Matching label synchronization

In the background, the LIM Matcher synchronizes in-memory index labels with Redis keys. For all the in-memory index labels, it sets keys in the following format: matching_label__<label>__<matcher_id>, e.g. matching_label__17cdbe41-c7f1-440b-b9ad-aad93c7176ee__10.16.5.160:5200. Label key being set have a TTL and will expire if not updated again. The presence of such a key in Redis means that some of the running LIM Matcher instances can process matching requests on the label.

Note

The <matcher_id> in a label key is the host & port of the LIM Matcher. The host is taken from the environment variable VL_LIM_MATCHER_HOST, or, if not set, it is guessed using the operation system socket API.

Reading these keys from the Redis will allow the Matching Plugin to get information for which LIM Matcher instances have loaded into memory the particular index labels.