# Attributes, Events and Status — OpenTelemetry

Source: https://www.skillbyai.com/en/opentelemetry/t-details

> Make spans useful.

## Describe what happened

**Attributes** are key-value pairs on a span (`http.request.method="POST"`, `http.response.status_code=502`, `db.system="postgresql"`, or your own such as `app.order.id`). **Events** are timestamped annotations within a span, and exceptions are recorded as events with type, message and stack trace. **Status** is Unset (the default), Ok or Error; instrumentation sets Error for failures such as 5xx server responses. **Links** connect spans across traces, for example a batch job processing messages from many requests.

## One span in detail

How a backend might display a failed payment call.

```text
span: POST /charge     kind: CLIENT     duration: 700 ms     status: ERROR
attributes:
  http.request.method      = POST
  url.full                 = https://gateway.example.com/charge
  http.response.status_code = 504
  server.address           = gateway.example.com
  app.payment.provider     = "acme-pay"
events:
  +698 ms  exception  type=TimeoutError  message="gateway timeout after 700 ms"
resource:
  service.name=payment-service  service.version=2.8.1  deployment.environment.name=prod
```

## Prefer semantic convention names

Using standard attribute names lets backends build service maps and dashboards automatically.

**Quiz:** How is an exception usually recorded on a span?

- [ ] As a new trace
- [x] As a span event with exception details, plus an Error status
- [ ] As a metric only
- [ ] By deleting the span

*Answer:* As a span event with exception details, plus an Error status. record_exception adds an event.