Big-Data-HPC-Platform/docs/ECLScheduler/ECLSched-Mods/ECLSchedComp.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<book>
  <bookinfo>
    <title>ECL Scheduler</title>

    <author>
      <firstname>Boca Raton</firstname>

      <surname>Documentation Team</surname>

      <affiliation>
        <orgname>Lexis Nexis</orgname>
      </affiliation>
    </author>

    <pubdate>2012</pubdate>
  </bookinfo>

  <chapter id="ECLSched_comp">
    <title>ECL Scheduler Component</title>

    <sect1 id="ECLSched_component" role="nobrk">
      <title>Installation and configuration</title>

      <para>The ECL Scheduler installs when you install the HPCC platform. It
      starts and stops using hpcc-init, just as all other HPCC
      components.</para>
    </sect1>

    <sect1>
      <title>Using the ECL Scheduler</title>

      <sect2>
        <title>ECL Language Statements Used</title>

        <para>The Following ECL Language Statements are used:</para>

        <sect3>
          <title>WHEN</title>

          <para>The <emphasis role="bold">WHEN </emphasis>service executes the
          action whenever the event is triggered. The optional <emphasis
          role="bold">COUNT </emphasis>option specifies the number of events
          to trigger instances of the action.</para>
        </sect3>

        <sect3>
          <title>NOTIFY</title>

          <para>The <emphasis role="bold">NOTIFY </emphasis>action triggers
          the event so that the <emphasis role="bold">WHEN </emphasis>workflow
          service can proceed with operations they are assigned to
          execute.</para>
        </sect3>

        <sect3>
          <title>EVENT</title>

          <para>The <emphasis role="bold">EVENT </emphasis>function returns a
          trigger event, which may be used within the <emphasis
          role="bold">WHEN </emphasis>workflow service or the <emphasis
          role="bold">NOTIFY</emphasis> action. EVENT is not really a
          statement, rather a parameter to WHEN/NOTIFY to describe what kind
          of event it is used for.</para>
        </sect3>

        <sect3>
          <title>CRON</title>

          <para>The <emphasis role="bold">CRON </emphasis>function defines a
          timer event for use within the <emphasis role="bold">WHEN
          </emphasis>workflow service. This is synonymous with <emphasis
          role="bold">EVENT(‘CRON’, time)</emphasis>. CRON itself is not a
          statement, rather a parameter to WHEN/NOTIFY to describe what kind
          of event it is used for.</para>
        </sect3>

        <sect3>
          <title>WAIT</title>

          <para>The <emphasis role="bold">WAIT </emphasis>function is a string
          constant containing the name of the event to wait for. It is used
          much like the <emphasis role="bold">WHEN</emphasis> workflow
          service, but may be used within conditional code.</para>
        </sect3>
      </sect2>

      <sect2>
        <title>Monitoring Functions in the Standard Library (STD.File)</title>

        <sect3>
          <title>MonitorFile</title>

          <para>The <emphasis role="bold">MonitorFile </emphasis>function
          creates a file monitor job in the DFU Server for a physical
          file.</para>
        </sect3>

        <sect3>
          <title>MonitorLogicalFileName</title>

          <para>The <emphasis role="bold">MonitorLogicalFileName
          </emphasis>function creates a file monitor job in the DFU Server for
          a logical file.</para>
        </sect3>
      </sect2>

      <sect2>
        <title>DFUPlus: Monitor Option</title>

        <para><programlisting>     dfuplus action=monitor event=MyEvent</programlisting></para>

        <para><variablelist>
            <varlistentry>
              <term><emphasis role="bold">Note</emphasis>:</term>

              <listitem>
                <para>DFUServer file monitoring (either using the Standard
                Library or DFUPlus) creates a DFU Workunit. While monitoring,
                the Workunit’s state is <emphasis>monitoring </emphasis>and
                once it triggers the event, it is set to
                <emphasis>finished</emphasis>. You can Abort a “monitoring”
                DFU Workunit to stop monitoring from ECL Watch.</para>
              </listitem>
            </varlistentry>
          </variablelist></para>
      </sect2>
    </sect1>

    <sect1 id="ECLSched_Interface">
      <title>Interface in ECL Watch</title>

      <para>To access the ECL Scheduler interface in ECL Watch, click on
      the<emphasis role="bold"> Event Scheduler </emphasis>link in the
      navigation sub-menu. The Scheduler interface displays and you can see
      the scheduled workunits, if any.</para>

      <para>The list of scheduled workunits has two significant columns, the
      <emphasis role="bold">EventName </emphasis>and the <emphasis
      role="bold">EventText</emphasis>.</para>

      <para><figure>
          <title>ECL Scheduler Interface</title>

          <mediaobject>
            <imageobject>
              <imagedata fileref="../../images/ESCHed01.jpg" />
            </imageobject>
          </mediaobject>
        </figure></para>

      <para>The EventName is a created when scheduling a workunit. The
      EventText is an accompanying sub event.</para>

      <para>You can trigger an event by entering the EventName and Event Text
      in the entry boxes and then pressing the <emphasis
      role="bold">PushEvent</emphasis> button. This is the same as triggering
      an event using NOTIFY.</para>

      <sect2 id="ECLSched_WorkunitList">
        <title>Scheduler Workunit List</title>

        <para>You can search scheduled workunits by cluster or event name. To
        filter by cluster or event name, click on the <emphasis
        role="bold">Filter</emphasis> Action button. The Filter sub-menu
        displays. Fill in values for the filter criteria, Eventname or
        Cluster, then press the <emphasis role="bold">Apply</emphasis> button.
        When you specify any Filter options, the Filter Action button displays
        <emphasis>Filter Set</emphasis>. <figure>
            <title>Workunits in the Scheduler Interface</title>

            <mediaobject>
              <imageobject>
                <imagedata fileref="../../images/ESCHed02.jpg" />
              </imageobject>
            </mediaobject>
          </figure></para>

        <para>You can sort the workunits by clicking on the column
        header.</para>

        <para>To view the workunit details, click on the workunit ID (WUID)
        link for the workunit.</para>
      </sect2>

      <sect2 id="ECLSched_PushingEvents" role="brk">
        <title>Pushing Events</title>

        <para>The Event Scheduler allow you to trigger or "push" an event to
        help manage and test your scheduled jobs.</para>

        <para><orderedlist>
            <listitem>
              <para>Press the <emphasis role="bold">PushEvent</emphasis>
              action button.</para>

              <para>The Push Event dialog opens.</para>
            </listitem>

            <listitem>
              <para>Enter the EventName:</para>

              <para>The EventName is a case-insensitive string constant naming
              the event to trap.</para>

              <para>See Also: EVENT</para>
            </listitem>

            <listitem>
              <para>Enter the EventText:</para>

              <para>The EventText is case-insensitive string constant naming
              the specific type of event to trap. It may contain * and ? to
              wildcard-match.</para>

              <para>See Also: EVENT</para>
            </listitem>

            <listitem>
              <para>Press the <emphasis role="bold">Apply</emphasis>
              button</para>

              <para>This is the equivalent of</para>

              <para><programlisting>  NOTIFY(EVENT(EventName,EventText));</programlisting></para>

              <para>See Also: NOTIFY, EVENT</para>

              <para><figure>
                  <title>PushEvent</title>

                  <mediaobject>
                    <imageobject>
                      <imagedata fileref="../../images/ESCHed03.jpg" />
                    </imageobject>
                  </mediaobject>
                </figure></para>
            </listitem>
          </orderedlist></para>
      </sect2>
    </sect1>
  </chapter>
</book>