Hi - I've asked this question previously many versions ago. Is

apply_map

the only way to map over

ifelse

and

case

statements?

hey guys, trying prefect for the first time now, seems an amazing piece of work

been having some problems organizing flow of flows:

customer_flow = Flow('customer_flow')
customer_flow.register(project_name="All Flows")

customer_uptodate = check_status(source='db.sqlite3', target='db_target.sqlite3', table='customers')
test_target_db = test_target_db()
test_source_db = test_source_db()

customer_flow.add_task(test_source_db)
customer_flow.add_task(test_target_db)
customer_flow.add_task(customer_uptodate)

I get the error “ValueError: Could not infer an active Flow context.” (edited) but I couldn’t understand what exactly i’m doing wrong using the imperative API. registered the flow, registerd the tasks, add_task to flow. i didn’t understand what could I do differently, since the error appears right at my first task (customer_uptodate = check_status(source=‘db.sqlite3’, target=‘db_target.sqlite3’, table=‘customers’)

any ideas, hints, suggestions, links to articles that could be of any help?

Hey, can I create a task which is triggered by a Retry? Or create some retry logic for multiple tasks? For instance, I spawn off a kubernetes job, but if the job fails, I first want to cleanup that job before retrying.

I am just starting with Prefect and using the local server. One question I have is around object sharing. If I have a client I need to setup to call something like Reddit. When I have multiple tasks that need to access it where do I set it up? Do I need to set it up repeatedly in each task? Pass it to the tasks via a simple parameter to the task? Looking for best practices on this please.

Hi, Can someone please help me with the - RuntimeError: Unable to find any timezone configuration? I have Helm Dask chart installed on AWS EKS cluster. The deployment has two load balancer services that expose dask-scheduler and Jupyter notebook. I am trying to register the flow to the prefect cloud from the deployed Jupyter Notebook. The workflow runs fine on the dask-scheduler. self._access_token_expires_at is part of the init so I can't set the timezone.

self._access_token_expires_at = pendulum.now()

RuntimeError                              Traceback (most recent call last)
<ipython-input-5-fa84dadfda8e> in <module>
----> 1 flow.register("prefect-workflow")

/opt/conda/lib/python3.8/site-packages/prefect/core/flow.py in register(self, project_name, build, labels, set_schedule_active, version_group_id, no_url, idempotency_key, **kwargs)
   1658             self.result = self.storage.result
   1659 
-> 1660         client = prefect.Client()
   1661 
   1662         registered_flow = client.register(

/opt/conda/lib/python3.8/site-packages/prefect/client/client.py in __init__(self, api_server, api_token)
     92         self._access_token = None
     93         self._refresh_token = None
---> 94         self._access_token_expires_at = pendulum.now()
     95         self._active_tenant_id = None
     96         self._attached_headers = {}  # type: Dict[str, str]

/opt/conda/lib/python3.8/site-packages/pendulum/__init__.py in now(tz)
    209 
    210     if tz is None or tz == "local":
--> 211         dt = _datetime.datetime.now(local_timezone())
    212     elif tz is UTC or tz == "UTC":
    213         dt = _datetime.datetime.now(UTC)

/opt/conda/lib/python3.8/site-packages/pendulum/tz/__init__.py in local_timezone()
     58     Return the local timezone.
     59     """
---> 60     return get_local_timezone()

/opt/conda/lib/python3.8/site-packages/pendulum/tz/local_timezone.py in get_local_timezone()
     33 
     34     if _local_timezone is None:
---> 35         tz = _get_system_timezone()
     36 
     37         _local_timezone = tz

/opt/conda/lib/python3.8/site-packages/pendulum/tz/local_timezone.py in _get_system_timezone()
     61         return _get_darwin_timezone()
     62 
---> 63     return _get_unix_timezone()
     64 
     65 

/opt/conda/lib/python3.8/site-packages/pendulum/tz/local_timezone.py in _get_unix_timezone(_root)
    240         return TimezoneFile(tzpath)
    241 
--> 242     raise RuntimeError("Unable to find any timezone configuration")
    243 
    244 

RuntimeError: Unable to find any timezone configuration

I get a similar error when I run: import pendulum pendulum.now()

This message was deleted.

Hi Prefect Experts, UI fails to connect to the

graphql

, not sure what causing this , any idea

Hi prefect team, I am wondering if there is a plan to implement executor callbacks now that 0.14.0 has migrated away from environments. I see this discussed here https://prefect-community.slack.com/archives/CL09KU1K7/p1602269846235100 but I don't see any mention of this in the changelog.

Hi Prefect experts, anyone can help with this ?

Hello all, I am attempting to run a docker container from within a prefect flow. Currently the file that I am trying to run lives within the file system as seen https://pastebin.com/NjuF5yFR here in my code. I have a volume that needs to be mounted for it to be able to locate the file, but I am unsure of the syntax. What am I doing wrong?

Any idea what this error message could mean when trying to run a flow from the GUI?

{'_schema': 'Invalid data type: None'}

That's all it says

Not seeing logs either

It runs fine in a notebook

We're using Prefect Core on a kubernetes cluster

Hello all, my company is happy with what I was able to do with Prefect and wants to move forth with deploying it, however, I was told that we would prefer for Prefect itself to be in a docker container when we do the deployment. I do see that their is a docker image on docker hub, however I cannot locate any docs on how to build the image. Can someone point me in the right direction?

Hi, probably dumb Q but from your docs on Task Concurrency -

This means that Prefect Cloud will ensure that no more than 10 tasks with the "database" tag will be running at any given time.

this also applies to mapped tasks, yes? So say I want to backfill some data off of a slow API endpoint, I don't want to bury the application with tons of concurrent requests but I also don't want to switch over to the LocalExecutor for the job. Could I set a concurrency limit of

2

for this API and will the mapped tasks behave as intended?

Quick q for the prefect devs: I'm curious why task concurrency limits are a cloud feature. This feels to me more like a core feature, since it is presumably something that has to be managed by agents, which are independent of cloud. https://docs.prefect.io/orchestration/concepts/task-concurrency-limiting.html

It looks like the latest

prefecthq/prefect:0.14.1

image doesn't contain the

dask-kubernetes

python module. Does anyone know if there's a different image to use or is it best to build my own image?

Hey, could someone point, how to get the number of threads and cores Dask worker has within Prefect task? I'm not spawning them from prefect but using the existing workers

Hello 😛refect: team— qq on versioning flows:

hi all, is there a reason that

CloudFlowRunner

and

CloudTaskRunner

are used when running a flow using a

LocalAgent

? I was expecting

FlowRunner

and

TaskRunner

to be used (the backend is also “server”)

Thought I'd mention this as it might be by design: the slack notification utilities used to work with prefect core alone, but after 0.11.5 they seem to require prefect cloud/server. I discovered this issue when trying to upgrade to 0.13.x in my quest to get my team's existing code to work with prefect server.

I am struggling a bit with a parameter. It is being passed into my task at run time still a parameter. When I try to pass it to something expecting a string it doesn’t evaluate to the value. What am I missing on how to use parameters as normal values at run time.

Hello, just arrived.

One of my flows, which usually works just fine, failed yesterday with this unusual error:

prefect.utilities.exceptions.ClientError: 400 Client Error: Bad Request for url: <https://api.prefect.io/graphql>

The following error messages were provided by the GraphQL server:

    INTERNAL_SERVER_ERROR: Variable "$input" got invalid value null at
        "input.states[0].task_run_id"; Expected non-nullable type UUID! not to be null.

The GraphQL query was:

    mutation($input: set_task_run_states_input!) {
            set_task_run_states(input: $input) {
                states {
                    id
                    message
                    status
            }
        }
    }

Runs (for different flows) after the failed run work again. This failed flow will run again at 4pm (in ~5h). Is this a known issue? Did I do something wrong?

Hello all, I have attempted to install prefect on a Ubuntu server via

pip3 install prefect

and when I run

prefect backend server

I get a

prefect: command not found

my python version is 3.6.8. What am I doing wrong?