Web request sequence visualization

Modern requests to web services are very complex. The service you are calling can call other services, they are other services, etc. All these requests can be executed in parallel. Of course, the logging system stores information from all participants in the request. But the clocks on different services can be slightly out of sync, so it is not easy to recreate the correct picture. And if we add message queues here (Azure EventHub, RabbitMQ, ...), the task becomes even more difficult.

Here I'll try to create a system that will allow us to quickly plot the sequence diagram of events during my request.

Ok, let's start.

NLog: rules and filters

In Confirmit we use NLog library for logging in .NET applications. Although there is a documentation for this library, I found it hard to understand how the loggers work. In this article, I’ll try to explain, how rules and filters are used by NLog. Let’s start.

Log level per request

Some time ago I was reading Technology Radar of ThoughtWorks. And there was a technique called "Log level per request". Here in Confirmit, we use logging widely. So I was wondering how to implement a similar solution. And now I'm ready to show you one possible implementation.

Gathering context information for logging

When you write messages to your logs, sometimes it may be useful to add context information. For example, if you write information about some error, you could also include input data in some form, to be able to reproduce the problem easily. Here I'll show how to gather this additional information.