This app is a simple Express app which demonstrates how distributed tracing works using the LightStep Javascript Tracer and OpenTracing instrumentation.
The application defaults to hosting a single user-facing page at localhost:3000. App structure is generated automatically by Express Generator. There is an additional route at localhost:3000/XHR which accepts GET requests and returns a link to the trace for that request in LightStep. The "front-end" includes the minified version of the LightStep Javascript Tracer, and is configured to automatically instrument all XHR requests. The "back-end" utilizes the NPM version of the LightStep Javascript Tracer, and is configured to create a child span for the inbound XHR requests from the "front-end". The OpenTracing SpanContext is propagated using HTTP headers.
You will need to include your LightStep access token before starting the service.
app.js
opentracing.initGlobalTracer(new lightstep.Tracer({
access_token : 'access-token-here',
component_name : 'node-training',
verbosity : 3
}));
views/index.ejs
<head>
<title><%= title %></title>
<link rel='stylesheet' href='/stylesheets/style.css' />
<script src="/javascripts/opentracing-browser.min.js"></script>
<script src="/javascripts/lightstep-tracer.min.js" data-init_global_tracer="true" data-access_token="access-token-here" data-component_name="browser-training" data-verbosity=3 data-instrument_page_load="false" data-xhr_instrumentation="true"></script>
</head>
Starting the service
Optional: Nodemon is included in the package.json and nodemon start can be used in substitution for npm start below.
git clonethis repo into your workspace- Include the LightStep access token in the two files referenced above
- Optional: remove the commented
span.setTagline inindex.jsand include an identifier in the value to make it easy to search for a trace later in LightStep - Install the dependnencies:
npm install - Start the service:
npm start
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