Context propagation, monitoring, and analyzing logs

Context propagation, monitoring, and log analysis are critical aspects of managing microservices in a distributed system. In this section, we take a deeper look at context propagation.

Context propagation

In microservices, where requests can traverse multiple services, propagating context information is essential for tracking and understanding the flow of requests. Contextual information, often in the form of headers or tokens, allows you to correlate logs across different microservices.

Here is an example of context propagation. In a Node.js environment with Express.js, you can use middleware to propagate context information:

// Middleware to add context to requests
app.use((req, res, next) => {
  // Add a unique request ID to the request
  req.requestId = generateRequestId();
  // Log the start of the request
  logger.info(`[${new Date()}] Start processing request ${req.requestId...