@Marvin, how do I execute the flow using API? I want to use the flow on react.js

To execute a Prefect flow using an API, especially from an external application like React.js, you'll need to interact with the Prefect REST API. Here's a concise guide on how to do this: 1. Set Up Prefect Server: Ensure that your Prefect server is running. This is necessary to interact with the API. 2. Create a Flow Deployment: First, you need to create a deployment of your flow. This can be done using the Prefect CLI or programmatically. Here's an example of creating a deployment programmatically:

python
   from prefect import flow, task

   @task
   def do_something_important(not_so_secret_value: str) -> None:
       print(f"Doing something important with {not_so_secret_value}!")

   @flow(log_prints=True)
   def some_work():
       # Your flow logic here
       pass

   if __name__ == "__main__":
       some_work.from_source(
           source="<https://github.com/your-repo/prefect-monorepo.git>",
           entrypoint="src/demo_project/demo_flow.py:some_work",
       ).deploy(
           name="demo-deployment",
           work_pool_name="local",
           job_variables={
               "env": {
                   "EXECUTION_ENVIRONMENT": "{{ $EXECUTION_ENVIRONMENT }}",
                   "MY_NOT_SO_SECRET_CONFIG": "{{ $MY_NOT_SO_SECRET_CONFIG }}",
               }
           },
       )

3. Trigger Flow Run via API: Use the Prefect REST API to trigger a flow run. You can use a tool like

fetch

in React.js to make a POST request to the Prefect API endpoint responsible for creating flow runs. Example API call:

javascript
   fetch('<http://your-prefect-server/api/flow_runs>', {
       method: 'POST',
       headers: {
           'Content-Type': 'application/json',
       },
       body: JSON.stringify({
           flow_id: 'your-flow-id',
           parameters: {
               // your flow parameters
           }
       }),
   })
   .then(response => response.json())
   .then(data => console.log('Flow run created:', data))
   .catch((error) => console.error('Error:', error));

4. Handle Responses: Make sure to handle the API responses appropriately in your React.js application. For more detailed information, you might want to explore the Prefect 3.x documentation and the Prefect REST API documentation. This approach allows you to trigger Prefect flows dynamically from a frontend application, integrating your data workflows seamlessly with your web application.

it wont be

POST /flow_runs

, itll be

POST /create_flow_run_from_deployment

but... there's probably a slicker way using events • create a deployment with a trigger • hit the webhook from your js

Thanks you @Nate 😃

If your flow is starting with a "Pending" status and you want it to execute immediately without scheduling, there are a few things you can check and adjust: 1. Immediate Execution: Ensure that your flow is set up to run immediately. In Prefect 3.x, you can execute flows directly without deploying them by calling the flow function in your script. This should bypass any scheduling and execute the flow immediately.

python
   from prefect import flow

   @flow(log_prints=True)
   def test(name: str = "Fulano!"):
       return f"Hello {name}!"

   if __name__ == "__main__":
       test()  # Directly calling the flow for immediate execution

2. Concurrency and Priority: If you're using a work pool or a Prefect server, check the concurrency limits and priority settings. Make sure that there are no constraints that might delay the execution of your flow. You can adjust these settings to prioritize your flow for immediate execution. 3. Infrastructure Settings: Review your infrastructure settings to ensure that there are no unnecessary delays in starting the flow runs. Prefect 3.x uses work pools instead of agents, so ensure your work pool is correctly configured and running. 4. Pending State Causes: The "Pending" state can be due to dependencies or conditions not being met. Ensure that there are no upstream tasks or conditions that are causing the flow to wait. 5. Prefect 3.x Gotchas: Be aware that Prefect 3.x has some changes and gotchas compared to previous versions. For instance, agents are replaced by workers, and infrastructure blocks are replaced by work pools. Ensure your setup aligns with these changes. For more details, you can refer to the Prefect 3.x documentation and explore concepts like work pools and concurrency. By ensuring that your flow is configured for immediate execution and that there are no constraints or misconfigurations, you should be able to reduce the time it spends in the "Pending" state.

How do I return faster from API without scheduled or something, just process?

hi @Adriano Resende - let me know if I have your question right are you saying that you want to bypass the scheduling side of things and just directly run the python function? if you're using a deployment (the main way to trigger work via webhook or REST API) then you will have to schedule a run. you can change how often the worker polls, but you still will likely have at least a couple seconds of latency. alternatively, you can have your own API that your frontend can call and the backend can just background the flow function (like how this slackbot works), though this is more to manage on your end