Cache tags for all entities of a certain type

Question

I understand how you can add cache tags to a custom query for a particular entity id (or list of them) but is there a way to add cache tags that will invalidate a query if any entity of type FOO is updated/added/deleted?

Answer 1

You could use the module handy_cache_tags, then you would have this type of tags:

handy_cache_tags:[entity_type]
handy_cache_tags:[entity_type]:[entity_bundle]

Answer 2

In your blockcache_examples.module file:

use Drupal\Core\Cache\Cache;
use Drupal\node\Entity\Node;

/**
 * Invalidate the custom tag if entities of type "page" get updated
 */
function blockcache_examples_node_update(Node $entity) {
  if($entity->getType() === 'page') {
    Cache::invalidateTags(['blockcache_examples_page_updates']);
  }
}

/**
 * Invalidate the custom tag if entities of type "page" get inserted
 */
function blockcache_examples_node_insert(Node $entity) {
  if($entity->getType() === 'page') {
    Cache::invalidateTags(['blockcache_examples_page_updates']);
  }
}

/**
 * Invalidate the custom tag if entities of type "page" get deleted
 */
function blockcache_examples_node_delete(Node $entity) {
  if($entity->getType() === 'page') {
    Cache::invalidateTags(['blockcache_examples_page_updates']);
  }
}

In your src/Plugin/Block/MyBlock.php (or controller, whatever):

/**
 * Only when node(s) of type 'page' are updated/insert/deleted. See .module file
 */
public function getCacheTags() {
  return Cache::mergeTags(parent::getCacheTags(), array('blockcache_examples_page_updates'));
}

Source: this video explaining block caching