Retry database delete if response is 409 (#328)

Fixes #327

Author: emerkle826

internal/provider/resource_database.go

@@ -28,7 +28,7 @@ var availableDbTypes = []string{
 
 var databaseCreateTimeout = time.Minute * 40
 var databaseReadTimeout = time.Minute * 5
-var databaseDeleteTimeout = time.Minute * 20
+var databaseDeleteTimeout = time.Minute * 40
 var databaseUpdateTimeout = time.Minute * 40
 
 func resourceDatabase() *schema.Resource {
@@ -323,6 +323,11 @@ func resourceDatabaseDelete(ctx context.Context, resourceData *schema.ResourceDa
 			return nil
 		}
 
+		// If the database is in Maintenance state, it will return a 409. We can retry this
+		if resp.StatusCode() == http.StatusConflict {
+			return retry.RetryableError(fmt.Errorf("Unable to terminate database %s. %s", databaseID, string(resp.Body)))
+		}
+
 		// All other 4XX status codes are NOT retried
 		if resp.StatusCode() >= http.StatusBadRequest {
 			return retry.NonRetryableError(fmt.Errorf("unexpected response attempting to terminate database. Status code: %d, message = %s", resp.StatusCode(), string(resp.Body)))