How can I create a Serilog enricher that reads from HttpContext.TraceIdentifier?
action-filter, asp.net-core-1.0, asp.net-core-mvc, serilog
Solution
I don't think you need an enricher for this.
Putting `{RequestId}` into the sink's `outputTemplate` gives me an ID like "0HL0GJPLR7AOD". If I set `HttpContext.TraceIdentifier` right before logging something then `{RequestId}` gives me exactly that ID so custom IDs also work with `{RequestId}`.
I think `{RequestId}` is a Microsoft.Extensions.Logging feature but it works out of the box with serilog (at least when you are using Serilog.Extensions.Logging).
Update: Don't forget to configure `Enrich.FromLogContext()`.
Problem
I've recently integrated Serilog into several .NET Standard class libraries, including some class libraries that are used by MVC 6 projects. What I'd like to do is enrich log entries with `HttpContext.TraceIdentifier`. I wrote an action filter that sets `HttpContext.TraceIdentifier` to a `Correlation-ID` request header value, if present: ``` public override void OnActionExecuting(ActionExecutingContext context) { StringValues correlationIds; Guid correlationId; if (!context.HttpContext.Request.Headers.TryGetValue(Constants.CorrelationIdHeaderName, out correlationIds) || correlationIds.Count != 1 || !Guid.TryParse(correlationIds[0], out correlationId)) { correlationId = _guidFactory.Random(); context.HttpContext.Response.Headers.Add(Constants.CorrelationIdHeaderName, correlationId.ToString("D")); } context.HttpContext.TraceIdentifier = correlationId.ToString("D"); base.OnActionExecuting(context); } ``` The problem is, how do I make Serilog aware, for the life of this request, of the correlation ID? Since it doesn't appear as though there is an `HttpContext.Current` property, I'm not sure how to create an enricher that will work. Is this even possible?