private static byte[] EncodeRequest(IRequestContext context, MetadataRequest request)
{
using (var message = EncodeHeader(context, request)) {
message.Write(request.Topics, true);
return(message.ToBytes());
}
}
/// <inheritdoc />
public bool Equals(MetadataRequest other)
{
if (ReferenceEquals(null, other))
{
return(false);
}
if (ReferenceEquals(this, other))
{
return(true);
}
return(topics.HasEqualElementsInOrder(other.topics));
}
/// <summary>
/// Given a collection of server connections, query for the topic metadata.
/// </summary>
/// <param name="router">The router which provides the route and metadata.</param>
/// <param name="request">Metadata request to make</param>
/// <param name="cancellationToken"></param>
/// <remarks>
/// Used by <see cref="Router"/> internally. Broken out for better testability, but not intended to be used separately.
/// </remarks>
/// <returns>MetadataResponse validated to be complete.</returns>
internal static async Task <MetadataResponse> GetMetadataAsync(this IRouter router, MetadataRequest request, CancellationToken cancellationToken)
{
return(await router.Configuration.RefreshRetry.TryAsync(
async (retryAttempt, elapsed) => {
var connections = router.Connections.ToList();
var connection = connections[retryAttempt % connections.Count];
var response = await connection.SendAsync(request, cancellationToken).ConfigureAwait(false);
if (response == null)
{
return new RetryAttempt <MetadataResponse>(null);
}
var results = response.brokers
.Select(ValidateServer)
.Union(response.topic_metadata.Select(ValidateTopic))
.Where(r => !r.IsValid.GetValueOrDefault())
.ToList();
var exceptions = results.Select(r => r.ToException(connection.Endpoint)).Where(e => e != null).ToList();
if (exceptions.Count == 1)
{
throw exceptions.Single();
}
if (exceptions.Count > 1)
{
throw new AggregateException(exceptions);
}
if (results.Count == 0)
{
return new RetryAttempt <MetadataResponse>(response);
}
foreach (var result in results.Where(r => !string.IsNullOrEmpty(r.Message)))
{
router.Log.Warn(() => LogEvent.Create(result.Message));
}
return new RetryAttempt <MetadataResponse>(response, false);
},
(ex, retryAttempt, retryDelay) => router.Log.Warn(() => LogEvent.Create(ex, $"Failed metadata request on attempt {retryAttempt}: Will retry in {retryDelay}")),
null, // return the failed response above, resulting in the final response
cancellationToken).ConfigureAwait(false));
}