Table of Contents

Event Sequence Source

By default, projections read from the event log. Use [FromEventSequence] to specify a different event sequence:

using Cratis.Chronicle.Keys;
using Cratis.Chronicle.Projections.ModelBound;

[FromEventSequence("custom-sequence")]
public record OrderSummary(
    [Key]
    Guid Id,

    [SetFrom<OrderPlaced>]
    decimal TotalAmount);

This corresponds to the fluent API:

projection.FromEventSequence(new EventSequenceId("custom-sequence"));

When to use

  • When you need to read from a specific event sequence rather than the default event log
  • For projections that should only consider events from a particular source or context
  • When working with partitioned or specialized event streams

Best practices

  • Only specify when you need to read from a non-default event sequence
  • Ensure the event sequence exists and contains the events your projection needs
  • Consider the implications of switching event sequences on existing projections