Package com.iohao.net.external.core

package com.iohao.net.external.core
Provides the core abstractions and runtime infrastructure for external servers, including protocol handling, session management, hooks, and internal communication integration.

See External Server for the architecture overview.

Responsibilities of the External Server 

1. Maintain long connections with users (players)
2. Help developers abstract away communication and connection details
3. Built-in connection methods: WebSocket, TCP. Custom selectors can add other transports.
4. Forward user (player) requests to the Gateway
5. Dynamic scaling (adding or removing) of server instances
6. Feature extensions, such as: route existence detection, route permissions, UserSession management, heartbeats,
and future features like circuit breakers, rate limiting, load shedding (or graceful degradation), and user traffic statistics.

Extension Scenario 

The External Server is primarily responsible for connections with users (players).
Suppose a single piece of hardware supports a maximum of 5000 user connections.
When the number of users reaches 7000, we can add another External Server to manage traffic and reduce load.

Due to the scalability and flexibility of the External Server, it can support concurrent online players ranging
from a few thousand to tens of millions.
This is because by increasing the number of External Servers, connection load balancing and traffic control
can be effectively managed, enabling the system to better withstand high concurrency pressure.

Switching, Support, and Extension of Connection Methods 

The External Server already provides support for TCP and WebSocket connection methods, and offers flexible ways
to switch between them.
TCP and WebSocket connection methods can be seamlessly integrated with the business code.
Developers can use a single set of business code, without any modification, to support multiple communication protocols.

Built-in TCP and WebSocket transports can be switched by changing the corresponding enumeration.
Multiple external servers can also coexist in one application to expose different transports.

Connection methods are extensible. Custom transports such as UDP or KCP can be integrated by registering a matching
ExternalJoinSelector and transport bootstrap.
Author:
渔民小镇
date:
2023-04-28