Compose database URL from several ENV variables in schema.prisma file

[MurzNN]

I have database access credentials in separate ENV variables like DB_USERNAME, DB_PASSSWORD, DB_DATABASE, but in schema.prisma file Prisma wants to see a full url like this:

datasource db {
  provider = "postgresql"
  url      = "postgresql://johndoe:mypassword@localhost:5432/my_database"
}

So, can I use environment variables as part of url string, like this "postgresql://$DB_USERNAME:$DB_PASSWORD@localhost:5432/$DB_DATABASE"?

If not, is there any other ways to compose database url from several ENV variables?

[MurzNN]

It is possible to use a single ENV variable as database url like this:

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

But does it work for concatenate several env variables?

[nurul3101]

Hey @MurzNN 👋
Are you looking to do something like this - Expanding Variables in env file?

Another alternative is to override database URL programmatically as mentioned here.
You could try constructing your database url before passing it in the PrismaClient Instance.

[MurzNN]

I'm already overriding database URL programmatically and it works for my application well, but the problem is that prisma migrate deploy command looks only to the prisma.schema file and fails on connecting step.

Yes, workaround is to duplicate database credentials and compose $DATABASE_URL string manually, but I'm not using .env file, all environment variables are passed to the container from Kubernetes, so better is to resolve this without adding new env variable to the infrastructure.

[janpio]

Have a look at the first link @nurul3101 posted @MurzNN - that is a workaround to compose variables via an .env file. That shuld also work for CLI commands (opposed to doing it in code).

[MurzNN]

Yes, workaround also is to fill the env variable directly with launching prisma:

DATABASE_URL="postgresql://$DB_USERNAME:$DB_PASSWORD@localhost:5432/$DB_DATABASE" prisma migrate deploy

[rolandboon]

The relevant docs mentioned by @nurul3101 has been moved to the following URL: https://www.prisma.io/docs/orm/more/development-environment/environment-variables/env-files#expanding-variables