Cache Kafka records — Conduktor Gateway

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Overview

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Benefits

• Improved performance. By serving fetched records from the cache, subsequent fetch requests can be served faster, reducing the overall latency and improving the response time for clients.
• Reduced load on Kafka cluster. With the cache Interceptor in place, the Kafka cluster experiences reduced load during fetch requests since a portion of the requests can be satisfied from the cache directly, reducing the number of requests hitting the cluster.
• Enhanced scalability. The cache Interceptor provides an additional layer of scalability by distributing the workload between the cache and the Kafka cluster. It can handle a higher volume of fetch requests without overwhelming the Kafka cluster.

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How the cache works

• Produced and fetched records both fill the cache. Gateway caches records after a successful produce (except with acks=0), and caches records the cluster returns for fetch requests that miss the cache.
• Cache entries are keyed by service account name. Within a Virtual Cluster, Gateway doesn’t serve records cached for one service account to another.
• Transactions bypass the cache. Gateway doesn’t cache transactional produce requests and doesn’t serve read_committed fetch requests from the cache.
• Errors aren’t cached. Gateway only caches responses without errors.

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Consumer offsets

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Configuration options

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CacheConfig

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RocksdbConfig

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InMemConfig

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Example

curl \
  --request PUT \
  --url 'http://localhost:8888/gateway/v2/interceptor' \
  --header 'Authorization: Basic YWRtaW46Y29uZHVrdG9y' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "kind": "Interceptor",
  "apiVersion": "gateway/v2",
  "metadata": {
    "name": "myCacheInterceptor"
  },
  "spec": {
    "pluginClass": "io.conduktor.gateway.interceptor.CacheInterceptorPlugin",
    "priority": 100,
    "config": {
      "topic": ".*",
      "cacheConfig": {
        "type": "ROCKSDB",
        "rocksdbConfig": {
          "dbPath": "/caching_storage",
          "cacheSize": 104857600
        }
      }
    }
  }
}'

apiVersion: gateway/v2
kind: Interceptor
metadata:
  name: myCacheInterceptor
  scope:
    vCluster: passthrough
spec:
  pluginClass: io.conduktor.gateway.interceptor.CacheInterceptorPlugin
  priority: 100
  config:
    topic: ".*"
    cacheConfig:
      type: ROCKSDB
      rocksdbConfig:
        dbPath: /caching_storage
        cacheSize: 104857600

conduktor apply -f cache-interceptor.yaml