiedPath, String username) throws IOException {
Collection newDirs = new ArrayList<>();
Path parent = qualifiedPath.getParent();
while (!parent.isRoot()) {
PathMetadata directory = metadataStore.get(parent);
if (directory == null || directory.isDeleted()) {
FileStatus status = new FileStatus(0, true, 1, 0, 0, 0, null, username,
null, parent);
PathMetadata meta = new PathMetadata(status, Tristate.FALSE, false);
newDirs.add(meta);
} else {
break;
}
parent = parent.getParent();
}
metadataStore.put(newDirs);
}
private static void addMoveStatus(Collection srcPaths,
Collection dstMetas,
Path srcPath,
FileStatus dstStatus) {
srcPaths.add(srcPath);
dstMetas.add(new PathMetadata(dstStatus));
}
/**
* Assert that the path is qualified with a host and scheme.
* @param p path to check
* @throws NullPointerException if either argument does not hold
*/
public static void assertQualified(Path p) {
URI uri = p.toUri();
// Paths must include bucket in case MetadataStore is shared between
// multiple S3AFileSystem instances
Preconditions.checkNotNull(uri.getHost(), "Null host in " + uri);
// This should never fail, but is retained for completeness.
Preconditions.checkNotNull(uri.getScheme(), "Null scheme in " + uri);
}
/**
* Assert that all paths are valid.
* @param paths path to check
* @throws NullPointerException if either argument does not hold
*/
public static void assertQualified(Path...paths) {
for (Path path : paths) {
assertQualified(path);
}
}
}
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