Egg Variables

Introduction

Variables are per-server settings, such as the game version or the maximum number of players. Each becomes an environment variable in the server's container, usable in the startup command, install script, and configuration files.

Manage them on the egg's Variables tab. The Panel also sets some variables for every server; see Built-In Variables.

Creating a Variable

Click Create Variable and fill in:

• Name: A friendly name users see, such as Max Players.
• Description: Tells users what the variable does.
• Environment Variable: The name inside the container, such as MAX_PLAYERS. Letters, numbers, and underscores only. Wings passes the name in uppercase, so use uppercase names to avoid confusion.
• Default Value: The value new servers start with.
• Users Can View: Whether users see the variable on their server's Startup page.
• Users Can Edit: Whether users may change the value.
• Input Rules: Laravel validation rules that every value must pass.

Click Create Variable to save it.

Using a Variable

Refer to a variable by its environment variable name. The syntax depends on where you use it:

Users see the startup command with values filled in for {{SERVER_MEMORY}}, {{SERVER_IP}}, {{SERVER_PORT}}, and the egg's own variables, and [hidden] for variables they cannot view. Placeholders are case-sensitive; any other placeholder stays as written.

Input Rules

Separate rules with |. The most common:

For example, required|string|max:20 requires text of at most 20 characters. New variables start with these rules.

Details that decide whether a value passes:

• between, max, and min compare the number only when the rules also include integer or numeric. Otherwise they count characters, so required|max:128 accepts 500.
• Values are trimmed at both ends, and an empty value reaches the rules as null. Without nullable, rules such as string fail on it.
• Rules are split at every |, so a | inside a regular expression cuts it in two. Leave | out of patterns.

The rules also set how the variable appears on the Startup page:

• boolean, in:0,1, or in:true,false shows a switch. If its rules also include string, the switch saves true or false; otherwise it saves 1 or 0. The boolean rule rejects true and false, so pair string with in:true,false instead.
• Any other in: rule shows a list of the allowed values.
• Everything else shows a text field.

java -Xms128M -Xmx4096M -jar paper.jar

Reserved Names

These environment variable names are reserved in any letter case:

SERVER_MEMORY, SERVER_IP, SERVER_PORT, ENV, HOME, USER, STARTUP, SERVER_UUID, and UUID.

Built-In Variables

Every server's container gets these variables, whatever its egg:

Wings sets TZ, STARTUP, SERVER_MEMORY, SERVER_IP, and SERVER_PORT first and skips an egg variable with any of those names.

The official Docker images also set USER=container and HOME=/home/container.

Changing a Server's Variables

Users change the variables they may edit on their server's Startup page. Administrators can change all of a server's variables on its Startup tab in the admin area. New values apply on the next start.