> ## Documentation Index
> Fetch the complete documentation index at: https://docs.prefect.io/llms.txt
> Use this file to discover all available pages before exploring further.
# How to create deployment triggers
> Learn how to define automations that trigger deployment runs based on events.
## Creating deployment triggers
To enable the simple configuration of event-driven deployments, Prefect provides **deployment triggers**—a shorthand for
creating automations that are linked to specific deployments to run them based on the presence or absence of events.
Deployment triggers are a special case of automations where the configured action is always running a deployment.
Trigger definitions for deployments are supported in `prefect.yaml`, `.serve`, and `.deploy`. At deployment time,
specified trigger definitions create linked automations triggered by events matching your chosen
[grammar](/v3/concepts/events/#event-grammar). Each trigger definition may include a [jinja template](https://en.wikipedia.org/wiki/Jinja_\(template_engine\))
to render the triggering `event` as the `parameters` of your deployment's flow run.
### Define triggers in `prefect.yaml`
You can include a list of triggers on any deployment in a `prefect.yaml` file:
```yaml theme={null}
deployments:
- name: my-deployment
entrypoint: path/to/flow.py:decorated_fn
work_pool:
name: my-work-pool
triggers:
- type: event
enabled: true
match:
prefect.resource.id: my.external.resource
expect:
- external.resource.pinged
parameters:
param_1: "{{ event }}"
```
### Scheduling delayed deployment runs
You can configure deployment triggers to run after a specified delay using the `schedule_after` field. This is useful for implementing opt-out workflows or providing review windows before automated actions:
```yaml theme={null}
deployments:
- name: campaign-execution
entrypoint: path/to/campaign.py:execute_campaign
work_pool:
name: my-work-pool
triggers:
- type: event
enabled: true
match:
prefect.resource.id: marketing.campaign
expect:
- campaign.proposal.created
schedule_after: "PT2H" # Wait 2 hours before execution
parameters:
campaign_id: "{{ event.resource.id }}"
```
The `schedule_after` field accepts:
* **ISO 8601 durations** (e.g., "PT2H" for 2 hours, "PT30M" for 30 minutes)
* **Seconds as integer** (e.g., 7200 for 2 hours)
* **Python timedelta objects** in code
This deployment creates a flow run when an `external.resource.pinged` event *and* an `external.resource.replied`
event have been seen from `my.external.resource`:
```yaml theme={null}
deployments:
- name: my-deployment
entrypoint: path/to/flow.py:decorated_fn
work_pool:
name: my-work-pool
triggers:
- type: compound
require: all
parameters:
param_1: "{{ event }}"
schedule_after: "PT1H" # Wait 1 hour before running
triggers:
- type: event
match:
prefect.resource.id: my.external.resource
expect:
- external.resource.pinged
- type: event
match:
prefect.resource.id: my.external.resource
expect:
- external.resource.replied
```
### Define deployment triggers using Terraform
You can also set up a deployment trigger via Terraform resources, specifically via the `prefect_automation` [resource](https://registry.terraform.io/providers/PrefectHQ/prefect/latest/docs/resources/automation).
```hcl theme={null}
resource "prefect_deployment" "my_deployment" {
name = "my-deployment"
work_pool_name = "my-work-pool"
work_queue_name = "default"
entrypoint = "path/to/flow.py:decorated_fn"
}
resource "prefect_automation" "event_trigger" {
name = "my-automation"
trigger = {
event = {
posture = "Reactive"
expect = ["external.resource.pinged"]
threshold = 1
within = 0
}
}
actions = [
{
type = "run-deployment"
source = "selected"
deployment_id = prefect_deployment.my_deployment.id
parameters = jsonencode({
"param_1" : "{{ event }}"
})
},
]
}
```
### Define triggers in `.serve` and `.deploy`
To create deployments with triggers in Python, the trigger types `DeploymentEventTrigger`,
`DeploymentMetricTrigger`, `DeploymentCompoundTrigger`, and `DeploymentSequenceTrigger` can be imported
from `prefect.events`:
```python theme={null}
from datetime import timedelta
from prefect import flow
from prefect.events import DeploymentEventTrigger
@flow(log_prints=True)
def decorated_fn(param_1: str):
print(param_1)
if __name__=="__main__":
decorated_fn.serve(
name="my-deployment",
triggers=[
DeploymentEventTrigger(
enabled=True,
match={"prefect.resource.id": "my.external.resource"},
expect=["external.resource.pinged"],
schedule_after=timedelta(hours=1), # Wait 1 hour before running
parameters={
"param_1": "{{ event }}",
},
)
],
)
```
As with prior examples, you must supply composite triggers with a list of underlying triggers:
```python theme={null}
from datetime import timedelta
from prefect import flow
from prefect.events import DeploymentCompoundTrigger
@flow(log_prints=True)
def decorated_fn(param_1: str):
print(param_1)
if __name__=="__main__":
decorated_fn.deploy(
name="my-deployment",
image="my-image-registry/my-image:my-tag",
triggers=[
DeploymentCompoundTrigger(
enabled=True,
name="my-compound-trigger",
require="all",
schedule_after=timedelta(minutes=30), # Wait 30 minutes
triggers=[
{
"type": "event",
"match": {"prefect.resource.id": "my.external.resource"},
"expect": ["external.resource.pinged"],
},
{
"type": "event",
"match": {"prefect.resource.id": "my.external.resource"},
"expect": ["external.resource.replied"],
},
],
parameters={
"param_1": "{{ event }}",
},
)
],
work_pool_name="my-work-pool",
)
```
### Pass triggers to `prefect deploy`
You can pass one or more `--trigger` arguments to `prefect deploy` as either a JSON string or a
path to a `.yaml` or `.json` file.
```bash theme={null}
# Pass a trigger as a JSON string
prefect deploy -n test-deployment \
--trigger '{
"enabled": true,
"match": {
"prefect.resource.id": "prefect.flow-run.*"
},
"expect": ["prefect.flow-run.Completed"]
}'
# Pass a trigger using a JSON/YAML file
prefect deploy -n test-deployment --trigger triggers.yaml
prefect deploy -n test-deployment --trigger my_stuff/triggers.json
```
For example, a `triggers.yaml` file could have many triggers defined:
```yaml theme={null}
triggers:
- enabled: true
match:
prefect.resource.id: my.external.resource
expect:
- external.resource.pinged
parameters:
param_1: "{{ event }}"
- enabled: true
match:
prefect.resource.id: my.other.external.resource
expect:
- some.other.event
parameters:
param_1: "{{ event }}"
```
Both of the above triggers would be attached to `test-deployment` after running `prefect deploy`.
**Triggers passed to `prefect deploy` will override any triggers defined in `prefect.yaml`**
While you can define triggers in `prefect.yaml` for a given deployment, triggers passed to `prefect deploy`
take precedence over those defined in `prefect.yaml`.
Note that deployment triggers contribute to the total number of automations in your workspace.
## Further reading
For more on the concepts behind deployment triggers, see the [Automations concepts](/v3/concepts/automations) page.