How to control parallel execution of job chains

Scope

• Use Case:
  • Consider the situation where:
    
    • A job chain is to start at a number of parallel job chains
    • Subsequent jobs in started job chains check if jobs from parallel chains completed successfully.
  • Usually a split & sync pattern is used for similar use cases, however, synchronizing includes that both jobs have to be completed.
  • Instead the current use case is about check and control if a job of a parallel chain has completed without forcing both jobs to run synchronously.

Solution

• Download: final_chain_job_chain_history.zip
• Extract the archive to a folder in your JobScheduler installation named ./config/live.
• The archive will extract the files to a sub-folder parallel_job_chain_control. 
• Note that you can store the sample files in any folder you like.

Pattern

Implementation

Components

• The solution contains six job chains:
  • JobChain1 runs Job1 and Job2 in parallel.
    • On successful completion of Job1 then JobChain2 is run
    • On successful completion of Job2 then JobChain3 is run
  • JobChain2 runs Job3 and Job4
  • JobChain3 runs Job5 and Job6
  • JobChain4 runs after successful completion of JobChain1
    • JobChain4 runs Job7, Job8, Job9
    • Job7 runs 1st
    • Job8 runs once Job7 and Job4 have run successfully
  • JobChain5 runs after successful completion of JobChain1
    • JobChain5 runs Job10, Job11 and Job12
    • Job10 runs 1st
    • Job11 runs once Job10, Job4 and Job6 have run successfully
    • Job12 runs once Job11 has completed successfully
  • JobChain6 runs once Job9 and Job12 have completed successfully

Usage

• Positive Check
  • Add an order to job_chain_A using JOC's Add Order context menu.
    • The order should pass through the job chain without errors.
  • Add an order to job_chain_B using JOC's Add Order context menu.
    • The order should also pass through the job chain without errors.
  • Add an order to job_chain_Z using JOC's Add Order context menu.
    • The order should pass through the job chain without errors as all pre-conditions are met.
• Negative Check
  • Modify the job do_something_job_chain_A to include an error, e.g. by adding the command exit 1 as the final line in the job script.
  • Add an order to job_chain_A:
    
    • The order should proceed with an error.
  • Add an order to job_chain_Z
    • The order should proceed with an error that is visible in the order log. This error will state that the predecessor job did not complete successfully.
    • The order will be set back and will be repeated according to the setback intervals that have been specified for the job check_predecessor_job_chain_Z.
  • Removing the modification to job do_something_job_chain_A and adding an order to job_chain_A that then runs successfully should result in a successful run of job_chain_Z - either by a new order added to job_chain_Z or by the next execution of the previous order that has been set back.

See also

• How to check the job chain history for previous job chain and order runs
• How to add a condition to check previous jobs before the execution of the current job chain