Telemetry

Motive

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

Manual for easy local grafana deployment

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'));

Another way for 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);
...

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'));

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'));

Note

If you are not running the express-openapi-validator middleware, its recommended to turn off the includeOperationId option in the collectMetricsExpressMiddleware function as the operation label will always be null.

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	from package.json	The service name
TELEMETRY_SERVICE_VERSION	string	from package.json	The service version
TELEMETRY_HOST_NAME	string	os.hostname()	The host name

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

* 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 miliseconds between sending data to the collector

* required (only when tracing 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