@Marvin How can I trigger one of my deployment flows to run from my python flask API? I have deployed prefect-server and prefect-worker to my kubernetes cluster which also hosts my flask API.

To trigger a Prefect deployment flow run from your Python Flask API, follow these steps: 1. Set up Prefect client: First, you need to install the Prefect client and set it up in your Flask environment. 2. Trigger Flow Run: Use the Prefect client to trigger a flow run from your Flask route. Here’s a code example demonstrating how to achieve this:

python
from flask import Flask, request, jsonify
from prefect.client import OrionClient

app = Flask(__name__)

@app.route('/trigger-flow', methods=['POST'])
def trigger_flow():
    deployment_id = request.json.get("deployment_id")
    parameters = request.json.get("parameters", {})
    
    client = OrionClient(api_url="http://<your-prefect-server>/api")
    
    flow_run = client.create_flow_run_from_deployment(
        deployment_id=deployment_id,
        parameters=parameters
    )
    
    return jsonify({
        "flow_run_id": flow_run.id,
        "details": f"Flow run triggered with ID: {flow_run.id}"
    })

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)

Links to Documentation and Examples: - Using Deployment Triggers: Deployments and Triggers - Example Flow: Basic Flow Example This setup allows you to handle POST requests to trigger specified flow runs with given parameters. Make sure to adjust the

api_url

for the

OrionClient

to point to your Prefect server's API endpoint.

@Marvin OrionClient does not exists, I do need a python client in my flask api to trigger my workflow. Can you show me how its done ?

To trigger a Prefect deployment flow from your Python Flask API, you can use the

PrefectClient

from the

prefect.client

module. Below is an example of how to set this up: 1. Install Prefect: Ensure you have the Prefect library installed:

bash
   pip install prefect

2. Flask API to Trigger Flow Run: Here's a sample Flask application demonstrating how to trigger a Prefect deployment flow run using the `PrefectClient`:

python
from flask import Flask, request, jsonify
from prefect.client import get_client

app = Flask(__name__)

@app.route('/trigger-flow', methods=['POST'])
def trigger_flow():
    deployment_id = request.json.get("deployment_id")
    parameters = request.json.get("parameters", {})
    
    async def create_flow_run():
        async with get_client() as client:
            flow_run = await client.create_flow_run_from_deployment(
                deployment_id=deployment_id,
                parameters=parameters
            )
            return flow_run

    flow_run = asyncio.run(create_flow_run())

    return jsonify({
        "flow_run_id": flow_run.id,
        "details": f"Flow run triggered with ID: {flow_run.id}"
    })

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)

Explanation: - Flask Setup: We set up a simple Flask application with an endpoint

/trigger-flow

to handle POST requests. - Prefect Client: We use the

get_client

method from

prefect.client

to get an instance of the Prefect client, which interacts with the Prefect API. - Asynchronous Flow Run Creation: The flow run creation is performed asynchronously using

asyncio.run

to ensure asynchronous operations are properly awaited. You need to replace

<your-prefect-server>

and other placeholders with actual values according to your Prefect server setup. This allows you to post JSON data to the Flask API endpoint to trigger Prefect deployments. Further Reading: - More on Deployments: Prefect Deployments - Guides for Interactive Workflows: Interactive Workflows Guide

@Marvin do this but without async

Sure, here's a revised version of the Flask application you can use to trigger a Prefect deployment flow run without using `async`: 1. Install Prefect:

bash
   pip install prefect

2. Flask API to Trigger Flow Run: Here's the updated Flask application:

python
from flask import Flask, request, jsonify
from prefect.client import Client

app = Flask(__name__)

@app.route('/trigger-flow', methods=['POST'])
def trigger_flow():
    deployment_id = request.json.get("deployment_id")
    parameters = request.json.get("parameters", {})
    
    client = Client()
    flow_run = client.create_flow_run_from_deployment(
        deployment_id=deployment_id,
        parameters=parameters
    )
    
    return jsonify({
        "flow_run_id": flow_run.id,
        "details": f"Flow run triggered with ID: {flow_run.id}"
    })

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)

### Explanation: - Client Setup: This script uses the synchronous

Client

class from

prefect.client

. - Trigger Flow: The route

/trigger-flow

obtains the deployment ID and parameters from the incoming POST request, then uses the client to create a flow run directly. This setup allows you to handle POST requests to trigger specified flow runs with given parameters in a non-async manner. Make sure to adjust the deployment ID and other necessary details to fit your specific use case.