Seeing what your code actually does: Intro to Observability
Details
[About the Event]
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EDIT 2026-07-10: If you are planning to attend tomorrow, please fill out the following Google Form!
https://docs.google.com/forms/d/e/1FAIpQLScC9PzGwLZxVFe5voIl025uc4abDm5ZDkgJDVUWDdU702zvPA/viewform
EDIT 2026-07-08: If you're going to be bringing your workstation to follow along, please confirm you already have git and docker installed on your workstation. Then run the following commands prior to the event to install the requisite docker containers we will be using, as it may take some time:
```
git clone https://github.com/open-telemetry/opentelemetry-demo
cd opentelemetry-demo
docker compose -f compose.yaml -f compose.full.yaml -f compose.observability.yaml up
```
If you'd like to stop the docker containers after the event, you can use:
```
docker compose -f compose.yaml -f compose.full.yaml -f compose.observability.yaml down --remove-orphans -v
```
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Who?
- Engineers who want to understand what their code is actually doing at runtime — especially those building with AI agents
What?
- AI can write your code, but it can't tell you why production is down. In this lecture, we'll cover observability: the missing stage after review that answers "why is it broken?" instead of just "does it look right?"
What will we cover?
- The three pillars: logs, metrics, and traces
- Structured logging and the canonical log line
- Correlation IDs: 80% of distributed tracing for an afternoon of work
- Real tracing with OpenTelemetry (auto instrumentation — no code changes required)
- Live demo: the OpenTelemetry Astronomy Shop (10 microservices, one docker compose up)
- Why averages lie and percentiles matter
- How to avoid a $65,000,000 observability bill
- Scar tissue: lessons every engineer learns the hard way
- What's next: observing LLM agents themselves
The concepts apply to any stack. If you want to follow along, install Docker Desktop beforehand so you can run the demo locally.
This is part of our ongoing series on agent-driven development pipelines.
Food will not be provided, but we encourage people to grab food together after the event.
This event and all Code Seoul events are FREE.
We are a non-profit organization dedicated to providing tech education to the Seoul community.
