ruby 31 lines · 6 steps

Wrapping Rails credentials in a gateway

A small class that reads Stripe secrets from Rails credentials and fails loudly when they're missing.

Explained by highlit

Rails Intermediate encapsulation credentials error handling fail-fast refactoring

1class PaymentGateway
class MissingCredentialError < StandardError; end
3 
def initialize(env: Rails.env)
  @env = env.to_sym
end
7 
def api_key
  fetch(:stripe, :api_key)
end
11 
def webhook_secret
  fetch(:stripe, :webhook_secret)
end
15 
def publishable_key
  fetch(:stripe, :publishable_key)
end
19 
private
21 
def fetch(*path)
  value = credentials.dig(*path)
  value || raise(MissingCredentialError, "Missing credential #{path.join('.')} for #{@env}")
end
26 
def credentials
  Rails.application.credentials.dig(@env) ||
    raise(MissingCredentialError, "No credentials configured for #{@env}")
end
31end

01 / 01

STEP 01

Walkthrough

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Three takeaways

1Wrapping raw credential access in named methods gives you clear call sites and a single place to change lookup logic.
2Raising a custom error at the point of a missing value surfaces misconfiguration immediately instead of as a confusing nil downstream.
3Passing the environment into the constructor keeps the class testable rather than hardwiring it to global state.

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