OpenTelemetry Instrumentation Document Load
This module provides automatic instrumentation for document load for Web applications, which may be loaded using the @opentelemetry/sdk-trace-web package.
If total installation size is not constrained, it is recommended to use the @opentelemetry/auto-instrumentations-web bundle with @opentelemetry/sdk-trace-web for the most seamless instrumentation experience.
Compatible with OpenTelemetry JS API and SDK 1.0+.
Installation
npm install --save @opentelemetry/instrumentation-document-loadUsage
import { ConsoleSpanExporter, SimpleSpanProcessor } from '@opentelemetry/sdk-trace-base';
import { WebTracerProvider } from '@opentelemetry/sdk-trace-web';
import { DocumentLoadInstrumentation } from '@opentelemetry/instrumentation-document-load';
import { XMLHttpRequestInstrumentation } from '@opentelemetry/instrumentation-xml-http-request';
import { registerInstrumentations } from '@opentelemetry/instrumentation';
import { B3Propagator } from '@opentelemetry/propagator-b3';
import { CompositePropagator, W3CTraceContextPropagator } from '@opentelemetry/core';
const provider = new WebTracerProvider();
provider.addSpanProcessor(new SimpleSpanProcessor(new ConsoleSpanExporter()));
provider.register({
propagator: new CompositePropagator({
propagators: [
new B3Propagator(),
new W3CTraceContextPropagator(),
],
}),
});
registerInstrumentations({
instrumentations: [
new DocumentLoadInstrumentation(),
new XMLHttpRequestInstrumentation({
ignoreUrls: [/localhost/],
propagateTraceHeaderCorsUrls: [
'http://localhost:8090',
],
}),
],
});Optional: Send a trace parent from your server
This instrumentation supports connecting the server side spans for the initial HTML load with the client side span for the load from the browser's timing API. This works by having the server send its parent trace context (trace ID, span ID and trace sampling decision) to the client.
Because the browser does not send a trace context header for the initial page navigation, the server needs to fake a trace context header in a middleware and then send that trace context header back to the client as a meta tag traceparent . The traceparent meta tag should be in the trace context W3C draft format . For example:
...
<head>
<!--
https://www.w3.org/TR/trace-context/
Set the `traceparent` in the server's HTML template code. It should be
dynamically generated server side to have the server's request trace Id,
a parent span Id that was set on the server's request span, and the trace
flags to indicate the server's sampling decision
(01 = sampled, 00 = notsampled).
'{version}-{traceId}-{spanId}-{sampleDecision}'
-->
<meta name="traceparent" content="00-ab42124a3c573678d4d8b21ba52df3bf-d21f7bc17caa5aba-01">
</head>
<body>
...
<script>
// and then initialise the WebTracer
// var webTracer = new WebTracer({ .......
</script>
</body>Optional : Add custom attributes to document load span if needed
If it is needed to add custom attributes to the document load span,and/or document fetch span and/or resource fetch spans, respective functions to do so needs to be provided as a config to the DocumentLoad Instrumentation as shown below. The attributes will be added to the respective spans before the individual are spans are ended. If the function throws an error , no attributes will be added to the span and the rest of the process continues.
const addCustomAttributesToSpan = (span: Span) => {
span.setAttribute('<custom.attribute.key>','<custom-attribute-value>');
}
registerInstrumentations({
instrumentations: [
new DocumentLoadInstrumentation({
applyCustomAttributesOnSpan: {
documentLoad: addCustomAttributesToSpan
}
})
]
})See examples/tracer-web for a short example.
Useful links
- For more information on OpenTelemetry, visit: https://opentelemetry.io/
- For more about OpenTelemetry JavaScript: https://github.com/open-telemetry/opentelemetry-js
- For help or feedback on this project, join us in GitHub Discussions
License
Apache 2.0 - See LICENSE for more information.