in prefect 1, how to return a value from a flow?
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# ask-communityj
Jon
10/13/2022, 7:23 PMin prefect 1, how to return a value from a flow?
im calling flows via
create_flow_run✅ 2
k
Kalise Richmond
10/13/2022, 7:52 PMHi Jon, I think you'll need to configure results and then you'll be able to grab the results from that
j
Jon
10/13/2022, 9:06 PMthanks @Kalise Richmond! is there a way that i can access the flow's results in memory? writing to a file is too heavy duty
Jon
10/13/2022, 9:14 PMperhaps there's a way to search a flow's state by uuid?
k
Kalise Richmond
10/13/2022, 9:27 PMhey Jon, are you just looking to pass the state or are you trying to pass a value from the first flow. Here's an example that might help
j
Jon
10/13/2022, 9:55 PMthis is what i'm looking for, but the example is a bit confusing. where does the task slug come from?
Jon
10/13/2022, 9:55 PM Copy code
"create_some_data-1"Jon
10/13/2022, 9:56 PMnvm, i have to add it
Jon
10/13/2022, 9:59 PMbut maybe i'm doing something wrong? Seems we can't find the slug?
Copy code
Error during execution of task: ValueError("No task runs found while querying for task runs where {'task': {'slug': {'_eq': 'bronze_file'}}, 'flow_run_id': {'_eq': '5720e378-3b21-4674-8c61-198aa5951f6c'}, 'map_index': {'_eq': -1}}") Copy code
@prefect.task(slug="bronze_file")
def generate_bronze_file():Jon
10/13/2022, 10:07 PMwhat is the "-1" coming from here?
"create_some_data-1"k
Kalise Richmond
10/13/2022, 10:08 PMI believe every instance of a task gets the number appended because you can map over tasks.
j
Jon
10/13/2022, 10:09 PMok, so if i call the task just once in my flow it'll have a "-1"?
k
Kalise Richmond
10/13/2022, 10:09 PMI think so. It's been a while since I've tried it out
Kalise Richmond
10/13/2022, 10:10 PMlooks like there is a
map_indexj
Jon
10/13/2022, 10:11 PMmy task isn't mapped?
Jon
10/13/2022, 10:12 PMit works by appending "-1"
🎉 1
Jon
10/13/2022, 10:13 PMIMO a bit too magical 🧙
Jon
10/13/2022, 10:13 PMalso the docs say that slugs are stable :
`slug (str, optional)`: The slug for this task. Slugs provide a stable ID for tasks so that the Prefect API can identify task run states. If a slug is not provided, one will be generated automatically once the task is added to a Flow.
Jon
10/13/2022, 10:13 PMso kinda confusing the slug actually changes here
Jon
10/13/2022, 10:13 PMJon
10/13/2022, 10:14 PMbut thx for your help
k
Kalise Richmond
10/13/2022, 10:15 PMThanks for the feedback. I’ll make sure to let our doc experts know 😃
🙌 1
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