ASP.Net WebAPI and CorrelationID/RefCorrelatonID

Somethings can be foreshadowed and some things are always expected. As is the case of looking in log files and not seeing a Correlation ID nor any RefCorrelation ID’s. Thing is when your logs do not have alot of throughput you can find your customers/clients/elements/daemons log entry with ease with just a log stamp (datetime). However , even with low latency Correlation ID’s should always be utilised.

What is a Correlation Identifier?  Simple Guid that is Unique and identifies a transaction. See the link for a more enterprise integration perspective, but in the end a guid is all this is.

A curious thing that I always see is that in all the logging examples:

1) No provisioning for Correlation ID’s
2) No provisioning for Ref Correlation ID’s

I then ponder on …

how is it that you correlate?

(Pun intended)

Inbound Web.API calls should have a header containing a Correlation ID. Which is a GUID that can clearly and uniquely identity the transaction.

This in turn then becomes the RefCorrelation ID in your log, as you spawn a Correlation ID of you own based on the Request.CorrelationID which is a unique identifier to the transaction. The client should see his/her payload coming back with an echo of the ID they sent in. At times the RefCorrelationID is also sent as an echo. All depending on requirements and standards.

I very much like this implementation:

The only variant that I advise is to accept a correlation ID from the client and to use the correlation ID from the request [request.GetCorrelationId()] as the Unique ID in the logs.



First example of standard flow a request comes in and is processed internally via multiple logging points. The RefCorrelation ID is what the client passed in, the Correlation ID is what we generated or decided was going to be the unique idenitfier.

In the second example another service is call. Say to process a payment.

Which ID is passed?

Your correlation ID is passed and the new service uses yours as a REF and generated a new unique ID for its transaction. So on and so forthat as many times as we have subsequent calls.

Having worked in integration for over 12 years, I know the value of being able to correlate all data especially when execitions can go from Java to ASP.Net Web.API to IBM MQ to Biztalk to Appliances.

Food for thought!