Monitoring Extension

If you want to get more detailed monitoring data, e.g. message packet size, or want to adopt other data source, e.g. InfluxDB, you can implement the Trace interface according to your requirements and inject it by WithTracer Option.

// Tracer is executed at the start and finish of an HTTP.
type Tracer interface {
   Start(ctx context.Context, c *app.RequestContext) context.Context
   Finish(ctx context.Context, c *app.RequestContext)
}

You can get TraceInfo from ctx. What is more, from TraceInfo you can get request time cost, package size, and error information returned from request, etc. Usage example：

type ServerTracer struct{
	// contain entities which recording metric
}

// Start record the beginning of an RPC invocation.
func (s *ServerTracer) Start(ctx context.Context, _ *app.RequestContext) context.Context {
	// do nothing
	return ctx
}

// Finish record after receiving the response of server.
func (s *ServerTracer) Finish(ctx context.Context, c *app.RequestContext) {
	ti := c.GetTraceInfo()
	rpcStart := ti.Stats().GetEvent(stats.HTTPStart)
	rpcFinish := ti.Stats().GetEvent(stats.HTTPFinish)
	cost := rpcFinish.Time().Sub(rpcStart.Time())
	// TODO: record the cost of request
}

Last modified July 13, 2023 : docs: update code example in kitex-generic call (#711) (f80b346)