Telemetry

Motive

This package goal is to make the experience of configuring and working with OpenTelemetry easier.

Manual for easy local grafana deployment

API documentation

Check the autogenerated documentation here.

example

Below are short examples for tracing and metrics. More examples are available at the examples folder, and the various opentelemetry repos.

Tracing

The following code shows a simple example of how to work with tracing. please notice that you need to manually install any auto-instrumentation library that you require.

import { Tracing } from '@map-colonies/telemetry';
import { trace } from '@opentelemetry/api';

const tracing = new Tracing();

tracing.start();

const tracer = trace.getTracer('tracing-name')

const span = tracer.startSpan('some-action');

span.setAttribute('some-attribute');

// DO STUFF

span.end();

tracing.stop().then(() => console.log('done'));
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Another way to initialize tracing with custom resource:

import { Tracing } from '@map-colonies/telemetry';
import { Resource } from '@opentelemetry/resources';

const resource = new Resource({ 'service.version': number, 'service.name': 'my-service-name' });

const tracing = new Tracing([], resource);
...
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Metrics

The following code shows a simple example of how to work with metrics.

import { Metrics } from '@map-colonies/telemetry';

const metrics = new Metrics('sample-meter');

const meter = metrics.start();

const counter = meter.createCounter('sample_counter');

counter.add(1);

metrics.stop().then(() => console.log('done'));
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Metrics middleware

The package provides a middleware for Express that will automatically measure the duration of each request and the number of requests. In addition, the middleware can be configured to collect NodeJS metrics.

import { collectMetricsExpressMiddleware } from '@map-colonies/telemetry/prom-metrics';
import express from 'express';
import { Registry } from 'prom-client';

const prom = collectMetricsExpressMiddleware({ registry: new Registry(), labels: { meow: 'a' } });

app.use('/metrics', prom);
app.get('/', (req, res) => {
  res.json({ x: 'd' });
});

app.listen(8080, () => console.log('server listening on 8080'));
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Semantic Conventions

The package's Semantic Conventions submodule defines a common set of (semantic) attributes which provide meaning to data when collecting, producing and consuming it.

Based on the official OpenTelemetry conventions

Link to full documentation

Configuration

Common configuration

name	allowed value	default value	description
TELEMETRY_SERVICE_NAME	string	package.json name	The name of the service to put as attribute
TELEMETRY_SERVICE_VERSION	string	package.json version	The version of the service to put as attribute
TELEMETRY_HOST_NAME	string	os.hostname()	The value of the hostname attribute to use, will override the hostname

Tracing configuration

name	allowed value	default value	description
TELEMETRY_TRACING_ENABLED	'true', 'false'	'false'	Should Tracing be enabled
TELEMETRY_TRACING_URL*	string	http://localhost:4318/v1/traces	The URL to the OpenTelemetry Collector
TELEMETRY_TRACING_RATIO	float	1	The amount of traces to sample (0-1)
TELEMETRY_TRACING_DEBUG	'true', 'false'	'false'	Enable debug mode for tracing which enables opentelemetry debug log and console trace export

* required (only when tracing is enabled).

Metric configuration

name	allowed value	default value	description
TELEMETRY_METRICS_ENABLED	'true', 'false'	'false'	Should Metrics be enabled
TELEMETRY_METRICS_URL*	string	http://localhost:4318/v1/metrics	The URL to the OpenTelemetry Collector
TELEMETRY_METRICS_INTERVAL	number	15000	The interval in milliseconds between sending data to the collector

* required (only when metrics is enabled).

How to release

Run the command npm run release -- to bump the version in all the files and create a changelog.

For more detailed documentation and examples check: https://github.com/conventional-changelog/standard-version