Spring Cloud Sleuth: implement micro-tracking service

I. Introduction

1. Micro between service communicate over a network, if we can track each request, the request to understand what the service through the micro, request time-consuming, network delay, time-consuming business logic and other indicators, it will be able to better analyze the system bottleneck, solve system issue;

2. Sleuth borrowed the term Google Dapper:

span: Span, basic unit of work, with a 64-bit ID that uniquely identifies, in addition to ID, further comprising description, event timestamp, data of key notes, span parent ID and the like;

trace: trace, a set of shared "root span" tree structure is called a span consisting trace, trace span all of the trace ID of the share;

annotation: labeling, there is a record for the event, wherein the core annotation to define the start and end request;

3. Integrate Spring Cloud Sleuth

Add spring-cloud-starter-sleuth-dependent;

Modify the configuration file;