Hi there. I am new to Prefect Orion. I am trying to schedule a flow run on my local Prefect server following the example POST request provided in the documentation. Here is my request:

POST: <http://localhost:4200/api/flow_runs/>

PAYLOAD:
{
  "name": "my_scheduled_flow",
  "deployment_id": "0ff88fc8-a71c-4b71-b8dd-078d6a36fb39",
  "flow_id": "94374bea-70ae-4e49-8988-e9077daa280a",
  "flow_version": "1.0",
  "state": {
    "type": "SCHEDULED",
    "name": "my_scheduled_flow",
    "message": "a message",
    "state_details": {
        "scheduled_time": "2022-02-18T16:10:49.005Z"
    }
  }
}

The flow run then appears in the server UI (as yellow) but never gets ran at the correct time. Does anyone have any idea on this? Am I missing an important part of the payload.

Hi @Donnchadh McAuliffe, I’ll ask one of the Orion engineers

thank you @Kevin Kho

Sounds good. Thanks for the info!

if possible @Kevin Kho could you provide an example REST API payload for creating an interval scheduled flow run? https://orion-docs.prefect.io/api-ref/rest-api/#/Flow%20Runs/create_flow_run_flow_runs__post For example, a flow run that should start at

2022-02-18T17:11:43.254Z

and then every 20 mins until the next day (

2022-02-18T18:11:43.254Z

) Thank you!

It’s really not recommended that you make the API Payload for that yourself because there are a bunch of steps needed to construct it, which is why the deployment interface exists

apologies @Kevin Kho I should've clarified what I'm trying to do. Say I have already deployed a flow to my prefect server - what would the api request look like to run that flow with an interval schedule? Where do I add the start time/end time and run time interval to the payload?

POST: <http://localhost:4200/api/flow_runs/>

PAYLOAD:
{
  "name": "my_scheduled_flow",
  "deployment_id": "0ff88fc8-a71c-4b71-b8dd-078d6a36fb39",
  "flow_id": "94374bea-70ae-4e49-8988-e9077daa280a",
  "flow_version": "1.0",
  "state": {
    "type": "SCHEDULED",
    "name": "my_scheduled_flow",
    "message": "a message",
    "state_details": {
        "scheduled_time": "2022-02-18T16:10:49.005Z"
    }
  }
}

You can attach a schedule to your DeploymentSpec:

from prefect import flow

@flow
def hello_world(name="world"):
    print(f"Hello {name}!")

from prefect.deployments import DeploymentSpec
from prefect.orion.schemas.schedules import IntervalSchedule
from datetime import timedelta

DeploymentSpec(
    flow=hello_world,
    name="hello-world-daily",
    schedule=IntervalSchedule(interval=timedelta(days=1)),
    tags=["earth"],
)

DeploymentSpec(
    flow=hello_world,
    name="hello-orion",
    schedule=IntervalSchedule(interval=timedelta(weeks=1)),
    parameters={"name": "Orion"},
    tags=["marvin"],
)

thank you, but say I don't want to specify the schedule when deploying the flow and I just want to deploy a generic flow and then run it using an API request. I have achieved this with scheduling a one off run as can be seen above, but how do I modify my payload to specify an interval schedule flow run?

I believe you can either: • deploy your flow to run on schedule as shown above with

DeploymentSpec

- the flow runs then get created via schedule • or trigger the flow run ad hoc via an API call as you did I think creating deployments and attaching schedules via an API call is not yet tested/documented so I would wait with that a bit.

ok thank you @Anna Geller, so for now the API call method only works for a one off schedule by the looks of it. If possible can you confirm that triggering an interval schedule flow run via an API call is on the roadmap for Prefect Orion official release? Really appreciate your help with this!

Sorry, I can't make any promises about the roadmap. But since this seems important to you I checked the API and it seems there is a route you can use to schedule a run for a deployment https://orion-docs.prefect.io/api-ref/rest-api/#/Deployments/schedule_deployment_deployments__id__schedule_post

fair enough, thank you @Anna Geller. The payload provided in the doc doesn't actually work I'm afraid:

POST: <http://localhost:4200/api/deployments/{deployment_id}/schedule>

PAYLOAD: {
  "start_time": "2022-02-21T17:00:00.000Z",
  "end_time": "2022-02-21T17:02:00.000Z",
  "max_runs": 4
}

it just returns

null, 200

and subsequently doesn't run at the specified times. I'm looking through the orion docs for schedules here, how do I specify the start and end time for the interval schedule of a deployment?

from prefect.deployments import DeploymentSpec
from prefect.orion.schemas.schedules import IntervalSchedule
from datetime import timedelta

DeploymentSpec(
    flow_location="/Developer/workflows/my_flow.py",
    name="my-first-deployment",
    parameters={"nums": [1, 2, 3, 4]}, 
    schedule=IntervalSchedule(interval=timedelta(minutes=15)),
)

I looked at it a bit more and I would encourage you to wait until you use this feature anywhere since it’s not yet fully tested/documented. This API endpoint is not yet meant to set schedules via API and it doesn’t work as you would like. Also, the API routes and database models are still under active development so even if this would work, there is no guarantee that this won’t change. In contrast, defining a schedule via a

DeploymentSpec

has been stable for many weeks now and I would encourage you to set schedule only via DeploymentSpec for now.

sounds good @Anna Geller, just final question from me regarding your recommendation "I would encourage you to set schedule only via DeploymentSpec for now." How do I add the start and end times to an interval schedule in the below python example? Its not specified in your schedule docs.

from prefect.deployments import DeploymentSpec
from prefect.orion.schemas.schedules import IntervalSchedule
from datetime import timedelta

DeploymentSpec(
    flow_location="/Developer/workflows/my_flow.py",
    name="my-first-deployment",
    parameters={"nums": [1, 2, 3, 4]}, 
    schedule=IntervalSchedule(interval=timedelta(minutes=15)),
)

That’s actually a good point, I will open an issue internally to discuss this since in Prefect 1.0 we do have start and end dates for both Cron and Interval schedules. Thanks for raising that

much appreciated!

Just out of curiosity, what’s your use-case for start and end dates on a schedule?

say you had a flow to collect data throughout an event that starts at a certain time and ends at a certain time. For example if you wanted to collect sports data intermittently from an API (say every 2mins) throughout a soccer match that takes place on a Saturday - you don't want to have to manually run the interval schedule at the start of the match and then manually stop it after 90mins (its the weekend and you're not on your laptop the entire time, instead on the Friday night you just want to "schedule" the interval schedule to begin at the match start time, run every 2mins and end after 90mins).

Unfortunately, Orion repo is currently private and I opened an issue there. But I'll do my best to keep you up to date. There's a lot to do regarding Orion, so it may take some time

thats fine, thanks again for all your help!

Your scheduled runs will be created as expected. The 100 flow runs is just an implementation detail of the scheduler services which tells you that 100 runs will be created immediately, but the next runs for your 2 week-period will be created later by the scheduler. E.g. in Prefect 1.0, the scheduler creates only 10 runs in advance, but all scheduled runs will be eventually created as they are getting closer to their expected scheduled start time.

ya thats what I thought but just wanted to confirm with ye. Thanks for answering all these questions, its helping us rule out any potential limitations we might have if we commit to Orion.

Not yet, here is an issue so that you can track the status https://github.com/PrefectHQ/prefect/issues/5620

thanks so much