@opencensus/nodejs

OpenCensus is a toolkit for collecting application performance and behavior data.

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OpenCensus for Node.js

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OpenCensus Node.js is an implementation of OpenCensus, a toolkit for collecting application performance and behavior monitoring data.

The library is in alpha stage and the API is subject to change.

Please join gitter for help or feedback on this project.

Installation

Install OpenCensus with:

npm install @opencensus/nodejs

Traces

Instrumenting an Application

OpenCensus for Node.js has automatic instrumentation out of the box for those modules:

This means that spans are automatically created for operations of those packages. To use it, simply start the tracing instance.

const tracing = require('@opencensus/nodejs');
tracing.start();

Similarly for Typescript:

import * as tracing from '@opencensus/nodejs';
tracing.start();

Manually Instrument an Application

In addition to automatic tracing, it is possible to manually create your own root and child spans.

const rootSpanOptions = { name: 'your root span' };
tracing.tracer.startRootSpan(rootSpanOptions, (rootSpan) => {

    // You can create as many child spans as needed
    childSpan = tracing.tracer.startChildSpan({
        name: 'name of your child span'
    });
    // Do some operation...
    // Finish the child span at the end of it's operation
    childSpan.end();

    // Finish the root span at the end of the operation
    rootSpan.end();
});

For manual only instrumentation see the @opencensus/nodejs-base package.

Tracing Options

Tracing has many options available to choose from. At tracing.start(), you can set the following:

Options Type Description
defaultAttributes Attributes Default attributes added to every span created by the tracer
bufferSize number The number of traces to be collected before exporting to a backend
bufferTimeout number Maximum time to wait before exporting to a backend
logger Logger A logger object
logLevel number Level of logger - 0: disable, 1: error, 2: warn, 3: info, 4: debug
samplingRate number Determines the span's sampling rate. Ranges from 0.0 to 1.0
propagation Propagation A propagation instance to use
maximumLabelValueSize number The maximum number of characters reported on a label value
plugins PluginNames A list of trace instrumentations plugins to load
exporter Exporter An exporter object

Plugins

OpenCensus can collect tracing data automatically using plugins. Users can also create and use their own plugins. Currently, OpenCensus supports automatic tracing for:

Propagation

OpenCensus collects distributed tracing. It is able to do so by propagating span data through services. Currently, OpenCensus supports:

Exporters

OpenCensus can export trace data to various backends. Currently, OpenCensus supports:

If no exporter is registered in the tracing instance, as default, a console log exporter is used.

Useful links

If you find any bugs or have a feature request, please open an issue on github!

The npm package download data comes from npm's download counts api and package details come from npms.io.