Environment

The BlueDragonMC/Server project loads several environment configuration options at startup that influence its interaction with other services.

Development and Production Modes

The server is determined to be in “Dev” or “Prod” mode by looking at the BLUEDRAGON_ENV_TYPE environment variable. If it’s set to DEV, DEVELOPMENT, TEST, or TESTING, the server runs in development mode. If it’s set to any other value, it runs in production mode.

If BLUEDRAGON_ENV_TYPE is not set, the fallback is to check for a directory called /server at the file system root. If it exists, then production mode is used; if not, development mode.

The mode determines the default values for several of the variables below, so it should be set before starting the server.

Environment Variable Reference

Environment variable	Defaults	Description
BLUEDRAGON_ENV_TYPE	DEV if /server does not exist, otherwise PROD	Overrides how the server determines whether it is in development or production mode.
BLUEDRAGON_QUEUE_TYPE	Dev: TEST Prod: IPC	Use “IPC” to connect to Puffin for queueing, or “TEST” for a fully-local/single-instance queue
BLUEDRAGON_MONGO_CONNECTION_STRING	Dev: mongodb://localhost:27017 Prod: mongodb://mongo:27017	The connection string that resolves to a MongoDB instance
BLUEDRAGON_PUFFIN_HOSTNAME	Dev: localhost Prod: puffin	The hostname that resolves to a Puffin instance
BLUEDRAGON_PUFFIN_PORT	50051	The port of Puffin’s gRPC server.
BLUEDRAGON_LUCKPERMS_HOSTNAME	Dev: http://localhost:8080 Prod: http://luckperms:8080	The hostname that resolves to a standalone LuckPerms instance
BLUEDRAGON_DEFAULT_GAME	Lobby	The game to automatically create on startup. Typically used to immediately initialize a lobby on each game server.
BLUEDRAGON_SERVER_NAME	The contents of the HOSTNAME variable, or a random dev name	Overrides the server name. In Kubernetes this is normally set from metadata.name.
BLUEDRAGON_HEALTH_PORT	8081	The port used for /health, /ready, and /drain.
BLUEDRAGON_SHUTDOWN_COUNTDOWN_SECONDS	7200	How long players have before a draining server stops, in seconds.
BLUEDRAGON_COUNTDOWN_HIDDEN_SECONDS	3600	How long the shutdown countdown stays hidden at the start of a drain, in seconds. At least 60 seconds is always visible.
BLUEDRAGON_TICK_TIMEOUT_MS	100	How long the server may go without a tick before it is considered unhealthy.
BLUEDRAGON_DRAIN_QUIESCENCE_MS	15000	How long a draining server must remain empty before stopping early.
BLUEDRAGON_LOBBY_TRANSFER_TIMEOUT_MS	30000	How long to wait for players to be moved to a lobby when the drain completes before kicking them, in milliseconds.
BLUEDRAGON_LIFECYCLE_DISABLED	Not set	If present, disables the lifecycle HTTP endpoints.
PUFFIN_VELOCITY_SECRET	Not set	The Velocity modern forwarding secret. If not present, Velocity forwarding is disabled and Mojang authentication is used instead.
BLUEDRAGON_GRPC_SERVER_PORT	50051	The port to listen on for gRPC requests.
SERVER_INSTANCE_MIN_INACTIVE_TIME	120000	The amount of time an instance must be inactive before it is cleaned up, in milliseconds.
SERVER_INSTANCE_CLEANUP_PERIOD	10000	The amount of time between instance cleanup tasks, in milliseconds.

View ConfiguredEnvironment source code for more details about server environment configuration.

Other Environment Information

• The Environment class also stores version information handled by the Blossom Gradle plugin. See VersionInfo for the interface that the generated GitVersionInfo implements.
• The environment contains a list of all registered games obtained from the GameLoader.

Server Naming

Every game server must have a unique name to interact properly with other services. The default ConfiguredEnvironment goes through the following process for determining a server’s name:

1. If BLUEDRAGON_SERVER_NAME is set, its value will be used as the server name.
2. Otherwise, if the HOSTNAME environment variable is set, its value will be used. Kubernetes sets this to the pod name.
3. Otherwise, a random name in the form dev-xxxxx-xxxxx will be created and used.

The result is then cached for future lookups.