F# 异步 lambda 与 C# 异步模型互操作

Question

我有这么一段代码（C#，Pulumi），想翻译成F#：

var registryInfo = repo.RegistryId.Apply(async (id) =>
        {
            var creds = await GetCredentials.InvokeAsync(new GetCredentialsArgs {RegistryId = id});
            var decodedData = Convert.FromBase64String(creds.AuthorizationToken);
            var decoded = ASCIIEncoding.ASCII.GetString(decodedData);

            var parts = decoded.Split(':');

            return new ImageRegistry
            {
                Server = creds.ProxyEndpoint,
                Username = parts[0],
                Password = parts[1],
            };
        });

到目前为止我设法做到的是：

let registryInfo = repo.RegistryId.Apply (fun id -> async {
let! creds = GetCredentialsArgs ( RegistryId = id) |> GetCredentials.InvokeAsync |> Async.AwaitTask
let decodedData = Convert.FromBase64String creds.AuthorizationToken
let decoded = ASCIIEncoding.ASCII.GetString decodedData
let parts = decoded.Split ':'
return ImageRegistry( Server = input creds.ProxyEndpoint, Username= input parts.[0], Password = input parts.[1])
} 
)

问题是上面的 F# 代码 returns Output<Async<ImageRegistry>>，而 C# 代码 returns 预期 Output<ImageRegistry>。我正在从 C# 过渡到 F#（以扩展我的技能），但我自己无法处理这种情况。这应该如何正确完成？

Answer 1

虽然对 Pulimu API 了解不多，但我猜 Apply 期待 Task<T>。

您可以使用 Async.StartAsTask 从 F# async 转换为 Task，如下所示：

let registryInfo = repo.RegistryId.Apply (fun id -> async {
//snip
return ImageRegistry( Server = input creds.ProxyEndpoint, Username= input parts.[0], Password = input parts.[1])
} |> Async.StartAsTask
)

尽管如果您正在使用 Task's，您可能会更好地使用 task 计算表达式，而不是使用 Ply (as of writing the native task support is still in development 等库的本机 F# async。

Answer 2

库 Pulumi.FSharp 为此提供了一个有用的助手 Outputs.applyAsync：

open Pulumi.FSharp

let registryInfo =
    repo.RegistryId |>
    Outputs.applyAsync (fun id -> async {
        let! creds = GetCredentialsArgs ( RegistryId = id) |> GetCredentials.InvokeAsync |> Async.AwaitTask
        let decodedData = Convert.FromBase64String creds.AuthorizationToken
        let decoded = ASCIIEncoding.ASCII.GetString decodedData
        let parts = decoded.Split ':'
        return ImageRegistry( Server = input creds.ProxyEndpoint, Username= input parts.[0], Password = input parts.[1])
    })

F# 异步 lambda 与 C# 异步模型互操作

F# async lambda interop with C# async model

c#

asynchronous

f#

pulumi