# ui.warning

The `ui.warning` function shows a warning message to the person running the program. Use it for a condition that deserves attention but does not stop the script; raise an error with `fail()` when the script cannot continue.

## Usage

```python
ui.warning(message)
```

## Arguments

- **`message`**

  Required. The text to show, as a string. It can be passed positionally or as `message = ...`. Passing a
  value of another type, such as an integer, fails with an argument error, so convert it with `str()` first.

## Returns

The return value is `None`. The message is a side effect and never becomes the step value.

## Behavior

- The message is written to the status channel (stderr) with Atmos UI formatting: a themed `⚠` marker
  followed by the text. Colors adapt to the terminal.
- Standard output is reserved for data, so `ui.warning` never changes what `print` or [`output`](/functions/automation/output)
  produce, so a program's result can be piped or captured without status lines mixed in.
- Inside [`steps.parallel`](/functions/automation/steps.parallel) tasks, each message is written as one whole line
  and prefixed with the task name, such as `[dev] `. Lines from different tasks can arrive in any order but never
  interleave within a line. A group with a single task writes without a prefix.
- Secrets that Atmos knows about are masked in the displayed text.

## Examples

### Show a message

```python
replicas = 1
if replicas < 2:
    ui.warning("Only " + str(replicas) + " replica configured; the service has no redundancy")

output = {"replicas": replicas}
```

```text
⚠ Only 1 replica configured; the service has no redundancy
```

### Use it in parallel tasks

```python
def audit(stack):
    ui.warning("Drift detected in " + stack)

steps.parallel(tasks = [steps.task(s, audit, args = [s]) for s in ["dev", "prod"]])
```

```text
[dev] ⚠ Drift detected in dev
[prod] ⚠ Drift detected in prod
```

## Errors

- Calling the function without a message, or with a message that is not a string, fails with an argument error that
  names `ui.warning`.

## Related

- [`ui.info`](/functions/automation/ui.info) and [`ui.success`](/functions/automation/ui.success) cover the other status levels.
- [`print`](/functions/automation/print) writes data to stdout, and [`log.info`](/functions/automation/log.info) writes diagnostics to the Atmos log.
- [Atmos Automation Language](/automation/language) and the [script step](/steps/type/script#step-output)