使用托管服务标识从Azure存储容器中获取blob对Azure函数进行授权

Question

当我试图使用分配了托管标识的系统在Azure Function应用程序中调用Azure函数以从Azure存储容器中获取blob时，我遇到了：

system.private.corelib:执行函数时出现异常: 。Microsoft.WindowsAzure.Storage：未经授权。 ionname>

[FunctionName("TestFetchTileViaSvcPrinId")]
public static async Task<HttpResponseMessage> RunAsync(
    [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
    ILogger log) {
    log.LogInformation("C# HTTP trigger function processed a request.");

    const string blobName = "https://<storageaccount>.blob.core.windows.net/...path.../<file>.jpg";

    // Get the initial access token and the interval at which to refresh it.
    var azureServiceTokenProvider = new AzureServiceTokenProvider();
    NewTokenAndFrequency tokenAndFrequency = TokenRenewerAsync(azureServiceTokenProvider, CancellationToken.None).GetAwaiter().GetResult();

    // Create storage credentials using the initial token, and connect the callback function to renew the token just before it expires
    var tokenCredential = new TokenCredential(tokenAndFrequency.Token, TokenRenewerAsync, azureServiceTokenProvider, tokenAndFrequency.Frequency.Value);

    var storageCredentials = new StorageCredentials(tokenCredential);

    var cloudBlockBlob = new CloudBlockBlob(new Uri(blobName), storageCredentials);

    using (var memoryStream = new MemoryStream()) {
        await cloudBlockBlob.DownloadToStreamAsync(memoryStream);  // Unauthorized exception is thrown here
        var httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK) {
            Content = new ByteArrayContent(memoryStream.ToArray())
        };
        httpResponseMessage.Headers.Add("Cache-Control", "max-age=31536000"); //31536000 seconds ~ 1 year
        httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg");
        return httpResponseMessage;
    }

}

Answer 1

我搞定了。正如Rohit所注意到的，经过编辑的blob完整路径（如最初发布的）错误地指定了Azure函数路径，而不是存储帐户路径。我后来解决了这个问题。然而，我在实现的路径中确实有一个错别字。更正路径解决了问题。