multistep
multistep is a Go library for building up complex actions using discrete, individual "steps." These steps are strung together and run in sequence to achieve a more complex goal. The runner handles cleanup, cancelling, etc. if necessary.
Basic Example
Make a step to perform some action. The step can access your "state", which is passed between steps by the runner.
type stepAdd struct{}
func (s *stepAdd) Run(state multistep.StateBag) multistep.StepAction {
// Read our value and assert that it is they type we want
value := state.Get("value").(int)
fmt.Printf("Value is %d\n", value)
// Store some state back
state.Put("value", value + 1)
return multistep.ActionContinue
}
func (s *stepAdd) Cleanup(multistep.StateBag) {
// This is called after all the steps have run or if the runner is
// cancelled so that cleanup can be performed.
}Make a runner and call your array of Steps.
func main() {
// Our "bag of state" that we read the value from
state := new(multistep.BasicStateBag)
state.Put("value", 0)
steps := []multistep.Step{
&stepAdd{},
&stepAdd{},
&stepAdd{},
}
runner := &multistep.BasicRunner{Steps: steps}
// Executes the steps
runner.Run(state)
}This will produce:
Value is 0
Value is 1
Value is 2