Hi @Marvin, I've deployed my remote Prefect server. Could you give me an example of how to deploy a flow on this server from my development machine?

Here's an example of how you could deploy a flow to a remote Prefect server from your development machine. This example assumes you have Prefect installed and a flow already defined. Make sure the code below reflects your specific setup and the flow you want to deploy.

python
import time
from prefect import flow, task

@task
def sleep(t: int):
    print(f"Going to sleep for {t} seconds...")
    time.sleep(t)
    print("...and I'm awake!")

@flow(log_prints=True)
def my_flow():
    sleep(3)
    future = sleep.submit(2)
    future.wait()
    sleep.map([5] * 10)

if __name__ == "__main__":
    my_flow()

In this script: - We have a simple task

sleep

that takes a number

t

which represents the number of seconds to sleep. - We have a flow

my_flow

which calls the

sleep

task in different ways (synchronously, asynchronously with

submit

, and concurrently with

map

). - By executing this script, the flow

my_flow

will be run, which includes running the

sleep

task. To actually deploy this flow to the remote server, make sure you: 1. Authenticate with the remote Prefect server from your development machine. 2. Save the flow as a file in your development machine. 3. Deploy the flow using the Prefect CLI or UI and point it to your remote server. Once these steps are completed, the remote server should pick up the flow and start executing it according to your configuration. Please adjust the example code and the deployment procedure to fit into your environment configuration and deployment strategies. If you need more specific instructions on any of these steps or need assistance with configuring your remote server, please let me know. For more information, use this code example URL: Prefect Submitting Tasks Code Example

@Marvin I have configured the correct URL, but my Prefect server is located behind an nginx server that I use for authentication. How can I pass the credentials?

For a Prefect server behind an nginx server used for authentication, you will likely need to include your authentication credentials in the requests you make to the Prefect server. The example code provided here does not directly address authentication with nginx. That is because Prefect itself does not handle nginx authentication – instead, you might need to integrate the authentication within your deployment process or use environmental variables, depending on how you have configured nginx to handle authentication. For instance, if you're using basic authentication, you may be able to use environment variables to pass your credentials to the Prefect client, modifying the client's headers to include an Authorization token. Here is a general approach that can be adapted into your Prefect deployment process:

python
from prefect import Client

# Set Prefect API URL
prefect_api_url = '<https://url-to-your-prefect-server>'

# Set the credentials (these could also be picked up from environment variables)
username = 'your_username'
password = 'your_password'

# Create an authorization token
auth_token = f'{username}:{password}'

# Initialize the Prefect Client
client = Client(api_server=prefect_api_url)

# Set the Authorization header on the client
client._session.headers.update({
    "Authorization": f"Basic {auth_token}"
})

# Now you can interact with the Prefect API
# For example: Creating a project, registering a flow, etc.

Please ensure that you encode the

auth_token

with Base64 encoding if you are passing basic credentials in a header. In production, it is always advisable not to hard-code credentials, but to use secrets management or environment variables. This example doesn't come from a direct link, but illustrates the general idea. Depending on the authentication method (basic auth, token auth, etc.), you might need to adjust the example accordingly. Note that passing credentials in code or via environment variables should be done securely and in accordance with best practices for secrets management. For more information and examples of deploying flows and interacting with the server, use the example code URL related to the deployment and serving of flows: Prefect Deployment Serving Example

@Marvin How would you complete the snipped below to manage the authentification to my reverse proxy, assuming that PREFECT_API_URL is already configured ? if name == "__main__": repo_info_deploy = repo_info.to_deployment( name="my-first-deployment", cron="* * * * *", tags=["testing", "tutorial"], description="Given a GitHub repository, logs repository statistics for that repo.", version="tutorial/deployments" ) serve( repo_info_deploy )

To manage authentication with a reverse proxy that sits in front of your Prefect server, you will need to ensure your reverse proxy and Prefect server can communicate authentication tokens or credentials securely. I'll provide you with an extended example, assuming you are using environment variables to pass authentication credentials. In real-world scenarios, these should be secured properly, perhaps using a service like Vault, managed environment variables, or Kubernetes secrets. First, you would need to import the necessary modules and set up the Prefect client with the proper authentication headers. This example uses

requests

to provide HTTP Basic Authentication:

python
from prefect import flow, Client
import requests
from requests.auth import HTTPBasicAuth
import os

# Assuming you have the following environment variables set
# PREFECT_API_URL: The URL to your Prefect Server
# PREFECT_API_KEY: The API Key for authentication
# (or PREFECT_USERNAME and PREFECT_PASSWORD for basic auth)

client = Client(api_server=os.getenv("PREFECT_API_URL"))

# Use token-based authentication as an example
api_key = os.getenv("PREFECT_API_KEY")
if api_key:
    client._session.headers.update({"Authorization": f"Bearer {api_key}"})
else:
    # Fall back to basic authentication
    username = os.getenv("PREFECT_USERNAME")
    password = os.getenv("PREFECT_PASSWORD")
    if username and password:
        auth = HTTPBasicAuth(username, password)
        client._session.auth = auth

# Define your flow and deployment object just before serving them

if __name__ == "__main__":
    repo_info_deploy = repo_info_to_deployment(
        name="my-first-deployment",
        cron="* * * * *",
        tags=["testing", "tutorial"],
        description="Given a GitHub repository, logs repository statistics for that repo.",
        version="tutorial/deployments"
    )

    serve(
       repo_info_deploy,
       # You may need additional arguments based on your serve function's requirements
    )

Keep in mind this code doesn't exactly show where the

serve

function and the

repo_info_to_deployment

function come from, which likely need to be imported or defined in your code. Please replace

repo_info_to_deployment

with your actual function or class responsible for creating a deployment object. The

serve

function should also be the Prefect serving method or your equivalent to register the deployment with your Prefect installation. Ensure that you never expose your API keys, passwords, or credentials in your source code. Always use a secure method to pass these values to your applications. Again, this example doesn't link to a specific Prefect example as it's a more general Python pattern for handling Basic or Bearer token authentication. Adjust it as necessary to suit the details of how your reverse proxy handles authentication.

you just need to set your

PREFECT_API_URL

as an env var that correctly points to your server according to your networking you dont often need to do this in code

Hello, Actually, the question was more about how to get through my nginx authentication (basic_auth type). I was getting a 401 Unauthorized error if I only filled in the variable PREFECT_API_URL. The variable PREFECT_API_KEY didn't make sense in my case, as I am not on Cloud. In the end, I succeeded by modifying my Nginx configuration and adding my machine's IP to the exceptions to not ask authentification. Let the fun begin!

ah! i could have read that better 🙂 glad you're on your way