# Module: constants

## Purpose

Centralizes shared configuration constants and provides the application-wide logging interface via Loguru.

## Public Interface

### Constants (cdef, module-level)

| Name          | Type | Value        |
|---------------|------|--------------|
| CDN_CONFIG    | str  | `"cdn.yaml"` |
| SMALL_SIZE_KB | int  | `3`          |

Note: `QUEUE_MAXSIZE`, `COMMANDS_QUEUE`, `ANNOTATIONS_QUEUE` are declared in the `.pxd` but not defined in the `.pyx` — they are unused in this codebase.

### Functions (cdef, Cython-only visibility)

| Function               | Signature                  | Description                  |
|------------------------|----------------------------|------------------------------|
| `log`                  | `cdef log(str log_message)` | Logs at INFO level via Loguru |
| `logerror`             | `cdef logerror(str error)`  | Logs at ERROR level via Loguru |

## Internal Logic

Loguru is configured with three sinks:
- **File sink**: under `LOG_DIR`, path template `log_loader_{time:YYYYMMDD}.txt`, INFO level, daily rotation, 30-day retention, async (enqueue=True)
- **Stdout sink**: DEBUG level, filtered to INFO/DEBUG/SUCCESS only, colorized
- **Stderr sink**: WARNING+ level, colorized

Log format: `[HH:mm:ss LEVEL] message`

## Dependencies

- **Internal**: none (leaf module)
- **External**: `loguru` (0.7.3), `os`, `sys`

## Consumers

- `hardware_service` — calls `log()`
- `cdn_manager` — calls `log()`, `logerror()`
- `api_client` — calls `log()`, `logerror()`, reads `CDN_CONFIG`, `SMALL_SIZE_KB`

## Data Models

None.

## Configuration

| Env Variable | Default | Description                          |
|--------------|---------|--------------------------------------|
| LOG_DIR      | `Logs`  | Directory for daily log files        |

The file sink uses Loguru’s `{time:YYYYMMDD}` in the filename under `LOG_DIR`.

## External Integrations

None.

## Security

None.

## Tests

No tests found.