// <Delegate>
/// <summary>
/// The delegate receives batches of changes as they are generated in the change feed and can process them.
/// </summary>
static async Task HandleChangesAsync(
ChangeFeedProcessorContext context,
IReadOnlyCollection <ToDoItem> changes,
CancellationToken cancellationToken)
{
Console.WriteLine($"Started handling changes for lease {context.LeaseToken}...");
Console.WriteLine($"Change Feed request consumed {context.Headers.RequestCharge} RU.");
// SessionToken if needed to enforce Session consistency on another client instance
Console.WriteLine($"SessionToken ${context.Headers.Session}");
// We may want to track any operation's Diagnostics that took longer than some threshold
if (context.Diagnostics.GetClientElapsedTime() > TimeSpan.FromSeconds(1))
{
Console.WriteLine($"Change Feed request took longer than expected. Diagnostics:" + context.Diagnostics.ToString());
}
foreach (ToDoItem item in changes)
{
Console.WriteLine($"Detected operation for item with id {item.id}, created at {item.creationTime}.");
// Simulate some asynchronous operation
await Task.Delay(10);
}
Console.WriteLine("Finished handling changes.");
}
private void ValidateContext(ChangeFeedProcessorContext changeFeedProcessorContext)
{
Assert.IsNotNull(changeFeedProcessorContext.LeaseToken);
Assert.IsNotNull(changeFeedProcessorContext.Diagnostics);
Assert.IsNotNull(changeFeedProcessorContext.Headers);
Assert.IsNotNull(changeFeedProcessorContext.Headers.Session);
Assert.IsTrue(changeFeedProcessorContext.Headers.RequestCharge > 0);
}
private void ValidateContext(ChangeFeedProcessorContext changeFeedProcessorContext)
{
Assert.IsNotNull(changeFeedProcessorContext.LeaseToken);
Assert.IsNotNull(changeFeedProcessorContext.Diagnostics);
Assert.IsNotNull(changeFeedProcessorContext.Headers);
Assert.IsNotNull(changeFeedProcessorContext.Headers.Session);
Assert.IsTrue(changeFeedProcessorContext.Headers.RequestCharge > 0);
string diagnosticsAsString = changeFeedProcessorContext.Diagnostics.ToString();
Assert.IsTrue(diagnosticsAsString.Contains("Change Feed Processor Read Next Async"));
}
async Task HandleChangeFeedStream(ChangeFeedProcessorContext context, Stream changes, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
var items = Serializer.DeserializeDocumentList <DbDoc>(changes);
await BatchProcessor.HandleAsync(items, cancellationToken).ConfigureAwait(false);
}