Feature Flags

Feature flags allow us to deploy in-progress or in-testing features safely. If you want to turn on a testable feature, you can enable the flag. If we ship an update with a flagged feature on, you can turn it off.

How Feature Flags Work

Feature flags are boolean values that control whether a feature is enabled or disabled. If a feature is causing issues, you can turn its flag off. This allows you to enjoy other aspects of the release version without the issues caused by the problematic feature. We also might ship a feature with the flag turned off by default, allowing you to opt-in to testing it.

Basic Usage

To use Feature Flags, you can create a json file called flags.user.json in /wp-content/uploads/etch/. This file allows you to override the default value for any specific flag on a flag-by-flag basis. Any flag not specified in your flags.user.json file will use its default value. If this file doesn't exist, or if it is an empty JSON object ({}), Etch will use the default flag values for all flags.

The file should use the following format:

{
    "FLAG_NAME": "on",
    "FLAG_NAME_2": "off"
}

info

The flags.user.json must be a valid JSON file. An invalid JSON file (including an empty file) will cause an error.

warning

Because flags defined in flags.user.json override their default values, you are responsible for managing these overrides across updates.

For example, if we ship an update where a flag that was previously off is now on, but you have set it to off in your flags.user.json file, your value will take precedence. You will have to remember to remove the flag from your file to get the new default behavior.

You can choose from the available flags below. Their default state is listed.

Available Feature Flags

Flag Name	Description	Default
ENABLE_DEBUG_LOG	Enables debug logging	off
ENABLE_SERVER_TIMING	Enables server timing headers for performance monitoring	off
REMOVE_WP_DEFAULT_CSS	Removes WordPress default CSS	on
ENABLE_WAF_COMPATIBILITY_WORKAROUND	Improves compatibility with WAF that don't allow PUT, PATCH or DELETE requests	on
UNSAVED_CHANGES_WARNING	Enables warning before closing tab with unsaved changes	on
RETURN_ACF_DYNAMIC_DATA	Enables returning data based on the ACF field settings.	off