Situation

Expectation

Institutions need to be able to schedule both the age to lost and aged to lost billing processes to be run during quieter periods for their libraries e.g. when the libraries are closed. This is to ensure these processes do not interfere with day to day processes by shifting the load on the system to a quieter part of the day.

Previous Decisions

• This aspect was excluded from the initial aged to lost work
• It was decided that FOLIO would not have general job scheduling capability, preferring that each module will provide this capability separately
• A periodic invocation mechanism was implemented in Okapi which allows a task to be executed each time a period has elapsed

Current State

At the moment, these two processes run at 30 or 35 minute intervals respectively using the Okapi _timer interface for basic scheduling. This approach means that the process runs throughout the working day.

The use of the timer interface means that

• only a single module instance is invoked for each process after the allotted period
• invocations of each process may overlap
• invocations of the two processes may overlap

Open Questions

• What are the needed scheduling options e.g. daily, weekly, specific days of the week?
• Can a process be executed on more than one schedule?
• What should happen if one of the processes fails?
• What are other background processes that need a similar capability (some are listed below)?

Possibly Related Areas

• Sending of scheduled patron notices also needs scheduling at a specific time
• Bursar exporting of fees / fines
• Data Export (as it defines the idea of a job)
• Data Import (as it defines the idea of a job)

Evaluation Criteria

• How are jobs configured?
• How is it decided which module instance executes a job?
• How are job executions granted permissions?
• How does the approach address concurrent execution?
• What coupling does this design introduce?

Design Options

In-module Scheduling using _timer interface

Overview

Implement a scheduling capability within mod-circulation with the aid of the existing Okapi _timer interface

Considerations

• Schedules would be set up using an API provided by mod-circulation
• Permissions would be provided as module permission for the process endpoints
• Choice of module instance is made by Okapi (assumed to be based upon version of module enabled for a tenant)
• Module instances would need to coordinate to avoid concurrent execution of the process
• Accuracy of when the process executes is dependent upon approach taken in mod-circulation
• Requires new interface dependency for storage of scheduling and job status (assuming business logic / storage constraint still in place, most likely mod-circulation-storage)

Entirely In-module Scheduling

Overview

Implement a scheduling capability within mod-circulation that does not rely on the existing _timer  interface. Processes would be executed with 

Considerations

• Schedules would be set up using an API provided by mod-circulation
• Permissions would need to be granted to a user either assigned or created for the processes
• Choice of module instance would require agreement / coordination between instances of the same version
• Module instances would need to coordinate to avoid concurrent execution of the process
• Accuracy of when the process executes is dependent upon approach taken in mod-circulation
• Requires new interface dependency for storage of scheduling and job status (assuming business logic / storage constraint still in place, most likely mod-circulation-storage)

Scheduler Module

Overview

Provide a scheduling 

Considerations

• Schedules would be set up in an API provided by the scheduling module
• Permissions would need to be granted to a user either assigned or created for the processes
• Choice of module instance would likely be made by Okapi (assuming scheduler modules uses HTTP via Okapi to start processes)
• Concurrent execution would be managed by scheduler module
• Accuracy of when the process executes is dependent upon approach taken in scheduling module
• Storage for schedule and execution management could be internal to scheduling module or a separate storage module

Variations

• Extend the scheduling capabilities of Okapi beyond the current _timer  interface
• Use Kafka instead of HTTP to manage process execution

External Scheduling Tool 

Overview

Scheduling can be done by external tools like cron

Considerations

• Schedules would be set up in the external tool (and cannot be configured from within FOLIO)
• Permissions would need to be granted to a user either assigned or created for the processes
• Choice of module instance would likely be made by Okapi (assuming scheduler modules uses HTTP via Okapi to start processes)
• Module instances would need to coordinate to avoid concurrent execution of the process
• Accuracy of when the process executes is dependent upon the external tool
• Could be left entirely up to the hosting provider or FOLIO may want to set expectations (e.g. like the use of AWS or min.io for file storage)

Related Information

• Design document for aged to lost processes
• JIRA issue for this design document
• JIRA issue where scheduling was first mentioned