Spring Cloud Sleuth is a rather small, simple project, which nevertheless provides some useful features for logging and tracing. If you refer to the example discussed in theUsing LogstashTCPAppender section, you can easily see that there is no possibility to filter all the logs related to single request. In a microservices-based environment, it is also very important to correlate messages exchanged by the applications when handling requests that are coming into the system. This is the main motivation in creating the Spring Cloud Sleuth project.
If Spring Cloud Sleuth is enabled for the application, it adds some HTTP headers to the requests, which allows you to link requests with the responses and the messages exchanged by independent applications, for example, through RESTful API. It defines two basic units of work—span and trace. Each of these is identified by a unique 64 bit ID. The value of the trace ID is equal to the initial value of the span ID. Span refers to a...
