Scheduling Jobs with the Windows PowerShell API
You can use the objects exposed by the N:Microsoft.PowerShell.ScheduledJob namespace to create a scheduled job, define when it runs, and get results about the completed job after it has run.
Triggering the Job
The first step in creating a scheduled job is specifying when the job should run. Do this by creating and configuring a T:Microsoft.PowerShell.ScheduledJob.ScheduledJobTrigger object. The following code creates a trigger that schedules a job to run a single time 20 seconds in the future.
ScheduledJobTrigger jobTrigger = ScheduledJobTrigger.CreateOnceTrigger(
DateTime.Now.AddSeconds(20), // Create trigger to start job 20 seconds after now.
TimeSpan.Zero, // No random delay
null, // No repetition interval time
null, // No repetition interval duration
1, // Trigger Id
true); // Create trigger enabled
Defining the Job
You define a Windows PowerShell job by creating a parameter dictionary. The following parameters are supported.
| Parameter Name | Description |
|---|---|
| Name | The name of the job. |
| ScriptBock | A Windows PowerShell script block that specifies what the job does. |
| FilePath | A path to a file that contains Windows PowerShell script block that specifies what the job does. |
| InitializationScript | A Windows PowerShell script block that initializes the job. |
| ArgumentList | An array of objects that specify arguments that the job takes. |
| RunAs32 | A boolean value that specifies whether to run the job in a 32-bit process. |
The following code creates a parameter dictionary object and sets the Name and ScriptBlock parameters.
string schedJobDefName = "MySampleSchedJob";
Dictionary<string, object> jobDefParameters = new Dictionary<string, object>();
jobDefParameters.Add("Name", schedJobDefName); // Unique name is required.
ScriptBlock scriptBlock = ScriptBlock.Create(@"1..5 | foreach {sleep 1; ""SchedJobOutput $_""}");
jobDefParameters.Add("ScriptBlock", scriptBlock); // A scriptblock or script FilePath
// is required.
Creating the Invocation and Job Definition Objects
You then create ScheduledJobInvocationInfo and ScheduledJobDefinition objects to run the job. The following code demonstrates this.
ScheduledJobInvocationInfo jobInvocationInfo = new ScheduledJobInvocationInfo(
nw JobDefinition(typeof(ScheduledJobSourceAdapter), scriptBlock.ToString(), schedJobDefName),
jobDefParameters);
schedJobDefinition = new ScheduledJobDefinition(
jobInvocationInfo, // Defines the PowerShell job to run.
new ScheduledJobTrigger[1] { jobTrigger }, // Defines when to run the PowerShell job.
null, // No custom options. We accept default.
null); // No credentials. PowerShell job is run
// in default Task Scheduler process, account.
Registering the Job with the Task Scheduler
The following code registers the job with the Windows Task Scheduler.
schedJobDefinition.Register();
registrationSucceeded = true;
Console.WriteLine("Scheduled job has been registered. Waiting 30 seconds for it to be started and run.");
Complete Code Example
The following is the complete code example from which the previous snippets were taken.
using System;
using System.Threading;
using System.Collections.Generic;
using System.Management.Automation; // Windows PowerShell namespace.
using Microsoft.PowerShell.ScheduledJob; // Windows PowerShell ScheduledJob namespace.
namespace Microsoft.Samples.PowerShell.ScheduledJob
{
/// <summary>
/// This class contains the Main entry point for the application.
/// </summary>
public class ScheduledJobSample
{
/// <summary>
/// This sample shows how to use the PowerShell ScheduledJob API to create
/// a simple PowerShell scheduled job, register it with a trigger object
/// that defines when the job will run and retrieve job run results from
/// the job file store.
/// </summary>
/// <param name="args"></param>
public static void Main(string[] args)
{
// ScheduledJobDefinition contains all elements of a PowerShell scheduled
// job including the PowerShell job script or script file path, scheduling
// triggers, and scheduling options.
ScheduledJobDefinition schedJobDefinition = null;
bool registrationSucceeded = false;
try
{
// First create a scheduled job trigger object. This object will
// define when the PowerShell job is scheduled to run. For this
// example we will create a trigger to run the job just one time
// 20 seconds after the trigger object is created.
// Note: If you are stepping through this code in a debugger you
// may want to increase the 20 seconds value so that the trigger time
// remains in the future once you register the scheduled job.
ScheduledJobTrigger jobTrigger = ScheduledJobTrigger.CreateOnceTrigger(
DateTime.Now.AddSeconds(20), // Create trigger to start job 20 seconds after now.
TimeSpan.Zero, // No random delay
null, // No repetition interval time
null, // No repetition interval duration
1, // Trigger Id
true); // Create trigger enabled
// Create a parameter dictionary that defines the PowerShell job.
// For this example we will create a simple script that runs for
// 5 seconds generating output.
// Here are the parameters supported to define the PowerShell job.
// Name - Job name string.
// ScriptBlock - PowerShell ScriptBlock type.
// FilePath - PowerShell script file path string.
// InitializationScript - PowerShell Scriptblock type.
// ArgumentList - object[] type.
// RunAs32 - Switch (boolean type).
string schedJobDefName = "MySampleSchedJob";
Dictionary<string, object> jobDefParameters = new Dictionary<string, object>();
jobDefParameters.Add("Name", schedJobDefName); // Unique name is required.
ScriptBlock scriptBlock = ScriptBlock.Create(@"1..5 | foreach {sleep 1; ""SchedJobOutput $_""}");
jobDefParameters.Add("ScriptBlock", scriptBlock); // A scriptblock or script FilePath
// is required.
// Now create a JobInvocation object that contains all information about
// the PowerShell job to run.
ScheduledJobInvocationInfo jobInvocationInfo = new ScheduledJobInvocationInfo(
new JobDefinition(typeof(ScheduledJobSourceAdapter), scriptBlock.ToString(), schedJobDefName),
jobDefParameters);
// Finally create the scheduled job definition object that pulls all
// of this information together.
schedJobDefinition = new ScheduledJobDefinition(
jobInvocationInfo, // Defines the PowerShell job to run.
new ScheduledJobTrigger[1] { jobTrigger }, // Defines when to run the PowerShell job.
null, // No custom options. We accept default.
null); // No credentials. PowerShell job is run
// in default Task Scheduler process, account.
// Next we register this scheduled job object with Windows Task Scheduler.
// The Task Scheduler will run the PowerShell script based on the provided job trigger.
schedJobDefinition.Register();
registrationSucceeded = true;
Console.WriteLine("Scheduled job has been registered. Waiting 30 seconds for it to be started and run.");
// You can see this PowerShell job task registered in the Task Scheduler UI.
// Look under path: Task Scheduler Library\Microsoft\Windows\PowerShell\ScheduledJobs
// Wait for Task Scheduler to run the PowerShell job. This should happen in 20 seconds
// and then the job will take about 5 seconds to run. If PowerShell job task doesn't
// run try increasing the trigger time in the ScheduledJobTrigger object. You can also
// run this task manually from the Task Scheduler UI.
for (int count = 1; count < 31; ++count)
{
Thread.Sleep(1000);
Console.WriteLine(count + " seconds elapsed");
}
Console.WriteLine();
Console.WriteLine("Job run results.");
Console.WriteLine();
// Since the PowerShell job runs in a non-interactive Task Scheduler
// process the job status and output data is written to a file based
// job store and the directory location is the current user local app
// data ($env:LOCALAPPDATA).
// This job store can be accessed through the ScheduledJobSourceAdapter class.
ScheduledJobSourceAdapter schedJobSourceAdapter = new ScheduledJobSourceAdapter();
IList<Job2> jobRuns = schedJobSourceAdapter.GetJobs();
foreach (var jobRun in jobRuns)
{
// Check for jobs in finished state.
// Note that job data is not written to the job store until the job
// has reached a finished state.
JobState jobState = jobRun.JobStateInfo.State;
if (jobState == JobState.Completed ||
jobState == JobState.Stopped ||
jobState == JobState.Failed)
{
// Write job run finished state.
Console.WriteLine("Job Status: " + jobRun.JobStateInfo.State);
Console.WriteLine();
Console.WriteLine("Job Data");
// Write output data.
foreach (var item in jobRun.Output)
{
Console.WriteLine(item.ToString());
}
// Write any errors.
foreach (var item in jobRun.Error)
{
Console.WriteLine(item.ToString());
}
}
}
Console.WriteLine();
Console.WriteLine("Press any key to continue...");
Console.ReadKey();
}
catch (ScheduledJobException e)
{
Console.WriteLine("Error: " + e.Message);
}
finally
{
// Unregister this scheduled job or an error will be thrown when
// running this sample code again (scheduled job already exists.)
// because all registered scheduled jobs must have a unique name.
if (registrationSucceeded)
{
schedJobDefinition.Remove(true);
}
}
}
}
}
Collaborate with us on GitHub
The source for this content can be found on GitHub, where you can also create and review issues and pull requests. For more information, see our contributor guide.
