@Marvin how to pull results from a flow run given flow run id?

In order to assist you with retrieving results from a flow run using its flow run ID, could you please confirm which version of Prefect you are using? Prefect 2.x and 3.x may have different methods or APIs for handling such queries.

@Marvin how to pull results from a flow run given flow run id in prefect 2.x?

To retrieve results from a flow run in Prefect 2.x using its flow run ID, you'll typically use the Prefect API or Prefect's Python client to query the underlying database where results are stored, often using cloud storage or filesystems configured for result persistence. Here's a general approach: 1. Persist Results: Ensure your flow is configured to persist results. This is done by setting

persist_result=True

in your task decorator and configuring

result_storage

, such as an S3 bucket or local filesystem.

python
    from prefect import flow, task
    from prefect.filesystems import S3

    @flow(result_storage=S3(bucket_path="my-bucket"))
    def my_flow():
        my_task()
    
    @task(persist_result=True, result_storage_key="my_task.json")
    def my_task():
        return "Task result"

    my_flow()

2. Retrieve Results: Results can be retrieved by accessing the result storage configured for your flow. Typically, you will locate the

result_storage_key

and use it to read the result data. 3. Querying with API: You may need to write a script that queries Prefect's API or uses Prefect's Python client. This script will take the

flow_run_id

and use it to locate and download the result from the specified storage. Check the Prefect documentation here for more details on configuring result storage and accessing run outputs. If you need further details on how to implement this with your specific set-up (like using specific storage solutions), feel free to ask!

@Marvin I have

flow_run_id=...

, how to pull the flow results from the server?

To retrieve the persisted result from a flow run in Prefect 2.x when you have the

flow_run_id

and have enabled result persistence, you would typically follow these steps: 1. Access Result Storage: Prefect does not directly store results in its API but references a storage location. You need to configure your flow or task to persist results using a specified storage system, such as S3 or a local filesystem. 2. Check Result Storage Configuration: Ensure your flow or task is set up with

result_storage

and

persist_result

as shown below:

python
   from prefect import flow, task
   from prefect.filesystems import S3

   @task(persist_result=True, result_storage_key="result-key.json")
   def my_task():
       return "Task result"

   @flow(result_storage=S3(bucket_path="my-bucket"))
   def my_flow():
       my_task()

   my_flow()

3. Retrieve Results: Since the results are stored in a location specified by

result_storage

, you need to manually access this storage system to retrieve the result. For instance, if you're using S3, you can use AWS SDKs like

boto3

in Python to fetch the file using the

result_storage_key

. Example using S3 with `boto3`:

python
import boto3

def get_result_from_s3(bucket_name, result_key):
    s3_client = boto3.client('s3')
    response = s3_client.get_object(Bucket=bucket_name, Key=result_key)
    return response['Body'].read()

# Example usage
result = get_result_from_s3('my-bucket', 'result-key.json')
print(result)

Make sure to replace

'my-bucket'

and

'result-key.json'

with your actual S3 bucket name and the key used when persisting results. You can refer to Prefect 2.x documentation for further details: Concepts - Results. Feel free to ask if you have more questions or need further clarification!

@Marvin but is there no way to do it in a storage-agnostic way with prefect functions?

It appears there isn't a built-in storage-agnostic method provided by Prefect 2.x to retrieve results using just the flow run ID directly without interacting with the specified storage system. Prefect relies on the storage configuration you set (e.g., S3, local files) to manage result persistence, so fetching the results typically involves interacting with that storage system directly. Currently, Prefect 2.x does not provide an abstracted or built-in function that would fetch results directly in a storage-agnostic way. You would generally need to handle the retrieval through the storage-specific interfaces as previously described. For advanced usage, or potential updates, you might periodically check the Prefect 2.x documentation or the Prefect community channels to see if such functionality is introduced in a newer release or through community-contributed extensions. If you have more specific requirements, feel free to ask!