# `Otel.Trace.IdGenerator`
[🔗](https://github.com/yangbancode/otel/blob/main/lib/otel/trace/id_generator.ex#L1)

Hardcoded random ID generator — the only generator this
SDK ships.

Generates non-zero random integers using `:rand.uniform/1`:
- trace_id: 128-bit (1 to 2^128 - 1)
- span_id: 64-bit (1 to 2^64 - 1)

Spec ref: `trace/sdk.md` §IdGenerator. The behaviour
abstraction (and a separate `Default` impl module) was
collapsed because the SDK ships only this generator and
users cannot substitute their own (per minikube-style
scope).

## Public API

| Function | Role |
|---|---|
| `generate_trace_id/0` | **SDK** (OTel API MUST) — `trace/sdk.md` §IdGenerator |
| `generate_span_id/0` | **SDK** (OTel API MUST) — `trace/sdk.md` §IdGenerator |

## Deferred Development-status features

- **Random TraceFlag bit.** Spec `trace/api.md` L237-L242
  defines bit 1 (`0x02`) of the W3C `trace-flags` byte as
  the *Random* flag, set when the IdGenerator produces
  trace IDs whose lower 7 bytes are random. Spec
  `trace/sdk.md` L902-L912 *"IdGenerator randomness"*
  (Status: Development) describes the SDK's responsibility
  to declare this property. Not implemented — `span.ex`
  currently sets only the Sampled bit (`0x01`) on the
  in-memory `trace_flags`. When stabilised, this module
  will gain a method describing its randomness profile and
  `span.ex` will set bit 1 accordingly.

## References

- OTel Trace SDK §IdGenerator: `opentelemetry-specification/specification/trace/sdk.md`

# `generate_span_id`

```elixir
@spec generate_span_id() :: Otel.Trace.SpanId.t()
```

**SDK** (OTel API MUST) — Generates a 64-bit span ID.

# `generate_trace_id`

```elixir
@spec generate_trace_id() :: Otel.Trace.TraceId.t()
```

**SDK** (OTel API MUST) — Generates a 128-bit trace ID.

---

*Consult [api-reference.md](api-reference.md) for complete listing*