Enable global persistent variables

Current Situation

• Global variables can be exposed to jobs and monitors by use of:
  1. Environment Variables: such variables are defined at JobScheduler start-up.
     • For a Master this is performed with the ./user_bin/jobscheduler_environment_variables.sh | .cmd script.
     • For an Agent this is performed with the ./bin/jobscheduler_agent_<port>.sh | .cmd instance script.
     • Such variables cannot be modified by jobs and monitors.
  2. JobScheduler Variables:
     • Such variables are configured with the ./config/scheduler.xml file like this:

       <params>
           <param name="scheduler.variable_name_prefix" value="SCHEDULER_PARAM_"/>
           <param name="my_variable" value="my_value"/>
       </params>
       

     • The variables can be accessed by environment variables using the respective prefix, for the above example this is SCHEDULER_PARAM_MY_VARIABLE. In addition the JobScheduler API includes methods to access and to modify such variables, see Variable_set reference. However, modifications are not persistent and will be effective for the given JobScheduler Master run only.
     • Such variables are valid within the scope of a JobScheduler Master instance, they are not forwarded in case of fail-over with a JobScheduler Master passive cluster.
• There is no way to use persistent global variables that work across JobScheduler Master instances in case of fail-over.

Desired Behavior

• A new type of Persistent Variables should be introduced that are stored with the JobScheduler database:
  • the variables are exposed as environment variables to shell jobs and they are exposed by API methods to scripted jobs (JavaScript, PowerShell).
  • access to Persistent Variables is consistent, i.e. concurrency of jobs modifying such variables is considered.
  • the variables are persistent across a number of JobScheduler Master instances in case of fail-over.

Maintainer Notes

• This feature is not assigned to a specific release for now. You can vote for this issue to make it real.
• Your input is welcome: let us know your requirements for use of global variables.