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/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.underfs;
import alluxio.AlluxioURI;
import alluxio.SyncInfo;
import alluxio.annotation.PublicApi;
import alluxio.collections.Pair;
import alluxio.conf.AlluxioConfiguration;
import alluxio.conf.PropertyKey;
import alluxio.recorder.Recorder;
import alluxio.security.authorization.AccessControlList;
import alluxio.security.authorization.AclEntry;
import alluxio.security.authorization.DefaultAccessControlList;
import alluxio.underfs.options.CreateOptions;
import alluxio.underfs.options.DeleteOptions;
import alluxio.underfs.options.FileLocationOptions;
import alluxio.underfs.options.ListOptions;
import alluxio.underfs.options.MkdirsOptions;
import alluxio.underfs.options.OpenOptions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.Closeable;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;
/**
* Alluxio stores data into an under layer file system. Any file system implementing this interface
* can be a valid under layer file system.
*
* There are two sets of APIs in the under file system:
* (1) normal operations (e.g. create, renameFile, deleteFile)
* (2) operations deal with the eventual consistency issue
* (e.g. createNonexistingFile, renameRenamableFile)
* When confirmed by Alluxio metadata that an operation should succeed but may fail because of the
* under filesystem eventual consistency issue, use the second set of APIs.
*/
@PublicApi
@ThreadSafe
// TODO(adit); API calls should use a URI instead of a String wherever appropriate
public interface UnderFileSystem extends Closeable {
/**
* The factory for the {@link UnderFileSystem}.
*/
class Factory {
private static final Logger LOG = LoggerFactory.getLogger(Factory.class);
private Factory() {} // prevent instantiation
/**
* Creates the {@link UnderFileSystem} instance according to its UFS path. This method should
* only be used for journal operations and tests.
*
* @param path journal path in ufs
* @param conf the configuration object w/o mount specific options
* @return the instance of under file system for Alluxio journal directory
*/
public static UnderFileSystem create(String path, AlluxioConfiguration conf) {
return create(path, UnderFileSystemConfiguration.defaults(conf));
}
/**
* Creates a client for operations involved with the under file system. An
* {@link IllegalArgumentException} is thrown if there is no under file system for the given
* path or if no under file system could successfully be created.
*
* @param path path
* @param ufsConf configuration object for the UFS
* @return client for the under file system
*/
public static UnderFileSystem create(String path, UnderFileSystemConfiguration ufsConf) {
return createWithRecorder(path, ufsConf, Recorder.noopRecorder());
}
/**
* Creates a client for operations involved with the under file system and record the
* execution process.
* An {@link IllegalArgumentException} is thrown if there is no under file system for the given
* path or if no under file system could successfully be created.
*
* @param path path
* @param ufsConf configuration object for the UFS
* @param recorder recorder used to record the detailed execution process
* @return client for the under file system
*/
public static UnderFileSystem createWithRecorder(String path,
UnderFileSystemConfiguration ufsConf, Recorder recorder) {
// Try to obtain the appropriate factory
List factories =
UnderFileSystemFactoryRegistry.findAllWithRecorder(path, ufsConf, recorder);
if (factories.isEmpty()) {
throw new IllegalArgumentException("No Under File System Factory found for: " + path);
}
List errors = new ArrayList<>();
for (UnderFileSystemFactory factory : factories) {
ClassLoader previousClassLoader = Thread.currentThread().getContextClassLoader();
try {
// Reflection may be invoked during UFS creation on service loading which uses context
// classloader by default. Stashing the context classloader on creation and switch it back
// when creation is done.
recorder.record(
"Trying to create UFS from factory {} of version {} for path {} with ClassLoader {}",
factory.getClass().getSimpleName(),
factory.getVersion(),
path,
factory.getClass().getClassLoader().getClass().getSimpleName());
Thread.currentThread().setContextClassLoader(factory.getClass().getClassLoader());
UnderFileSystem underFileSystem =
new UnderFileSystemWithLogging(path, factory.create(path, ufsConf), ufsConf);
// Use the factory to create the actual client for the Under File System
recorder.record("UFS created with factory {}",
factory.getClass().getSimpleName());
return underFileSystem;
} catch (Throwable e) {
// Catching Throwable rather than Exception to catch service loading errors
errors.add(e);
String errorMsg = String.format(
"Failed to create UnderFileSystem by factory %s: %s",
factory.getClass().getSimpleName(), e);
recorder.record(errorMsg);
LOG.warn(errorMsg);
} finally {
Thread.currentThread().setContextClassLoader(previousClassLoader);
}
}
// If we reach here no factories were able to successfully create for this path likely due to
// missing configuration since if we reached here at least some factories claimed to support
// the path
// Need to collate the errors
IllegalArgumentException e = new IllegalArgumentException(
String.format("Unable to create an UnderFileSystem instance for path: %s", path));
for (Throwable t : errors) {
e.addSuppressed(t);
}
throw e;
}
/**
* @param conf configuration
* @return the instance of under file system for Alluxio root directory
*/
public static UnderFileSystem createForRoot(AlluxioConfiguration conf) {
String ufsRoot = conf.getString(PropertyKey.MASTER_MOUNT_TABLE_ROOT_UFS);
boolean readOnly = conf.getBoolean(PropertyKey.MASTER_MOUNT_TABLE_ROOT_READONLY);
Map ufsConf =
conf.getNestedProperties(PropertyKey.MASTER_MOUNT_TABLE_ROOT_OPTION);
return create(ufsRoot, new UnderFileSystemConfiguration(conf, readOnly)
.createMountSpecificConf(ufsConf));
}
}
/**
* The different types of space indicate the total space, the free space and the space used in the
* under file system.
*/
enum SpaceType {
/**
* Indicates the storage capacity of the under file system.
*/
SPACE_TOTAL(0),
/**
* Indicates the amount of free space available in the under file system.
*/
SPACE_FREE(1),
/**
* Indicates the amount of space used in the under file system.
*/
SPACE_USED(2),
;
private final int mValue;
SpaceType(int value) {
mValue = value;
}
/**
* @return the integer value of this enum value
*/
public int getValue() {
return mValue;
}
}
/**
* Cleans up the under file system. If any data or files are created
* and not completed/aborted correctly in normal ways, they should be cleaned in this method.
*/
void cleanup() throws IOException;
/**
* Takes any necessary actions required to establish a connection to the under file system from
* the given master host e.g. logging in
*
* Depending on the implementation this may be a no-op
*
*
* @param hostname the host that wants to connect to the under file system
*/
void connectFromMaster(String hostname) throws IOException;
/**
* Takes any necessary actions required to establish a connection to the under file system from
* the given worker host e.g. logging in
*
* Depending on the implementation this may be a no-op
*
*
* @param hostname the host that wants to connect to the under file system
*/
void connectFromWorker(String hostname) throws IOException;
/**
* Creates a file in the under file system with the indicated name. Parents directories will be
* created recursively.
*
* @param path the file name
* @return A {@code OutputStream} object
*/
OutputStream create(String path) throws IOException;
/**
* Creates a file in the under file system with the specified {@link CreateOptions}.
* Implementations should make sure that the path under creation appears in listings only
* after a successful close and that contents are written in its entirety or not at all.
*
* @param path the file name
* @param options the options for create
* @return A {@code OutputStream} object
*/
OutputStream create(String path, CreateOptions options) throws IOException;
/**
* Creates a file in the under file system with the indicated name.
*
* Similar to {@link #create(String)} but
* deals with the delete-then-create eventual consistency issue.
*
* @param path the file name
* @return A {@code OutputStream} object
*/
OutputStream createNonexistingFile(String path) throws IOException;
/**
* Creates a file in the under file system with the specified {@link CreateOptions}.
*
* Similar to {@link #create(String, CreateOptions)} but
* deals with the delete-then-create eventual consistency issue.
*
* @param path the file name
* @param options the options for create
* @return A {@code OutputStream} object
*/
OutputStream createNonexistingFile(String path, CreateOptions options) throws IOException;
/**
* Deletes a directory from the under file system with the indicated name non-recursively. A
* non-recursive delete is successful only if the directory is empty.
*
* @param path of the directory to delete
* @return true if directory was found and deleted, false otherwise
*/
boolean deleteDirectory(String path) throws IOException;
/**
* Deletes a directory from the under file system with the indicated name.
*
* @param path of the directory to delete
* @param options for directory delete semantics
* @return true if directory was found and deleted, false otherwise
*/
boolean deleteDirectory(String path, DeleteOptions options) throws IOException;
/**
* Deletes a directory from the under file system.
*
* Similar to {@link #deleteDirectory(String)} but
* deals with the create-delete eventual consistency issue.
*
* @param path of the directory to delete
* @return true if directory was found and deleted, false otherwise
*/
boolean deleteExistingDirectory(String path) throws IOException;
/**
* Deletes a directory from the under file system with the indicated name.
*
* Similar to {@link #deleteDirectory(String, DeleteOptions)} but
* deals with the create-then-delete eventual consistency issue.
*
* @param path of the directory to delete
* @param options for directory delete semantics
* @return true if directory was found and deleted, false otherwise
*/
boolean deleteExistingDirectory(String path, DeleteOptions options) throws IOException;
/**
* Deletes a file from the under file system with the indicated name.
*
* @param path of the file to delete
* @return true if file was found and deleted, false otherwise
*/
boolean deleteFile(String path) throws IOException;
/**
* Deletes a file from the under file system with the indicated name.
*
* Similar to {@link #deleteFile(String)} but
* deals with the create-then-delete eventual consistency issue.
*
* @param path of the file to delete
* @return true if file was found and deleted, false otherwise
*/
boolean deleteExistingFile(String path) throws IOException;
/**
* Checks if a file or directory exists in under file system.
*
* @param path the absolute path
* @return true if the path exists, false otherwise
*/
boolean exists(String path) throws IOException;
/**
* Gets the ACL and the Default ACL of a file or directory in under file system.
*
* @param path the path to the file or directory
* @return the access control list, along with a Default ACL if it is a directory
* return null if ACL is unsupported or disabled
* @throws IOException if ACL is supported and enabled but cannot be retrieved
*/
@Nullable
Pair getAclPair(String path) throws IOException;
/**
* Gets the block size of a file in under file system, in bytes.
*
* @deprecated block size should be returned as part of the {@link UfsFileStatus} from
* {@link #getFileStatus(String)} or {@link #getExistingFileStatus(String)}
*
* @param path the file name
* @return the block size in bytes
*/
@Deprecated
long getBlockSizeByte(String path) throws IOException;
/**
* Gets the under file system configuration.
*
* @return the configuration
*/
default AlluxioConfiguration getConfiguration() throws IOException {
return UnderFileSystemConfiguration.emptyConfig();
}
/**
* Gets the directory status. The caller must already know the path is a directory. This method
* will throw an exception if the path exists, but is a file.
*
* @param path the path to the directory
* @return the directory status
* @throws FileNotFoundException when the path does not exist
*/
UfsDirectoryStatus getDirectoryStatus(String path) throws IOException;
/**
* Gets the directory status.
*
* Similar to {@link #getDirectoryStatus(String)} but
* deals with the write-then-get-status eventual consistency issue.
*
* @param path the path to the directory
* @return the directory status
*/
UfsDirectoryStatus getExistingDirectoryStatus(String path) throws IOException;
/**
* Gets the list of locations of the indicated path.
*
* @param path the file name
* @return The list of locations
*/
List getFileLocations(String path) throws IOException;
/**
* Gets the list of locations of the indicated path given options.
*
* @param path the file name
* @param options method options
* @return The list of locations
*/
List getFileLocations(String path, FileLocationOptions options) throws IOException;
/**
* Gets the file status. The caller must already know the path is a file. This method will
* throw an exception if the path exists, but is a directory.
*
* @param path the path to the file
* @return the file status
* @throws FileNotFoundException when the path does not exist
*/
UfsFileStatus getFileStatus(String path) throws IOException;
/**
* Gets the file status.
*
* Similar to {@link #getFileStatus(String)} but
* deals with the write-then-get-status eventual consistency issue.
*
* @param path the path to the file
* @return the file status
*/
UfsFileStatus getExistingFileStatus(String path) throws IOException;
/**
* Computes and returns a fingerprint for the path. The fingerprint is used to determine if two
* UFS files are identical. The fingerprint must be deterministic, and must not change if a
* file is only renamed (identical content and permissions). Returns
* {@link alluxio.Constants#INVALID_UFS_FINGERPRINT} if there is any error.
*
* @deprecated
* @param path the path to compute the fingerprint for
* @return the string representing the fingerprint
*/
@Deprecated
String getFingerprint(String path);
/**
* Computes and returns a fingerprint for the path. The fingerprint is used to determine if two
* UFS files are identical. The fingerprint must be deterministic, and must not change if a
* file is only renamed (identical content and permissions). Returns
* {@link Fingerprint#INVALID_FINGERPRINT} if there is any error.
*
* The default implementation relies on {@link #getFingerprint(String)} and there is one extra
* parsing. This default implementation is mainly for backward compatibility.
* Override this for performance.
*
* @param path the path to compute the fingerprint for
* @return the string representing the fingerprint
*/
default Fingerprint getParsedFingerprint(String path) {
return Fingerprint.parse(getFingerprint(path));
}
/**
* An {@link UnderFileSystem} may be composed of one or more "physical UFS"s. This method is used
* to determine the operation mode based on the physical UFS operation modes. For example, if this
* {@link UnderFileSystem} is composed of physical UFS hdfs://ns1/ and hdfs://ns2/ with read
* operations split b/w the two, with physicalUfsState{hdfs://ns1/:NO_ACCESS,
* hdfs://ns2/:READ_WRITE} this method can return READ_ONLY to allow reads to proceed from
* hdfs://ns2/.
*
* @param physicalUfsState the state of physical UFSs for this {@link UnderFileSystem}; keys are
* expected to be normalized (ending with /)
* @return the desired operation mode for this UFS
*/
UfsMode getOperationMode(Map physicalUfsState);
/**
* An {@link UnderFileSystem} may be composed of one or more "physical UFS"s. This method
* returns all underlying physical stores; normalized with only scheme and authority.
*
* @return physical UFSs this {@link UnderFileSystem} is composed of
*/
List getPhysicalStores();
/**
* Queries the under file system about the space of the indicated path (e.g., space left, space
* used and etc).
*
* @param path the path to query
* @param type the type of queries
* @return The space in bytes
*/
long getSpace(String path, SpaceType type) throws IOException;
/**
* Gets the file or directory status. The caller does not need to know if the path is a file or
* directory. This method will determine the path type, and will return the appropriate status.
*
* @param path the path to get the status
* @return the file or directory status
* @throws FileNotFoundException when the path does not exist
*/
UfsStatus getStatus(String path) throws IOException;
/**
* Gets the file or directory status.
*
* Similar to {@link #getStatus(String)} but
* deals with the write-then-get-status eventual consistency issue.
*
* @param path the path to get the status
* @return the file or directory status
*/
UfsStatus getExistingStatus(String path) throws IOException;
/**
* Returns the name of the under filesystem implementation.
*
* The name should be lowercase and not include any spaces, e.g. "hdfs", "s3".
*
* @return name of the under filesystem implementation
*/
String getUnderFSType();
/**
* Checks if a directory exists in under file system.
*
* @param path the absolute directory path
* @return true if the path exists and is a directory, false otherwise
*/
boolean isDirectory(String path) throws IOException;
/**
* Checks if a directory exists in under file system.
*
* Similar to {@link #isDirectory(String)} but
* deals with the write-then-list eventual consistency issue.
*
* @param path the absolute directory path
* @return true if the path exists and is a directory, false otherwise
*/
boolean isExistingDirectory(String path) throws IOException;
/**
* Checks if a file exists in under file system.
*
* @param path the absolute file path
* @return true if the path exists and is a file, false otherwise
*/
boolean isFile(String path) throws IOException;
/**
* @return true if under storage is an object store, false otherwise
*/
boolean isObjectStorage();
/**
* Denotes if the under storage supports seeking. Note, the under file system subclass that
* returns true for this method should return the input stream extending
* {@link SeekableUnderFileInputStream} in the {@link #open(String, OpenOptions)} method.
*
* @return true if under storage is seekable, false otherwise
*/
boolean isSeekable();
/**
* Returns an array of statuses of the files and directories in the directory denoted by this
* abstract pathname.
*
*
* If this abstract pathname does not denote a directory, then this method returns {@code null}.
* Otherwise an array of statuses is returned, one for each file or directory in the directory.
* Names denoting the directory itself and the directory's parent directory are not included in
* the result. Each string is a file name rather than a complete path.
*
*
* There is no guarantee that the name strings in the resulting array will appear in any specific
* order; they are not, in particular, guaranteed to appear in alphabetical order.
*
* @param path the abstract pathname to list
* @return An array with the statuses of the files and directories in the directory denoted by
* this abstract pathname. The array will be empty if the directory is empty. Returns
* {@code null} if this abstract pathname does not denote a directory.
*/
@Nullable
UfsStatus[] listStatus(String path) throws IOException;
/**
* Returns an array of statuses of the files and directories in the directory denoted by this
* abstract pathname, with options.
*
*
* If this abstract pathname does not denote a directory, then this method returns {@code null}.
* Otherwise an array of statuses is returned, one for each file or directory. Names denoting the
* directory itself and the directory's parent directory are not included in the result. Each
* string is a path relative to the given directory.
*
*
* There is no guarantee that the name strings in the resulting array will appear in any specific
* order; they are not, in particular, guaranteed to appear in alphabetical order.
*
* @param path the abstract pathname to list
* @param options for list directory
* @return An array of statuses naming the files and directories in the directory denoted by this
* abstract pathname. The array will be empty if the directory is empty. Returns
* {@code null} if this abstract pathname does not denote a directory.
*/
@Nullable
UfsStatus[] listStatus(String path, ListOptions options) throws IOException;
/**
* Creates the directory named by this abstract pathname. If the folder already exists, the method
* returns false. The method creates any necessary but nonexistent parent directories.
*
* @param path the folder to create
* @return {@code true} if and only if the directory was created; {@code false} otherwise
*/
boolean mkdirs(String path) throws IOException;
/**
* Creates the directory named by this abstract pathname, with specified
* {@link MkdirsOptions}. If the folder already exists, the method returns false.
*
* @param path the folder to create
* @param options the options for mkdirs
* @return {@code true} if and only if the directory was created; {@code false} otherwise
*/
boolean mkdirs(String path, MkdirsOptions options) throws IOException;
/**
* Opens an {@link InputStream} for a file in under filesystem at the indicated path.
*
* @param path the file name
* @return The {@code InputStream} object
*/
InputStream open(String path) throws IOException;
/**
* Opens an {@link InputStream} for a file in under filesystem at the indicated path.
*
* @param path the file name
* @param options to open input stream
* @return The {@code InputStream} object
*/
InputStream open(String path, OpenOptions options) throws IOException;
/**
* Opens an {@link InputStream} for a file in under filesystem at the indicated path.
*
* Similar to {@link #open(String)} but
* deals with the write-then-read eventual consistency issue.
*
* @param path the file name
* @return The {@code InputStream} object
*/
InputStream openExistingFile(String path) throws IOException;
/**
* Opens an {@link InputStream} for a file in under filesystem at the indicated path.
*
* Similar to {@link #open(String, OpenOptions)} but
* deals with the write-then-read eventual consistency issue.
*
* @param path the file name
* @param options to open input stream
* @return The {@code InputStream} object
*/
InputStream openExistingFile(String path, OpenOptions options) throws IOException;
/**
* Renames a directory from {@code src} to {@code dst} in under file system.
*
* @param src the source directory path
* @param dst the destination directory path
* @return true if succeed, false otherwise
*/
boolean renameDirectory(String src, String dst) throws IOException;
/**
* Renames a directory from {@code src} to {@code dst} in under file system.
*
* Similar to {@link #renameDirectory(String, String)} but
* deals with the write-src-then-rename and delete-dst-then-rename eventual consistency issue.
*
* @param src the source directory path
* @param dst the destination directory path
* @return true if succeed, false otherwise
*/
boolean renameRenamableDirectory(String src, String dst) throws IOException;
/**
* Renames a file from {@code src} to {@code dst} in under file system.
*
* @param src the source file path
* @param dst the destination file path
* @return true if succeed, false otherwise
*/
boolean renameFile(String src, String dst) throws IOException;
/**
* Renames a file from {@code src} to {@code dst} in under file system.
*
* Similar to {@link #renameFile(String, String)} but
* deals with the write-src-then-rename and delete-dst-then-rename eventual consistency issue.
*
* @param src the source file path
* @param dst the destination file path
* @return true if succeed, false otherwise
*/
boolean renameRenamableFile(String src, String dst) throws IOException;
/**
* Returns an {@link AlluxioURI} representation for the {@link UnderFileSystem} given a base
* UFS URI, and the Alluxio path from the base.
*
* The default implementation simply concatenates the path to the base URI. This should be
* overridden if a subclass needs alternate functionality.
*
* @param ufsBaseUri the base {@link AlluxioURI} in the ufs
* @param alluxioPath the path in Alluxio from the given base
* @return the UFS {@link AlluxioURI} representing the Alluxio path
*/
AlluxioURI resolveUri(AlluxioURI ufsBaseUri, String alluxioPath);
/**
* Sets the access control list of a file or directory in under file system.
* if the ufs does not support acls, this is a noop.
* This will overwrite the ACL and defaultACL in the UFS.
*
* @param path the path to the file or directory
* @param aclEntries the access control list + default acl represented in a list of acl entries
*/
void setAclEntries(String path, List aclEntries) throws IOException;
/**
* Changes posix file mode.
*
* @param path the path of the file
* @param mode the mode to set in short format, e.g. 0777
*/
void setMode(String path, short mode) throws IOException;
/**
* Sets the user and group of the given path. An empty implementation should be provided if
* unsupported.
*
* @param path the path of the file
* @param owner the new owner to set, unchanged if null
* @param group the new group to set, unchanged if null
*/
void setOwner(String path, String owner, String group) throws IOException;
/**
* Whether this type of UFS supports flush.
*
* @return true if this type of UFS supports flush, false otherwise
*/
boolean supportsFlush() throws IOException;
/**
* Whether this type of UFS supports active sync.
*
* @return true if this type of UFS supports active sync, false otherwise
*/
boolean supportsActiveSync();
/**
* Return the active sync info for the specified syncPoints.
*
* @return active sync info consisting of what changed for these sync points
*/
SyncInfo getActiveSyncInfo() throws IOException;
/**
* Add Sync Point.
*
* @param uri ufs uri to start
*/
void startSync(AlluxioURI uri) throws IOException;
/**
* Stop Sync Point.
*
* @param uri ufs uri to stop
*/
void stopSync(AlluxioURI uri) throws IOException;
/**
* Start Active Sync.
*
* @param txId the transaction id to start receiving event
* @return true if active sync started
*/
boolean startActiveSyncPolling(long txId) throws IOException;
/**
* Stop Active Sync.
*
* @return true if active sync stopped
*/
boolean stopActiveSyncPolling() throws IOException;
}