alluxio.util

Class ShellUtils

java.lang.Object

alluxio.util.ShellUtils

@ThreadSafe
public final class ShellUtils
extends Object

A utility class for running Unix commands.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ShellUtils.ExitCodeException This is an IOException with exit code added.

Field Summary

Fields

Modifier and Type	Field and Description
static String	COMMON_SSH_OPTS Common shell OPTS to prevent stalling.
static String	MOUNT_COMMAND a Unix command for getting mount information.
static String	SET_PERMISSION_COMMAND a Unix command to set permission.
static String	TOKEN_SEPARATOR_REGEX Token separator regex used to parse Shell tool outputs.

Method Summary

Modifier and Type	Method and Description
static CommandReturn	execCmdWithBackup(ShellCommand cmd, ShellCommand backupCmd) Executes a shell command.
static String	execCommand(String... cmd) Static method to execute a shell command.
static CommandReturn	execCommandWithOutput(String... cmd) Static method to execute a shell command and tolerate non-zero exit code.
static String[]	getGroupsForUserCommand(String user) Gets a Unix command to get a given user's groups list.
static String[]	getSetPermissionCommand(String perm, String filePath) Returns a Unix command to set permission.
static List<UnixMountInfo>	getUnixMountInfo() Gets system mount information.
static UnixMountInfo	parseMountInfo(String line)
static CommandReturn	scpCommandWithOutput(String hostname, String fromFile, String toFile, boolean isDir) Static method to execute an scp command to copy a remote file/dir to local.
static CommandReturn	sshExecCommandWithOutput(String hostname, String... cmd) Static method to execute a shell command remotely via ssh.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

COMMON_SSH_OPTS

public static final String COMMON_SSH_OPTS

Common shell OPTS to prevent stalling. a. Disable StrictHostKeyChecking to prevent interactive prompt b. Set timeout for establishing connection with host

See Also:

Constant Field Values

SET_PERMISSION_COMMAND

public static final String SET_PERMISSION_COMMAND

a Unix command to set permission.

See Also:

Constant Field Values

MOUNT_COMMAND

public static final String MOUNT_COMMAND

a Unix command for getting mount information.

See Also:

Constant Field Values

TOKEN_SEPARATOR_REGEX

public static final String TOKEN_SEPARATOR_REGEX

Token separator regex used to parse Shell tool outputs.

See Also:

Constant Field Values

Method Detail

getGroupsForUserCommand

public static String[] getGroupsForUserCommand(String user)

Gets a Unix command to get a given user's groups list.

Parameters:

user - the user name

Returns:

the Unix command to get a given user's groups list

getSetPermissionCommand

public static String[] getSetPermissionCommand(String perm,
                                               String filePath)

Returns a Unix command to set permission.

Parameters:

perm - the permission of file

filePath - the file path

Returns:

the Unix command to set permission

getUnixMountInfo

public static List<UnixMountInfo> getUnixMountInfo()
                                            throws IOException

Gets system mount information. This method should only be attempted on Unix systems.

Returns:

system mount information

Throws:

IOException

parseMountInfo

public static UnixMountInfo parseMountInfo(String line)

Parameters:

line - the line to parse

Returns:

the parsed UnixMountInfo

execCommand

public static String execCommand(String... cmd)
                          throws IOException

Static method to execute a shell command. The StdErr is not returned. If execution failed

Parameters:

cmd - shell command to execute

Returns:

the output of the executed command

Throws:

IOException - in various situations: 1. ShellUtils.ExitCodeException when exit code is non-zero 2. when the executable is not valid, i.e. running ls in Windows 3. execution interrupted 4. other normal reasons for IOException

execCommandWithOutput

public static CommandReturn execCommandWithOutput(String... cmd)
                                           throws IOException

Static method to execute a shell command and tolerate non-zero exit code. Preserves exit code. Stderr is redirected to stdout.

Parameters:

cmd - shell command to execute

Returns:

the output of the executed command

Throws:

IOException - in various situations: 1. when the executable is not valid, i.e. running ls in Windows 2. execution interrupted 3. other normal reasons for IOException

sshExecCommandWithOutput

public static CommandReturn sshExecCommandWithOutput(String hostname,
                                                     String... cmd)
                                              throws IOException

Static method to execute a shell command remotely via ssh. Preserves exit code. Stderr redirected to stdout. SSH must be password-less.

Parameters:

hostname - Hostname where the command should execute

cmd - shell command to execute

Returns:

the output of the executed command

Throws:

IOException - in various situations: 1. when the executable is not valid, i.e. running ls in Windows 2. execution interrupted 3. other normal reasons for IOException

scpCommandWithOutput

public static CommandReturn scpCommandWithOutput(String hostname,
                                                 String fromFile,
                                                 String toFile,
                                                 boolean isDir)
                                          throws IOException

Static method to execute an scp command to copy a remote file/dir to local. Preserves exit code. Stderr redirected to stdout.

Parameters:

hostname - Hostname where the command should execute

fromFile - File path on remote host

toFile - File path to copy to on localhost

isDir - Is the file a directory

Returns:

the output of the executed command

Throws:

IOException - in various situations: 1. when the executable is not valid, i.e. running ls in Windows 2. execution interrupted 3. other normal reasons for IOException

execCmdWithBackup

public static CommandReturn execCmdWithBackup(ShellCommand cmd,
                                              ShellCommand backupCmd)
                                       throws IOException

Executes a shell command. If it fails, try the backup command.

Parameters:

cmd - the primary command

backupCmd - a backup option

Returns:

the CommandReturn with combined output

Throws:

IOException