Environment variable configuratioun

Contents:

• Soummary
  • Maitter
  • Decisioun
  • Staunin
• Pairticulars
  • Assumptiouns
  • Limitatiouns
  • Positiouns
  • Argiment
  • Implicatiouns
• Relatit
  • Relatit decisiouns
  • Relatit requirements
  • Relatit artefacts
  • Relatit principles
• Jottins

Soummary

Maitter

We want oor applications tae be configurable ayont artefacts/binaries/source, sic that ae build can behave differently dependin on its deployment environment.

• Tae accomplish this, we want tae uise environment variable configuratioun.

• We want tae manage the configuratioun bi uisin files that we can version control.

• We want tae provide some developer experience ergonomics, sic as kennin whit can be configured an onie relevant defaults.

Decisioun

Decidit on .env files wi relatit default file an schema file.

Staunin

Decidit. Open tae considerin new capabilities as they come up.

Pairticulars

Assumptiouns

We favour separatin the application code an environment code. We assume the app needs tae wark differently in different environments, sic as in a develapment environment, test environment, demo environment, production environment, etc.

We favour the industry practice o "12 factor app" an even mair the relatit practice o "15 factor app".

Mony o oor previous projects hae uised the convention o a .env file or similar .env directory. There's a typical practice o keepin thir oot o version control, an instead uisin some ither wey tae deploy them, version them, an manage them.

Limitatiouns

We want tae keep secrets oot o oor source code management (SCM) version control system (VCS).

We want tae aim for compatibility wi popular saftware frameworks an leebraries. For example, Node haes a module "dotenv" for readin environment variable configuratioun.

Positiouns

We consideret a few approaches:

• Store config in the app sic as in a file config.js file.

• Store config in the environment sic as in a file .env.

• Fetch config frae a kent locatioun sic as a licence server.

Argiment

We selectit the approach o a file .env acause:

• It is popular includin amang experts.

• It follaes the pattern o .env files which oor teams hae successfully uised mony times on mony projects.

• It is simple. Notably, We are fine for noo wi the significant trade-offs that we see, sic as a lack o audit capabilities as compared tae an approach o a licence server.

Implicatiouns

We need tae figure oot a wey tae separate environment variable configuratioun that is public frae onie secrets management.

Relatit

Relatit decisiouns

We expect aw oor applications tae uise this approach.

We will plan tae upgrade onie o oor applications that uise a less-capable approach, sic as hardcodin in a binary or in source code.

We will keep as-is onie o oor applications that uise a mair-capable approach, sic as a licensin server.

Relatit requirements

We will add devops capabilities for the files, includin hooks, tests, an continuous integratioun.

We need tae train aw developer teammates on this decisioun.

Relatit artefacts

Each area whaur we deploy will need its ain .env file an relatit files.

Relatit principles

Easily reversible.

Jottins

Example file .env:

NAME=Alice Anderson
EMAIL=alice@example.com

Example file .env.defaults:

NAME=Joe Doe
EMAIL=joe@example.com

Example file .env.schema wi juist the keys:

NAME
EMAIL