private async Task ExecuteAsync(CancellationToken cancellationToken = default)
{
if (cancellationToken.IsCancellationRequested)
{
_logger.LogInformation($"{nameof(StoreProjector<TProjection>)}.{nameof(ExecuteAsync)} was cancelled before execution");
cancellationToken.ThrowIfCancellationRequested();
}
using (var context = _projectionDbContextFactory.Create())
{
var state = await context.ProjectionStates.FindAsync(_name);
if (state == null)
{
state = new ProjectionState
{
Name = _name,
CreatedDate = DateTimeOffset.UtcNow,
Position = 0
};
context.ProjectionStates.Add(state);
await context.SaveChangesAsync(cancellationToken);
}
while (!cancellationToken.IsCancellationRequested)
{
try
{
await context.Entry(state).ReloadAsync();
var page = await _eventStore.GetEventsAsync(state.Position);
foreach (var @event in page.Events)
{
await _projectionManager.HandleAsync(@event.Payload);
}
if (state.Position == page.Offset)
{
await Task.Delay(_options.Value.Interval);
}
else
{
state.Position = page.Offset;
state.LastModifiedDate = DateTimeOffset.UtcNow;
await context.SaveChangesAsync();
}
}
catch (Exception ex)
{
_logger.LogCritical(ex, $"Process '{typeof(TProjection).Name}' failed at postion '{state.Position}' due to an unexpected error. See exception details for more information.");
break;
}
}
}
}