fix(resources): purge PostgresFlex instances in one nuke run

DeleteInstance is a soft delete; the instance stays listed as Deleted,
so libnuke waited on it forever. Remove now soft-deletes, polls until
the instance reaches Deleted, then force-deletes to fully purge.

Author: qaiser42

resources/postgresflex-instance.go

@@ -3,6 +3,7 @@ package resources
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"github.com/sirupsen/logrus"
 
@@ -32,13 +33,15 @@ func init() {
 //
 // Endpoints used:
 //   - GET    /v2/projects/{projectId}/regions/{region}/instances
+//   - GET    /v2/projects/{projectId}/regions/{region}/instances/{instanceId}
 //   - DELETE /v2/projects/{projectId}/regions/{region}/instances/{instanceId}
 //   - DELETE /v2/projects/{projectId}/regions/{region}/instances/{instanceId}/force
 //
 // Deleting an instance is a soft delete: it stays listed with status
-// "Deleted" during the retention window. Remove therefore force-deletes
-// instances already in that state so a nuke run converges instead of
-// re-deleting the same instance forever.
+// "Deleted" during the retention window, so libnuke would wait on it
+// forever (Remove is only invoked once per item per run). Remove therefore
+// soft-deletes, polls until the instance reaches "Deleted", then
+// force-deletes to purge it within the same run.
 type PostgresFlexInstance struct {
 	*BaseResource `property:",inline"`
 
@@ -49,14 +52,48 @@ type PostgresFlexInstance struct {
 	Status string
 }
 
+const postgresFlexStatusDeleted = "Deleted"
+
 func (r *PostgresFlexInstance) Remove(ctx context.Context) error {
 	if r.api == nil {
 		return fmt.Errorf("PostgresFlexInstance.Remove: api client not set")
 	}
-	if r.Status == "Deleted" {
-		return r.api.ForceDeleteInstance(ctx, r.ProjectID, r.Region, r.ID).Execute()
+	if r.Status != postgresFlexStatusDeleted {
+		if err := r.api.DeleteInstance(ctx, r.ProjectID, r.Region, r.ID).Execute(); err != nil {
+			return fmt.Errorf("delete instance: %w", err)
+		}
+		if err := r.waitUntilDeleted(ctx); err != nil {
+			return err
+		}
+	}
+	if err := r.api.ForceDeleteInstance(ctx, r.ProjectID, r.Region, r.ID).Execute(); err != nil {
+		return fmt.Errorf("force delete instance: %w", err)
+	}
+	return nil
+}
+
+// waitUntilDeleted polls the instance until the soft delete has landed
+// (status "Deleted"); force delete is rejected before that.
+func (r *PostgresFlexInstance) waitUntilDeleted(ctx context.Context) error {
+	ctx, cancel := context.WithTimeout(ctx, 10*time.Minute)
+	defer cancel()
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		resp, err := r.api.GetInstance(ctx, r.ProjectID, r.Region, r.ID).Execute()
+		if err != nil {
+			return fmt.Errorf("get instance while waiting for soft delete: %w", err)
+		}
+		if item, ok := resp.GetItemOk(); ok && item.GetStatus() == postgresFlexStatusDeleted {
+			return nil
+		}
+		select {
+		case <-ctx.Done():
+			return fmt.Errorf("timed out waiting for instance %s to reach %s state: %w", r.ID, postgresFlexStatusDeleted, ctx.Err())
+		case <-ticker.C:
+		}
 	}
-	return r.api.DeleteInstance(ctx, r.ProjectID, r.Region, r.ID).Execute()
 }
 
 func (r *PostgresFlexInstance) Properties() types.Properties { return PropsFromStruct(r) }