Command Scheduler

Description

Command Scheduler is a capability exposed through the Web Admin Console that allows administrators to schedule Command Line Shell Commands to be run at specified intervals. 

Usage

The Command Scheduler allows administrators to schedule Command Line Shell Commands to be run in a "platform-independent" method. For instance, if an administrator wanted to use the Catalog commands to export all records of a Catalog to a directory, the administrator could write a cron job or a scheduled task to remote into the container and execute the command. Writing these types of scripts are specific to the administrator's operating system and also requires extra logic for error handling if the container is up. The administrator instead could simply create a Command Schedule, which currently requires only two fields. The Command Scheduler only runs when the container is running so there would be no need to verify if the container was up. In addition, when the container is restarted, the commands are rescheduled and executed again. 

Scheduling a Command

1. Navigate to the Web Admin Console
2. Click on the Configuration tab.
3. Find the Platform Command Scheduler configuration and click on the title or the "+" button. This will create a new configuration.
4. Type the command or commands to be executed in the Command text field. Commands can be separated by a semicolon and will be executed in order from left to right.
5. Type in a positive integer for the Interval In Seconds field. 
6. Click Save. Once the Save button has been clicked, the command will be executed immediately. It's next scheduled execution happens after the amount of seconds specified in Interval In Seconds and repeats indefinitely until the container is shutdown or the Scheduled Command is deleted.

Updating a Scheduled Command

1. Navigate to the Web Admin Console
2. Click on the Configuration tab.
3. Under the Platform Command Scheduler configuration are all the scheduled commands. Scheduled commands have the following syntax ddf.platform.scheduler.Command.{GUID} such as ddf.platform.scheduler.Command.4d60c917-003a-42e8-9367-1da0f822ca6e.
4. Find the desired configuration to modify and update either the Command text field or the Interval In Seconds field or both. 
5. Click Save. Once the Save button has been clicked, the command will be executed immediately. It's next scheduled execution happens after the amount of seconds specified in Interval In Seconds and repeats indefinitely until the container is shutdown or the Scheduled Command is deleted.

Command Output

Commands that normally write out to the console instead will write out to the distribution's log. For instance if an echo Hello World command was to run every five seconds, the log would look like as follows:

16:01:32,582 | INFO  | heduler_Worker-1 | ddf.platform.scheduler.CommandJob          68 | platform-scheduler   | Executing command [echo Hello World]
16:01:32,583 | INFO  | heduler_Worker-1 | ddf.platform.scheduler.CommandJob          70 | platform-scheduler   | Execution Output: Hello World
16:01:37,581 | INFO  | heduler_Worker-4 | ddf.platform.scheduler.CommandJob          68 | platform-scheduler   | Executing command [echo Hello World]
16:01:37,582 | INFO  | heduler_Worker-4 | ddf.platform.scheduler.CommandJob          70 | platform-scheduler   | Execution Output: Hello World

In other words, administrators can see the status of a run within the log as long as INFO was set as the status level.