Implement single-owner managed takeover

internal/publish/plan.go

@@ -21,6 +21,7 @@ const (
 	ActionFailConflict         Action = "fail_conflict"
 	ActionFailUnmanaged        Action = "fail_unmanaged"
 	ActionForceReplace         Action = "force_replace"
+	ActionReplaceTakeover      Action = "replace_takeover"
 )
 
 type Request struct {
@@ -36,6 +37,7 @@ type Request struct {
 	Links                 *config.Links
 	State                 config.StatePolicy
 	Reconciliation        config.ReconciliationPolicy
+	Takeover              config.TakeoverPolicy
 	Transformers          TransformerResolver
 	Transfer              config.TransferPolicy
 	DistributorVersion    string
@@ -96,10 +98,14 @@ func Build(ctx context.Context, req Request) (Plan, error) {
 	if err != nil {
 		return Plan{}, err
 	}
-	comparison := compareDestination(req, status)
-	action, reason := actionForComparison(comparison, req.Transfer, req.Force)
 	reconciliation := normalizeReconciliation(req.Reconciliation)
 	stateMode := normalizeState(req.State).Mode
+	comparison := compareDestination(req, status)
+	action, reason := actionForComparison(comparison, req.Transfer, req.Force)
+	if takeoverActionAllowed(req, status, comparison, stateMode, action) {
+		action = ActionReplaceTakeover
+		reason = comparison.Reason
+	}
 	plan := Plan{
 		PipelineID:            req.PipelineID,
 		DestinationID:         req.DestinationID,
@@ -162,6 +168,11 @@ func validateRequest(req Request) error {
 	default:
 		return fmt.Errorf("state.mode must be %s or %s", config.StateModeSingleOwner, config.StateModeSharedRoot)
 	}
+	switch normalizeTakeover(req.Takeover).Mode {
+	case config.TakeoverModeSamePipeline, config.TakeoverModeSameSource, config.TakeoverModeAnyManaged, config.TakeoverModeNever:
+	default:
+		return fmt.Errorf("takeover.mode must be %s, %s, %s, or %s", config.TakeoverModeSamePipeline, config.TakeoverModeSameSource, config.TakeoverModeAnyManaged, config.TakeoverModeNever)
+	}
 	return nil
 }
 
@@ -179,6 +190,13 @@ func normalizeState(policy config.StatePolicy) config.StatePolicy {
 	return policy
 }
 
+func normalizeTakeover(policy config.TakeoverPolicy) config.TakeoverPolicy {
+	if policy.Mode == "" {
+		policy.Mode = config.TakeoverModeSamePipeline
+	}
+	return policy
+}
+
 func compareDestination(req Request, status state.DestinationStatus) state.Comparison {
 	if normalizeState(req.State).Mode == config.StateModeSharedRoot {
 		scope := state.CurrentOwnerScope(req.PipelineID, req.DestinationID)
@@ -207,24 +225,6 @@ func compareDestination(req Request, status state.DestinationStatus) state.Compa
 		return comparison
 	}
 	comparison := state.Compare(req.SourceBundle.Manifest, req.PipelineID, req.DestinationID, status)
-	if req.PathMapping != config.PathMappingFixed || comparison.Outcome != state.OutcomeDifferentSourceConflict || status.State == nil {
-		return comparison
-	}
-	destinationManifest := status.State.Source.Manifest
-	if destinationManifest.Created.Before(req.SourceBundle.Manifest.Created) {
-		return state.Comparison{Outcome: state.OutcomeDestinationOlder, Reason: "fixed destination source is older than selected source"}
-	}
-	if destinationManifest.Created.After(req.SourceBundle.Manifest.Created) {
-		return state.Comparison{
-			Outcome: state.OutcomeDestinationNewer,
-			Reason:  "fixed destination source is newer than selected source",
-			Detail: state.ComparisonDetail{
-				Kind:                state.ComparisonDetailDestinationNewer,
-				CurrentSourceID:     req.SourceBundle.Manifest.ID,
-				DestinationSourceID: destinationManifest.ID,
-			},
-		}
-	}
 	return comparison
 }
 
@@ -296,7 +296,7 @@ func planSharedRootOwner(ctx context.Context, req Request, status state.Destinat
 
 func isWriteAction(action Action) bool {
 	switch action {
-	case ActionPublishNew, ActionReplaceOlder, ActionForceReplace:
+	case ActionPublishNew, ActionReplaceOlder, ActionReplaceTakeover, ActionForceReplace:
 		return true
 	default:
 		return false
@@ -439,3 +439,32 @@ func actionForComparison(comparison state.Comparison, transfer config.TransferPo
 		return ActionFailConflict, "unsupported comparison outcome"
 	}
 }
+
+func takeoverActionAllowed(req Request, status state.DestinationStatus, comparison state.Comparison, stateMode string, action Action) bool {
+	if stateMode != config.StateModeSingleOwner || status.State == nil {
+		return false
+	}
+	if action == ActionForceReplace {
+		return false
+	}
+	switch comparison.Detail.Kind {
+	case state.ComparisonDetailPipelineIDMismatch,
+		state.ComparisonDetailDestinationIDMismatch,
+		state.ComparisonDetailDifferentSourceID:
+	default:
+		return false
+	}
+	takeover := normalizeTakeover(req.Takeover)
+	switch takeover.Mode {
+	case config.TakeoverModeSamePipeline:
+		return status.State.PipelineID == req.PipelineID
+	case config.TakeoverModeSameSource:
+		return status.State.Source.Manifest.ID == req.SourceBundle.Manifest.ID
+	case config.TakeoverModeAnyManaged:
+		return true
+	case config.TakeoverModeNever:
+		return false
+	default:
+		return false
+	}
+}