I’m also running into a problem with the environment variable setup. Rather than providing a single string for the connection URL we prefer to have 4 strings that later get concatenated together, i.e.:

MONGO_OPTIONS=ssl=true&replicaSet=shard-1&authSource=admin&retryWrites=true
MONGO_APP_USER=user
MONGO_APP_PASSWORD=password
MONGO_HOST_CONNECTION=<http://shard-1.mongodb.net:27017|shard-1.mongodb.net:27017>

Whilst not essential, we have multiple different productionlike tiers (testing, staging, production etc) and we use this pattern everywhere. And we source the username and password from a secrets manager, and the other two from a shared template. It would be annoying to have to change this. I understand from this GitHub Issue that I can’t concatenate multiple variables in the

schema.prisma

file (which itself is a pretty frustrating limitation), but instead I can pass in an optional param to the Prisma Client, i.e.

const DB_CONNECTION_URL = `mongodb://${process.env.MONGO_APP_USER}:${process.env.MONGO_APP_PASSWORD}@${process.env.MONGO_HOST_CONNECTION}/tools?${process.env.MONGO_OPTIONS}`;
const prisma = new PrismaClient({
  datasources: { db: { url: DB_CONNECTION_URL } },
});

However, this is not working. Prisma is still using the connection URL provided in the

schema.prisma

file. I assume this is a bug?

For this you could create a

.env

file since there you can combine env vars using the format specified by dotenv-expand like

DATABASE_URL="mongodb://${MONGO_APP_USER}:${MONGO_APP_PASSWORD}@${MONGO_HOST_CONNECTION}/tools?${MONGO_OPTIONS}"

and have your schema like

// schema.prisma
datasource db {
  provider = "mongodb"
  url      = env("DATABASE_URL")
}

See https://www.prisma.io/docs/guides/development-environment/environment-variables#expanding-variables

Thanks @Joël. That should work for the app running within node, but wouldn’t that break running

prisma

from the CLI, i.e. if I wanted to pull a new schema with

npx prisma db pull

presumably that would need the

DATABASE_URL

to be set as a static string?

No problem! Happy it helped 🙂