/// <summary>
/// Determine whether a local package is the same as a package on an AzDO feed.
/// </summary>
/// <param name="localPackageFullPath"></param>
/// <param name="packageContentUrl"></param>
/// <param name="client"></param>
/// <returns></returns>
/// <remarks>
/// Open a stream to the local file and an http request to the package. There are a couple possibilities:
/// - The returned headers includes a content MD5 header, in which case we can
/// hash the local file and just compare those.
/// - No content MD5 hash, and the streams must be compared in blocks. This is a bit trickier to do efficiently,
/// since we do not necessarily want to read all bytes if we can help it. Thus, we should compare in blocks. However,
/// the streams make no gaurantee that they will return a full block each time when read operations are performed, so we
/// must be sure to only compare the minimum number of bytes returned.
/// </remarks>
private async Task <bool> IsLocalPackageIdenticalToFeedPackage(string localPackageFullPath, string packageContentUrl, HttpClient client)
{
Log.LogMessage($"Getting package content from {packageContentUrl} and comparing to {localPackageFullPath}");
try
{
using (Stream localFileStream = File.OpenRead(localPackageFullPath))
using (HttpResponseMessage response = await client.GetAsync(packageContentUrl))
{
response.EnsureSuccessStatusCode();
// Check the headers for content length and md5
bool md5HeaderAvailable = response.Headers.TryGetValues("Content-MD5", out var md5);
bool lengthHeaderAvailable = response.Headers.TryGetValues("Content-Length", out var contentLength);
if (lengthHeaderAvailable && long.Parse(contentLength.Single()) != localFileStream.Length)
{
Log.LogMessage(MessageImportance.Low, $"Package '{localPackageFullPath}' has different length than remote package '{packageContentUrl}'.");
return(false);
}
if (md5HeaderAvailable)
{
var localMD5 = AzureStorageUtils.CalculateMD5(localPackageFullPath);
if (!localMD5.Equals(md5.Single(), StringComparison.OrdinalIgnoreCase))
{
Log.LogMessage(MessageImportance.Low, $"Package '{localPackageFullPath}' has different MD5 hash than remote package '{packageContentUrl}'.");
}
return(true);
}
const int BufferSize = 64 * 1024;
// Otherwise, compare the streams
var remoteStream = await response.Content.ReadAsStreamAsync();
return(await CompareStreamsAsync(localFileStream, remoteStream, BufferSize));
}
}
catch (Exception e)
{
// This is an error. It means we were unable to push using nuget, and then could not access to the package otherwise.
Log.LogWarning($"Failed to determine whether an existing package on the feed has the same content: {e.Message}");
return(false);
}
}
/// <summary>
/// Determine whether a local package is the same as a package on an AzDO feed.
/// </summary>
/// <param name="localPackageFullPath"></param>
/// <param name="packageContentUrl"></param>
/// <param name="client"></param>
/// <returns></returns>
/// <remarks>
/// Open a stream to the local file and an http request to the package. There are a couple possibilities:
/// - The returned headers includes a content MD5 header, in which case we can
/// hash the local file and just compare those.
/// - No content MD5 hash, and the streams must be compared in blocks. This is a bit trickier to do efficiently,
/// since we do not necessarily want to read all bytes if we can help it. Thus, we should compare in blocks. However,
/// the streams make no gaurantee that they will return a full block each time when read operations are performed, so we
/// must be sure to only compare the minimum number of bytes returned.
/// </remarks>
public static async Task <PackageFeedStatus> CompareLocalPackageToFeedPackage(string localPackageFullPath, string packageContentUrl, HttpClient client, TaskLoggingHelper log)
{
log.LogMessage($"Getting package content from {packageContentUrl} and comparing to {localPackageFullPath}");
PackageFeedStatus result = PackageFeedStatus.Unknown;
ExponentialRetry RetryHandler = new ExponentialRetry
{
MaxAttempts = MaxRetries
};
bool success = await RetryHandler.RunAsync(async attempt =>
{
try
{
using (Stream localFileStream = File.OpenRead(localPackageFullPath))
using (HttpResponseMessage response = await client.GetAsync(packageContentUrl))
{
response.EnsureSuccessStatusCode();
// Check the headers for content length and md5
bool md5HeaderAvailable = response.Headers.TryGetValues("Content-MD5", out var md5);
bool lengthHeaderAvailable = response.Headers.TryGetValues("Content-Length", out var contentLength);
if (lengthHeaderAvailable && long.Parse(contentLength.Single()) != localFileStream.Length)
{
log.LogMessage(MessageImportance.Low, $"Package '{localPackageFullPath}' has different length than remote package '{packageContentUrl}'.");
result = PackageFeedStatus.ExistsAndDifferent;
return(true);
}
if (md5HeaderAvailable)
{
var localMD5 = AzureStorageUtils.CalculateMD5(localPackageFullPath);
if (!localMD5.Equals(md5.Single(), StringComparison.OrdinalIgnoreCase))
{
log.LogMessage(MessageImportance.Low, $"Package '{localPackageFullPath}' has different MD5 hash than remote package '{packageContentUrl}'.");
}
result = PackageFeedStatus.ExistsAndDifferent;
return(true);
}
const int BufferSize = 64 * 1024;
// Otherwise, compare the streams
var remoteStream = await response.Content.ReadAsStreamAsync();
var streamsMatch = await GeneralUtils.CompareStreamsAsync(localFileStream, remoteStream, BufferSize);
result = streamsMatch ? PackageFeedStatus.ExistsAndIdenticalToLocal : PackageFeedStatus.ExistsAndDifferent;
return(true);
}
}
// String based comparison because the status code isn't exposed in HttpRequestException
// see here: https://github.com/dotnet/runtime/issues/23648
catch (HttpRequestException e)
{
if (e.Message.Contains("404 (Not Found)"))
{
result = PackageFeedStatus.DoesNotExist;
return(true);
}
// Retry this. Could be an http client timeout, 500, etc.
return(false);
}
});
return(result);
}