core.js

const honeycombBeeline = require('honeycomb-beeline');

let honeycomb = honeycombBeeline({
    writeKey: <writekey>,
    dataset: 'staging',
    serviceName: 'fakecore',
});

const http = require('http');
const server = http.createServer();
const port = 2222;

function doThing(callback) {
    setTimeout(() => {
        callback(null, { beep: 'boop' });
    }, 1000);
}

function serve() {
    server.on('request', (request, response) => {
        const { traceId, parentSpanId } = honeycomb.unmarshalTraceContext(
            request.headers[honeycomb.TRACE_HTTP_HEADER.toLowerCase()],
        );

        const trace = honeycomb.startTrace({ name: request.url }, traceId, parentSpanId);

        doThing(
            honeycomb.bindFunctionToTrace((error, result, context) => {
                response.writeHead(200, { 'Content-Type': 'application/json' });
                response.end(JSON.stringify(result));
                honeycomb.finishTrace(trace);
            }),
        );
    });

    server.on('listening', () => console.log(`Listening on port: ${port}`));
    server.listen(port, (err) => {
        if (err) {
            return console.log('something bad happened', err)
        }
    });
}

serve();

gateway.js

const honeycombBeeline = require('honeycomb-beeline');

let honeycomb = honeycombBeeline({
    writeKey: <writekey>,
    dataset: 'staging',
    serviceName: 'fakegateway',
});

const http = require('http');
const makeRequest = require('request');

const server = http.createServer();
const port = 1111;

function proxyRequest(request, response, trace) {
    let traceContext = honeycomb.marshalTraceContext(honeycomb.getTraceContext());
    request.headers = { ...request.headers, traceContext };

    const proxiedRequest = makeRequest(`http://localhost:2222${request.url}`);

    proxiedRequest.on('response', honeycomb.bindFunctionToTrace((proxyResponse) => {
        const { statusCode, headers } = proxyResponse;
        response.writeHead(statusCode, headers);
        proxyResponse.pipe(response);
        honeycomb.finishTrace(trace);
    }));

    request.pipe(proxiedRequest);
}

function serve() {
    server.on('request', (request, response) => {
        const trace = honeycomb.startTrace({ name: "ServeURL" });
        proxyRequest(request, response, trace);
    });

    server.on('listening', () => console.log(`Listening on port: ${port}`));

    server.listen(port);
}

serve();