@opencensus/core

What are @opencensus/core's main functionalities?

const { Tracing } = require('@opencensus/core');
const tracing = Tracing.instance;

// Configure tracing
tracing.start({samplingRate: 1});

// Create a custom span
const rootSpan = tracing.tracer.startRootSpan({name: 'main'}, rootSpan => {
  // Do work within the span
  rootSpan.end(); // End the span
});

const { Metrics, MeasureUnit } = require('@opencensus/core');
const metrics = Metrics.instance;

// Create a measure
const requestCountMeasure = metrics.createMeasureInt64('request_count', MeasureUnit.UNIT, 'Count of requests received');

// Create and register a view to aggregate the data
metrics.createView('request_count_view', requestCountMeasure, 'count', [], 'The count of requests', []);

// Record data
metrics.record([{measure: requestCountMeasure, value: 1}]);

0.0.9 - 2019-02-12

• Add Metrics API.
• Add Resource API.
• Add Tags API.
• Add Gauges (DoubleGauge, LongGauge, DerivedDoubleGauge, DerivedLongGauge) APIs.
• Add support for supplying instrumentation configuration via tracing option. Option argument added to instrumentation interface.
• Add ignoreIncomingPaths and ignoreOutgoingUrls support to the http and https tracing instrumentations.
• Add opencensus-resource-util to auto detect AWS, GCE and Kubernetes(K8S) monitored resource, based on the environment where the application is running.
• Add optional uncompressedSize and compressedSize fields to MessageEvent interface.
• Add a setStatus method in the Span.
• OpenCensus Stackdriver Trace Exporter is updated to use Stackdriver Trace V2 APIs.

This release has multiple breaking changes. Please test your code accordingly after upgrading.

• Modify Logger interface: level made optional, silly removed.
• The new Stats() has been deprecated on Stats class. The global singleton globalStats object should be used instead. Also, registerView() is separated out from createView().
• Use TagKey, TagValue and TagMap to create the tag keys, tag values.
• The status field on Span is no longer a number, use CanonicalCode instead.
• Add enum type for MessageEvent, Link and SpanKind, instead of string.

Old code

const { Stats } = require("@opencensus/core");
const stats = new Stats();

// Counts/groups the lengths of lines read in.
const mLineLengths = stats.createMeasureInt64(
  "demo/line_lengths",
  MeasureUnit.BYTE,
  "The distribution of line lengths"
);

// Create tag keys
const tagKeys = ["method", "status"];

// Create and register the view
stats.createView(
  "demo/lines_in",
  mLineLengths,
  AggregationType.COUNT,
  tagKeys,
  "The number of lines from standard input"
);

// Records measurements
stats.record({
  measure: mLineLengths,
  tags,
  value: 2
});

New code

// Gets the global stats instance
const { globalStats } = require("@opencensus/core");

// Counts/groups the lengths of lines read in.
const mLineLengths = globalStats.createMeasureInt64(
  "demo/line_lengths",
  MeasureUnit.BYTE,
  "The distribution of line lengths"
);

// Creates the method and status key
const methodKey = {name: "method"};
const statusKey = {name: "status"};

// Creates the view
const view = globalStats.createView(
  "demo/lines_in",
  mLineLengths,
  AggregationType.COUNT,
  [methodKey, statusKey],
  "The number of lines from standard input"
);

// Registers the view
globalStats.registerView(view);

// Creates tags map -> key/value pair
const tagMap = new TagMap();
tagMap.set(methodKey, {value: 'REPL'});
tagMap.set(statusKey, {value: 'OK'});

// Creates measurements (measure + value)
const measurements = [{
  measure: mLineLengths,
  value: 2
}];

// Records measurement with tagMap
globalStats.record(measurements, tagMap);