Cached Prisma

A Prisma client abstraction that simplifies caching.

Installing

npm install cached-prisma

Documentation

Documentation and more detailed examples are hosted on Github Pages.

Usage

client.user.create({ data: { name: "Joel" } });

// This populates the cache
client.user.findFirst({ where: { name: "Joel" } });

// This is retrieved from the cache
client.user.findFirst({ where: { name: "Joel" } });

To control the object used for cache storage you can extend the Prisma class:

import { LruCache } from "cached-prisma";

class CustomPrisma extends Prisma {
  static override cacheFactory = () => new LruCache(100);
}

To implement the cache we need to divert the prisma client's internals so that we can return cached values without hitting the database. To do this we can use a singleton instance for the client and cache objects.

import { Prisma } from "cached-prisma";

const client1 = new Prisma().client;
const client2 = new Prisma().client;

client1 === client2;

import { Prisma } from "cached-prisma";

const cache1 = new Prisma().cache;
const cache2 = new Prisma().cache;

cache1 === cache2;

Minimal example

Create a prisma schema.

datasource db {
  url      = env("DATABASE_URL")
  provider = "postgresql"
}

generator client {
  provider = "prisma-client-js"
}

model User {
  id   Int    @id @default(autoincrement())
  name String
}

Create a database. In this example we create a postgres container. You can switch the db, user and password for your environment.

docker run --rm -d              \
  -p 5432:5432                  \
  -e POSTGRES_DB=db             \
  -e POSTGRES_USER=user         \
  -e POSTGRES_PASSWORD=password \
  postgres:13

Define the DATABASE_URL environment variable mentioned in our prisma schema.

export DATABASE_URL=postgresql://user:password@localhost:5432/db

Generate the types for your client.

npx prisma generate

Migrate the database.

npx prisma migrate dev

Now we can create our client:

import { Prisma } from "cached-prisma";

const client = new Prisma().client;

client.user.create({ data: { name: "Joel" } });

Discussion

The default cache is a fixed size queue that pops values as it surpasses its maximum length.

import LruMap from "collections/lru-map";

new LruCache(100);

Memcached support is provided out of the box:

import { Memcached } from "cached-prisma";

class CustomPrisma extends Prisma {
  static override cacheFactory = () => new Memcached("127.0.0.1:11211", 10);
}

The second parameter to the Memcached constructor is the storage lifetime of each write in seconds.

Caches implement safe read and write methods:

export interface Cache {
  read: (key: string) => Promise<Maybe<string>>;
  write: (key: string, value: string) => Promise<void>;
  flush: () => Promise<void>;
}

We cache the following methods which do not mutate state:

• findUnique
• findMany
• findFirst
• queryRaw
• aggregate
• count

After any of the following state mutating methods we flush the cache:

• create
• createMany
• delete
• deleteMany
• executeRaw
• update
• updateMany
• upsert

Tooling

Dependencies

To install dependencies:

yarn install

Tests

To run tests:

docker run --rm -d              \
  -p 5432:5432                  \
  -e POSTGRES_DB=db             \
  -e POSTGRES_USER=user         \
  -e POSTGRES_PASSWORD=password \
  postgres:13

docker run --rm -d \
  -p 11211:11211   \
  memcached:1.6.9

export DATABASE_URL=postgresql://user:password@localhost:5432/db
yarn prisma generate --schema ./test/prisma/schema.prisma
yarn prisma migrate dev --schema ./test/prisma/schema.prisma

yarn test

Documentation

To generate the documentation locally:

yarn docs

Linters

To run linters:

yarn lint

Formatters

To run formatters:

yarn format

Contributing

Please read this repository's Code of Conduct which outlines our collaboration standards and the Changelog for details on breaking changes that have been made.

This repository adheres to semantic versioning standards. For more information on semantic versioning visit SemVer.

Bump2version is used to version and tag changes. For example:

bump2version patch

Contributors

• Joel Lefkowitz - Initial work

Remarks

Lots of love to the open source community!