55 lines
1.7 KiB
Go
55 lines
1.7 KiB
Go
// multistep is a library for building up complex actions using individual,
|
|
// discrete steps.
|
|
package multistep
|
|
|
|
import "context"
|
|
|
|
// A StepAction determines the next step to take regarding multi-step actions.
|
|
type StepAction uint
|
|
|
|
const (
|
|
ActionContinue StepAction = iota
|
|
ActionHalt
|
|
)
|
|
|
|
// This is the key set in the state bag when using the basic runner to
|
|
// signal that the step sequence was cancelled.
|
|
const StateCancelled = "cancelled"
|
|
|
|
// This is the key set in the state bag when a step halted the sequence.
|
|
const StateHalted = "halted"
|
|
|
|
type StepRunnableWithContext interface {
|
|
RunWithContext(context.Context, StateBag) StepAction
|
|
}
|
|
|
|
// Step is a single step that is part of a potentially large sequence
|
|
// of other steps, responsible for performing some specific action.
|
|
type Step interface {
|
|
// Run is called to perform the action. The parameter is a "state bag"
|
|
// of untyped things. Please be very careful about type-checking the
|
|
// items in this bag.
|
|
//
|
|
// The return value determines whether multi-step sequences continue
|
|
// or should halt.
|
|
Run(StateBag) StepAction
|
|
|
|
// Cleanup is called in reverse order of the steps that have run
|
|
// and allow steps to clean up after themselves. Do not assume if this
|
|
// ran that the entire multi-step sequence completed successfully. This
|
|
// method can be ran in the face of errors and cancellations as well.
|
|
//
|
|
// The parameter is the same "state bag" as Run, and represents the
|
|
// state at the latest possible time prior to calling Cleanup.
|
|
Cleanup(StateBag)
|
|
}
|
|
|
|
// Runner is a thing that runs one or more steps.
|
|
type Runner interface {
|
|
// Run runs the steps with the given initial state.
|
|
Run(StateBag)
|
|
|
|
// Cancel cancels a potentially running stack of steps.
|
|
Cancel()
|
|
}
|