Postgres

Service and functions for working with AWS RDS Postgres databases using Prisma.

Table of Contents

• Installation
• Development
• Deployment
• Services
  • PostgresService
• When used as a dependency
• Libraries
  • getPrismaClient

Installation

From the command line run:

npm install @saws/postgres

Then add the PostgresService to your saws.js file.

Development

In development, the PostgresService will stand up a postgres database inside of docker running locally. In addition it will create a database for you automatically and run any existing migrations in that newly created database. It will also generate your prisma client from your schema.prisma file. It will also watch for changes on your schema.prisma file and regenerate your prisma client for you.

When you run in development for the first time with a new PostgresService in your saws.js file, it will automatically do the following:

• Install any missing dependencies required for prisma
• Create your prisma/schema.prisma file
• Create a .env file in the root of your application so that any prisma command line command you run can access your locally running database.

Deployment

When you deploy a PostgresService, it will stand up and configure the following for you:

• A Postgres DB RDS instance.
• A security group for the RDS instance

In order to run Postgres within the free tier, you can not use Aurora. It does not have any free tier allowance. The closest you can get is with an Aurora Serverless Data API. Unfortunately Prisma does not support the Serverless Data API yet. As such to make working with your deployed postgres database as seemless as possible from Lambda, the postgres db is marked as Publicly Accessable. This will not be acceptable for some people. For others, that risk is tolerable. I'd love to support Aurora serverless as it's an even more hands off deployment of Postgres but until Prisma can support Data API, there aren't many other great options.

Services

@saws/postgres includes 1 function to get a preconfigured prisma client.

PostgresService

You can require the PostgresService and use it in your saws.js file like so:

const { PostgresService } = require('@saws/postgres/postgres-service')

// will almost exclusively be used as a dependency to other services
const func = new PostgresService({
  name: 'my-func',
})

The PostgresService constructor accepts the following options:

name: string

The name of your service. This should be unique across all of your services.

dependencies: ServiceDefinition[]

An array of all of the other services this service depends on. This will ensure that permissions, environment variables, and execution order are all set up.

imageName?: string

Allows you to customize which postgres docker image is used when in local development.

When used as a dependency

When a PostgresService is used as a dependency, it will automatically attach (where applicable) the following environment variables into the dependent services:

• SERVICE_NAME_POSTGRES_USERNAME: string - The created username to connect to the database
• SERVICE_NAME_POSTGRES_PASSWORD: string - The created password to connect to the database (will be a v4 UUID)
• SERVICE_NAME_POSTGRES_HOST: string - The host url of your database instance
• SERVICE_NAME_POSTGRES_PORT: string - The host port of your database instance
• SERVICE_NAME_POSTGRES_DB_NAME: string - The database name of your created database in the instance

Libraries

@saws/postgres utilizes Prisma as it's client and exposes a function, getPrismaClient to obtain a pre-configured prisma client.

getPrismaClient

The getPrismaClient function will return a preconfigured prisma object for connecting to your database.

Example usage:

import { getPrismaClient } from '@saws/postgres/get-prisma-client'

const prisma = new getPrismaClient('your-postgres-service-name')

In order for the getPrismaClient class to work in a service, that service must list your function service as a dependency.