Package edu.isi.pegasus.planner.selector.site

Class NonJavaCallout

java.lang.Object
edu.isi.pegasus.planner.selector.site.Abstract
edu.isi.pegasus.planner.selector.site.AbstractPerJob
edu.isi.pegasus.planner.selector.site.NonJavaCallout
All Implemented Interfaces:
SiteSelector
public class NonJavaCallout extends AbstractPerJob
This is the class that implements a call-out to a site selector which is an application or executable script. In order to use the site selector implemented by this class, the property pegasus.selector.site must be set to value NonJavaCallout.

This site selector implements a popen() like call to an external application that conforms to the API laid out here. The name of the application to run is specified by the property pegasus.selector.site.path. Its value points to a locally available application.

If the external executable requires certain environment variables to be set for execution, these can be specified in the property files, using the prefix pegasus.selector.site.env . The name of the environment variable is obtained by stripping the prefix. For example, to set the variable PATH to a certain value, use the following entry in your user property file: 

   pegasus.selector.site.env.PATH = /usr/bin:/bin:/usr/X11R6/bin
The site selector populates the environment of the external application with the following default properties, which can be overwritten by user-specified properties:
keyvalue
PEGASUS_HOME As set by the system
CLASSPATH From java.class.path
JAVA_HOME From java.home
USER From user.name, if present
LOGNAME From user.name, if present
HOME From user.home, if present
TMP From java.io.tmpdir, if present
TZ From user.timezone, if present

The user can specify the environment variables, by specifying the properties with the prefix pegasus.selector.site.env. prefix. for e.g user can override the default user.name property by setting the property pegasus.selector.site.env.user.home .

The external application is invoked with one commandline argument. This argument is the name of a temporary file. The temporary file is created for each invocation anew by the site selecting caller. Being temporary, the file is deleted after the site selector returns with success. The deletion of the file is governed by the property pegasus.selector.site.keep.tmp. It can have a tristate value with the valid values being 

              ALWAYS
              NEVER
              ONERROR

The external application is expected to write one line to stdout. The line starts with the string SOLUTION:, followed by the chosen site handle. Optionally, separated by a colon, the name of a jobmanager for the site can be provided by the site selector. Two examples for successful site selections are: 

   SOLUTION:mysite:my.job.mgr/jobmanager-batch
   SOLUTION:siteY
Note, these are two examples. The site selector only returns one line with the appropriate solution. If no site is found to be eligble, the poolhandle should be set to NONE by the site selector.

The temporary file is the corner stone of the communication between the site selecting caller and the external site selector. It is a collection of key-value pairs. Each pair is separated by an equals (=) sign, and stands on a line of its own. There are no multi-line values permitted.

The following pairs are generated for the siteselector temporary file:

#keyvalue
1version The version of the site selector API, currently 2.0
1transformation The fully-qualified definition identifier for the TR, ns::id:vs.
1derivation The fully-qualified definition identifier for the DV, ns::id:vs.
1job.level The job's depth in the DFS tree of the workflow DAG
1job.id The job's ID, as used in the DAX file.
Nresource.id A pool handle, followed by a whitespace, followed by a gridftp server. Typically, each gridftp server is enumerated once, so you may have multiple occurances of the same site.
Minput.lfn An input LFN, optionally followed by a whitespace and filesize.
1wf.name The label of the DAX, as found in the DAX's root element.
1wf.index The DAX index, which is incremented for each partition.
1wf.time The mtime of the workflow.
1wf.manager The name of the workflow manager to be used, e.g. dagman.
1vo.name unused at present, name of the virtual organization who runs this WF.
1vo.group unused at present, usage not clear .

In order to detect malfunctioning site selectors, a timeout is attached with each site selector, see property pegasus.selector.site.timeout. By default, a site selector is given up upon after 60 s.

Version:
$Revision$
Author:
Karan Vahi, Jens Vöckler
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    KEEP_ALWAYS
    The state denoting always to keep the temporary files.
    static final int
    KEEP_NEVER
    The state denoting never to keep the temporary files.
    static final int
    KEEP_ONERROR
    The state denoting to keep the temporary files only in case of error.
    private edu.isi.pegasus.planner.classes.ADag
    mAbstractDag
    The abstract DAG.
    private static final String
    mDescription
    The description of the site selector.
    private Map
    mEnvVar
    The map that contains the environment variables including the default ones that are set while calling out to the site selector unless they are overridden by the values set in the properties file.
    private int
    mKeepTMP
    The tristate value for whether keeping the temporary files generated or not.
    private String
    mSiteSelectorPath
    The path to the site selector.
    private int
    mTimeout
    The timeout value in seconds after which to timeout, in the case where the external site selector does nothing (nothing on stdout nor stderr).
    static final String
    PREFIX_PROPERTIES
    The prefix of the property names that specify the environment variables that need to be set before calling out to the site selector.
    static final String
    PREFIX_TEMPORARY_FILE
    The prefix to be used while creating a temporary file to pass to the external siteselector.
    static final String
    SOLUTION_PREFIX
    The prefix that the site selector writes out on its stdout to designate that it is sending a solution.
    static final String
    SUFFIX_TEMPORARY_FILE
    The suffix to be used while creating a temporary file to pass to the external siteselector.
    static final String
    VERSION
    The version number associated with this API of non java callout site selection.

    Fields inherited from class edu.isi.pegasus.planner.selector.site.Abstract

    mBag, mLogger, mProps, mSiteStore, mTCMapper

    Fields inherited from interface edu.isi.pegasus.planner.selector.SiteSelector

    SITE_NOT_FOUND

  • Constructor Summary

    Constructors
    Constructor
    Description
    NonJavaCallout()
    The default constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    String
    description()
    Returns a brief description of the site selection technique implemented by this class.
    private String[]
    getEnvArrFromMap()
    Generates an array of environment variables.
    private int
    getKeepTMPValue(String value)
    Returns the int value corresponding to the string value passed.
    private String
    getTempFilename()
    Creates a temporary file and obtains its name.
    void
    initialize(edu.isi.pegasus.planner.classes.PegasusBag bag)
    Initializes the site selector.
    private void
    loadEnvironmentVariables()
    Initializes the internal hash that collects environment variables.
    static void
    main(String[] args)
    The main program that allows you to test.
    void
    mapJob(edu.isi.pegasus.planner.classes.Job job, List sites)
    Calls out to the external site selector.
    void
    mapWorkflow(edu.isi.pegasus.planner.classes.ADag workflow, List sites)
    Maps the jobs in the workflow to the various grid sites.
    private boolean
    parseStdOut(edu.isi.pegasus.planner.classes.Job job, String s)
    Extracts the chosen site from the site selector's answer.
    private File
    prepareInputFile(edu.isi.pegasus.planner.classes.Job job, List pools)
    Writes job knowledge into the temporary file passed to the external site selector.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • PREFIX_TEMPORARY_FILE

      public static final String PREFIX_TEMPORARY_FILE
      The prefix to be used while creating a temporary file to pass to the external siteselector.
      See Also:

    • SUFFIX_TEMPORARY_FILE

      public static final String SUFFIX_TEMPORARY_FILE
      The suffix to be used while creating a temporary file to pass to the external siteselector.

    • PREFIX_PROPERTIES

      public static final String PREFIX_PROPERTIES
      The prefix of the property names that specify the environment variables that need to be set before calling out to the site selector.
      See Also:

    • SOLUTION_PREFIX

      public static final String SOLUTION_PREFIX
      The prefix that the site selector writes out on its stdout to designate that it is sending a solution.
      See Also:

    • VERSION

      public static final String VERSION
      The version number associated with this API of non java callout site selection.
      See Also:

    • KEEP_NEVER

      public static final int KEEP_NEVER
      The state denoting never to keep the temporary files.
      See Also:

    • KEEP_ONERROR

      public static final int KEEP_ONERROR
      The state denoting to keep the temporary files only in case of error.
      See Also:

    • KEEP_ALWAYS

      public static final int KEEP_ALWAYS
      The state denoting always to keep the temporary files.
      See Also:

    • mDescription

      private static final String mDescription
      The description of the site selector.
      See Also:

    • mEnvVar

      private Map mEnvVar
      The map that contains the environment variables including the default ones that are set while calling out to the site selector unless they are overridden by the values set in the properties file.

    • mTimeout

      private int mTimeout
      The timeout value in seconds after which to timeout, in the case where the external site selector does nothing (nothing on stdout nor stderr).

    • mKeepTMP

      private int mKeepTMP
      The tristate value for whether keeping the temporary files generated or not.

    • mSiteSelectorPath

      private String mSiteSelectorPath
      The path to the site selector.

    • mAbstractDag

      private edu.isi.pegasus.planner.classes.ADag mAbstractDag
      The abstract DAG.

  • Constructor Details

    • NonJavaCallout

      public NonJavaCallout()
      The default constructor.

  • Method Details

    • initialize

      public void initialize(edu.isi.pegasus.planner.classes.PegasusBag bag)
      Initializes the site selector.
      Specified by:
      initialize in interface SiteSelector
      Overrides:
      initialize in class Abstract
      Parameters:
      bag - the bag of objects that is useful for initialization.

    • mapWorkflow

      public void mapWorkflow(edu.isi.pegasus.planner.classes.ADag workflow, List sites)
      Maps the jobs in the workflow to the various grid sites. The jobs are mapped by setting the site handle for the jobs.
      Specified by:
      mapWorkflow in interface SiteSelector
      Overrides:
      mapWorkflow in class AbstractPerJob
      Parameters:
      workflow - the workflow.
      sites - the list of String objects representing the execution sites that can be used.

    • description

      public String description()
      Returns a brief description of the site selection technique implemented by this class.
      Returns:
      a self-description of this site selector.

    • mapJob

      public void mapJob(edu.isi.pegasus.planner.classes.Job job, List sites)
      Calls out to the external site selector. The method converts a Job object into an API-compliant temporary file. The file's name is provided as single commandline argument to the site selector executable when it is invoked. The executable, representing the external site selector, provides its answer on stdout. The answer is captures, and returned.
      Specified by:
      mapJob in class AbstractPerJob
      Parameters:
      job - is a representation of the DAX compute job whose site of execution need to be determined.
      sites - the list of String objects representing the execution sites that can be used.

      FIXME: Some site selector return an empty string on failures. Also: NONE could be a valid site name.

      See Also:
      • Job

    • prepareInputFile

      private File prepareInputFile(edu.isi.pegasus.planner.classes.Job job, List pools)
      Writes job knowledge into the temporary file passed to the external site selector. The job knowledge derives from the contents of the DAX job's Job record, and the a list of site candidates. The format of the file is laid out in the class's introductory documentation.
      Parameters:
      job - is a representation of the DAX compute job whose site of execution need to be determined.
      pools - is a list of site candidates. The items of the list are String objects.
      Returns:
      the temporary input file was successfully prepared. A value of null implies that an error occured while writing the file.
      See Also:

    • parseStdOut

      private boolean parseStdOut(edu.isi.pegasus.planner.classes.Job job, String s)
      Extracts the chosen site from the site selector's answer. Parses the stdout sent by the selector, to see, if the execution pool and the jobmanager were sent or not.
      Parameters:
      job - the job that has to be mapped.
      s - is the stdout received from the site selector.
      Returns:
      boolean indicating if the stdout was succesfully parsed and job populated.

    • getTempFilename

      private String getTempFilename()
      Creates a temporary file and obtains its name. This method returns the absolute path to a temporary file in the system's TEMP directory. The file is guarenteed to be unique for the current invocation of the virtual machine.

      FIXME: However, since we return a filename and not an opened file, race conditions are still possible.

      Returns:
      the absolute path of a newly created temporary file.

    • loadEnvironmentVariables

      private void loadEnvironmentVariables()
      Initializes the internal hash that collects environment variables. These variables are set up to run the external helper application. Environment variables come from two source.
      1. Default environment variables, fixed, hard-coded.
      2. User environment variables, from properties.

    • getEnvArrFromMap

      private String[] getEnvArrFromMap()
      Generates an array of environment variables. The variables are kept in an internal map. Converts the environment variables in the map to the array format.
      Returns:
      array of enviroment variables set, or null if the map is empty.
      See Also:

    • getKeepTMPValue

      private int getKeepTMPValue(String value)
      Returns the int value corresponding to the string value passed.
      Parameters:
      value - the string value for keeping the temporary files.
      Returns:
      the corresponding int value.
      See Also:

    • main

      public static void main(String[] args)
      The main program that allows you to test. FIXME: Test programs should have prefix Test.....java
      Parameters:
      args - the arguments