<@ULVA73B9P> how do set task run concurrency limit...
# ask-marvin
c
@Marvin how do set task run concurrency limits through tags using prefect cloud
m
To set task run concurrency limits using tags in Prefect Cloud, you can specify a concurrency limit for tasks with a specific tag. This helps manage the number of tasks running simultaneously, especially when resources are limited. Here's how you can do it: 1. Tag Your Tasks: Assign tags to your tasks that you want to manage. For example, if tasks are interacting with a database that only allows 10 connections, tag these tasks appropriately. 2. Set Concurrency Limits: You can set a concurrency limit for a tag, which restricts the number of concurrent task runs with that tag. If a task has multiple tags, it will run only if all tags have available concurrency. 3. Implementation in Prefect Cloud: - Navigate to the Prefect Cloud UI. - Go to the "Settings" or "Configuration" section where you can manage task concurrency settings. - Define the concurrency limit for each tag as needed. 4. Execution Behavior: Prefect checks these tag limits whenever a task run attempts to enter a Running state. Tasks with tags that have reached their concurrency limit will be delayed. For more detailed steps, you can refer to the Prefect documentation on task run limits. Here's a brief overview of the relevant Prefect API components: - `tags`: Manage and apply tags to your tasks. - `task`: Define and configure tasks within your flows. If you have any specific implementation questions or need further assistance, feel free to ask!
c
@Marvin there is no setting for task concurrency settings in configuration
m
It seems I made an error in describing the UI process. Prefect Cloud does not have a direct UI setting for task concurrency limits. Instead, you manage concurrency through code by using tags and setting limits programmatically. Here's how you can do it: 1. Define Tags in Code: When defining your tasks, assign tags to them. For example:
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python
   from prefect import task, flow

   @task(tags=["database"])
   def my_task():
       # Task logic here
       pass
2. Set Concurrency Limits Using Prefect Cloud API: You can set concurrency limits for tags via the Prefect Cloud API or CLI. Unfortunately, I don't have direct access to the exact API calls or CLI commands, but generally, it involves interacting with Prefect's orchestration layer to specify these limits. 3. Check Prefect Cloud Documentation: Since the specific API or CLI usage can change, it's best to refer to the latest Prefect Cloud documentation or their support for precise instructions on setting these limits. For more information, you can refer to the Prefect documentation on task run limits. If you need further assistance, Prefect's community or support channels might provide the latest practices and tools.
c
@Marvin how can I use the rest api to get a list of flow runs in a queue
m
To use the Prefect REST API to get a list of flow runs in a queue, you can interact with the
PrefectClient
to query flow runs. Here's a general approach you might take in Python, assuming you are using Prefect 3.x: 1. Set up the Prefect Client: You'll need to create a
PrefectClient
instance to interact with the API. 2. Query Flow Runs: Use the client to query flow runs by specifying the desired filters, such as the queue name. Here's a basic outline of how you might structure the code:
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python
from prefect.client.orchestration import PrefectClient
from prefect.client.schemas import FlowRunFilter, FlowRunSort

async def get_flow_runs_in_queue(queue_name: str):
    async with PrefectClient() as client:
        flow_run_filter = FlowRunFilter(queue_name=queue_name)
        flow_runs = await client.read_flow_runs(
            flow_run_filter=flow_run_filter,
            sort=FlowRunSort.EXPECTED_START_TIME_ASC
        )
        return flow_runs

# Example usage
# flow_runs = asyncio.run(get_flow_runs_in_queue("your-queue-name"))
### Key Points: - PrefectClient: This is used to interact with the Prefect API. - FlowRunFilter: Allows you to filter flow runs based on specific criteria, such as the queue name. - FlowRunSort: You can sort the flow runs by attributes like expected start time. You can find more details on the Prefect API and filtering options in the Prefect GitHub repository. If you are interested in further customization or additional filtering options, you might want to explore the Prefect documentation or the source code directly.
c
@Marvin How would I do that with another http client using POST /work_pools/workpool-tf-nonproduction/get_scheduled_flow_runs
m
To use an HTTP client to make a POST request to the endpoint
/work_pools/workpool-tf-nonproduction/get_scheduled_flow_runs
, you can follow this general approach: 1. Set Up Your HTTP Client: Use a library like
requests
in Python to make the HTTP request. 2. Make the POST Request: Send a POST request to the specified endpoint with any necessary headers or payload. Here's a basic example using Python's
requests
library:
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python
import requests

# Define the endpoint URL
url = "<https://your-prefect-api-url.com/work_pools/workpool-tf-nonproduction/get_scheduled_flow_runs>"

# Define any headers or authentication if required
headers = {
    "Authorization": "Bearer YOUR_API_TOKEN",
    "Content-Type": "application/json"
}

# Define the payload if any specific parameters are needed
payload = {
    # Add any necessary parameters here
}

# Make the POST request
response = <http://requests.post|requests.post>(url, headers=headers, json=payload)

# Check the response
if response.status_code == 200:
    flow_runs = response.json()
    print("Scheduled Flow Runs:", flow_runs)
else:
    print("Failed to retrieve flow runs:", response.status_code, response.text)
### Key Points: - URL: Replace
<https://your-prefect-api-url.com>
with your actual Prefect API URL. - Authorization: Use the appropriate method to authorize your request, such as a Bearer token. - Payload: Include any specific parameters required by the API endpoint. For further details, you may want to refer to the Prefect API documentation or your specific deployment's API documentation if there are custom configurations.