feat: ensure both old and new RDB instances reach stable states during engine upgrade

Author: jremy42

internal/services/rdb/instance.go

@@ -968,15 +968,6 @@ func ResourceRdbInstanceUpdate(ctx context.Context, d *schema.ResourceData, m an
 			return diag.FromErr(fmt.Errorf("engine version %s is not available for upgrade from %s. Available versions: %v",
 				newEngineStr, oldEngine.(string), availableVersions))
 		}
-
-		// MajorUpgradeWorkflow performs a blue/green deployment:
-		// 1. Creates a snapshot of the current instance
-		// 2. Creates a new instance with the target engine version
-		// 3. Restores data from the snapshot
-		// 4. Migrates endpoints (WithEndpoints=true) to the new instance
-		// 5. Returns the new instance with a different ID
-		// Note: Scaleway manages the lifecycle of the source instance. It remains available
-		// for potential rollback and is eventually cleaned up by Scaleway's infrastructure.
 		upgradeInstanceRequests = append(upgradeInstanceRequests,
 			rdb.UpgradeInstanceRequest{
 				Region:     region,
@@ -988,7 +979,6 @@ func ResourceRdbInstanceUpdate(ctx context.Context, d *schema.ResourceData, m an
 			})
 	}
 
-	// Carry out the upgrades
 	for i := range upgradeInstanceRequests {
 		_, err = waitForRDBInstance(ctx, rdbAPI, region, ID, d.Timeout(schema.TimeoutUpdate))
 		if err != nil && !httperrors.Is404(err) {
@@ -1002,13 +992,41 @@ func ResourceRdbInstanceUpdate(ctx context.Context, d *schema.ResourceData, m an
 
 		if upgradeInstanceRequests[i].MajorUpgradeWorkflow != nil && upgradedInstance.ID != ID {
 			tflog.Info(ctx, fmt.Sprintf("Engine upgrade created new instance, updating ID from %s to %s", ID, upgradedInstance.ID))
+			oldInstanceID := ID
 			ID = upgradedInstance.ID
 			d.SetId(regional.NewIDString(region, ID))
-		}
 
-		_, err = waitForRDBInstance(ctx, rdbAPI, region, ID, d.Timeout(schema.TimeoutUpdate))
-		if err != nil && !httperrors.Is404(err) {
-			return diag.FromErr(err)
+			_, err = waitForRDBInstance(ctx, rdbAPI, region, ID, d.Timeout(schema.TimeoutUpdate))
+			if err != nil && !httperrors.Is404(err) {
+				return diag.FromErr(err)
+			}
+
+			_, err = waitForRDBInstance(ctx, rdbAPI, region, oldInstanceID, d.Timeout(schema.TimeoutUpdate))
+			if err != nil && !httperrors.Is404(err) {
+				tflog.Warn(ctx, fmt.Sprintf("Old instance %s not ready for deletion: %v", oldInstanceID, err))
+			} else {
+				_, err = rdbAPI.DeleteInstance(&rdb.DeleteInstanceRequest{
+					Region:     region,
+					InstanceID: oldInstanceID,
+				}, scw.WithContext(ctx))
+				if err != nil && !httperrors.Is404(err) {
+					tflog.Warn(ctx, fmt.Sprintf("Failed to delete old instance %s: %v", oldInstanceID, err))
+				} else {
+					_, err = rdbAPI.WaitForInstance(&rdb.WaitForInstanceRequest{
+						Region:     region,
+						InstanceID: oldInstanceID,
+						Timeout:    scw.TimeDurationPtr(d.Timeout(schema.TimeoutUpdate)),
+					}, scw.WithContext(ctx))
+					if err != nil && !httperrors.Is404(err) {
+						tflog.Warn(ctx, fmt.Sprintf("Error waiting for old instance %s deletion: %v", oldInstanceID, err))
+					}
+				}
+			}
+		} else {
+			_, err = waitForRDBInstance(ctx, rdbAPI, region, ID, d.Timeout(schema.TimeoutUpdate))
+			if err != nil && !httperrors.Is404(err) {
+				return diag.FromErr(err)
+			}
 		}
 	}
 

internal/services/rdb/instance_test.go

@@ -1544,29 +1544,6 @@ func TestAccInstance_EndpointErrorHandling(t *testing.T) {
 	})
 }
 
-func isInstancePresent(tt *acctest.TestTools, n string) resource.TestCheckFunc {
-	return func(s *terraform.State) error {
-		rs, ok := s.RootModule().Resources[n]
-		if !ok {
-			return fmt.Errorf("resource not found: %s", n)
-		}
-
-		rdbAPI, region, ID, err := rdb.NewAPIWithRegionAndID(tt.Meta, rs.Primary.ID)
-		if err != nil {
-			return err
-		}
-
-		_, err = rdbAPI.GetInstance(&rdbSDK.GetInstanceRequest{
-			InstanceID: ID,
-			Region:     region,
-		})
-		if err != nil {
-			return err
-		}
-
-		return nil
-	}
-}
 func TestAccInstance_EngineUpgrade(t *testing.T) {
 	tt := acctest.NewTestTools(t)
 	defer tt.Cleanup()
@@ -1731,3 +1708,26 @@ func TestAccInstance_EngineUpgrade(t *testing.T) {
 	})
 }
 
+func isInstancePresent(tt *acctest.TestTools, n string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[n]
+		if !ok {
+			return fmt.Errorf("resource not found: %s", n)
+		}
+
+		rdbAPI, region, ID, err := rdb.NewAPIWithRegionAndID(tt.Meta, rs.Primary.ID)
+		if err != nil {
+			return err
+		}
+
+		_, err = rdbAPI.GetInstance(&rdbSDK.GetInstanceRequest{
+			InstanceID: ID,
+			Region:     region,
+		})
+		if err != nil {
+			return err
+		}
+
+		return nil
+	}
+}