multilevel

Combines multiple caches as levels, performing read-through and write-through operations across them.

# Config fields, showing default values
label: ""
multilevel: [] # No default (required)

Examples

Hot and cold cache

The multilevel cache is useful for reducing traffic against a remote cache by routing it through a local cache. In the following example requests will only go through to the memcached server if the local memory cache is missing the key.

yaml
pipeline:
  processors:
    - branch:
        processors:
          - cache:
              resource: leveled
              operator: get
              key: ${! json("key") }
          - catch:
            - mapping: 'root = {"err":error()}'
        result_map: 'root.result = this'

cache_resources:
  - label: leveled
    multilevel: [ hot, cold ]

  - label: hot
    memory:
      default_ttl: 60s

  - label: cold
    memcached:
      addresses: [ TODO:11211 ]
      default_ttl: 60s