# Schedule
Workflows can run on a repeating basis with schedules. This is suitable in cases where a workflow is run against a dynamically expanding input, like an API service or directory of files.
The schedule method takes a cron expression, list of static elements (which dynamically expand i.e. API service, directory listing) and an optional maximum number of iterations.
Below are a couple example cron expressions.
```bash
# ┌─────────────── minute (0 - 59)
# | ┌───────────── hour (0 - 23)
# | | ┌─────────── day of the month (1 - 31)
# | | | ┌───────── month (1 - 12)
# | | | | ┌─────── day of the week (0 - 6)
# | | | | | ┌───── second (0 - 59)
# | | | | | |
* * * * * * # Run every second
0/5 * * * * # Run every 5 minutes
0 0 1 * * # Run monthly on 1st
0 0 1 1 * # Run on Jan 1 at 12am
0 0 * * mon,wed # Run Monday and Wednesday
```
## Python
Simple workflow [scheduled](../#txtai.workflow.base.Workflow.schedule) with Python.
```python
workflow = Workflow(tasks)
workflow.schedule("0/5 * * * *", elements)
```
See the link below for a more detailed example.
| Notebook | Description | |
|:----------|:-------------|------:|
| [Workflow Scheduling](https://github.com/neuml/txtai/blob/master/examples/27_Workflow_scheduling.ipynb) | Schedule workflows with cron expressions | [](https://colab.research.google.com/github/neuml/txtai/blob/master/examples/27_Workflow_scheduling.ipynb) |
## Configuration
Simple workflow scheduled with configuration.
```yaml
workflow:
index:
schedule:
cron: 0/5 * * * *
elements: [...]
tasks: [...]
```
```python
# Create and run the workflow
from txtai import Application
# Create and run the workflow
app = Application("workflow.yml")
# Wait for scheduled workflows
app.wait()
```
See the links below for more information on cron expressions.
- [cron overview](https://en.wikipedia.org/wiki/Cron)
- [croniter - library used by txtai](https://github.com/kiorky/croniter)