Set default values for schema url fields

[HosseinAgha]

My proposals

1. Add a syntax in Prisma Schema Language for setting a default value if env variable was empty. e.g.

datasource db {
  provider = "postgresql"
  url = env('POSTGRES_URL') || "postgresql://dev@localhost/testdb"
}

2. As a better option add support for schema definition in JavaScript/Typescript (e.g. schema.prisma.js)

Why I think creating a new schema language isn't a good idea?

• Please re read your article on the problems of schema first development.
• I worry that in time you reach the same conclusion and you end up with a schema language that tries to solve everything but is not as good as a real programming language.
• I think having a real general purpose programming language at your disposal is always a good idea. (take Webpack config or many other tools for example)
• I understand that Prisma is a cross language tool (Go driver for example) but it is also written in JS and Generator and Lift need node to run. So I see no harm in having a schema.prisma.js option.

What are the use cases for these?

I’m struggling to add Prisma 2 to my development workflow.
I have a complex NodeJS server that connects to some DBs and outside services. We try our best to keep initial configuration for new developers as simple as possible (setup everything in the first npm run dev).
We use docker to initialize and run the DBs and external services and setup some default credentials for dev databases.
In the dev server we set the same default credentials for our DB connectors so new developers don’t have to worry about DB config at all.
The current url system for Prima Schema Language only accepts environment variables. It is a good thing for production but not the dev env.
Using .env file is not a good option for us as each new developer should create it and add the default configs to it.

[HosseinAgha]

It is worth mentioning that we are currently using photon's datasources argument to override the database URL like this:

const photon = new Photon({
      datasources: {
          db: {
            url: process.env.POSTGRES_URL || "postgresql://dev@localhost/testdb",
          },
      },
});

But using this approach Lift will still use the value in schema.prisma.

[janpio]

A note: This might also be solved by adding a second param default (of fallback) to the env() method.

[matthewmueller]

Hi @HosseinAgha!

For 1., we're definitely going to add a default env argument, it'll likely look like this

env("POSTGRES_URL", default: "postgresql://dev@localhost/testdb")

For 2., thanks for bringing this up! We've created a new issue for this discussion.

[blevine]

Was the default for the connection url functionality ever added?

[pantharshit00]

@blevine No, we didn't get any more requests for this so this was never pushed again up the priority classification.

[blevine]

That's too bad. It seems to have been almost completely implemented and would have been a good enhancement.

[Milananas]

I guess this is still not implemented? I have a good use case for this feature at the moment as well.

[danablend]

I would be happy to see an implementation of this as well! :-)

[2pmflow]

Would love to see this implemented. It would help with zero downtime migrations of database credentials.

Supporting something similar to env("NEW_DATABASE_URL") || env("DATABASE_URL") would let the application handle two database credentials at once.

[janpio]

How would that work @2pmflow, specifically? If it falls back to the second value if the first env var is empty, can you not also just update the only single environment variable to the new value instead?