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在TopShelf中使用异步WhenStarted和WhenStopped方法

topshelf async-await .net c#

1

Chris · 技术社区 · 7 年前

one mentionon their github pages 声明不应以这种方式使用async。

但是,尽管如此,它的编译和运行(大部分)还可以。那么这是正确的还是应该使用 .Wait() 相反呢?

var host = HostFactory.New(hostConfig =>
{
    hostConfig.Service<StreamClient>(serviceConfig =>
    {
        serviceConfig.ConstructUsing(name => new StreamClient());
        serviceConfig.WhenStarted(async tc => await tc.Start());
        serviceConfig.WhenStopped(async tc => await tc.Stop());
    });

    hostConfig.RunAsLocalSystem();

    hostConfig.SetDescription("Stream Client Service");
    hostConfig.SetDisplayName("Stream Client Service");
    hostConfig.SetServiceName("StreamClientService");
});

host.Run();

@Nkosi问方法签名是什么样子的,它们是异步的,并且启动内部客户机和进程。

public async Task Start()
{
    // Dont start again if we are already running, or if we are already in the starting state
    if (this.Running || this.Starting)
    {
        return;
    }

    await this.slackService.SendSlackServiceEvent(ServiceEventType.Starting, serviceName, applicationVersion);

    this.Starting = true;
    this.Stopping = false;

    var configurationBuilder = new ClientConfigurationBuilder();

    ClientConfiguration clientConfiguration;
    if (Constants.UseLocalConnection)
    {
        await this.OnClientDebugMessage($"Using Local Connection");
        clientConfiguration = configurationBuilder.CreateLocalConfiguration();
    }
    else
    {
        await this.OnClientDebugMessage($"Using SQL Connection");
        clientConfiguration = configurationBuilder.CreateSqlConfiguration();
    }

    this.ClusterGrainClient = await this.StartClient(clientConfiguration);

    if (this.ClusterGrainClient == null)
    {
        using (ConsoleColours.TextColour(ConsoleColor.Red))
        {
            await this.OnClientDebugMessage($"Cluster client null, aborting!");
        }

        return;
    }

    this.Running = true;

    await this.OnClientStarted();
    await this.slackService.SendSlackServiceEvent(ServiceEventType.Started, serviceName, applicationVersion);
    this.Starting = false;

}

2 回复 | 直到 7 年前

1

3

Nkosi 7 年前

你基本上是在做一个 async void

参考 Async/Await - Best Practices in Asynchronous Programming

将start和stop方法转换为引发可以在内部等待的异步事件的同步方法。

public void Start() {
    Started += OnStarted; //subscribe to event
    Started(this, EventArgs.Empty); //raise event
}

private event EventHandler Started = delegate { };

private async void OnStart(object sender, EventArgs args) {
    Started -= OnStarted;        
    await StartAsync();
}

public async Task StartAsync() {
    // ...
}

然后正常启动

serviceConfig.WhenStarted(_ => _.Start());

2

5

Paulo Morgado 7 年前

我自己从来没有试过,但你可以这样试:

public void Start() => this.StartAsync().GetAwaiter().GetResult();
public void Stop() => this.Stop().GetAwaiter().GetResult();

public async Task StartAsync()
{
    // ...
}

public async Task StopAsync()
{
    // ...
}