Scheduled

The scheduled functions allow to run an operation according to a given schedule. It is preferred to use repeat, retry, or combination of both functions for most use cases, as they provide a more convenient DSL. In fact retry and repeat use scheduled internally.

Operation definition

Similarly to the retry and repeat APIs, the operation can be provided:

• directly using a by-name parameter, i.e. f: => T

• using a by-name Either[E, T]

• or using an arbitrary error mode, accepting the computation in an F context: f: => F[T].

Configuration

The scheduled config consists of:

• a Schedule, which indicates how many times the operation should be run, provides a duration based on which a sleep is calculated and provides an initial delay if configured.

• a SleepMode, which determines how the sleep between subsequent operations should be calculated:

  • Interval - default for repeat operations, where the sleep is calculated as the duration provided by schedule minus the duration of the last operation (can be negative, in which case the next operation occurs immediately).

  • Delay - default for retry operations, where the sleep is just the duration provided by schedule.

• afterAttempt - a callback function that is invoked after each operation and determines if the scheduler loop should continue. Used for onRetry, shouldContinueOnError, shouldContinueOnResult and adaptive retries in retry API. Defaults to always continuing.

Schedule

See the retry documentation for an overview of the available ways to create and modify a Schedule.

Testing schedules

Schedules can be tested by forcing the evaluation of Schedule.intervals and inspecting the resulting lazy list of intervals.