# Trace Each Requests

# Supported trace span list

All of the spands mentioned below are implemented and opened by default.

Other requirements please create a Issue on GitHub.

# How to view trace link

You can view it via Restful API

curl http://127.0.0.1:7002/trace?appName=my-site # my-site 是您的应用名

It can also be viewed through GUI Dashboard, check docs.

# about sampling rate

Default sampling rate is:

{
  rate: process.env.NODE_ENV !== 'production' ? 100 : 10,
  // If the trace with the highest priority is out of the sample rate limit,
  // such as a wrong trace.
  priority: true 
}

Production environment is 10%, otherwise 100%.

That can be changed via global config, docs.

# How to add a new kind of spans

You can access all the interfaces about tracing via the single instance TraceManager object.

const {traceManager} = require('dorapan');

Get the current available tracer object via getCurrentTracer(), like:

const tracer = traceManager.getCurrentTracer(); // If not in a trace link, will got a undefined
const span = tracer.startSpan('custom_span');
span.finish();

More please check API References:

• TraceManager
• Tracer
• The Tracer object extended and implemented OpenTracer, so please check it also.

# Principle

TODO