The Solr Stack

CDCP’s search facility is provided by Apache Solr (https://solr.apache.org/) and an associated stack of services.

CUDL Solr

The core search facility is provided by Solr and can be found in https://github.com/cambridge-collection/cudl-solr.

CUDL Search API

Solr’s API is a protected. It can only be accessed from within the CDCP subnet by one component: the cudl-search API (https://github.com/cambridge-collection/cudl-search). This API provides the endpoints for all search-related actions. By default, only GET requests (i.e. queries) are publicly available. All destructive actions, such as submitting a file for indexing or deleting a file, are implemented via PUT and POST requests. These requests are only available to certain key components in CDCP’s private subnet, like the cudl-solr-listener.

CUDL Solr Listener

Whenever a Solr JSON file is changed, AWS queues an SNS message. These messages are sent to the cudl-solr-listener (https://github.com/cambridge-collection/cudl-solr-listener), which verifies that the JSON file is plausibly valid before submitting it for reindexing.