meet.js Wrocław 2026-06-11

DATA/DATE: June 11th / 11 czerwca 2026

GODZINA/HOUR: 17:30

MIEJSCE/VENUE: Klubokawiarnia Mleczarnia, ul. Włodkowica 5, Wrocław (poziom -1)

WSTĘP/ENTRY: wolny/free

JĘZYK/LANGUAGE: event prowadzony będzie po polsku i po angielsku / the event will be conducted in Polish and English

Już 11-go czerwca, w czwartek, w kultowej wrocławskiej Mleczarni odbędzie się kolejny meetJS Wrocław, tym razem we współpracy z aleno.me !

Ramowa agenda:

*17:30 - warm-up
*18:00 - intro
*~18:10 - Radosław Miernik - Logs are not enough
*~18:55 - przerwa na piwo/beer / kawę/coffee / herbatę/tea
*~19:10 - ​Szymon Bartczak - How to Pass the Context?
*~19:55 - przerwa na piwo/beer / kawę/coffee / herbatę/tea
*do ostatniego uczestnika - networking / integracja :)

---

Radosław Miernik - Logs are not enough

Abstract
It's Friday night and the app is down. You go through the runbook* (you have one, right?), and that involves grepping through millions of log lines. It starts with prepared queries and nice dashboards, but you need more and more -- counts, averages, distincts... Luckily, most logging stacks allow you to do that already, so everything is taken care of soon*.

But what if it's not about the average request, but some pesky edge case? The procedure is the same, but now you have to thread through logs of tens of services, check the code while at it, and... Yeah, at some point you realize that the one thing you actually needed is not logged.

My goal is to show you how we deal with the latter at aleno. It's not magic, just an awful lot of ~~monkey-patched code~~ instrumentations. And the result? A clear trace view, just like this one. Oh, and you can create charts from it, too!

Tags
Grafana, OpenTelemetry, Prometheus, Tracing.

---

Szymon Bartczak - How to Pass the Context?

Abstract
It’s just another ordinary day for your Node server. A request shows up, gets processed, receives a response, and disappears without a word. No thank you. At best, it leaves behind a quiet ACK.
But every single request carries something with it - a Context backpack. And somehow, your server is expected to carry that backpack all the way through the journey.

One day, you got curious. You set up cameras to watch these requests more closely, to see what really happens along the way. And that’s when things got strange.

The camera crew follows everything... except the backpack. They see the request, they trace its path - but they never seem to carry the Context with them. And yet, somehow, they always know what’s inside.

So how are they doing it?
Maybe the backpack doesn’t need to be carried at all. Maybe it can be stored somewhere safe - like a locker - and picked up only when something inside is actually needed.

In this talk, I’ll walk you through how we can do exactly that - no extra packages, just a few lines of code. We’ll build a simple way to store and access context, and explore what else we can sneak into those lockers.

And in the end, we’ll take a peek behind the scenes of our mysterious camera crew to see how OpenTelemetry pulls it off.

Tags
async-hooks, AsyncLocalStorage, OpenTelemetry, Context Propagation