sequelize-transparent-cache-nats

NATS adaptor for sequelize-transparent-cache.

Stores sequelize objects in NATS using a KeyValue Bucket

Example usage

NOTE: NATS uses milliseconds for durations when configuring a bucket (ttl and markerTTL). But setting the ttl per-key is done as a string duration (e.g. 5s).

Example with Bucket TTL

By setting the TTL (max_age) at the bucket level all keys will be expired based on this value.

const { connect } = require('@nats-io/transport-node')
const { jetstream } = require('@nats-io/jetstream')
const { Kvm } = require('@nats-io/kv')

// connect to the default server 127.0.0.1:4222

async function start() {
  const nc = await connect()

  const js = jetstream(nc)
  const kvBucket = await new Kvm(js).create('bucket', { ttl: 1_000 }) // ttl is specified in ms

  const NatsAdaptor = require('sequelize-transparent-cache-nats')
  const natsAdaptor = new NatsAdaptor({
    client: kvBucket,
    namespace: 'example',
  })
}

start()

Example with Bucket Marker TTL and per-key TTL

If per-Key TTLs are required then the bucket needs to be created with the markerTTL option.

const js = jetstream(nc)
const kvBucket = await new Kvm(js).create('bucket', { markerTTL: 1_000 }) // ttl are specified in ms

// set cache key, and set ttl
await User.cache('find-with-ttl', { ttl: '30s' }).findAll({ where: { name: 'Dan' } })

Constructor arguments

| Param | Type | Required | Description | |-------------|------------------|----------|---------------------------------------------------------------------------------| | client | Bucket instance | yes | Configured KV Bucket | | namespace | string | no | Prefix for all keys |

Storing format

Each object stored as single JSON string. Namespace delimeter is ".".

| Key | Value | |--------------------------------------|-----------------| | <namespace>.<modelName>.<objectId> | {JSON string} |

For more info see sequelize-transparent-cache