'use strict';

const opentelemetry = require('@opentelemetry/core');
const config = require('./setup');

/**
 * The trace instance needs to be initialized first, if you want to enable
 * automatic tracing for built-in plugins (DNS in this case).
 */
config.setupTracerAndExporters('dns-client-service');

const dns = require('dns').promises;
const tracer = opentelemetry.getTracer('example-dns');

/** A function which makes a dns lookup and handles response. */
function makeLookup() {
    // span corresponds to dns lookup. Here, we have manually created
    // the span, which is created to track work that happens outside of the
    // dns lookup query.
    const span = tracer.startSpan('dnsLookup');
    tracer.withSpan(span, async () => {
        try {
            await dns.lookup('montreal.ca');
        } catch (error) {
            span.setAttributes({
                'error.name': error.name,
                'error.message': error.message
            });
        }finally{
            console.log(`traceid: ${span.context().traceId}`);
            span.end();
        }
    });

    // The process must live for at least the interval past any traces that
    // must be exported, or some risk being lost if they are recorded after the
    // last export.
    console.log('Sleeping 5 seconds before shutdown to ensure all records are flushed.')
    setTimeout(() => { console.log('Completed.'); }, 5000);
}

makeLookup();