// steps is the ordered sequence of workflow steps to orchestrate a service instance change
func (p plan) steps() (steps []step.Step) {
if p.newFeatures.NodeCount == 0 {
for i := 0; i < p.clusterModel.NodeCount(); i++ {
steps = append(steps, step.NewStepRemoveRandomNode(p.clusterModel, "", p.allCells, p.logger))
}
return
}
// we know the leader must survive because the cluster isn't being deleted
leaderID, _ := p.patroni.ClusterLeader(p.clusterModel.InstanceID())
addedNodes := false
for i := 0; i < p.clusterGrowingBy(); i++ {
steps = append(steps, step.NewStepAddNode(p.clusterModel, p.patroni, p.availableCells, p.logger))
addedNodes = true
}
replicasToBeReplaced, leaderToBeReplaced := p.nodesToBeReplaced(leaderID)
for _ = range replicasToBeReplaced {
steps = append(steps, step.NewStepAddNode(p.clusterModel, p.patroni, p.availableCells, p.logger))
addedNodes = true
}
if leaderToBeReplaced != nil {
steps = append(steps, step.NewStepAddNode(p.clusterModel, p.patroni, p.availableCells, p.logger))
addedNodes = true
}
if addedNodes {
steps = append(steps, step.NewWaitForAllMembers(p.clusterModel, p.patroni, p.logger))
}
removedNodes := false
for _, replica := range replicasToBeReplaced {
steps = append(steps, step.NewStepRemoveNode(replica, p.clusterModel, p.allCells, p.logger))
removedNodes = true
}
for i := 0; i < p.clusterShrinkingBy(); i++ {
steps = append(steps, step.NewStepRemoveRandomNode(p.clusterModel, leaderID, p.allCells, p.logger))
removedNodes = true
}
if removedNodes {
steps = append(steps, step.NewWaitForAllMembers(p.clusterModel, p.patroni, p.logger))
}
if leaderToBeReplaced != nil {
steps = append(steps, step.NewStepFailoverFrom(p.clusterModel, leaderID, p.patroni, p.logger))
steps = append(steps, step.NewStepRemoveNode(leaderToBeReplaced, p.clusterModel, p.allCells, p.logger))
}
steps = append(steps, step.NewWaitForLeader(p.clusterModel, p.patroni, p.logger))
return
}
// steps is the ordered sequence of workflow steps to orchestrate a service instance change
func (p plan) steps() (steps []step.Step) {
addedNodes := false
for i := 0; i < p.clusterGrowingBy(); i++ {
steps = append(steps, step.NewStepAddNode(p.clusterModel, p.patroni, p.availableCells, p.logger))
addedNodes = true
}
nodesToBeReplaced := p.nodesToBeReplaced()
for _ = range nodesToBeReplaced {
steps = append(steps, step.NewStepAddNode(p.clusterModel, p.patroni, p.availableCells, p.logger))
addedNodes = true
}
if addedNodes {
steps = append(steps, step.NewWaitForAllMembers(p.clusterModel, p.patroni, p.logger))
}
removedNodes := false
for _, replica := range p.replicas(nodesToBeReplaced) {
steps = append(steps, step.NewStepRemoveNode(replica, p.clusterModel, p.allCells, p.logger))
removedNodes = true
}
if leader := p.leader(nodesToBeReplaced); leader != nil {
steps = append(steps, step.NewStepRemoveLeader(leader, p.clusterModel, p.allCells, p.logger))
removedNodes = true
}
if removedNodes {
steps = append(steps, step.NewWaitForAllMembers(p.clusterModel, p.patroni, p.logger))
}
for i := 0; i < p.clusterShrinkingBy(); i++ {
steps = append(steps, step.NewStepRemoveRandomNode(p.clusterModel, p.allCells, p.logger))
}
if p.newFeatures.NodeCount > 0 {
steps = append(steps, step.NewWaitForLeader(p.clusterModel, p.patroni, p.logger))
}
return
}