Add Configuration Settings

Occasionally we need a new setting to be created so that users have a bit more control over the inner workings of NCA. This details the process of adding settings:

• Open up src/config/config.go and add a value to the Config struct.
• Choose the data type. In most cases a primitive is fine: string, int, float64, etc.
• Decide if the value should be pulled directly from the settings file or if you need to massage data manually. The former is usually the best option, but not always possible.
• If the value is pulled directly from settings, set up the struct tags:
  • At a minimum you must define which settings value will populate the Go config structure; e.g., the config.Ghostscript value specifies setting:"GHOSTSCRIPT" in the struct tag, telling us the settings file’s “GHOSTSCRIPT” value is to be used.
  • If you want validation, use a “type” struct tag, e.g., the “Webroot” setting uses type:"url" to specify that the value must be a valid URL.
• If the value is not directly pulled from settings, modify Parse() to read the raw setting and set the config field accordingly.
• Open settings-example and add the setting with some documentation (bash-style comments) explaning what it does and how it should be used. When you can, make sure the default “just works” with a standard docker setup.

Notes:

• If you need more validation than what is provided, you can add that to the Parse() function. MinimumIssuePages, for instance, ensures it’s always at least 1.
• If you add a workflow path, you may need to alter test/copy-sources.go in order to automatically create that path for testing.