Implement graceful shutdown for Garnet server

[yuseok-kim-edushare]

This pull request introduces a comprehensive and robust graceful shutdown mechanism for the Garnet server, both for Windows service and console application scenarios. The changes ensure that when a shutdown is requested (via service stop, Ctrl+C, or process exit), the server stops accepting new connections, waits for existing connections to finish, commits all data (AOF), and takes a checkpoint if necessary, all within a configurable timeout. This significantly improves data durability and operational reliability during shutdowns.

Mainly goal is Close #1382 and Resolve #1390
This PR reflect #1383 (comment)

Graceful Shutdown Implementation

• Added a new ShutdownAsync method to main/GarnetServer/GarnetServer that orchestrates the graceful shutdown process: stops accepting new connections, waits for active connections to finish (with timeout), commits AOF, and takes a checkpoint if tiered storage is enabled.
• Modified the Windows service (Worker.StopAsync) and console app (Program.Main) to use the new ShutdownAsync method, ensuring consistent and graceful shutdown behavior in both entrypoints. [1] [2]

Server Interface and Networking Enhancements

• Extended the server interface (libs/server/Servers/IGarnetServer) and base classes to support stopping listening for new connections via a new StopListening method, and implemented this for TCP servers to close the listen socket cleanly. [1] [2] [3]

Data Durability and Checkpointing

• Added new APIs in libs/server/Servers/StoreApi to take a checkpoint and to check if AOF or storage tier is enabled, supporting the shutdown flow for data durability.

Infrastructure and Code Quality Improvements

• Ensured proper disposal patterns and resource cleanup, including calling base.Dispose() and suppressing finalization.
• Updated using directives and minor code structure for clarity and consistency. [1] [2] [3]

Configuration and Timeout Handling

• Added configuration for shutdown timeout in the Windows service host, defaulting to 5 seconds for graceful shutdown.

These changes collectively make server shutdowns safer and more reliable, reducing the risk of data loss or corruption during restarts or deployments.

[Copilot]

Pull request overview

This pull request implements a comprehensive graceful shutdown mechanism for the Garnet server, addressing GitHub issues #1382 and #1390. The implementation provides a coordinated shutdown process that stops accepting new connections, waits for active connections to complete, commits the Append-Only File (AOF), and takes checkpoints for tiered storage—all within configurable timeouts. This enhancement significantly improves data durability and operational reliability during server restarts and deployments.

Key Changes:

• Added ShutdownAsync method to coordinate graceful shutdown with connection draining, AOF commit, and checkpointing
• Introduced StopListening method to cleanly stop accepting new connections while preserving existing ones
• Updated both console application and Windows service entry points to use the new graceful shutdown flow with proper timeout handling

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
main/GarnetServer/Program.cs	Converted Main to async, added shutdown signal handlers (Ctrl+C, ProcessExit), implemented graceful shutdown with timeout and disposal coordination
libs/host/GarnetServer.cs	Added ShutdownAsync method orchestrating stop-listening, connection waiting, AOF commit, and checkpoint operations
libs/server/Servers/IGarnetServer.cs	Extended interface with StopListening method for graceful shutdown support
libs/server/Servers/GarnetServerBase.cs	Added virtual StopListening method with default no-op implementation
libs/server/Servers/GarnetServerTcp.cs	Implemented StopListening by closing listen socket and tracking listening state
libs/server/Servers/StoreApi.cs	Added TakeCheckpoint method and storage tier/AOF enabled properties for shutdown logic
hosting/Windows/Garnet.worker/Worker.cs	Updated StopAsync to call ShutdownAsync before disposal, improved Dispose pattern with base.Dispose and GC.SuppressFinalize
hosting/Windows/Garnet.worker/Program.cs	Added HostOptions configuration for 5-second shutdown timeout and System namespace import

Comments suppressed due to low confidence (1)

main/GarnetServer/Program.cs:16

• Disposable 'CancellationTokenSource' is created but not disposed.

            var shutdownCts = new CancellationTokenSource();

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