ProjectAres

Custom Bukkit/Bungee plugins used by the former Overcast Network

License

ProjectAres is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

A copy of the GNU Affero General Public License is included in the file LICENSE.txt

Status

These plugins were converted from an internal project to open source in a rush, so they are not yet well adapted for third party use. Improving this adaptation is a top development priority, specifically:

• Build/deployment infrastructure
• Eliminating dependencies on external plugins (e.g. raven-minecraft)
• Allowing network features to be fully disabled
• Expanding standalone functionality
• Map author username lookup through Mojang API
• Documentation for third-parties (e.g. "how do I run this thing??")

Contents

• Util Utility code library (not a plugin) used by everything
  • core Utils independent of Bukkit or Bungee
  • bukkit Bukkit utils
  • bungee Bungee utils
• API Client
  • api Data models and services, not related to Minecraft
  • minecraft Code specific to Minecraft, including standalone service implementations
  • bukkit Bukkit plugin
  • bungee Bungee plugin
  • ocn Hybrid plugin implementing OCN's HTTP and AMQP services
• Commons Functionality common to all servers e.g. friends, nicknames, etc.
  • core Code that is common to Bukkit and Bungee plugins
  • bukkit Bukkit plugin
  • bungee Bungee plugin
• PGM Primary Bukkit plugin on match servers
• Lobby Main Bukkit plugin on lobby servers
• Tourney Bukkit plugin that extends PGM with tournament-related functionality

OCN plugins not found in this repo:

• Raven - Sentry error reporting client
• BukkitSettings - Framework for player settings i.e. /get, /set, and /toggle commands
• Channels - Framework used to split up team/observer chat
• ChatModerator - Chat censorship

Direct dependencies between the Bukkit plugins:

• API -> Raven
• Commons -> API, BukkitSettings, Channels
• PGM -> Commons, API, BukkitSettings, Channels
• Tourney -> PGM, Commons, API

The API plugin is used by all the other plugins to interact with the data model. It is split into interface and implementation layers, allowing different backends to be used. There is a built-in default backend that implements minimal functionality for running a standalone server. The api-ocn plugin is the backend implementation for the former Overcast Network.

Development Environment

A development environment should have at least one Bungee, Lobby, and PGM server, preferably running the same plugins as in production.

Appropriate SportBukkit settings are provided in bukkit.yml.sample in this folder. Of particular importance are these:

• settings.bungeecord: true This is required in order to connect through Bungee
• settings.isolate-plugins: true Isolate the class loaders of plugins without a dpendency relationship. Without this, plugins can get the wrong versions of common libraries from other plugins.
• settings.legacy-knockback: true Emulate knockback mechanics from older versions of Minecraft
• settings.water-pushes-tnt: false Disable water pushing TNT, a newer Minecraft feature that we don't use.

Everything from the Web repo will need to be running as well, and each server will need to be configured through the Servers admin page. The config.yml for the API plugin specifies the server ID, which must match the one displayed on the admin page.

The PGM server should be configured to load the entire production map repo. This will ensure that PGM code changes don't break any maps, at least not at load-time.

Production Environment

• Bungee proxies

  • OCN BungeeCord fork https://github.com/OvercastNetwork/BungeeCord
  • Commons
  • API

• All Bukkit servers

  • SportBukkit https://github.com/OvercastNetwork/SportBukkit
  • Raven-minecraft https://github.com/OvercastNetwork/raven-minecraft
  • Commons
  • API
  • BukkitSettings
  • Channels
  • ChatModerator
  • CommandBook
  • NullTerrain (generates empty chunks)
  • WorldEdit
  • NoCheatPlus

• Lobbies

  • Lobby

• Development/practice servers

  • PGM

• Public match servers

  • PGM

• Tournament match servers

  • Tourney
  • PGM

Coding Guidelines

• General
  • Use your judgment always. Any rule can be broken with a good reason. Don't follow a rule without understanding its purpose.
  • Write code for readability above all else. Always think about how another developer would work with your code.
  • Avoid repetitive code. Factor out the repetition, if there is a reasonable way to do so.
  • We have a lot of legacy code lying around. Be careful not to build on obsolete systems or use outdated conventions.
• Formatting
  • For basic things like tab size and bracket placement, just match the existing code.
  • Use whatever layout you feel makes the code most readable, even if that differs from case to case.
  • You can use concise formats in places where it helps readability (e.g. single-line getters).
• Comments
  • Try to write code that is obvious enough so that it doesn't need to be explained with comments.
  • In places where a reader might be confused or miss something important, use comments to fill them in.
  • Don't put redundant or obvious things in comments or javadocs.
  • Ensure your IDE is not inserting any generated comments.
• Nulls
  • Strongly prefer java.util.Optional over null, generally speaking.
  • Use empty collections as nil values for collections.
  • Use @Nullable wherever nulls are allowed. Place it before the type, if possible.
  • Don't use @Nonnull. Assume anything (in our own code) without @Nullable is never null.
  • Use checkNotNull on constructor arguments for manually created objects. Don't check @Injected values, they cannot be null.
• Structure
  • Design classes to do one thing only. If a class provides multiple services, break them down into seperate public interfaces and keep the class private.
  • Use final fields, and create immutable data types, wherever possible.
  • Don't create unnecessary getters and setters, only what is actually used.
  • No mutable static fields, collections, or any other static state (there are a few exceptions, such as caches and ThreadLocals).
  • Getters don't have to start with get, but they can if you think it's important.
• Injection
  • We use Guice everywhere. You will need to understand it thoroughly.
  • Follow the Guice best practices (especially that one).
  • We sometimes use the term "manifest" in place of "module", to avoid confusion with PGM modules.
  • Using Guice in a Bukkit plugin environment has proven to be somewhat complex. You don't have to understand all of that, but there are a few things you should know:
    • Each plugin has its own private module in which most of its bindings live.
    • Each plugin instance is bound to org.bukkit.plugin.Plugin inside its private module.
    • Anything that indirectly depends on Plugin will need to be bound in some plugin's private module.
    • If other plugins need access to that thing, it needs to be exposed.
    • Avoid depending on Plugin directly. There are specific bindings for most Bukkit service types (e.g. Configuration) and several interfaces of our own that wrap small parts of the Bukkit API (e.g. BukkitEventBus).
    • If you really need a Plugin, always inject the base interface, never a specific plugin's class. This makes it easy to move things between plugins.
    • If the same @Singleton type is provisioned in multiple plugins, we will detect it and throw an exception. If you actually want a per-plugin singleton, make it @PluginScoped.
    • PluginFacets are service objects registered with a specific plugin to share its lifecycle callbacks (i.e. enable() and disable()). They are also registered automatically in the appropriate way if they implement various interfaces such as Listener (see the javadocs for details).
• Exceptions
  • Detect errors as early as possible, ideally at server startup. This applies to both user errors and internal assertions.
  • Only catch specific exceptions that you are expecting and can handle thoroughly. Don't hide exceptions that other handlers need to know about.
  • Avoid catching common exceptions like IllegalArgumentException, because it's hard to be certain where they come from. If you need to catch them, keep the code inside the try block as small as possible.
  • Don't catch all exceptions or try to handle internal errors for no particular reason. We have a nice framework for dealing with unhandled exceptions at the top-level.
  • If you need to implement a general exception handler, inject a tc.oc.commons.core.exception.ExceptionHandler and pass it the exceptions.
  • Ensure that all errors are seen by a human who knows how to fix them:
    • Pure user errors only need to be sent to the user who provided the bad input
    • Map errors can be sent to builders in-game (and in Sentry too, on production servers) using the MapdevLogger.
    • Any unexpected exception on any server must notify developers somehow i.e. through the LoggingExceptionHandler or some system logger. You can tell the user about the error so they know what's going on, but don't expect them to deal with it.
• Concurrency
  • Avoid concurrency. It's hard, and we don't have a general solution for doing it safely.
  • A Bukkit server has a single "main thread" where most game logic runs, and multiple background threads for I/O and serialization. All Events (except AsyncEvents) and scheduled tasks (except async tasks) run on the main thread.
  • Our own plugins use background thread pools for API operations, which use HTTP and AMQP.
  • Never block the main thread on API calls, or any other I/O operation. Use ListenableFutures and FutureCallbacks to handle API results.
  • Don't use the Bukkit API, or any of our own APIs, from a background thread, unless it is explicitly allowed by the API. Use MainThreadExecutor or SyncExecutor to get back on the main thread from a background thread.
  • A Bungee server is entirely multi-threaded. Handlers for a specific event run in sequence, but seperate events and tasks can run concurrently. This is one of the reasons we avoid doing things in Bungee.
• Localization
  • All in-game text must be localized.
  • To add a text string to the game, put the english template in one of the .properties files in Commons.
  • Use a TranslatableComponent to display the localized message. However, it must pass through the ComponentRenderContext before being sent to the player. That will apply the server-side translations.
  • Any changes to the templates must be sent to Crowdin before volunteers can start translating them. This is done with the Crowdin integration tool by running crowdin-cli upload sources in the Commons folder. This should be done after the new code is deployed to production.
• Libraries
  • TODO
• Utilities
  • TODO
• Testing
  • TODO
• Logging
  • TODO

Workflow

• We use Git, with a typical feature branch workflow
• Trivial changes and emergency fixes can be merged straight to the master branch
• Any significant change requires a PR, and code review by at least one other developer. This applies indiscriminately to all developers. Everyone should have their code reviewed, and anyone can review anyone else's code.
• Once a change has been merged to master, it should be deployed ASAP so that problems can be found. Deploying several old changes at once just makes it harder to trace bugs to their source.
• Without automated tests, we rely heavily on user reports and Sentry alerts to discover regressions. Developers should be around for at least a few hours after their change is deployed, in case something breaks.