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The File Size Monitor can be configured from job or order parameters.

The following parameters are used:

Parameter	Required	Default	Description
`monitor_file_change_location`	yes		The full path of a file that should be monitored.
`monitor_file_change_timeout`	yes		The max. duration in seconds that repeated checks for steady file size are performed.
`monitor_file_change_interval`	no	1	Specifies the number of seconds that the monitor sleeps between repeated checks of the file size.
`monitor_file_change_exit_code`	no		Optionally sets the exit code of the current job to the specified value if the monitored files is not being found steady. This works for shell jobs exclusively.
`monitor_file_change_error_state`	no		Optionally sets the order to the specified state if the monitored file is not being found steady

Order Implementation

An order can be used to carry the parameters for the File Size Monitor.

The order can be implemented like this:

Code Block

language	xml
title	Order Implementation Sample
linenumbers	true
collapse	true

<order>
    <params >
        <param  name="monitor_file_change_location" value="/tmp/jobscheduler/file/some_changing_file.txt"/>
        <param  name="monitor_file_change_timeout" value="30"/>

        <param  name="monitor_file_change_error_state" value="error"/>
    </params>


    <run_time />
</order>

Job Implementation

A job that makes use of the File Size Monitor can reference the monitor by the <monitor.use> element.

The job can be implemented as a shell job or as an API job for any of the supported languages, e.g.

Code Block

language	xml
title	Job Implementation Sample
linenumbers	true
collapse	true

<job  order="yes" stop_on_error="no">
    <script  language="shell">
        <![CDATA[
echo hello world
        ]]>
    </script>


    <monitor.use  ordering="0" monitor="monitor_file_change"/>


    <run_time />
</job>

Explanations

...

- - line 2 to 6: implements the job script
  - line 8: references the monitor script

Monitor Implementation

sThe File Size Monitor is implemented as follows:

Code Block

language	js
title	Monitor implementationImplementation
linenumbers	true
collapse	true

function spooler_process_before() {

    var rc = true;

    // merge parameters from task and order
    var params = spooler_task.params;
    params.merge( spooler_task.order.params );

    // required parameters
    var monitorLocation = params.value( 'monitor_file_change_location' );
    var monitorTimeout = params.value( 'monitor_file_change_timeout' );

    // optional parameters
    var monitorInterval = params.value( 'monitor_file_change_interval' );
    var monitorExitCode = params.value( 'monitor_file_change_exit_code' );
    var monitorErrorState = params.value( 'monitor_file_change_error_state' );
 
    if ( !monitorLocation ) {
        spooler_log.error( '.. parameter missing: monitor_file_change_location' );
        return false;
    }

    if ( !monitorTimeout ) {
        spooler_log.error( '.. parameter missing: monitor_file_change_timeout' );
        return false;
    } else {
        monitorTimeout = parseInt( monitorTimeout );
    }

    if ( !monitorInterval ) {
        monitorInterval = 1;
    } else {
        monitorInterval = parseInt( monitorInterval );
    }

    if ( !monitorExitCode ) {
        monitorExitCode = 1;
    } else {
        monitorExitCode = parseInt( monitorExitCode );
    }

    // let's use a Java package for file operations
    var monitorFile = new java.io.File( monitorLocation );
    if ( !monitorFile.isFile() ) {
        spooler_log.error( 'file does not exist: ' + monitorLocation );
        return false;
    } else {
        spooler_log.info( '.. monitoring file for max. ' + monitorTimeout + ' seconds: ' + monitorLocation );
    }

    var currentDuration = 0;
    var fileSize = 0;
    var lastFileSize = 0;

    do {
        lastFileSize = monitorFile.length();
        spooler_log.info( '.. current file size: ' + lastFileSize + ' bytes' );
        java.lang.Thread.sleep( monitorInterval * 1000 );
        fileSize = monitorFile.length();
        currentDuration = currentDuration + monitorInterval;
    } while ( (fileSize != lastFileSize) && (currentDuration < monitorTimeout) )

    if ( fileSize === lastFileSize ) {
        spooler_log.info( '.. file size is steady after ' + currentDuration + ' seconds (' + fileSize + ' bytes): ' + monitorLocation );
    } else {
        spooler_log.info( '.. giving up as file size is not steady after ' + currentDuration + ' seconds (' + fileSize + ' bytes): ' + monitorLocation );
        rc = false;

        if ( monitorExitCode ) {
            spooler_log.info( '.. setting task exit code: ' + monitorExitCode );
            spooler_task.exit_code = monitorExitCode;
        }

        if ( monitorErrorState ) {
            spooler_log.info( '.. moving order to error state: ' + monitorErrorState );
            spooler_task.order.state = monitorErrorState;
        }
    }

    return rc;
}

Explanations
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Key

Order Implementation

Job Implementation

Monitor Implementation