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Ruby on Rails latest stable (v6.1.7.7) - 0 notes

Storing Encrypted Credentials in Source Control

The Rails `credentials` commands provide access to encrypted credentials, so you can safely store access tokens, database passwords, and the like safely inside the app without relying on a mess of ENVs.

This also allows for atomic deploys: no need to coordinate key changes to get everything working as the keys are shipped with the code.

Setup

Applications after Rails 5.2 automatically have a basic credentials file generated that just contains the secret_key_base used by MessageVerifiers/MessageEncryptors, like the ones signing and encrypting cookies.

For applications created prior to Rails 5.2, we’ll automatically generate a new credentials file in `config/credentials.yml.enc` the first time you run `bin/rails credentials:edit`. If you didn’t have a master key saved in `config/master.key`, that’ll be created too.

Don’t lose this master key! Put it in a password manager your team can access. Should you lose it no one, including you, will be able to access any encrypted credentials.

Don’t commit the key! Add `config/master.key` to your source control’s ignore file. If you use Git, Rails handles this for you.

Rails also looks for the master key in `ENV[“RAILS_MASTER_KEY”]`, if that’s easier to manage.

You could prepend that to your server’s start command like this:

RAILS_MASTER_KEY="very-secret-and-secure" server.start

Set up Git to Diff Credentials

Rails provides `rails credentials:diff –enroll` to instruct Git to call `rails credentials:diff` when `git diff` is run on a credentials file.

Running the command enrolls the project such that all credentials files use the “rails_credentials” diff driver in .gitattributes.

Additionally since Git requires the driver itself to be set up in a config file that isn’t tracked Rails automatically ensures it’s configured when running `credentials:edit`.

Otherwise each co-worker would have to run enable manually, including on each new repo clone.

Editing Credentials

This will open a temporary file in `$EDITOR` with the decrypted contents to edit the encrypted credentials.

When the temporary file is next saved the contents are encrypted and written to `config/credentials.yml.enc` while the file itself is destroyed to prevent credentials from leaking.

Environment Specific Credentials

The `credentials` command supports passing an `–environment` option to create an environment specific override. That override will take precedence over the global `config/credentials.yml.enc` file when running in that environment. So:

bin/rails credentials:edit --environment development

will create `config/credentials/development.yml.enc` with the corresponding encryption key in `config/credentials/development.key` if the credentials file doesn’t exist.

The encryption key can also be put in `ENV[“RAILS_MASTER_KEY”]`, which takes precedence over the file encryption key.

In addition to that, the default credentials lookup paths can be overridden through `config.credentials.content_path` and `config.credentials.key_path`.

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