Message Flow and Threading Model

Event Loop

The main function of each service process (e.g. src/lobbysvr/service/app/lobbysvr_main.cpp) performs:

1. Constructs atfw::atapp::app;
2. logic_server_setup_common (src/server_frame/logic/logic_server_setup.cpp) assembles common modules, event callbacks, and the service discovery index;
3. app.add_module(cs_msg_dispatcher::me(), ss_msg_dispatcher::me(), db_msg_dispatcher::me(), business modules...);
4. app.run(uv_default_loop(), argc, argv, nullptr).

All atbus send/receive, Redis replies, timers, and DNS queries are invoked back on this single libuv loop; time-consuming operations are always wrapped as coroutine tasks, which suspend via co_await (or the libcopp equivalent macros) and are resumed by the dispatcher using task_id + sequence.

Client Message Flow (CS)

cs_msg_dispatcher handles the four types of gateway::server_message: kAddSession (create session), kPost (upstream message, starts a CS task action), kRemoveSession (logout), and kSetRouterRsp. Downstream messages are returned to atgateway via session::send_msg_to_client / cs_msg_dispatcher::send_data / broadcast_data / send_kickoff / send_set_router.

Inter-Service Message Flow (SS)

• The caller-side code is generated by rpc_call_api_for_ss.*.mako: it assembles an SSMsg → ss_msg_dispatcher::send_to_proc (by bus id / name / discovery node) → app::send_message → atbus; cross-service-group traffic can be forwarded through atproxy.
• Supports unary / stream / no-wait / broadcast / metadata / user / router variants; broadcast can be addressed by type, zone, or metadata index.
• Responses resume the waiting task via internal::wait_and_unpack_ss_response using destination_task_id + sequence.
• ss_msg_dispatcher embeds DNS lookup (uv_getaddrinfo + custom_resume) to resolve peer addresses on demand.

Database Message Flow

db_msg_dispatcher manages Redis cluster and raw (sentinel) dual-channel connections based on hiredis-happ, supports SCRIPT LOAD and embedded Lua (CAS, KL index trimming); replies are unpacked and then resume the corresponding task. See Data Layer for details.

Suspend/Resume Primitives

Primitive	Location	Purpose
rpc::wait	rpc/rpc_utils.h	Wait for SSMsg / db_message (optionally with timeout), supports multiple waiters
rpc::custom_wait / rpc::custom_resume	rpc/rpc_utils.h	Suspend/resume by type address + sequence (custom wakeups such as DNS, router)
rpc::async_invoke	rpc/rpc_async_invoke.h	Wrap any callable and start it as a real task
RPC_AWAIT_* / RPC_RETURN_*	rpc/rpc_common_types.h	Macros that hide the differences between the std-coroutine and libcopp implementations