Egg Variables

One powerful feature of eggs is the ability to define variables that can be used to customize the server's startup and configuration without editing the startup command directly. Egg variables are exposed as environment variables to the server and can be referenced in the install script or config files.

To manage an egg's variables, create the egg (or edit an existing one) and navigate to the Variables tab on the egg configuration page.

Types of Egg Variables

• Default Variables: These are provided by the Panel/Wings automatically for every server. You do not need to create these; they always exist.

• Custom Variables: These are defined by you on the egg's Variables tab.

Default Variables

These are injected into every server environment by default and can be referenced using the following syntaxes:

• In the startup command: {{VARIABLE}}
• In scripts: $VARIABLE_NAME
• In configuration parser entries: {{env.VARIABLE}}

Custom Variables

Each variable allows you to define:

• The Environment Variable, for example: MAX_PLAYERS
• A default value
• Description (shown to the user in the panel)
• Validation Rules
• Whether it is viewable or editable by the user

Creating a New Variable

When creating a new custom variable, you will provide:

• Name: A friendly name for the variable (e.g. "Max Players").

• Description: A description shown to the user (explain what the variable does).

• Environment Variable: The actual environment variable name used in code (use UPPERCASE letters, numbers, and underscores only). For example, MAX_PLAYERS. This is the name that will be referenced in the startup command or configuration files.

• Default Value: (Optional) A default value for this variable. This will be used if the user doesn't input anything else.

• User Permissions: Whether the user can view and/or edit this variable on their server:

  • Users Can View — If set, the user can see this variable (and its value) in their server's settings.
  • Users Can Edit — If set, the user can change the value of this variable from the default. (If neither option is enabled, the variable is essentially hidden from the user's front-end view, though it still exists in the server's environment.)

Validation Rules

Rules: Validation rules for the user's input. This uses Laravel's validation rule format. Common rules include:

• required — value must be provided
• nullable — value can be left empty
• string — must be a string
• numeric — must be a number
• boolean — must be true or false
• between:1,10 — string length or numeric value between 1 and 10
• max:64 — maximum string length or numeric value
• in:value1,value2 — must be one of the listed values (e.g., in:true,false)
• regex:/pattern/ — must match a regex pattern

Rules are combined with |. For example, required|string|between:1,10 means the value is required, must be a string, and 1 to 10 characters in length. To require a value ending in ".jar", you could use required|regex:/^([\w\d._-]+)(\.jar)$/.

After creating custom variables, both the custom and default variables can be seen when viewing the server's startup in the Panel (in both Admin and client views). The startup command preview will show these variables substituted with their actual values.