grpc-go/examples/features/gracefulstop

Graceful Stop

This example demonstrates how to gracefully stop a gRPC server using Server.GracefulStop(). The graceful shutdown process involves two key steps:

• Initiate Server.GracefulStop(). This function blocks until all currently running RPCs have completed. This ensures that in-flight requests are allowed to finish processing.

• It's crucial to call Server.Stop() with a timeout before calling GracefulStop(). This acts as a safety net, ensuring that the server eventually shuts down even if some in-flight RPCs don't complete within a reasonable timeframe. This prevents indefinite blocking.

Try it

go run server/main.go

go run client/main.go

Explanation

The server starts with a client streaming and unary request handler. When client streaming is started, client streaming handler signals the server to initiate graceful stop and waits for the stream to be closed or aborted. Until theServer.GracefulStop() is initiated, server will continue to accept unary requests. Once Server.GracefulStop() is initiated, server will not accept new unary requests.

Client will start the client stream to the server and starts making unary requests until receiving an error. Error will indicate that the server graceful shutdown is initiated so client will stop making further unary requests and closes the client stream.

Server and client will keep track of number of unary requests processed on their side. Once the client has successfully closed the stream, server returns the total number of unary requests processed as response. The number from stream response should be equal to the number of unary requests tracked by client. This indicates that server has processed all in-flight requests before shutting down.