org.apache.flink.runtime.util

Class EnvironmentInformation

java.lang.Object

org.apache.flink.runtime.util.EnvironmentInformation

public class EnvironmentInformation
extends Object

Utility class that gives access to the execution environment of the JVM, like the executing user, startup options, or the JVM version.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EnvironmentInformation.RevisionInformation Revision information encapsulates information about the source code revision of the Flink code.

Field Summary

Fields

Modifier and Type	Field and Description
static String	UNKNOWN

Method Summary

Modifier and Type	Method and Description
static String	getHadoopUser() Gets the name of the user that is running the JVM.
static String	getHadoopVersionString()
static String	getJvmStartupOptions() Gets the system parameters and environment parameters that were passed to the JVM on startup.
static String[]	getJvmStartupOptionsArray() Gets the system parameters and environment parameters that were passed to the JVM on startup.
static String	getJvmVersion() Gets the version of the JVM in the form "VM_Name - Vendor - Spec/Version".
static long	getMaxJvmHeapMemory() The maximum JVM heap size, in bytes.
static long	getOpenFileHandlesLimit() Tries to retrieve the maximum number of open file handles.
static EnvironmentInformation.RevisionInformation	getRevisionInformation() Returns the code revision (commit and commit date) of Flink, as generated by the Maven builds.
static long	getSizeOfFreeHeapMemory() Gets an estimate of the size of the free heap memory.
static long	getSizeOfFreeHeapMemoryWithDefrag() Gets an estimate of the size of the free heap memory.
static String	getTemporaryFileDirectory() Gets the directory for temporary files, as returned by the JVM system property "java.io.tmpdir".
static String	getVersion() Returns the version of the code as String.
static void	logEnvironmentInfo(org.slf4j.Logger log, String componentName, String[] commandLineArgs) Logs information about the environment, like code revision, current user, Java version, and JVM parameters.

Methods inherited from class java.lang.Object

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

Field Detail

UNKNOWN

public static final String UNKNOWN

See Also:

Constant Field Values

Method Detail

getVersion

public static String getVersion()

Returns the version of the code as String. If version == null, then the JobManager does not run from a Maven build. An example is a source code checkout, compile, and run from inside an IDE.

Returns:

The version string.

getRevisionInformation

public static EnvironmentInformation.RevisionInformation getRevisionInformation()

Returns the code revision (commit and commit date) of Flink, as generated by the Maven builds.

Returns:

The code revision.

getHadoopUser

public static String getHadoopUser()

Gets the name of the user that is running the JVM.

Returns:

The name of the user that is running the JVM.

getMaxJvmHeapMemory

public static long getMaxJvmHeapMemory()

The maximum JVM heap size, in bytes.

This method uses the -Xmx value of the JVM, if set. If not set, it returns (as a heuristic) 1/4th of the physical memory size.

Returns:

The maximum JVM heap size, in bytes.

getSizeOfFreeHeapMemoryWithDefrag

public static long getSizeOfFreeHeapMemoryWithDefrag()

Gets an estimate of the size of the free heap memory. NOTE: This method is heavy-weight. It triggers a garbage collection to reduce fragmentation and get a better estimate at the size of free memory. It is typically more accurate than the plain version getSizeOfFreeHeapMemory().

Returns:

An estimate of the size of the free heap memory, in bytes.

getSizeOfFreeHeapMemory

public static long getSizeOfFreeHeapMemory()

Gets an estimate of the size of the free heap memory. The estimate may vary, depending on the current level of memory fragmentation and the number of dead objects. For a better (but more heavy-weight) estimate, use getSizeOfFreeHeapMemoryWithDefrag().

Returns:

An estimate of the size of the free heap memory, in bytes.

getJvmVersion

public static String getJvmVersion()

Gets the version of the JVM in the form "VM_Name - Vendor - Spec/Version".

Returns:

The JVM version.

getJvmStartupOptions

public static String getJvmStartupOptions()

Gets the system parameters and environment parameters that were passed to the JVM on startup.

Returns:

The options passed to the JVM on startup.

getJvmStartupOptionsArray

public static String[] getJvmStartupOptionsArray()

Gets the system parameters and environment parameters that were passed to the JVM on startup.

Returns:

The options passed to the JVM on startup.

getTemporaryFileDirectory

public static String getTemporaryFileDirectory()

Gets the directory for temporary files, as returned by the JVM system property "java.io.tmpdir".

Returns:

The directory for temporary files.

getOpenFileHandlesLimit

public static long getOpenFileHandlesLimit()

Tries to retrieve the maximum number of open file handles. This method will only work on UNIX-based operating systems with Sun/Oracle Java versions.

If the number of max open file handles cannot be determined, this method returns -1.

Returns:

The limit of open file handles, or -1, if the limit could not be determined.

logEnvironmentInfo

public static void logEnvironmentInfo(org.slf4j.Logger log,
                                      String componentName,
                                      String[] commandLineArgs)

Logs information about the environment, like code revision, current user, Java version, and JVM parameters.

Parameters:

log - The logger to log the information to.

componentName - The component name to mention in the log.

commandLineArgs - The arguments accompanying the starting the component.

getHadoopVersionString

public static String getHadoopVersionString()