evennia/docs/source/Concepts/Server-Lifecycle.md

Evennia Server Lifecycle

As part of your game design you may want to change how Evennia behaves when starting or stopping. A common use case would be to start up some piece of custom code you want to always have available once the server is up.

Evennia has three main life cycles, all of which you can add custom behavior for:

• Database life cycle: Evennia runs on top of one several supported databases. It's possible to wipe this database to 'start over' without needing to separately download Evennia anew.
• Reboot life cycle: From When Evennia starts from zero, to it being fully shut down, which means both Portal and Server are stopped. This kicks all players.
• Reload life cycle: This is the main runtime, until a "reload" event. Reloads do not kick any players.

When Evennia first starts

This is the beginning of the Database life cycle, just after the database is created and migrated for the first time. After that it won't run again unless you wipe the database and initialize a new one (see Choosing a Database).

Hooks called, in sequence:

1. evennia.server.initial_setup.handle_setup(last_step=None): Evennia's core initialization function. This is what creates the #1 Character (tied to the superuser) and Limbo. It calls the next hook below and also understands to restart at the last failed step if there was some issue. You should normally not override this function unless you really know what you are doing, but in that case you'd do so by setting settings.INITIAL_SETUP_MODULE to your own module with a handle_setup function in it.
2. mygame/server/conf/at_initial_setup.py contains a single function, at_initial_setup(), which will be called without arguments. It's called last in the setup sequence by the above function. Use this to add your own custom behavior or to tweak the initialization. If you for example wanted to change the auto-generated Limbo room, you should do it from here. If you want to change where this function is found, you can do so by changing settings.AT_INITIAL_SETUP_HOOK_MODULE.

When Evennia starts and shutdowns

This is the Reboot life cycle. Evennia consists of two main processes, the Portal and the Server. On a reboot or shutdown, both Portal and Server shuts down, which means all players are disconnected.

Each process call a series of hooks located in mygame/server/conf/at_server_startstop.py. You can customize the module used with settings.AT_SERVER_STARTSTOP_MODULE - this can even be a list of modules, if so, the appropriately-named functions will be called from each module, in sequence.

All hooks are called without arguments.

The use of the term 'server' in the hook-names indicate the whole of Evennia, not just the Server component.

Server cold start

Starting the server from zero, after a full stop. This is done with evennia start from the terminal.

1. at_server_init() - Always called first in the startup sequence.
2. at_server_cold_start() - Only called on cold starts.
3. at_server_start() - Always called last in the startup sequece.

Server cold shutdown

Shutting everything down. Done with shutdown in-game or evennia stop from the terminal.

1. at_server_cold_stop() - Only called on cold stops.
2. at_server_stop() - Always called last in the stopping sequence.

Server reboots

This is done with evennia reboot and effectively constitutes an automatic cold shutdown followed by a cold start controlled from the evennia launcher. There are no special reboot hooks for this, instead it looks like you'd expect:

1. at_server_cold_stop()
2. at_server_stop() (after this, both Server + Portal have both shut down)
3. at_server_init() (like a cold start)
4. at_server_cold_start()
5. at_server_start()

When Evennia reloads and resets

This is the Reload life cycle. As mentioned above, Evennia consists of two components, the Portal and Server. During a reload, only the Server component is shut down and restarted. Since the Portal stays up, players are not disconnected.

All hooks are called without arguments.

Server reload

Reloads are initiated with the reload command in-game, or with evennia reload from the terminal.

1. at_server_reload_stop() - Only called on reload stops.
2. at_server_stop - Always called last in the stopping sequence.
3. at_server_init() - Always called first in startup sequence.
4. at_server_reload_start() - Only called on a reload (re)start.
5. at_server_start() - Always called last in the startup sequence.

Server reset

A 'reset' is a hybrid reload state, where the reload is treated as a cold shutdown only for the sake of running hooks (players are not disconnected). It's run with reset in-game or with evennia reset from the terminal.

1. at_server_cold_stop()
2. at_server_stop() (after this, only Server has shut down)
3. at_server_init() (Server coming back up)
4. at_server_cold_start()
5. at_server_start()