Make it easier to merge configuration into config at runtime

Context

Related #13952

We’re experimenting with different ways to satisfy security requirements for one of our clients, where they’re not allowed to use environment variables to store secrets. We tried a bunch of different approaches; one of them is to load secrets before reading configs and merging them into configuration. This proved surprisingly difficult. We tried to modify main() in packages/backend/src/index.ts to read secrets before calling loadBackendConfig, but we couldn’t figure out the right way to load those values into the config object.

Feature Suggestion

Provide an API to merge or derive a config object by merging a POJO into a config.

Possible Implementation

Something like this would be great,

const static = await loadBackendConfig({
  argv: process.argv,
  logger,
});
  
const config = static.merge({
  backend: {
     database: {
        password: await readFromSecretStore('db_password')
     }
  }
})

Is this possible?

[OrkoHunter]

I have recently also seen companies frown upon secrets in configs via environment variables - they are so peculiar about their own secret managers, and want to use that only. So +1 to updating configs during runtime or #13952. 😃

[freben]

@shailendra-ahir-cbre There’s a “Subscribe” button in the right sidebar for that purpose.