Key/Value

Nitric provides functionality for provisioning and interacting with persistent key/value stores.

Definitions

Key Value Store

Key value stores act as a database which provides the functionality for efficient storage and retrieval of data. The data is fetched via a unique key, which is associated with a value. Due to the uniqueness of the key, accessing the data is incredibly efficient and will occur in constant time as there is no need for complex lookups.

Key

A key is a unique string that acts as a references to a value. Anytime a value is updated or read from a key value store, it is done so by referencing the key.

Value

Values are the data that is stored in the key value store. They are referenced by a key and can be any JSON serializable object.

Creating Key Value Stores

Here's an example of how to create a key value store, with permissions for getting, setting, and deleting:

import { kv } from '@nitric/sdk'

const countries = kv('Countries').allow('get', 'set', 'delete')

Creating Key Value Pairs

Key value pairs are created based on the key and the contents of the value. If a key already exists in the key value store, then its value will be overwritten.

Key value stores that are created using the Nitric SDK are compatible across cloud providers.

The below example first creates a key value store that has permissions for setting. It then adds a key to the store called USA and a value which describes the country.

import { kv } from '@nitric/sdk'

const countries = kv('Countries').allow('set')

await countries.set('USA', {
  name: 'United States of America',
  population: 329500000,
})

To update a value call set with the same key and a new value.

await countries.set('USA', {
  name: 'United States of America',
  population: 330000000,
})

Accessing Values

Values can be accessed from a store by calling the get method with the key of the value you want to retrieve.

import { kv } from '@nitric/sdk'

const countries = kv('Countries').allow('get')

const country = await country.get('USA')

Deleting Values

Values can be deleted from the key value store by referencing the key.

The below example first creates a key value store that has permissions for deleting and setting. It then creates a value called USA, which is deleted using delete on the key.

import { kv } from '@nitric/sdk'

const countries = kv('Countries').allow('delete', 'set')

await countries.set('USA', {
  name: 'United States of America',
  population: 329500000,
})

await countries.delete('USA')

Listing Keys

Keys can be listed and filtered by an optional prefix.

The below example first creates a key value store that has permissions for listing. It then lists all keys in the store.

import { kv } from '@nitric/sdk'

const countries = kv('Countries').allow('get')

for await (const key of countries.keys()) {
  console.log(key)
}

Cloud Service Mapping

Each cloud provider comes with a set of default services used when deploying resources. You can find the default services for each cloud provider below.