Custom Drupal 7 module to toggle the Storage API "External" setting for Amazon S3 containers. See: https://www.drupal.org/node/1832364

storage_api_external.info

name = "S3 External Toggle"
description = "Enable to set all Storage API Amazon S3 containers to 'External' (disable to reverse the setting)"
package = "Storage API"
core = 7.x
version = 7.x-1.0

dependencies[] = storage

storage_api_external.module

<?php
/**
  * Implement hook_enable()
  */
function storage_api_external_enable() {
  db_update('storage_container')
    ->fields(array('external' => 1))
    ->condition('service_id', 'storage:s3', '=')
    ->execute();
}

/**
  * Implement hook_disable()
  */
function storage_api_external_disable() {
  db_update('storage_container')
    ->fields(array('external' => 0))
    ->condition('service_id', 'storage:s3', '=')
    ->execute();
}