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<@ULVA73B9P> I am a bit confused because I cannot manage to retrieve the current state of a flow. I ...
# marvin-in-the-wild
a
@Marvin I am a bit confused because I cannot manage to retrieve the current state of a flow. I am using prefect 2 sdk in python. The triggering of the flow works fine so I dont think its a credential issue. However when I try to retrieve the state of the flow, I get prefect.exceptions.ObjectNotFound error. This is the code i am using:
Copy code
async with get_client() as client:
        flow_run = await client.read_flow_run(flow_run_id)
        print(flow_run.state.message)
        return flow_run.state.is_completed(), flow_run.state.message
        response = await client.hello()
        return response.json()
Do you have any idea why it cannot manage to find this flow?
m
It seems you're encountering an 
ObjectNotFound
error when trying to retrieve the current state of a flow run using Prefect 2.x. The issue might not be related to credentials as you mentioned, but possibly on how the flow run ID is being handled. Here's a breakdown of the potential causes and steps you might take to troubleshoot: 1. Flow Run ID: Ensure that the 
flow_run_id
variable you're passing to 
client.read_flow_run
actually contains a valid and existing flow run ID. If it's empty or contains an incorrect ID, the API won't be able to find the flow run, resulting in 
ObjectNotFound
. 2. Race Conditions: If the flow is very new, there might be a slight delay before the state is available for reading. A short pause between initiating the flow and reading the flow run might help. Consider adding a delay using 
asyncio.sleep
. 3. Logging and Error Handling: Before calling 
client.read_flow_run
, try to log the 
flow_run_id
to verify it's correct. Implement error handling to log the specific error message, which can give more context. 4. Documentation Check: Refer to the Prefect 2.x documentation for more insights about 
get_client()
and how it should be used, as errors could also arise from there. Prefect 2.x Concepts 5. Prefect Server/Cloud: Ensure that the Prefect server or cloud you're using is correctly set up and accessible from your environment. 6. Additional Debugging: Consider adding logging around the flow run initiation to confirm that it's being created successfully and that the ID is logged immediately after creation. These checks and modifications should help you diagnose and fix the issue. If the problem persists, please provide more context or logs, and we can continue troubleshooting!
To resolve the issue with the 
prefect.exceptions.ObjectNotFound
error, let's go through your code and a few potential solutions: 1. Correct Flow Run ID: Ensure that 
flow_run_id
is correct and actually corresponds to a valid flow run. You can verify this by checking the Prefect dashboard or logs. 2. Flow Run Registration Delay: After triggering a flow, it might take some time for the flow run to be fully registered in Prefect's backend. You might want to introduce a small delay after triggering the flow before trying to read its state. 3. Error Handling: Enhance your code to handle potential 
ObjectNotFound
exceptions gracefully. Use a try-except block to catch and manage the situation where the flow run ID may not exist. 4. Correct API Usage: Ensure that the API calls are being used as intended. The second return statement 
return response.json()
may never be reached because there's already an earlier return. Also make sure these API calls match your flow's state and execution pattern. Here's a refactor suggestion incorporating these:
Copy code
python
async with get_client() as client:
    try:
        flow_run = await client.read_flow_run(flow_run_id)
        # Access state message
        state_message = flow_run.state.message if flow_run.state else "No state found"
        print(state_message)
        return flow_run.state.is_completed(), state_message
    except prefect.exceptions.ObjectNotFound:
        print(f"Flow run with ID {flow_run_id} not found.")
        # Handle this case appropriately, maybe by returning a default value or re-trying
        return False, "Flow run not found"
Also, review the Prefect documentation on using Prefect client to ensure there aren’t any missed configurations. Apply these checks and adjustments to troubleshoot and resolve the error you are encountering with retrieving the flow’s state.
The 
prefect.exceptions.ObjectNotFound
error typically indicates that the flow run ID you're trying to access does not exist in the Prefect backend or database. Here are a few steps to help troubleshoot this issue: 1. Confirm the Flow Run ID: Ensure that the 
flow_run_id
you are using is accurate. It might be beneficial to print the ID before making the call to confirm it is what you expect. 2. Check Flow Run Existence: You can verify the existence of the flow run by listing all flow runs and checking if your specific 
flow_run_id
is present. This can be done through the Prefect UI by navigating to the "Flow runs" section, or by using the Prefect API to list the flow runs. 3. Review Permissions and Authentication: While you mentioned that triggering flows is functioning correctly, ensure that the credentials and permissions used for querying flow run states are properly configured. 4. Version Mismatch: Ensure that the Prefect library version you're using matches any server or cloud environment, as discrepancies might lead to unexpected errors. The Prefect 2.x documentation does not specifically address this error directly for your described scenario, but generally, issues with retrieving objects are due to incorrect IDs or network/configuration errors. If none of these solutions resolve the problem, consider reaching out to Prefect's support or community forums with complete details and logs, as the issue might be more nuanced based on your particular setup.
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