@InterfaceAudience.Public @InterfaceStability.Evolving public interface LaunchableService extends Service
The command line options will be passed down before the
Service.init(Configuration) operation is invoked via an
After the service has been successfully started via
execute() method is called to execute the
service. When this method returns, the service launcher will exit, using
the return code from the method as its exit option.
|Modifier and Type||Method and Description|
Propagate the command line arguments.
Run a service.
Configuration bindArgs(Configuration config, List<String> args) throws Exception
This method is called before
Any non-null configuration that is returned from this operation
becomes the one that is passed on to that
This permits implementations to change the configuration before
the init operation. As the ServiceLauncher only creates
an instance of the base
Configuration class, it is
recommended to instantiate any subclass (such as YarnConfiguration)
that injects new resources.
config- the initial configuration build up by the service launcher.
args- list of arguments passed to the command line after any launcher-specific commands have been stripped.
Exception- any problem
int execute() throws Exception
The return value becomes the exit code of the launched process.
If an exception is raised, the policy is:
ExitUtil.ExitException: the exception is passed up unmodified.
ExitCodeProvider: A new
ServiceLaunchExceptionis created with the exit code and message of the thrown exception; the thrown exception becomes the cause.
ServiceLaunchExceptionis created with the exit code
LauncherExitCodes.EXIT_EXCEPTION_THROWNand the message of the original exception (which becomes the cause).
org.apache.hadoop.util.ExitUtil.ExitException- an exception passed up as the exit code and error text.
Exception- any exception to report. If it provides an exit code this is used in a wrapping exception.
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