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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.
/*
* 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;
import com.amazonaws.AbortedException;
import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.ClientConfiguration;
import com.amazonaws.Protocol;
import com.amazonaws.SdkBaseException;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.EnvironmentVariableCredentialsProvider;
import com.amazonaws.auth.InstanceProfileCredentialsProvider;
import com.amazonaws.retry.RetryUtils;
import com.amazonaws.services.dynamodbv2.model.AmazonDynamoDBException;
import com.amazonaws.services.dynamodbv2.model.LimitExceededException;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughputExceededException;
import com.amazonaws.services.dynamodbv2.model.ResourceNotFoundException;
import com.amazonaws.services.s3.model.AmazonS3Exception;
import com.amazonaws.services.s3.model.MultiObjectDeleteException;
import com.amazonaws.services.s3.model.S3ObjectSummary;
import com.google.common.base.Preconditions;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;
import org.apache.hadoop.fs.RemoteIterator;
import org.apache.hadoop.fs.s3a.auth.NoAuthWithAWSException;
import org.apache.hadoop.fs.s3native.S3xLoginHelper;
import org.apache.hadoop.net.ConnectTimeoutException;
import org.apache.hadoop.security.ProviderUtils;
import org.apache.hadoop.util.VersionInfo;
import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.Nullable;
import java.io.Closeable;
import java.io.EOFException;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.SocketTimeoutException;
import java.net.URI;
import java.nio.file.AccessDeniedException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ExecutionException;
import static org.apache.hadoop.fs.s3a.Constants.*;
/**
* Utility methods for S3A code.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public final class S3AUtils {
private static final Logger LOG = LoggerFactory.getLogger(S3AUtils.class);
static final String CONSTRUCTOR_EXCEPTION = "constructor exception";
static final String INSTANTIATION_EXCEPTION
= "instantiation exception";
static final String NOT_AWS_PROVIDER =
"does not implement AWSCredentialsProvider";
static final String ABSTRACT_PROVIDER =
"is abstract and therefore cannot be created";
static final String ENDPOINT_KEY = "Endpoint";
/** Filesystem is closed; kept here to keep the errors close. */
static final String E_FS_CLOSED = "FileSystem is closed!";
/**
* Core property for provider path. Duplicated here for consistent
* code across Hadoop version: {@value}.
*/
static final String CREDENTIAL_PROVIDER_PATH =
"hadoop.security.credential.provider.path";
/**
* Encryption SSE-C used but the config lacks an encryption key.
*/
public static final String SSE_C_NO_KEY_ERROR =
S3AEncryptionMethods.SSE_C.getMethod()
+ " is enabled but no encryption key was declared in "
+ SERVER_SIDE_ENCRYPTION_KEY;
/**
* Encryption SSE-S3 is used but the caller also set an encryption key.
*/
public static final String SSE_S3_WITH_KEY_ERROR =
S3AEncryptionMethods.SSE_S3.getMethod()
+ " is enabled but an encryption key was set in "
+ SERVER_SIDE_ENCRYPTION_KEY;
private static final String EOF_MESSAGE_IN_XML_PARSER
= "Failed to sanitize XML document destined for handler class";
private static final String BUCKET_PATTERN = FS_S3A_BUCKET_PREFIX + "%s.%s";
private S3AUtils() {
}
/**
* Translate an exception raised in an operation into an IOException.
* The specific type of IOException depends on the class of
* {@link AmazonClientException} passed in, and any status codes included
* in the operation. That is: HTTP error codes are examined and can be
* used to build a more specific response.
*
* @see S3 Error responses
* @see Amazon S3 Error Best Practices
* @see Dynamo DB Commmon errors
* @param operation operation
* @param path path operated on (must not be null)
* @param exception amazon exception raised
* @return an IOE which wraps the caught exception.
*/
public static IOException translateException(String operation,
Path path,
AmazonClientException exception) {
return translateException(operation, path.toString(), exception);
}
/**
* Translate an exception raised in an operation into an IOException.
* The specific type of IOException depends on the class of
* {@link AmazonClientException} passed in, and any status codes included
* in the operation. That is: HTTP error codes are examined and can be
* used to build a more specific response.
* @param operation operation
* @param path path operated on (may be null)
* @param exception amazon exception raised
* @return an IOE which wraps the caught exception.
*/
@SuppressWarnings("ThrowableInstanceNeverThrown")
public static IOException translateException(@Nullable String operation,
String path,
SdkBaseException exception) {
String message = String.format("%s%s: %s",
operation,
path != null ? (" on " + path) : "",
exception);
if (!(exception instanceof AmazonServiceException)) {
Exception innerCause = containsInterruptedException(exception);
if (innerCause != null) {
// interrupted IO, or a socket exception underneath that class
return translateInterruptedException(exception, innerCause, message);
}
if (signifiesConnectionBroken(exception)) {
// call considered an sign of connectivity failure
return (EOFException)new EOFException(message).initCause(exception);
}
if (exception instanceof NoAuthWithAWSException) {
// the exception raised by AWSCredentialProvider list if the
// credentials were not accepted.
return (AccessDeniedException)new AccessDeniedException(path, null,
exception.toString()).initCause(exception);
}
return new AWSClientIOException(message, exception);
} else {
if (exception instanceof AmazonDynamoDBException) {
// special handling for dynamo DB exceptions
return translateDynamoDBException(path, message,
(AmazonDynamoDBException)exception);
}
IOException ioe;
AmazonServiceException ase = (AmazonServiceException) exception;
// this exception is non-null if the service exception is an s3 one
AmazonS3Exception s3Exception = ase instanceof AmazonS3Exception
? (AmazonS3Exception) ase
: null;
int status = ase.getStatusCode();
message = message + ":" + ase.getErrorCode();
switch (status) {
case 301:
case 307:
if (s3Exception != null) {
if (s3Exception.getAdditionalDetails() != null &&
s3Exception.getAdditionalDetails().containsKey(ENDPOINT_KEY)) {
message = String.format("Received permanent redirect response to "
+ "endpoint %s. This likely indicates that the S3 endpoint "
+ "configured in %s does not match the AWS region containing "
+ "the bucket.",
s3Exception.getAdditionalDetails().get(ENDPOINT_KEY), ENDPOINT);
}
ioe = new AWSRedirectException(message, s3Exception);
} else {
ioe = new AWSRedirectException(message, ase);
}
break;
case 400:
ioe = new AWSBadRequestException(message, ase);
break;
// permissions
case 401:
case 403:
ioe = new AccessDeniedException(path, null, message);
ioe.initCause(ase);
break;
// the object isn't there
case 404:
case 410:
ioe = new FileNotFoundException(message);
ioe.initCause(ase);
break;
// out of range. This may happen if an object is overwritten with
// a shorter one while it is being read.
case 416:
ioe = new EOFException(message);
ioe.initCause(ase);
break;
// this has surfaced as a "no response from server" message.
// so rare we haven't replicated it.
// Treating as an idempotent proxy error.
case 443:
case 444:
ioe = new AWSNoResponseException(message, ase);
break;
// throttling
case 503:
ioe = new AWSServiceThrottledException(message, ase);
break;
// internal error
case 500:
ioe = new AWSStatus500Exception(message, ase);
break;
case 200:
if (exception instanceof MultiObjectDeleteException) {
// failure during a bulk delete
return translateMultiObjectDeleteException(message,
(MultiObjectDeleteException) exception);
}
// other 200: FALL THROUGH
default:
// no specific exit code. Choose an IOE subclass based on the class
// of the caught exception
ioe = s3Exception != null
? new AWSS3IOException(message, s3Exception)
: new AWSServiceIOException(message, ase);
break;
}
return ioe;
}
}
/**
* Extract an exception from a failed future, and convert to an IOE.
* @param operation operation which failed
* @param path path operated on (may be null)
* @param ee execution exception
* @return an IOE which can be thrown
*/
public static IOException extractException(String operation,
String path,
ExecutionException ee) {
IOException ioe;
Throwable cause = ee.getCause();
if (cause instanceof AmazonClientException) {
ioe = translateException(operation, path, (AmazonClientException) cause);
} else if (cause instanceof IOException) {
ioe = (IOException) cause;
} else {
ioe = new IOException(operation + " failed: " + cause, cause);
}
return ioe;
}
/**
* Recurse down the exception loop looking for any inner details about
* an interrupted exception.
* @param thrown exception thrown
* @return the actual exception if the operation was an interrupt
*/
static Exception containsInterruptedException(Throwable thrown) {
if (thrown == null) {
return null;
}
if (thrown instanceof InterruptedException ||
thrown instanceof InterruptedIOException ||
thrown instanceof AbortedException) {
return (Exception)thrown;
}
// tail recurse
return containsInterruptedException(thrown.getCause());
}
/**
* Handles translation of interrupted exception. This includes
* preserving the class of the fault for better retry logic
* @param exception outer exception
* @param innerCause inner cause (which is guaranteed to be some form
* of interrupted exception
* @param message message for the new exception.
* @return an IOE which can be rethrown
*/
private static InterruptedIOException translateInterruptedException(
SdkBaseException exception,
final Exception innerCause,
String message) {
InterruptedIOException ioe;
if (innerCause instanceof SocketTimeoutException) {
ioe = new SocketTimeoutException(message);
} else {
String name = innerCause.getClass().getName();
if (name.endsWith(".ConnectTimeoutException")
|| name.endsWith("$ConnectTimeoutException")) {
// TCP connection http timeout from the shaded or unshaded filenames
// com.amazonaws.thirdparty.apache.http.conn.ConnectTimeoutException
ioe = new ConnectTimeoutException(message);
} else {
// any other exception
ioe = new InterruptedIOException(message);
}
}
ioe.initCause(exception);
return ioe;
}
/**
* Is the exception an instance of a throttling exception. That
* is an AmazonServiceException with a 503 response, any
* exception from DynamoDB for limits exceeded, an
* {@link AWSServiceThrottledException},
* or anything which the AWS SDK's RetryUtils considers to be
* a throttling exception.
* @param ex exception to examine
* @return true if it is considered a throttling exception
*/
public static boolean isThrottleException(Exception ex) {
return ex instanceof AWSServiceThrottledException
|| ex instanceof ProvisionedThroughputExceededException
|| ex instanceof LimitExceededException
|| (ex instanceof AmazonServiceException
&& 503 == ((AmazonServiceException)ex).getStatusCode())
|| (ex instanceof SdkBaseException
&& RetryUtils.isThrottlingException((SdkBaseException) ex));
}
/**
* Cue that an AWS exception is likely to be an EOF Exception based
* on the message coming back from an XML/JSON parser. This is likely
* to be brittle, so only a hint.
* @param ex exception
* @return true if this is believed to be a sign the connection was broken.
*/
public static boolean signifiesConnectionBroken(SdkBaseException ex) {
return ex.toString().contains(EOF_MESSAGE_IN_XML_PARSER);
}
/**
* Translate a DynamoDB exception into an IOException.
*
* @param path path in the DDB
* @param message preformatted message for the exception
* @param ddbException exception
* @return an exception to throw.
*/
public static IOException translateDynamoDBException(final String path,
final String message,
final AmazonDynamoDBException ddbException) {
if (isThrottleException(ddbException)) {
return new AWSServiceThrottledException(message, ddbException);
}
if (ddbException instanceof ResourceNotFoundException) {
return (FileNotFoundException) new FileNotFoundException(message)
.initCause(ddbException);
}
final int statusCode = ddbException.getStatusCode();
final String errorCode = ddbException.getErrorCode();
IOException result = null;
// 400 gets used a lot by DDB
if (statusCode == 400) {
switch (errorCode) {
case "AccessDeniedException":
result = (IOException) new AccessDeniedException(
path,
null,
ddbException.toString())
.initCause(ddbException);
break;
default:
result = new AWSBadRequestException(message, ddbException);
}
}
if (result == null) {
result = new AWSServiceIOException(message, ddbException);
}
return result;
}
/**
* A MultiObjectDeleteException is raised if one or more delete objects
* listed in a bulk DELETE operation failed.
* The top-level exception is therefore just "something wasn't deleted",
* but doesn't include the what or the why.
* This translation will extract an AccessDeniedException if that's one of
* the causes, otherwise grabs the status code and uses it in the
* returned exception.
* @param message text for the exception
* @param ex exception to translate
* @return an IOE with more detail.
*/
public static IOException translateMultiObjectDeleteException(String message,
MultiObjectDeleteException ex) {
List keys;
StringBuffer result = new StringBuffer(ex.getErrors().size() * 100);
result.append(message).append(": ");
String exitCode = "";
for (MultiObjectDeleteException.DeleteError error : ex.getErrors()) {
String code = error.getCode();
result.append(String.format("%s: %s: %s%n", code, error.getKey(),
error.getMessage()));
if (exitCode.isEmpty() || "AccessDenied".equals(code)) {
exitCode = code;
}
}
if ("AccessDenied".equals(exitCode)) {
return (IOException) new AccessDeniedException(result.toString())
.initCause(ex);
} else {
return new AWSS3IOException(result.toString(), ex);
}
}
/**
* Get low level details of an amazon exception for logging; multi-line.
* @param e exception
* @return string details
*/
public static String stringify(AmazonServiceException e) {
StringBuilder builder = new StringBuilder(
String.format("%s: %s error %d: %s; %s%s%n",
e.getErrorType(),
e.getServiceName(),
e.getStatusCode(),
e.getErrorCode(),
e.getErrorMessage(),
(e.isRetryable() ? " (retryable)": "")
));
String rawResponseContent = e.getRawResponseContent();
if (rawResponseContent != null) {
builder.append(rawResponseContent);
}
return builder.toString();
}
/**
* Get low level details of an amazon exception for logging; multi-line.
* @param e exception
* @return string details
*/
public static String stringify(AmazonS3Exception e) {
// get the low level details of an exception,
StringBuilder builder = new StringBuilder(
stringify((AmazonServiceException) e));
Map details = e.getAdditionalDetails();
if (details != null) {
builder.append('\n');
for (Map.Entry d : details.entrySet()) {
builder.append(d.getKey()).append('=')
.append(d.getValue()).append('\n');
}
}
return builder.toString();
}
/**
* Create a files status instance from a listing.
* @param keyPath path to entry
* @param summary summary from AWS
* @param blockSize block size to declare.
* @param owner owner of the file
* @return a status entry
*/
public static S3AFileStatus createFileStatus(Path keyPath,
S3ObjectSummary summary,
long blockSize,
String owner) {
long size = summary.getSize();
return createFileStatus(keyPath,
objectRepresentsDirectory(summary.getKey(), size),
size, summary.getLastModified(), blockSize, owner);
}
/**
* Create a file status for object we just uploaded. For files, we use
* current time as modification time, since s3a uses S3's service-based
* modification time, which will not be available until we do a
* getFileStatus() later on.
* @param keyPath path for created object
* @param isDir true iff directory
* @param size file length
* @param blockSize block size for file status
* @param owner Hadoop username
* @return a status entry
*/
public static S3AFileStatus createUploadFileStatus(Path keyPath,
boolean isDir, long size, long blockSize, String owner) {
Date date = isDir ? null : new Date();
return createFileStatus(keyPath, isDir, size, date, blockSize, owner);
}
/* Date 'modified' is ignored when isDir is true. */
private static S3AFileStatus createFileStatus(Path keyPath, boolean isDir,
long size, Date modified, long blockSize, String owner) {
if (isDir) {
return new S3AFileStatus(Tristate.UNKNOWN, keyPath, owner);
} else {
return new S3AFileStatus(size, dateToLong(modified), keyPath, blockSize,
owner);
}
}
/**
* Predicate: does the object represent a directory?.
* @param name object name
* @param size object size
* @return true if it meets the criteria for being an object
*/
public static boolean objectRepresentsDirectory(final String name,
final long size) {
return !name.isEmpty()
&& name.charAt(name.length() - 1) == '/'
&& size == 0L;
}
/**
* Date to long conversion.
* Handles null Dates that can be returned by AWS by returning 0
* @param date date from AWS query
* @return timestamp of the object
*/
public static long dateToLong(final Date date) {
if (date == null) {
return 0L;
}
return date.getTime();
}
/**
* Create the AWS credentials from the providers, the URI and
* the key {@link Constants#AWS_CREDENTIALS_PROVIDER} in the configuration.
* @param binding Binding URI, may contain user:pass login details;
* may be null
* @param conf filesystem configuration
* @return a credentials provider list
* @throws IOException Problems loading the providers (including reading
* secrets from credential files).
*/
public static AWSCredentialProviderList createAWSCredentialProviderSet(
URI binding, Configuration conf) throws IOException {
AWSCredentialProviderList credentials = new AWSCredentialProviderList();
Class[] awsClasses = loadAWSProviderClasses(conf,
AWS_CREDENTIALS_PROVIDER);
if (awsClasses.length == 0) {
credentials.add(new SimpleAWSCredentialsProvider(binding, conf));
credentials.add(new EnvironmentVariableCredentialsProvider());
credentials.add(InstanceProfileCredentialsProvider.getInstance());
} else {
for (Class aClass : awsClasses) {
credentials.add(createAWSCredentialProvider(conf,
aClass,
binding));
}
}
// make sure the logging message strips out any auth details
LOG.debug("For URI {}, using credentials {}",
S3xLoginHelper.toString(binding), credentials);
return credentials;
}
/**
* Load list of AWS credential provider/credential provider factory classes.
* @param conf configuration
* @param key key
* @param defaultValue list of default values
* @return the list of classes, possibly empty
* @throws IOException on a failure to load the list.
*/
public static Class[] loadAWSProviderClasses(Configuration conf,
String key,
Class... defaultValue) throws IOException {
try {
return conf.getClasses(key, defaultValue);
} catch (RuntimeException e) {
Throwable c = e.getCause() != null ? e.getCause() : e;
throw new IOException("From option " + key + ' ' + c, c);
}
}
/**
* Create an AWS credential provider from its class by using reflection. The
* class must implement one of the following means of construction, which are
* attempted in order:
*
*
* - a public constructor accepting java.net.URI and
* org.apache.hadoop.conf.Configuration
* - a public static method named getInstance that accepts no
* arguments and returns an instance of
* com.amazonaws.auth.AWSCredentialsProvider, or
* - a public default constructor.
*
*
* @param conf configuration
* @param credClass credential class
* @param uri URI of the FS
* @return the instantiated class
* @throws IOException on any instantiation failure.
*/
public static AWSCredentialsProvider createAWSCredentialProvider(
Configuration conf,
Class credClass,
URI uri) throws IOException {
AWSCredentialsProvider credentials;
String className = credClass.getName();
if (!AWSCredentialsProvider.class.isAssignableFrom(credClass)) {
throw new IOException("Class " + credClass + " " + NOT_AWS_PROVIDER);
}
if (Modifier.isAbstract(credClass.getModifiers())) {
throw new IOException("Class " + credClass + " " + ABSTRACT_PROVIDER);
}
LOG.debug("Credential provider class is {}", className);
try {
// new X(uri, conf)
Constructor cons = getConstructor(credClass, URI.class,
Configuration.class);
if (cons != null) {
credentials = (AWSCredentialsProvider)cons.newInstance(uri, conf);
return credentials;
}
// new X(conf)
cons = getConstructor(credClass, Configuration.class);
if (cons != null) {
credentials = (AWSCredentialsProvider)cons.newInstance(conf);
return credentials;
}
// X.getInstance()
Method factory = getFactoryMethod(credClass, AWSCredentialsProvider.class,
"getInstance");
if (factory != null) {
credentials = (AWSCredentialsProvider)factory.invoke(null);
return credentials;
}
// new X()
cons = getConstructor(credClass);
if (cons != null) {
credentials = (AWSCredentialsProvider)cons.newInstance();
return credentials;
}
// no supported constructor or factory method found
throw new IOException(String.format("%s " + CONSTRUCTOR_EXCEPTION
+ ". A class specified in %s must provide a public constructor "
+ "accepting Configuration, or a public factory method named "
+ "getInstance that accepts no arguments, or a public default "
+ "constructor.", className, AWS_CREDENTIALS_PROVIDER));
} catch (InvocationTargetException e) {
Throwable targetException = e.getTargetException();
if (targetException == null) {
targetException = e;
}
if (targetException instanceof IOException) {
throw (IOException) targetException;
} else if (targetException instanceof SdkBaseException) {
throw translateException("Instantiate " + className, "",
(SdkBaseException) targetException);
} else {
// supported constructor or factory method found, but the call failed
throw new IOException(className + " " + INSTANTIATION_EXCEPTION
+ ": " + targetException,
targetException);
}
} catch (ReflectiveOperationException | IllegalArgumentException e) {
// supported constructor or factory method found, but the call failed
throw new IOException(className + " " + INSTANTIATION_EXCEPTION
+ ": " + e,
e);
}
}
/**
* Return the access key and secret for S3 API use.
* or indicated in the UserInfo of the name URI param.
* @param name the URI for which we need the access keys; may be null
* @param conf the Configuration object to interrogate for keys.
* @return AWSAccessKeys
* @throws IOException problems retrieving passwords from KMS.
*/
public static S3xLoginHelper.Login getAWSAccessKeys(URI name,
Configuration conf) throws IOException {
S3xLoginHelper.rejectSecretsInURIs(name);
Configuration c = ProviderUtils.excludeIncompatibleCredentialProviders(
conf, S3AFileSystem.class);
String bucket = name != null ? name.getHost() : "";
// get the secrets from the configuration
// get the access key
String accessKey = lookupPassword(bucket, c, ACCESS_KEY);
// and the secret
String secretKey = lookupPassword(bucket, c, SECRET_KEY);
return new S3xLoginHelper.Login(accessKey, secretKey);
}
/**
* Get a password from a configuration, including JCEKS files, handling both
* the absolute key and bucket override.
* @param bucket bucket or "" if none known
* @param conf configuration
* @param baseKey base key to look up, e.g "fs.s3a.secret.key"
* @param overrideVal override value: if non empty this is used instead of
* querying the configuration.
* @return a password or "".
* @throws IOException on any IO problem
* @throws IllegalArgumentException bad arguments
*/
@Deprecated
public static String lookupPassword(
String bucket,
Configuration conf,
String baseKey,
String overrideVal)
throws IOException {
return lookupPassword(bucket, conf, baseKey, overrideVal, "");
}
/**
* Get a password from a configuration, including JCEKS files, handling both
* the absolute key and bucket override.
* @param bucket bucket or "" if none known
* @param conf configuration
* @param baseKey base key to look up, e.g "fs.s3a.secret.key"
* @return a password or "".
* @throws IOException on any IO problem
* @throws IllegalArgumentException bad arguments
*/
public static String lookupPassword(
String bucket,
Configuration conf,
String baseKey)
throws IOException {
return lookupPassword(bucket, conf, baseKey, null, "");
}
/**
* Get a password from a configuration, including JCEKS files, handling both
* the absolute key and bucket override.
* @param bucket bucket or "" if none known
* @param conf configuration
* @param baseKey base key to look up, e.g "fs.s3a.secret.key"
* @param overrideVal override value: if non empty this is used instead of
* querying the configuration.
* @param defVal value to return if there is no password
* @return a password or the value of defVal.
* @throws IOException on any IO problem
* @throws IllegalArgumentException bad arguments
*/
public static String lookupPassword(
String bucket,
Configuration conf,
String baseKey,
String overrideVal,
String defVal)
throws IOException {
String initialVal;
Preconditions.checkArgument(baseKey.startsWith(FS_S3A_PREFIX),
String.format("%s does not start with $%s", baseKey, FS_S3A_PREFIX));
// if there's a bucket, work with it
if (StringUtils.isNotEmpty(bucket)) {
String subkey = baseKey.substring(FS_S3A_PREFIX.length());
String shortBucketKey = String.format(
BUCKET_PATTERN, bucket, subkey);
String longBucketKey = String.format(
BUCKET_PATTERN, bucket, baseKey);
// set from the long key unless overidden.
initialVal = getPassword(conf, longBucketKey, overrideVal);
// then override from the short one if it is set
initialVal = getPassword(conf, shortBucketKey, initialVal);
} else {
// no bucket, make the initial value the override value
initialVal = overrideVal;
}
return getPassword(conf, baseKey, initialVal, defVal);
}
/**
* Get a password from a configuration, or, if a value is passed in,
* pick that up instead.
* @param conf configuration
* @param key key to look up
* @param val current value: if non empty this is used instead of
* querying the configuration.
* @return a password or "".
* @throws IOException on any problem
*/
private static String getPassword(Configuration conf, String key, String val)
throws IOException {
return getPassword(conf, key, val, "");
}
/**
* Get a password from a configuration, or, if a value is passed in,
* pick that up instead.
* @param conf configuration
* @param key key to look up
* @param val current value: if non empty this is used instead of
* querying the configuration.
* @param defVal default value if nothing is set
* @return a password or "".
* @throws IOException on any problem
*/
private static String getPassword(Configuration conf,
String key,
String val,
String defVal) throws IOException {
return StringUtils.isEmpty(val)
? lookupPassword(conf, key, defVal)
: val;
}
/**
* Get a password from a configuration/configured credential providers.
* @param conf configuration
* @param key key to look up
* @param defVal value to return if there is no password
* @return a password or the value in {@code defVal}
* @throws IOException on any problem
*/
static String lookupPassword(Configuration conf, String key, String defVal)
throws IOException {
try {
final char[] pass = conf.getPassword(key);
return pass != null ?
new String(pass).trim()
: defVal;
} catch (IOException ioe) {
throw new IOException("Cannot find password option " + key, ioe);
}
}
/**
* String information about a summary entry for debug messages.
* @param summary summary object
* @return string value
*/
public static String stringify(S3ObjectSummary summary) {
StringBuilder builder = new StringBuilder(summary.getKey().length() + 100);
builder.append(summary.getKey()).append(' ');
builder.append("size=").append(summary.getSize());
return builder.toString();
}
/**
* Get a integer option >= the minimum allowed value.
* @param conf configuration
* @param key key to look up
* @param defVal default value
* @param min minimum value
* @return the value
* @throws IllegalArgumentException if the value is below the minimum
*/
static int intOption(Configuration conf, String key, int defVal, int min) {
int v = conf.getInt(key, defVal);
Preconditions.checkArgument(v >= min,
String.format("Value of %s: %d is below the minimum value %d",
key, v, min));
LOG.debug("Value of {} is {}", key, v);
return v;
}
/**
* Get a long option >= the minimum allowed value.
* @param conf configuration
* @param key key to look up
* @param defVal default value
* @param min minimum value
* @return the value
* @throws IllegalArgumentException if the value is below the minimum
*/
static long longOption(Configuration conf,
String key,
long defVal,
long min) {
long v = conf.getLong(key, defVal);
Preconditions.checkArgument(v >= min,
String.format("Value of %s: %d is below the minimum value %d",
key, v, min));
LOG.debug("Value of {} is {}", key, v);
return v;
}
/**
* Get a long option >= the minimum allowed value, supporting memory
* prefixes K,M,G,T,P.
* @param conf configuration
* @param key key to look up
* @param defVal default value
* @param min minimum value
* @return the value
* @throws IllegalArgumentException if the value is below the minimum
*/
public static long longBytesOption(Configuration conf,
String key,
long defVal,
long min) {
long v = conf.getLongBytes(key, defVal);
Preconditions.checkArgument(v >= min,
String.format("Value of %s: %d is below the minimum value %d",
key, v, min));
LOG.debug("Value of {} is {}", key, v);
return v;
}
/**
* Get a size property from the configuration: this property must
* be at least equal to {@link Constants#MULTIPART_MIN_SIZE}.
* If it is too small, it is rounded up to that minimum, and a warning
* printed.
* @param conf configuration
* @param property property name
* @param defVal default value
* @return the value, guaranteed to be above the minimum size
*/
public static long getMultipartSizeProperty(Configuration conf,
String property, long defVal) {
long partSize = conf.getLongBytes(property, defVal);
if (partSize < MULTIPART_MIN_SIZE) {
LOG.warn("{} must be at least 5 MB; configured value is {}",
property, partSize);
partSize = MULTIPART_MIN_SIZE;
}
return partSize;
}
/**
* Ensure that the long value is in the range of an integer.
* @param name property name for error messages
* @param size original size
* @return the size, guaranteed to be less than or equal to the max
* value of an integer.
*/
public static int ensureOutputParameterInRange(String name, long size) {
if (size > Integer.MAX_VALUE) {
LOG.warn("s3a: {} capped to ~2.14GB" +
" (maximum allowed size with current output mechanism)", name);
return Integer.MAX_VALUE;
} else {
return (int)size;
}
}
/**
* Returns the public constructor of {@code cl} specified by the list of
* {@code args} or {@code null} if {@code cl} has no public constructor that
* matches that specification.
* @param cl class
* @param args constructor argument types
* @return constructor or null
*/
private static Constructor getConstructor(Class cl, Class... args) {
try {
Constructor cons = cl.getDeclaredConstructor(args);
return Modifier.isPublic(cons.getModifiers()) ? cons : null;
} catch (NoSuchMethodException | SecurityException e) {
return null;
}
}
/**
* Returns the public static method of {@code cl} that accepts no arguments
* and returns {@code returnType} specified by {@code methodName} or
* {@code null} if {@code cl} has no public static method that matches that
* specification.
* @param cl class
* @param returnType return type
* @param methodName method name
* @return method or null
*/
private static Method getFactoryMethod(Class cl, Class returnType,
String methodName) {
try {
Method m = cl.getDeclaredMethod(methodName);
if (Modifier.isPublic(m.getModifiers()) &&
Modifier.isStatic(m.getModifiers()) &&
returnType.isAssignableFrom(m.getReturnType())) {
return m;
} else {
return null;
}
} catch (NoSuchMethodException | SecurityException e) {
return null;
}
}
/**
* Propagates bucket-specific settings into generic S3A configuration keys.
* This is done by propagating the values of the form
* {@code fs.s3a.bucket.${bucket}.key} to
* {@code fs.s3a.key}, for all values of "key" other than a small set
* of unmodifiable values.
*
* The source of the updated property is set to the key name of the bucket
* property, to aid in diagnostics of where things came from.
*
* Returns a new configuration. Why the clone?
* You can use the same conf for different filesystems, and the original
* values are not updated.
*
* The {@code fs.s3a.impl} property cannot be set, nor can
* any with the prefix {@code fs.s3a.bucket}.
*
* This method does not propagate security provider path information from
* the S3A property into the Hadoop common provider: callers must call
* {@link #patchSecurityCredentialProviders(Configuration)} explicitly.
* @param source Source Configuration object.
* @param bucket bucket name. Must not be empty.
* @return a (potentially) patched clone of the original.
*/
public static Configuration propagateBucketOptions(Configuration source,
String bucket) {
Preconditions.checkArgument(StringUtils.isNotEmpty(bucket), "bucket");
final String bucketPrefix = FS_S3A_BUCKET_PREFIX + bucket +'.';
LOG.debug("Propagating entries under {}", bucketPrefix);
final Configuration dest = new Configuration(source);
for (Map.Entry entry : source) {
final String key = entry.getKey();
// get the (unexpanded) value.
final String value = entry.getValue();
if (!key.startsWith(bucketPrefix) || bucketPrefix.equals(key)) {
continue;
}
// there's a bucket prefix, so strip it
final String stripped = key.substring(bucketPrefix.length());
if (stripped.startsWith("bucket.") || "impl".equals(stripped)) {
//tell user off
LOG.debug("Ignoring bucket option {}", key);
} else {
// propagate the value, building a new origin field.
// to track overwrites, the generic key is overwritten even if
// already matches the new one.
String origin = "[" + StringUtils.join(
source.getPropertySources(key), ", ") +"]";
final String generic = FS_S3A_PREFIX + stripped;
LOG.debug("Updating {} from {}", generic, origin);
dest.set(generic, value, key + " via " + origin);
}
}
return dest;
}
/**
* Delete a path quietly: failures are logged at DEBUG.
* @param fs filesystem
* @param path path
* @param recursive recursive?
*/
public static void deleteQuietly(FileSystem fs,
Path path,
boolean recursive) {
try {
fs.delete(path, recursive);
} catch (IOException e) {
LOG.debug("Failed to delete {}", path, e);
}
}
/**
* Delete a path: failures are logged at WARN.
* @param fs filesystem
* @param path path
* @param recursive recursive?
*/
public static void deleteWithWarning(FileSystem fs,
Path path,
boolean recursive) {
try {
fs.delete(path, recursive);
} catch (IOException e) {
LOG.warn("Failed to delete {}", path, e);
}
}
/**
* Create a new AWS {@code ClientConfiguration}.
* All clients to AWS services MUST use this for consistent setup
* of connectivity, UA, proxy settings.
* @param conf The Hadoop configuration
* @param bucket Optional bucket to use to look up per-bucket proxy secrets
* @return new AWS client configuration
*/
public static ClientConfiguration createAwsConf(Configuration conf,
String bucket)
throws IOException {
final ClientConfiguration awsConf = new ClientConfiguration();
initConnectionSettings(conf, awsConf);
initProxySupport(conf, bucket, awsConf);
initUserAgent(conf, awsConf);
return awsConf;
}
/**
* Initializes all AWS SDK settings related to connection management.
*
* @param conf Hadoop configuration
* @param awsConf AWS SDK configuration
*/
public static void initConnectionSettings(Configuration conf,
ClientConfiguration awsConf) {
awsConf.setMaxConnections(intOption(conf, MAXIMUM_CONNECTIONS,
DEFAULT_MAXIMUM_CONNECTIONS, 1));
boolean secureConnections = conf.getBoolean(SECURE_CONNECTIONS,
DEFAULT_SECURE_CONNECTIONS);
awsConf.setProtocol(secureConnections ? Protocol.HTTPS : Protocol.HTTP);
awsConf.setMaxErrorRetry(intOption(conf, MAX_ERROR_RETRIES,
DEFAULT_MAX_ERROR_RETRIES, 0));
awsConf.setConnectionTimeout(intOption(conf, ESTABLISH_TIMEOUT,
DEFAULT_ESTABLISH_TIMEOUT, 0));
awsConf.setSocketTimeout(intOption(conf, SOCKET_TIMEOUT,
DEFAULT_SOCKET_TIMEOUT, 0));
int sockSendBuffer = intOption(conf, SOCKET_SEND_BUFFER,
DEFAULT_SOCKET_SEND_BUFFER, 2048);
int sockRecvBuffer = intOption(conf, SOCKET_RECV_BUFFER,
DEFAULT_SOCKET_RECV_BUFFER, 2048);
awsConf.setSocketBufferSizeHints(sockSendBuffer, sockRecvBuffer);
String signerOverride = conf.getTrimmed(SIGNING_ALGORITHM, "");
if (!signerOverride.isEmpty()) {
LOG.debug("Signer override = {}", signerOverride);
awsConf.setSignerOverride(signerOverride);
}
}
/**
* Initializes AWS SDK proxy support in the AWS client configuration
* if the S3A settings enable it.
*
* @param conf Hadoop configuration
* @param bucket Optional bucket to use to look up per-bucket proxy secrets
* @param awsConf AWS SDK configuration to update
* @throws IllegalArgumentException if misconfigured
* @throws IOException problem getting username/secret from password source.
*/
public static void initProxySupport(Configuration conf,
String bucket,
ClientConfiguration awsConf) throws IllegalArgumentException,
IOException {
String proxyHost = conf.getTrimmed(PROXY_HOST, "");
int proxyPort = conf.getInt(PROXY_PORT, -1);
if (!proxyHost.isEmpty()) {
awsConf.setProxyHost(proxyHost);
if (proxyPort >= 0) {
awsConf.setProxyPort(proxyPort);
} else {
if (conf.getBoolean(SECURE_CONNECTIONS, DEFAULT_SECURE_CONNECTIONS)) {
LOG.warn("Proxy host set without port. Using HTTPS default 443");
awsConf.setProxyPort(443);
} else {
LOG.warn("Proxy host set without port. Using HTTP default 80");
awsConf.setProxyPort(80);
}
}
final String proxyUsername = lookupPassword(bucket, conf, PROXY_USERNAME,
null, null);
final String proxyPassword = lookupPassword(bucket, conf, PROXY_PASSWORD,
null, null);
if ((proxyUsername == null) != (proxyPassword == null)) {
String msg = "Proxy error: " + PROXY_USERNAME + " or " +
PROXY_PASSWORD + " set without the other.";
LOG.error(msg);
throw new IllegalArgumentException(msg);
}
awsConf.setProxyUsername(proxyUsername);
awsConf.setProxyPassword(proxyPassword);
awsConf.setProxyDomain(conf.getTrimmed(PROXY_DOMAIN));
awsConf.setProxyWorkstation(conf.getTrimmed(PROXY_WORKSTATION));
if (LOG.isDebugEnabled()) {
LOG.debug("Using proxy server {}:{} as user {} with password {} on " +
"domain {} as workstation {}", awsConf.getProxyHost(),
awsConf.getProxyPort(),
String.valueOf(awsConf.getProxyUsername()),
awsConf.getProxyPassword(), awsConf.getProxyDomain(),
awsConf.getProxyWorkstation());
}
} else if (proxyPort >= 0) {
String msg =
"Proxy error: " + PROXY_PORT + " set without " + PROXY_HOST;
LOG.error(msg);
throw new IllegalArgumentException(msg);
}
}
/**
* Initializes the User-Agent header to send in HTTP requests to AWS
* services. We always include the Hadoop version number. The user also
* may set an optional custom prefix to put in front of the Hadoop version
* number. The AWS SDK internally appends its own information, which seems
* to include the AWS SDK version, OS and JVM version.
*
* @param conf Hadoop configuration
* @param awsConf AWS SDK configuration to update
*/
private static void initUserAgent(Configuration conf,
ClientConfiguration awsConf) {
String userAgent = "Hadoop " + VersionInfo.getVersion();
String userAgentPrefix = conf.getTrimmed(USER_AGENT_PREFIX, "");
if (!userAgentPrefix.isEmpty()) {
userAgent = userAgentPrefix + ", " + userAgent;
}
LOG.debug("Using User-Agent: {}", userAgent);
awsConf.setUserAgentPrefix(userAgent);
}
/**
* An interface for use in lambda-expressions working with
* directory tree listings.
*/
@FunctionalInterface
public interface CallOnLocatedFileStatus {
void call(LocatedFileStatus status) throws IOException;
}
/**
* An interface for use in lambda-expressions working with
* directory tree listings.
*/
@FunctionalInterface
public interface LocatedFileStatusMap {
T call(LocatedFileStatus status) throws IOException;
}
/**
* Apply an operation to every {@link LocatedFileStatus} in a remote
* iterator.
* @param iterator iterator from a list
* @param eval closure to evaluate
* @return the number of files processed
* @throws IOException anything in the closure, or iteration logic.
*/
public static long applyLocatedFiles(
RemoteIterator iterator,
CallOnLocatedFileStatus eval) throws IOException {
long count = 0;
while (iterator.hasNext()) {
count++;
eval.call(iterator.next());
}
return count;
}
/**
* Map an operation to every {@link LocatedFileStatus} in a remote
* iterator, returning a list of the results.
* @param return type of map
* @param iterator iterator from a list
* @param eval closure to evaluate
* @return the list of mapped results.
* @throws IOException anything in the closure, or iteration logic.
*/
public static List mapLocatedFiles(
RemoteIterator iterator,
LocatedFileStatusMap eval) throws IOException {
final List results = new ArrayList<>();
applyLocatedFiles(iterator,
(s) -> results.add(eval.call(s)));
return results;
}
/**
* Map an operation to every {@link LocatedFileStatus} in a remote
* iterator, returning a list of the all results which were not empty.
* @param return type of map
* @param iterator iterator from a list
* @param eval closure to evaluate
* @return the flattened list of mapped results.
* @throws IOException anything in the closure, or iteration logic.
*/
public static List flatmapLocatedFiles(
RemoteIterator iterator,
LocatedFileStatusMap> eval) throws IOException {
final List results = new ArrayList<>();
applyLocatedFiles(iterator,
(s) -> eval.call(s).map(r -> results.add(r)));
return results;
}
/**
* List located files and filter them as a classic listFiles(path, filter)
* would do.
* @param fileSystem filesystem
* @param path path to list
* @param recursive recursive listing?
* @param filter filter for the filename
* @return the filtered list of entries
* @throws IOException IO failure.
*/
public static List listAndFilter(FileSystem fileSystem,
Path path, boolean recursive, PathFilter filter) throws IOException {
return flatmapLocatedFiles(fileSystem.listFiles(path, recursive),
status -> maybe(filter.accept(status.getPath()), status));
}
/**
* Convert a value into a non-empty Optional instance if
* the value of {@code include} is true.
* @param include flag to indicate the value is to be included.
* @param value value to return
* @param type of option.
* @return if include is false, Optional.empty. Otherwise, the value.
*/
public static Optional maybe(boolean include, T value) {
return include ? Optional.of(value) : Optional.empty();
}
/**
* Patch the security credential provider information in
* {@link #CREDENTIAL_PROVIDER_PATH}
* with the providers listed in
* {@link Constants#S3A_SECURITY_CREDENTIAL_PROVIDER_PATH}.
*
* This allows different buckets to use different credential files.
* @param conf configuration to patch
*/
static void patchSecurityCredentialProviders(Configuration conf) {
Collection customCredentials = conf.getStringCollection(
S3A_SECURITY_CREDENTIAL_PROVIDER_PATH);
Collection hadoopCredentials = conf.getStringCollection(
CREDENTIAL_PROVIDER_PATH);
if (!customCredentials.isEmpty()) {
List all = Lists.newArrayList(customCredentials);
all.addAll(hadoopCredentials);
String joined = StringUtils.join(all, ',');
LOG.debug("Setting {} to {}", CREDENTIAL_PROVIDER_PATH,
joined);
conf.set(CREDENTIAL_PROVIDER_PATH, joined,
"patch of " + S3A_SECURITY_CREDENTIAL_PROVIDER_PATH);
}
}
/**
* Get any SSE key from a configuration/credential provider.
* This operation handles the case where the option has been
* set in the provider or configuration to the option
* {@code OLD_S3A_SERVER_SIDE_ENCRYPTION_KEY}.
* IOExceptions raised during retrieval are swallowed.
* @param bucket bucket to query for
* @param conf configuration to examine
* @return the encryption key or ""
* @throws IllegalArgumentException bad arguments.
*/
static String getServerSideEncryptionKey(String bucket,
Configuration conf) {
try {
return lookupPassword(bucket, conf, SERVER_SIDE_ENCRYPTION_KEY);
} catch (IOException e) {
LOG.error("Cannot retrieve " + SERVER_SIDE_ENCRYPTION_KEY, e);
return "";
}
}
/**
* Get the server-side encryption algorithm.
* This includes validation of the configuration, checking the state of
* the encryption key given the chosen algorithm.
*
* @param bucket bucket to query for
* @param conf configuration to scan
* @return the encryption mechanism (which will be {@code NONE} unless
* one is set.
* @throws IOException on any validation problem.
*/
static S3AEncryptionMethods getEncryptionAlgorithm(String bucket,
Configuration conf) throws IOException {
S3AEncryptionMethods sse = S3AEncryptionMethods.getMethod(
lookupPassword(bucket, conf,
SERVER_SIDE_ENCRYPTION_ALGORITHM));
String sseKey = getServerSideEncryptionKey(bucket, conf);
int sseKeyLen = StringUtils.isBlank(sseKey) ? 0 : sseKey.length();
String diagnostics = passwordDiagnostics(sseKey, "key");
switch (sse) {
case SSE_C:
if (sseKeyLen == 0) {
throw new IOException(SSE_C_NO_KEY_ERROR);
}
break;
case SSE_S3:
if (sseKeyLen != 0) {
throw new IOException(SSE_S3_WITH_KEY_ERROR
+ " (" + diagnostics + ")");
}
break;
case SSE_KMS:
LOG.debug("Using SSE-KMS with {}",
diagnostics);
break;
case NONE:
default:
LOG.debug("Data is unencrypted");
break;
}
LOG.debug("Using SSE-C with {}", diagnostics);
return sse;
}
/**
* Provide a password diagnostics string.
* This aims to help diagnostics without revealing significant password details
* @param pass password
* @param description description for text, e.g "key" or "password"
* @return text for use in messages.
*/
private static String passwordDiagnostics(String pass, String description) {
if (pass == null) {
return "null " + description;
}
int len = pass.length();
switch (len) {
case 0:
return "empty " + description;
case 1:
return description + " of length 1";
default:
return description + " of length " + len + " ending with "
+ pass.charAt(len - 1);
}
}
/**
* Close the Closeable objects and ignore any Exception or
* null pointers.
* (This is the SLF4J equivalent of that in {@code IOUtils}).
* @param log the log to log at debug level. Can be null.
* @param closeables the objects to close
*/
public static void closeAll(Logger log,
Closeable... closeables) {
if (log == null) {
log = LOG;
}
for (Closeable c : closeables) {
if (c != null) {
try {
log.debug("Closing {}", c);
c.close();
} catch (Exception e) {
log.debug("Exception in closing {}", c, e);
}
}
}
}
/**
* Close the Closeable objects and ignore any Exception or
* null pointers.
* (This is the SLF4J equivalent of that in {@code IOUtils}).
* @param log the log to log at debug level. Can be null.
* @param closeables the objects to close
*/
public static void closeAutocloseables(Logger log,
AutoCloseable... closeables) {
if (log == null) {
log = LOG;
}
for (AutoCloseable c : closeables) {
if (c != null) {
try {
log.debug("Closing {}", c);
c.close();
} catch (Exception e) {
log.debug("Exception in closing {}", c, e);
}
}
}
}
/**
* Set a bucket-specific property to a particular value.
* If the generic key passed in has an {@code fs.s3a. prefix},
* that's stripped off, so that when the the bucket properties are propagated
* down to the generic values, that value gets copied down.
* @param conf configuration to set
* @param bucket bucket name
* @param genericKey key; can start with "fs.s3a."
* @param value value to set
*/
public static void setBucketOption(Configuration conf, String bucket,
String genericKey, String value) {
final String baseKey = genericKey.startsWith(FS_S3A_PREFIX) ?
genericKey.substring(FS_S3A_PREFIX.length())
: genericKey;
conf.set(FS_S3A_BUCKET_PREFIX + bucket + '.' + baseKey, value, "S3AUtils");
}
/**
* Clear a bucket-specific property.
* If the generic key passed in has an {@code fs.s3a. prefix},
* that's stripped off, so that when the the bucket properties are propagated
* down to the generic values, that value gets copied down.
* @param conf configuration to set
* @param bucket bucket name
* @param genericKey key; can start with "fs.s3a."
*/
public static void clearBucketOption(Configuration conf, String bucket,
String genericKey) {
final String baseKey = genericKey.startsWith(FS_S3A_PREFIX) ?
genericKey.substring(FS_S3A_PREFIX.length())
: genericKey;
String k = FS_S3A_BUCKET_PREFIX + bucket + '.' + baseKey;
LOG.debug("Unset {}", k);
conf.unset(k);
}
/**
* Get a bucket-specific property.
* If the generic key passed in has an {@code fs.s3a. prefix},
* that's stripped off.
* @param conf configuration to set
* @param bucket bucket name
* @param genericKey key; can start with "fs.s3a."
* @return the bucket option, null if there is none
*/
public static String getBucketOption(Configuration conf, String bucket,
String genericKey) {
final String baseKey = genericKey.startsWith(FS_S3A_PREFIX) ?
genericKey.substring(FS_S3A_PREFIX.length())
: genericKey;
return conf.get(FS_S3A_BUCKET_PREFIX + bucket + '.' + baseKey);
}
/**
* Path filter which ignores any file which starts with . or _.
*/
public static final PathFilter HIDDEN_FILE_FILTER = new PathFilter() {
@Override
public boolean accept(Path path) {
String name = path.getName();
return !name.startsWith("_") && !name.startsWith(".");
}
@Override
public String toString() {
return "HIDDEN_FILE_FILTER";
}
};
/**
* A Path filter which accepts all filenames.
*/
public static final PathFilter ACCEPT_ALL = new PathFilter() {
@Override
public boolean accept(Path file) {
return true;
}
@Override
public String toString() {
return "ACCEPT_ALL";
}
};
}