go-app/pkg/srv/grpc/grpc_run.go

package grpc

import (
	"context"
	"net"

	"go.opentelemetry.io/otel/codes"
	semconv "go.opentelemetry.io/otel/semconv/v1.27.0"
)

// TODO: Implement
func (a *appGRPCServer) runGRPCServer(spanCtx context.Context) error {
	_, span := a.tracer.Start(spanCtx, "appgrpc.init.start")
	defer span.End()

	span.SetAttributes(
		semconv.RPCSystemGRPC,
		semconv.NetworkProtocolName("grpc"),
		semconv.ServerAddress(a.opts.Listen),
	)

	a.shutdownFunc = a.getShutdownFunc()

	l, err := net.Listen("tcp", a.opts.Listen)
	if err != nil {
		a.logger.Err(err).Send()
		span.RecordError(err)
		span.SetStatus(codes.Error, "failed to acquire net listener")
		return err
	}

	span.AddEvent("network listener acquired")

	// Launch GRPC Server
	go func() {
		if err := a.server.Serve(l); err != nil {
			a.logger.Err(err).Send()
			a.doneChan <- err
		}
	}()

	span.AddEvent("grpc server goroutine launched")
	span.SetStatus(codes.Ok, "")

	return nil
}

func (a *appGRPCServer) getShutdownFunc() func(context.Context) error {
	return func(ctx context.Context) error {
		stoppedChan := make(chan any)

		go func() {
			a.server.GracefulStop()
			stoppedChan <- nil
		}()

		select {
		case <-stoppedChan:
			a.logger.Warn().Msg("GRPC server shut down gracefully")
			return nil
		case <-ctx.Done():
			a.logger.Warn().Msg("GRPC server shut down hard")
			a.server.Stop()
			return ctx.Err()
		}
	}
}