gmrc `connectionString` should be ignored if `DATABASE_URL` exists in the env

[Sam Levin]

Hey Benjie. We've nearly completed our adoption of graphile-migrate and as a team, we're loving it. A lot of great philosophies at play. Awesome work all around.

Our development team has a 'zero config' dev environment philosophy where a lot of settings are hard-coded to repositories (with insecure defaults). We're trying to replicate this for graphile-migrate but the migrate command appears to be preferring connectionString - even though DATABASE_URL exists.

Thoughts? ENV var precedence is fairly typical in the config world. Am I right in assuming that migrate would/should follow suit?

[Benjie]

No; explicit always wins over implicit. If you provide a connection string explicitly via the Graphile Migrate config file then that will override the implicit and generic environmental variable DATABASE_URL that may have come from anywhere and could relate to some other service such as PostGraphile or Graphile Worker or even a completely different project.

Perhaps there's an alternative way we can solve this; for example a .js config file where you can set connectionString: process.env.DATABASE_URL || "fallback"

This'd be the place to apply that change:

migrate/src/commands/_common.ts

Lines 7 to 23 in 08e0b27

 export const GMRC_PATH = `${process.cwd()}/.gmrc`; 
  
 export async function getSettings(): Promise<Settings> { 
   let data; 
   try { 
     data = await fsp.readFile(GMRC_PATH, "utf8"); 
   } catch (e) { 
     throw new Error( 
       "No .gmrc file found; please run `graphile-migrate init` first.", 
     ); 
   } 
   try { 
     return JSON5.parse(data); 
   } catch (e) { 
     throw new Error("Failed to parse .gmrc file: " + e.message); 
   } 
 } 

I think read .gmrc if present, otherwise try .gmrc.js.