Make Inexor capable to run multiple instances

[aschaeffer]

Motivation

Making Inexor able to run multiple instances would mean we can start and stop servers and clients at runtime.

Requirements

• [x] Separate Inexor Flex in it's own repository (#360)
• [x] Inexor Lifecycle (Initialising Inexor Tree, RPC and parsing command line options) (#354)
• [x] Define the default ports (#367)

Architecture

In order to achieve multi instance capabilities, we have to redesign the architecture:

• [x] One instance of Inexor Flex manages 0..N instances of Inexor Core
  • Start an instance
  • Stop an instance
• [x] Only one instance of Inexor Flex is allowed
  • Starting Inexor Flex again will parse and execute the given command line commands (for example: ./inexor start client starts a new instance of the Inexor Core Client)
• [x] Each instance of Inexor Core has an instance id
  • The instance id is the GRPC port
  • Passing the instance id as command line option

Inexor Tree

• [x] Inexor Flex manages the overall Inexor Tree
• [x] For each instance of Inexor Core a sub tree is created
  • The sub tree is initialized before an instance of Inexor Core is started
  • The path of the sub tree starts with the instance id
  • The REST urls contains the instance id

User Interface (HUD / Application) for Inexor Core (Client) instances

• Inexor Flex provides the user interface for all instances of Inexor Core
• Each REST request must contain the instance id

Inexor Flex Business Logic

• A lot of services can be shared across all instances:
  • InexorTree REST API (instance id)
  • TextureManager
  • ServerListManager
• Other services have to be created for each instance of Inexor Core:
  • Game State
  • Game Mode

Future

• Inexor Core (Server): Server Management
  • Inexor Flex provides a web Interface
  • Create a new server instance
  • Configure a server instance
  • Start and stop a server instance
• Inexor Core (Client): Multi user input support
  • Assign a mouse to a instance of Inexor Core
  • Assign a keyboard to a instance of Inexor Core
• Inexor Core (Client): Split screen support
  • Inexor Flex arranges the positions of the windows of Inexor Core
  • Vertical split screen
  • Borderless window
  • First instance of Inexor Core: left side
  • Second instance of Inexor Core: right side
  • Horizontal split screen
  • Borderless window
  • First instance of Inexor Core: upper area
  • Second instance of Inexor Core: lower area
  • Monitor split screen
  • Borderless window
  • Each instance is positioned on a separate monitor

[a-teammate]

+1 Very good summary

Just the splitscreen support should be done on one Client instance (for performance)

[Fohlen]

Restricting the flex server to a single instance could be done using https://nodejs.org/api/process.html#process_process_pid .. then adding a command which looks up the pid and adding an appropriate script to the package.json would be the way to go with npm start && npm stop, although shutdown via port is probably more desirable.

[aschaeffer]

Done in flex/master.