<@ULVA73B9P> is it possible to use prefect client ...
# ask-marvin
r
@Marvin is it possible to use prefect client without async?
m
thought for 64.8 seconds
The signature confirms that
get_client()
takes an optional
sync_client
parameter which defaults to
False
. When set to
True
, it returns a
SyncPrefectClient
instead of the standard async
PrefectClient
. All client operations that would normally require
await
in the async version can be called directly with the sync client. The sync client handles all the necessary synchronous HTTP requests under the hood. Is there a specific operation you're trying to perform with the client? I can provide more targeted examples based on your needs.
r
@Marvin Hi. I have a python script with synchronous prefect client, this script it used to deploy and run 2 other flows present in some git repo sequentially only once(deploying second after completion of first). When i run this script using python, things execute in correct order and it works fine but when i run this script using prefect it keeps deploying the first flow multiple times and does not deploy second flow at all. I have mentioned retries=0, and there are online workers present in the work-pool assigned to this first flow but these deployments never get picked and stay in pending state only. If anyone has any idea about why is this happening please let me know (edited)
m
thought for 89.6 seconds
Based on the research and the issue you're describing, I think I understand what might be happening. Could you please share a simplified version of your orchestration script? However, I can already suggest a few potential causes and solutions: 1. When running a script that orchestrates deployments as a Prefect flow itself, you need to ensure you're properly waiting for flow run completion before proceeding. Here's a pattern that should work:
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python
from prefect import flow
from prefect import get_client

@flow
def orchestrate_deployments():
    client = get_client(sync_client=True)
    
    # Deploy and run first flow
    first_deployment = first_flow.from_source(
        source="<https://github.com/your/repo>",
        entrypoint="path/to/flow.py:flow_name"
    ).deploy(...)
    
    # Create and wait for first flow run
    first_run = client.create_flow_run(deployment=first_deployment.id)
    first_run_result = client.wait_for_flow_run(first_run.id, timeout=0)  # timeout=0 means wait indefinitely
    
    # Only proceed if the first flow succeeded
    if first_run_result.state.is_completed():
        # Deploy and run second flow
        second_deployment = second_flow.from_source(...)
        ...
2. The issue with multiple deployments of the first flow might be happening because: - The flow might be retriggering itself due to some configuration - There might be a loop in the logic that's not visible without seeing the code - The flow might be failing and retrying (even though you mentioned retries=0) 3. For the pending state issue: - Check if the work pool and worker are properly configured - Verify that the worker is actually running and polling for work - Check if there are any infrastructure or permission issues preventing the worker from picking up the runs Could you share: 1. A simplified version of your orchestration script? 2. How you're running this script as a Prefect flow? 3. The work pool type you're using? This would help me provide a more specific solution to your issue.
r
@Marvin this is the overview of my workflow File run.py -> deploy deployment-manager flow File deployment.py -> contains deployment-manager flow -> deployment-manager flow ⇒ Create deployment flow1 Run deployment flow1 Wait for completion of flow1 Create deployment flow2 Run deployment flow2 Wait for completion of flow2 Exit File code.py -> contains flow1 and flow2 flows
m
thought for 19.9 seconds
Could you share: 1. Are you seeing any specific error messages? 2. What work pool type are you using? 3. Are your flows completing successfully when run directly with Python? This will help me provide more targeted assistance.
r
@Marvin i run this file run.py to deploy deployment-manager flow which is supposed to run flow1 and then flow2 but it ends up just deploying many flow1 instances and does not run any of them and never deploys flow2 but when i run deployment.py file simply using python, it runs fine and deploys flow1 and flow2 correctly
m
thought for 18.0 seconds
I understand better now - there's a key difference in how you're running it that's causing this behavior. Let me clarify: When you run
deployment.py
directly with Python, it executes the synchronous code as expected. However, when you run it as a Prefect flow (through
run.py
), you're essentially creating a flow that creates deployments, which can lead to unexpected behavior. Let me help you modify your approach. Could you share: 1. How are you deploying the deployment-manager flow in
run.py
? Are you using something like:
Copy code
python
deployment_manager.from_source(...).deploy()
or some other method? 2. What work pool type are you using? (e.g., process, kubernetes, etc.) In the meantime, here's a suggested modification that should work more reliably:
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python
# deployment.py
from prefect import flow, get_client
from prefect.states import State

@flow(name="deployment-manager", retries=0)
def deployment_manager():
    # Use sync client
    client = get_client(sync_client=True)
    
    # Deploy flow1
    print("Deploying flow1...")
    flow1_deployment = flow1.from_source(
        source="<https://github.com/your/repo>",
        entrypoint="code.py:flow1"
    ).deploy(
        name="flow1-deployment",
        work_pool_name="your-work-pool",
        skip_upload=True  # Add this to prevent multiple uploads
    )
    
    print(f"Created deployment: {flow1_deployment.id}")
    
    # Run flow1 and wait
    print("Starting flow1...")
    flow1_run = client.create_flow_run(
        deployment=flow1_deployment.id,
        state=State(name="SCHEDULED")  # Explicitly set initial state
    )
    
    print(f"Waiting for flow1 run {flow1_run.id}...")
    flow1_result = client.wait_for_flow_run(
        flow1_run.id,
        timeout=0,  # wait indefinitely
        return_on_states=[State.COMPLETED, State.FAILED, State.CRASHED]
    )
    
    print(f"Flow1 finished with state: {flow1_result.state.name}")
    
    if not flow1_result.state.is_completed():
        raise Exception(f"Flow1 failed with state: {flow1_result.state.name}")
    
    # Similar pattern for flow2
    print("Deploying flow2...")
    # ... rest of the code
And for
run.py
, instead of deploying the deployment-manager flow, you might want to run it directly:
Copy code
python
# run.py
from deployment import deployment_manager

if __name__ == "__main__":
    deployment_manager()
If you really need to deploy the deployment-manager as a flow itself, you'll need to handle it differently. Could you share your current
run.py
code and I can help modify it specifically? Some additional suggestions: 1. Add logging statements (as shown above) to track exactly where the process is getting stuck 2. You might want to check if there are any existing deployments before creating new ones:
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python
existing_deployments = client.read_deployments(
    name="flow1-deployment"
)
if existing_deployments:
    # Either use existing deployment or delete it first
    pass
3. Make sure your workers are running and able to pick up the work:
Copy code
python
# You can check work pool status
work_pools = client.read_work_pools()
workers = client.read_workers()
Could you share: 1. Your current
run.py
code 2. The work pool type you're using 3. Whether you see any error messages in the logs 4. Whether the workers are running and healthy This will help me provide a more specific solution to your issue.
r
@Marvin this is my run.py
Copy code
import os
import sys
from prefect.client.schemas.schedules import CronSchedule

os.environ['PREFECT_API_URL'] = "{api}"

def create_deployment():
    from deployment import main
    
    deployment_id = main.from_source(
        source="{git_link}",
        entrypoint="deployment.py:main"
    ).deploy(
        name="deployment-manager",
        work_pool_name="default-agent-pool",
        schedule=CronSchedule(cron="18 11 * * *"),
        tags=["deployment", "manager", "scheduled"],
        ignore_warnings=True
    )

if __name__ == "__main__":
    create_deployment()
m
thought for 52.1 seconds
You can create a process work pool with:
Copy code
bash
prefect work-pool create "process-pool" --type process
Then update your deployment code to use this work pool instead of the agent pool. Would you like me to explain any part of these changes in more detail? Also, could you confirm: 1. Are you seeing any specific error messages in your logs? 2. Are you able to see the flow runs in the UI when they're created? 3. Is your worker/agent running and healthy?
r
@Marvin 070759.420 | INFO | prefect.flow_runs.worker - Worker 'ProcessWorker 833802f3-2954-4480-9afa-0b04528daa22' submitting flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' 070802.522 | INFO | prefect.flow_runs.runner - Opening process... 070803.043 | INFO | prefect.flow_runs.worker - Completed submission of flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' 070806.709 | INFO | Flow run 'naughty-oyster' - > Running access_token step... 070806.715 | ERROR | Flow run 'naughty-oyster' - Step has unexpected additional keys: repo, branch, access_token 070806.716 | ERROR | Flow run 'naughty-oyster' - Unexpected exception encountered when trying to load flow Traceback (most recent call last): File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 163, in run_steps step_output = await run_step(step, upstream_outputs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 119, in run_step raise ValueError( ValueError: Step has unexpected additional keys: repo, branch, access_token The above exception was the direct cause of the following exception: Traceback (most recent call last): File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/engine.py", line 112, in <module> flow: "Flow[..., Any]" = load_flow(flow_run) ^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flow_engine.py", line 140, in load_flow flow = run_coro_as_sync( ^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/utilities/asyncutils.py", line 207, in run_coro_as_sync return call.result() ^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 365, in result return self.future.result(timeout=timeout) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 192, in result return self.__get_result() ^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/concurrent/futures/_base.py", line 401, in __get_result raise self._exception File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 441, in _run_async result = await coro ^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/utilities/asyncutils.py", line 188, in coroutine_wrapper return await task ^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/client/utilities.py", line 69, in wrapper return await func(client, *args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flows.py", line 2657, in load_flow_from_flow_run output = await run_steps( ^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 191, in run_steps raise StepExecutionError(f"Encountered error while running {fqn}") from exc prefect.deployments.steps.core.StepExecutionError: Encountered error while running access_token 070806.722 | ERROR | prefect.engine - Execution of flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' exited with unexpected exception Traceback (most recent call last): File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 163, in run_steps step_output = await run_step(step, upstream_outputs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 119, in run_step raise ValueError( ValueError: Step has unexpected additional keys: repo, branch, access_token The above exception was the direct cause of the following exception: Traceback (most recent call last): File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/engine.py", line 57, in handle_engine_signals yield File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/engine.py", line 112, in <module> flow: "Flow[..., Any]" = load_flow(flow_run) ^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flow_engine.py", line 140, in load_flow flow = run_coro_as_sync( ^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/utilities/asyncutils.py", line 207, in run_coro_as_sync return call.result() ^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 365, in result return self.future.result(timeout=timeout) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 192, in result return self.__get_result() ^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/concurrent/futures/_base.py", line 401, in __get_result raise self._exception File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 441, in _run_async result = await coro ^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/utilities/asyncutils.py", line 188, in coroutine_wrapper return await task ^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/client/utilities.py", line 69, in wrapper return await func(client, *args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flows.py", line 2657, in load_flow_from_flow_run output = await run_steps( ^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 191, in run_steps raise StepExecutionError(f"Encountered error while running {fqn}") from exc prefect.deployments.steps.core.StepExecutionError: Encountered error while running access_token 070808.180 | ERROR | prefect.flow_runs.runner - Process for flow run 'naughty-oyster' exited with status code: 1 070809.019 | INFO | prefect.flow_runs.worker - Reported flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' as crashed: Flow run infrastructure exited with non-zero status code 1. 070809.721 | INFO | prefect.flow_runs.runner - Loading flow to check for on_crashed hooks 070810.453 | INFO | Flow run 'naughty-oyster' - > Running access_token step... 070810.455 | ERROR | Flow run 'naughty-oyster' - Step has unexpected additional keys: repo, branch, access_token + Exception Group Traceback (most recent call last): | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/cli/_utilities.py", line 44, in wrapper | return fn(*args, **kwargs) | ^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/cli/_types.py", line 156, in sync_fn | return asyncio.run(async_fn(*args, **kwargs)) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/asyncio/runners.py", line 190, in run | return runner.run(main) | ^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/asyncio/runners.py", line 118, in run | return self._loop.run_until_complete(task) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/asyncio/base_events.py", line 653, in run_until_complete | return future.result() | ^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/cli/worker.py", line 169, in start | await worker.start( | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/workers/process.py", line 154, in start | async with self as worker: | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/workers/process.py", line 299, in aexit | await super().__aexit__(*exc_info) | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/workers/base.py", line 1580, in aexit | raise exceptions[0] from None | File "/data/anaconda3/envs/renv2/lib/python3.11/contextlib.py", line 716, in aexit | cb_suppress = await cb(*exc_details) | ^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/runner/runner.py", line 1535, in aexit | await self._exit_stack.__aexit__(*exc_info) | File "/data/anaconda3/envs/renv2/lib/python3.11/contextlib.py", line 733, in aexit | raise exc_details[1] | File "/data/anaconda3/envs/renv2/lib/python3.11/contextlib.py", line 716, in aexit | cb_suppress = await cb(*exc_details) | ^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/anyio/_backends/_asyncio.py", line 763, in aexit | raise BaseExceptionGroup( | ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception) +-+---------------- 1 ---------------- | Traceback (most recent call last): | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 163, in run_steps | step_output = await run_step(step, upstream_outputs) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 119, in run_step | raise ValueError( | ValueError: Step has unexpected additional keys: repo, branch, access_token | | The above exception was the direct cause of the following exception: | | Traceback (most recent call last): | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/runner/runner.py", line 1336, in _submit_run_and_capture_errors | await self._run_on_crashed_hooks(flow_run=flow_run, state=terminal_state) | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/runner/runner.py", line 1476, in _run_on_crashed_hooks | flow = await load_flow_from_flow_run( | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/client/utilities.py", line 69, in wrapper | return await func(client, *args, **kwargs) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flows.py", line 2657, in load_flow_from_flow_run | output = await run_steps( | ^^^^^^^^^^^^^^^^ | File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 191, in run_steps | raise StepExecutionError(f"Encountered error while running {fqn}") from exc | prefect.deployments.steps.core.StepExecutionError: Encountered error while running access_token +------------------------------------ An exception occurred. what is this issue
m
Your message was too long, here's your message at the allowed limit: 07 07 59 420 | INFO | prefect flow_runs worker - Worker 'ProcessWorker 833802f3-2954-4480-9afa-0b04528daa22' submitting flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' 07 08 02 522 | INFO | prefect flow_runs runner - Opening process 07 08 03 043 | INFO | prefect flow_runs worker - Completed submission of flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' 07 08 06 709 | INFO | Flow run 'naughty-oyster' - > Running access_token step 07 08 06 715 | ERROR | Flow run 'naughty-oyster' - Step has unexpected additional keys repo branch access_token 07 08 06 716 | ERROR | Flow run 'naughty-oyster' - Unexpected exception encountered when trying to load flow Traceback (most recent call last) File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/deployments/steps/core py line 163 in run_steps step_output = await run_step(step upstream_outputs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/deployments/steps/core py line 119 in run_step raise ValueError( ValueError Step has unexpected additional keys repo branch access_token The above exception was the direct cause of the following exception Traceback (most recent call last) File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/engine py line 112 in <module> flow Flow[ Any] = load_flow(flow_run) ^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/flow_engine py line 140 in load_flow flow = run_coro_as_sync( ^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/utilities/asyncutils py line 207 in run_coro_as_sync return call result() ^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/_internal/concurrency/calls py line 365 in result return self future result(timeout=timeout) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/_internal/concurrency/calls py line 192 in result return self __get_result() ^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/concurrent/futures/_base py line 401 in __get_result raise self _exception File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/_internal/concurrency/calls py line 441 in _run_async result = await coro ^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/utilities/asyncutils py line 188 in coroutine_wrapper return await task ^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/client/utilities py line 69 in wrapper return await func(client *args **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/flows py line 2657 in load_flow_from_flow_run output = await run_steps( ^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/deployments/steps/core py line 191 in run_steps raise StepExecutionError(f Encountered error while running {fqn} ) from exc prefect deployments steps core StepExecutionError Encountered error while running access_token 07 08 06 722 | ERROR | prefect engine - Execution of flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' exited with unexpected exception Traceback (most recent call last) File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/deployments/steps/core py line 163 in run_steps step_output = await run_step(step upstream_outputs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/deployments/steps/core py line 119 in run_step raise ValueError( ValueError Step has unexpected additional keys repo branch access_token The above exception was the direct cause of the following exception Traceback (most recent call last) File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/engine py line 57 in handle_engine_signals yield File /data/anaconda3/envs/renv
2/lib/python3 11/site-packages/prefect/engine py line 112 in <module> flow Flow[ Any] = load_flow(flow_run) ^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/flow_engine py line 140 in load_flow flow = run_coro_as_sync( ^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/utilities/asyncutils py line 207 in run_coro_as_sync return call result() ^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/_internal/concurrency/calls py line 365 in result return self future result(timeout=timeout) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/_internal/concurrency/calls py line 192 in result return self __get_result() ^^^^^^^^^^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/concurrent/futures/_base py line 401 in __get_result raise self _exception File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/_internal/concurrency/calls py line 441 in _run_async result = await coro ^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/utilities/asyncutils py line 188 in coroutine_wrapper return await task ^^^^^^^^^^ File /data/anaconda3/envs/renv2/lib/python3 11/site-packages/prefect/client/utilities py line 69 in wrapper return await
r
@Marvin 070759.420 | INFO | prefect.flow_runs.worker - Worker 'ProcessWorker 833802f3-2954-4480-9afa-0b04528daa22' submitting flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' 070802.522 | INFO | prefect.flow_runs.runner - Opening process... 070803.043 | INFO | prefect.flow_runs.worker - Completed submission of flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' 070806.709 | INFO | Flow run 'naughty-oyster' - > Running access_token step... 070806.715 | ERROR | Flow run 'naughty-oyster' - Step has unexpected additional keys: repo, branch, access_token 070806.716 | ERROR | Flow run 'naughty-oyster' - Unexpected exception encountered when trying to load flow Traceback (most recent call last): File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 163, in run_steps step_output = await run_step(step, upstream_outputs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 119, in run_step raise ValueError( ValueError: Step has unexpected additional keys: repo, branch, access_token The above exception was the direct cause of the following exception: Traceback (most recent call last): File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/engine.py", line 112, in <module> flow: "Flow[..., Any]" = load_flow(flow_run) ^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flow_engine.py", line 140, in load_flow flow = run_coro_as_sync( ^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/utilities/asyncutils.py", line 207, in run_coro_as_sync return call.result() ^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 365, in result return self.future.result(timeout=timeout) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 192, in result return self.__get_result() ^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/concurrent/futures/_base.py", line 401, in __get_result raise self._exception File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/_internal/concurrency/calls.py", line 441, in _run_async result = await coro ^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/utilities/asyncutils.py", line 188, in coroutine_wrapper return await task ^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/client/utilities.py", line 69, in wrapper return await func(client, *args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/flows.py", line 2657, in load_flow_from_flow_run output = await run_steps( ^^^^^^^^^^^^^^^^ File "/data/anaconda3/envs/renv2/lib/python3.11/site-packages/prefect/deployments/steps/core.py", line 191, in run_steps raise StepExecutionError(f"Encountered error while running {fqn}") from exc prefect.deployments.steps.core.StepExecutionError: Encountered error while running access_token 070806.722 | ERROR | prefect.engine - Execution of flow run 'f6034b2c-7f67-4df9-9d14-c1360a0b2d90' exited with unexpected exception what is this issue
m
thought for 31.2 seconds
I apologize for the confusion. The GitHub block has been moved to a separate package. Here's the updated correct way to handle this: 1. First, install the GitHub integration:
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pip install prefect-github
2. Then modify your code:
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python
from prefect_github import GitHubRepository
from prefect.client.schemas.schedules import CronSchedule

# For private repositories, create a GitHub block
github_credentials = GitHubRepository.create(
    name="my-github",
    repository="<https://github.com/your-org/your-repo>",
    reference="main",  # or your branch name
    access_token="your-token"  # if it's a private repository
)
github_credentials.save("my-github")

def create_deployment():
    from deployment import main
    
    # For public repository:
    deployment_id = main.from_source(
        source="<https://github.com/your-org/your-repo>",
        entrypoint="deployment.py:main"
    ).deploy(
        name="deployment-manager",
        work_pool_name="default-agent-pool",
        schedule=CronSchedule(cron="18 11 * * *"),
        tags=["deployment", "manager", "scheduled"],
        ignore_warnings=True
    )

    # OR for private repository using the block:
    deployment_id = main.from_source(
        source="github/my-github",  # Reference the saved block
        entrypoint="deployment.py:main"
    ).deploy(
        name="deployment-manager",
        work_pool_name="default-agent-pool",
        schedule=CronSchedule(cron="18 11 * * *"),
        tags=["deployment", "manager", "scheduled"],
        ignore_warnings=True
    )
The error you're seeing is because the deployment is trying to use old-style configuration parameters that are no longer supported in Prefect 3.x. By using one of the methods above, you should resolve the "unexpected additional keys" error. Would you like me to explain any part of this in more detail? Also, could you share which type of repository you're using (public or private) so I can provide more specific guidance?
r
how do i do this using yaml, give syntax @Marvin
m
thought for 28.1 seconds
Here's the YAML syntax for your deployment. Create a file named `deployment.yaml`:
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yaml
# deployment.yaml
deployments:
  - name: "deployment-manager"
    entrypoint: "deployment.py:main"  # your flow function
    schedule:
      cron: "18 11 * * *"
    tags:
      - "deployment"
      - "manager"
      - "scheduled"
    work_pool_name: "default-agent-pool"

    # For public repository:
    source:
      type: "github"
      repository: "<https://github.com/your-org/your-repo>"
      reference: "main"  # or your branch name

    # OR for private repository:
    # source:
    #   type: "github"
    #   repository: "<https://github.com/your-org/your-repo>"
    #   reference: "main"  # or your branch name
    #   access_token: "{{ GITHUB_ACCESS_TOKEN }}"  # Use environment variable
To use this YAML file, you have several options: 1. For public repositories, deploy using:
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prefect deploy --file deployment.yaml
2. For private repositories, first set up your GitHub credentials:
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# Set your GitHub token as an environment variable
export GITHUB_ACCESS_TOKEN="your-token"

# Then deploy
prefect deploy --file deployment.yaml
3. Alternative for private repos using GitHub block: First, create a GitHub block:
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python
# In a Python script or notebook
from prefect_github import GitHubRepository

github_block = GitHubRepository.create(
    name="my-github",
    repository="<https://github.com/your-org/your-repo>",
    reference="main",
    access_token="your-token"
)
github_block.save("my-github")
Then modify your YAML to use the block:
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yaml
# deployment.yaml
deployments:
  - name: "deployment-manager"
    entrypoint: "deployment.py:main"
    schedule:
      cron: "18 11 * * *"
    tags:
      - "deployment"
      - "manager"
      - "scheduled"
    work_pool_name: "default-agent-pool"
    source:
      type: "github"
      block: "github/my-github"  # Reference the saved block
Some important notes: 1. Make sure your YAML file is in the correct directory structure 2. The
entrypoint
should point to your flow function 3. The
work_pool_name
should match your existing work pool 4. For private repositories, never commit the access token directly in the YAML file You can also include additional configuration in the YAML:
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yaml
deployments:
  - name: "deployment-manager"
    entrypoint: "deployment.py:main"
    schedule:
      cron: "18 11 * * *"
    tags:
      - "deployment"
      - "manager"
      - "scheduled"
    work_pool_name: "default-agent-pool"
    source:
      type: "github"
      repository: "<https://github.com/your-org/your-repo>"
      reference: "main"
    is_schedule_active: true  # Enable/disable schedule
    parameters: {}  # Add any flow parameters here
    enforce_parameter_schema: true
    version: null  # Optional version tag
    description: "Deployment manager flow"  # Optional description
    path: null  # Optional path within the repository
    pull_steps:  # Optional pull steps configuration
      - prefect.deployments.steps.git_clone
To deploy using this YAML: 1. Save the YAML file in your project directory 2. Run the deployment command:
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prefect deploy --file deployment.yaml
3. Verify the deployment:
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prefect deployment ls
Would you like me to explain any part of the YAML configuration in more detail? Also, are you working with a public or private repository? This would help me provide more specific guidance.
r
@Marvin is there any way to create deployments within a flow run without having unexpected behaviour
m
thought for 64.6 seconds
Based on the research, here's the recommended way to create and manage deployments within a flow run:
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python
from prefect import flow
from prefect.client import get_client
from prefect.deployments import run_deployment
from prefect.flows import load_flow_from_source

@flow(name="deployment_creator")
def create_and_run_deployments():
    client = get_client(sync_client=True)
    
    # 1. Create first flow deployment
    flow1_deployment = flow1.from_source(
        source="<https://github.com/your-org/your-repo>",
        entrypoint="flows.py:flow1"
    ).deploy(
        name="flow1-deployment",
        work_pool_name="your-work-pool",
        tags=["flow1"]
    )
    
    # 2. Run the deployment and wait for completion
    flow1_run = run_deployment(
        name="flow1-deployment",
        timeout=0,  # wait indefinitely
        as_subflow=False  # Run as independent flow, not as subflow
    )
    
    # 3. Only proceed if flow1 succeeded
    if not flow1_run.state.is_completed():
        raise Exception(f"Flow1 failed with state: {flow1_run.state.name}")
    
    # 4. Create and run second flow deployment
    flow2_deployment = flow2.from_source(
        source="<https://github.com/your-org/your-repo>",
        entrypoint="flows.py:flow2"
    ).deploy(
        name="flow2-deployment",
        work_pool_name="your-work-pool",
        tags=["flow2"]
    )
    
    flow2_run = run_deployment(
        name="flow2-deployment",
        timeout=0,
        as_subflow=False
    )
    
    return "All deployments completed"

# For scheduled execution of the deployment creator
@flow(name="scheduled_deployment_manager")
def scheduled_deployment_manager():
    return create_and_run_deployments()
Key points to prevent unexpected behavior: 1. Use
as_subflow=False
: This ensures the deployments run independently and don't inherit the parent flow's context. 2. Wait for Completion: The
run_deployment
function handles waiting for completion automatically. 3. Error Handling: Check the state of each flow run before proceeding. 4. Synchronous Client: Use the sync client for better control flow. If you need to schedule this deployment creator:
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python
# deployment.yaml
deployments:
  - name: "deployment-manager"
    entrypoint: "your_file.py:scheduled_deployment_manager"
    schedule:
      cron: "0 0 * * *"  # Example schedule
    work_pool_name: "your-work-pool"
    source:
      type: "github"
      repository: "<https://github.com/your-org/your-repo>"
      reference: "main"
Or programmatically:
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python
scheduled_deployment_manager.from_source(
    source="<https://github.com/your-org/your-repo>",
    entrypoint="your_file.py:scheduled_deployment_manager"
).deploy(
    name="deployment-manager",
    work_pool_name="your-work-pool",
    schedule=(CronSchedule(cron="0 0 * * *")),
)
To verify the behavior, you can: 1. Monitor the flow runs in the UI 2. Check the logs for each deployment 3. Use the client to query deployment states:
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python
client = get_client(sync_client=True)
deployments = client.read_deployments()
for deployment in deployments:
    print(f"Deployment {deployment.name}: {deployment.status}")
Would you like me to explain any part of this in more detail? Or do you have a specific use case that needs additional customization?
r
@Marvin what is default value of this as_subflow
m
thought for 19.5 seconds
As we can see from the signature,
as_subflow
defaults to
True
. This is important because it means that by default, when you run a deployment from within a flow, it will run as a subflow of the parent flow. This default behavior (
as_subflow=True
) means: 1. The deployment will run as a child of the current flow 2. The parent flow will wait for the subflow to complete 3. The subflow's state will affect the parent flow's state 4. The runs will be linked in the UI as parent/child If you're experiencing unexpected behavior with deployments running multiple times or not in the expected order, setting
as_subflow=False
might help because: 1. The deployment will run independently 2. It won't inherit context from the parent flow 3. It will be treated as a separate flow run Here's an example showing the difference:
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python
from prefect import flow
from prefect.deployments import run_deployment

@flow
def orchestrator_flow():
    # This will run as a subflow (default behavior)
    run1 = run_deployment(
        name="flow1-deployment"  # as_subflow defaults to True
    )
    
    # This will run as an independent flow
    run2 = run_deployment(
        name="flow2-deployment",
        as_subflow=False
    )
If you're creating deployments that need to run independently of your orchestrator flow, you should explicitly set
as_subflow=False
. This is particularly important when: 1. You want the deployments to run independently 2. You're experiencing issues with recursive deployments 3. You need separate logging or monitoring for each flow 4. You want to avoid parent/child flow relationships Would you like me to provide more examples or explain any specific scenario you're dealing with?
r
@Marvin i am using this method
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flow_from_source = self.flows[index].from_source(
                source=source_dir,
                entrypoint=self.entrypoints[index]
            )
            
            # Create deployment
            deployment = flow_from_source.to_deployment(
                name=deployment_name,
                work_pool_name=work_pool_name,
                job_variables=self.job_variables[index]
            )
how do i define as_subflow parameter here
m
thought for 14.4 seconds
When using
from_source
and
to_deployment
, the
as_subflow
parameter isn't set at this stage - it's a parameter used when actually running the deployment. If you want to control the
as_subflow
behavior, you'll need to handle it when you run the deployment. Here's how you can modify your code to include this control:
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# First create the deployment as you're doing
flow_from_source = self.flows[index].from_source(
    source=source_dir,
    entrypoint=self.entrypoints[index]
)

# Create deployment
deployment = flow_from_source.to_deployment(
    name=deployment_name,
    work_pool_name=work_pool_name,
    job_variables=self.job_variables[index]
)

# Deploy it
deployment_id = deployment.apply()

# Then when you want to run it, you can control as_subflow
from prefect.deployments import run_deployment

# Run the deployment with as_subflow=False
flow_run = run_deployment(
    name=deployment_name,  # or f"{deployment.flow_name}/{deployment_name}"
    as_subflow=False,     # This will run it independently
    timeout=0             # Optional: wait indefinitely for completion
)
If you're running multiple deployments sequentially, you might want to structure it like this:
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python
from prefect import flow
from prefect.deployments import run_deployment

@flow
def create_and_run_deployments():
    deployments = []
    
    # Create all deployments first
    for index in range(len(self.flows)):
        flow_from_source = self.flows[index].from_source(
            source=source_dir,
            entrypoint=self.entrypoints[index]
        )
        
        deployment = flow_from_source.to_deployment(
            name=f"deployment-{index}",
            work_pool_name=work_pool_name,
            job_variables=self.job_variables[index]
        )
        
        deployment_id = deployment.apply()
        deployments.append(deployment)
    
    # Then run them sequentially
    for deployment in deployments:
        flow_run = run_deployment(
            name=deployment.name,
            as_subflow=False,  # Run independently
            timeout=0          # Wait for completion
        )
        
        # Optional: Check if the run completed successfully
        if not flow_run.state.is_completed():
            raise Exception(f"Deployment {deployment.name} failed with state: {flow_run.state.name}")
Key points: 1.
to_deployment()
creates the deployment configuration 2.
apply()
registers the deployment with Prefect 3.
run_deployment()
is where you control the
as_subflow
behavior If you're experiencing issues with deployments running multiple times or not in the expected order, setting
as_subflow=False
when running the deployment should help resolve those issues. Would you like me to explain any part of this in more detail or help with a specific scenario you're dealing with?
r
@Marvin i am using client to run deployments client = get_client(sync_client=True) flow_run = client.create_flow_run_from_deployment(deployment_id) flow_run_id = str(flow_run.id)
m
thought for 68.2 seconds
I apologize for the error in checking the signature. However, the code examples provided above should work with the current Prefect client. The key points are: 1. Setting
parent_task_run_id=None
ensures the flow runs independently 2. Using
wait_for_flow_run
helps ensure proper sequencing 3. Checking the final state helps with error handling Would you like me to explain any part of this in more detail or help with a specific scenario you're dealing with?
r
@Marvin what are subflows, and does creating subflows within a flow run cause issues?
m
thought for 81.3 seconds
Let me break this down: ### What are Subflows? Subflows are flows that are called from within another flow. They: 1. Run in the same process as the parent flow 2. Share the same execution context 3. Are visible as child flows in the UI 4. Can access data from the parent flow Example of a subflow:
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python
from prefect import flow

@flow
def subflow(x):
    return x * 2

@flow
def parent_flow():
    # This creates a subflow
    result = subflow(5)
    return result
### Benefits of Subflows: 1. Code Organization: Break down complex workflows 2. Reusability: Use the same flow in different parent flows 3. Visibility: Clear parent-child relationship in the UI 4. Data Sharing: Easy data passing between flows ### Potential Issues with Subflows: 1. Resource Constraints:
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python
@flow
def resource_intensive_subflow():
    # Uses same resources as parent
    large_computation()

@flow
def parent_flow():
    # These run in the same process
    for _ in range(10):
        resource_intensive_subflow()  # Might cause memory/CPU issues
2. Error Propagation:
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python
@flow
def subflow():
    raise Exception("Subflow error")

@flow
def parent_flow():
    try:
        subflow()  # Parent flow will fail if subflow fails
    except Exception as e:
        # Need explicit handling
        pass
3. Complexity with Deep Nesting:
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python
@flow
def deep_subflow():
    return "deep"

@flow
def middle_subflow():
    return deep_subflow()

@flow
def parent_flow():
    return middle_subflow()  # Can become hard to debug
### Best Practices: 1. Use Independent Flows when you need:
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python
from prefect.deployments import run_deployment

@flow
def orchestrator_flow():
    # Run as independent flow, not subflow
    run_deployment(
        name="other-flow/deployment",
        as_subflow=False
    )
2. Use Subflows when you need:
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python
@flow
def data_processing_subflow(data):
    return process(data)

@flow
def main_flow():
    data = load_data()
    # Use subflow for logical grouping
    processed = data_processing_subflow(data)
3. Handle Resources Carefully:
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python
@flow
def parent_flow():
    # Run subflows in parallel with care
    from prefect.tasks import task_input_hash
    
    results = []
    for item in items:
        result = subflow.submit(item)  # Careful with memory
        results.append(result)
### When to Use What: Use Subflows When: - You need tight coupling between flows - You want to share memory/context - The flows are part of the same logical process - You need simple data passing between flows Use Independent Flows When: - You need isolation - Flows should run in separate processes - You want independent scaling - You need different resource allocations - You're orchestrating separate deployments ### Example of Safe Subflow Usage:
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python
from prefect import flow, task
from typing import List

@task
def check_resources():
    # Verify available memory/CPU
    pass

@flow
def safe_subflow(data: List):
    check_resources()
    return process_chunk(data)

@flow
def parent_flow(all_data: List):
    # Break into manageable chunks
    chunks = split_data(all_data)
    
    results = []
    for chunk in chunks:
        # Process in controlled manner
        result = safe_subflow(chunk)
        results.append(result)
    
    return combine_results(results)
Would you like me to elaborate on any of these aspects or provide more specific examples for your use case?
r
@Marvin can i assign a different work-pool to a subflow
m
thought for 57.7 seconds
Based on the research, if you want to run a flow in a different work pool than its parent, you shouldn't use it as a subflow. Instead, you should create a separate deployment for that flow and run it independently. Here's how:
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python
from prefect import flow
from prefect.deployments import run_deployment

# Instead of this (subflow that can't use different work pool):
@flow
def subflow():
    return "result"

@flow
def parent_flow():
    result = subflow()  # Will run in same work pool as parent

# Do this instead (independent flows that can use different work pools):
@flow
def flow_to_run_separately():
    return "result"

@flow
def orchestrator_flow():
    # This will run in a different work pool
    result = run_deployment(
        name="flow-to-run-separately/deployment-name",
        as_subflow=False,  # Important: run as independent flow
        work_queue_name="different-work-queue"  # Optional: specify work queue
    )

# Deploy the flows to different work pools
flow_to_run_separately.from_source(
    source="your_source",
    entrypoint="flows.py:flow_to_run_separately"
).deploy(
    name="deployment-name",
    work_pool_name="different-work-pool"  # This flow uses a different work pool
)

orchestrator_flow.from_source(
    source="your_source",
    entrypoint="flows.py:orchestrator_flow"
).deploy(
    name="orchestrator-deployment",
    work_pool_name="main-work-pool"  # This flow uses the main work pool
)
If you're using the client directly:
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python
from prefect import flow
from prefect import get_client

@flow
def orchestrator_flow():
    client = get_client(sync_client=True)
    
    # Create flow run in different work pool
    flow_run = client.create_flow_run_from_deployment(
        deployment_id="deployment-id",
        parent_task_run_id=None,  # Run independently
    )
    
    # Wait for completion if needed
    final_state = client.wait_for_flow_run(
        flow_run_id=str(flow_run.id),
        timeout=0
    )
Key points: 1. Subflows always run in the same work pool as their parent flow 2. To use a different work pool, you need to: - Create a separate deployment for the flow - Run it independently (not as a subflow) - Use
run_deployment
with
as_subflow=False
or use the client 3. This gives you more flexibility but requires proper deployment management Would you like me to provide more specific examples or explain any part of this in more detail?
r
@Marvin does creating new independent deployments within a flow cause unexpected behaviour
m
thought for 46.7 seconds
Yes, creating new deployments within a flow can cause unexpected behavior, particularly: 1. Recursive Deployment Issues: If not carefully managed, flows can create deployments that trigger themselves 2. Resource Consumption: Multiple deployments created in a loop can overwhelm the system 3. Scheduling Conflicts: New deployments might interfere with existing schedules Here are the safer approaches to handle this: ### 1. Create Deployments Outside Flows (Recommended)
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python
# deployment_setup.py
def setup_deployments():
    # Create all deployments here, outside of any flow
    flow1.from_source(
        source="your_repo",
        entrypoint="flows.py:flow1"
    ).deploy(
        name="flow1-deployment",
        work_pool_name="your-pool"
    )
    
    flow2.from_source(
        source="your_repo",
        entrypoint="flows.py:flow2"
    ).deploy(
        name="flow2-deployment",
        work_pool_name="your-pool"
    )

if __name__ == "__main__":
    setup_deployments()
### 2. If You Must Create Deployments Within a Flow:
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python
from prefect import flow
from prefect import get_client

@flow
def deployment_manager():
    client = get_client(sync_client=True)
    
    # Check if deployment already exists
    existing_deployments = client.read_deployments(
        name="flow1-deployment"
    )
    
    if not existing_deployments:
        # Only create if it doesn't exist
        new_deployment = flow1.from_source(
            source="your_repo",
            entrypoint="flows.py:flow1"
        ).deploy(
            name="flow1-deployment",
            work_pool_name="your-pool",
            schedule=None  # Important: avoid automatic scheduling
        )
    
    # Run the deployment
    flow_run = client.create_flow_run_from_deployment(
        deployment=existing_deployments[0].id if existing_deployments else new_deployment.id
    )
### 3. Use Event-Based Triggers Instead:
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python
from prefect.deployments import DeploymentEventTrigger

# Create deployments with event triggers
flow2.from_source(
    source="your_repo",
    entrypoint="flows.py:flow2"
).deploy(
    name="flow2-deployment",
    work_pool_name="your-pool",
    triggers=[
        DeploymentEventTrigger(
            deployment_name="flow1-deployment",
            event_type="completed"
        )
    ]
)
### Best Practices to Avoid Issues: 1. Separate Creation from Execution:
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python
# Create deployments in a separate script
# run.py
def setup():
    create_all_deployments()

def run_orchestration():
    run_existing_deployments()

if __name__ == "__main__":
    setup()  # Run once
    run_orchestration()  # Run as needed
2. Use Idempotent Creation:
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python
@flow
def safe_deployment_manager():
    client = get_client(sync_client=True)
    
    def get_or_create_deployment(name, flow_obj, **kwargs):
        existing = client.read_deployments(name=name)
        if existing:
            return existing[0]
        
        return flow_obj.from_source(...).deploy(
            name=name,
            **kwargs
        )
3. Control Flow Run Creation:
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python
@flow
def orchestrate_flows():
    client = get_client(sync_client=True)
    
    # Create flow runs with explicit control
    flow_run = client.create_flow_run_from_deployment(
        deployment_id=deployment_id,
        state=None,  # Don't auto-schedule
        parent_task_run_id=None  # Run independently
    )
    
    # Wait for completion before proceeding
    final_state = client.wait_for_flow_run(
        flow_run_id=str(flow_run.id),
        timeout=0
    )
4. Use Version Control:
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python
@flow
def versioned_deployment_manager():
    deployment = flow1.from_source(
        source="your_repo",
        entrypoint="flows.py:flow1"
    ).deploy(
        name=f"flow1-deployment-{version}",  # Version your deployments
        work_pool_name="your-pool",
        version=version  # Track versions
    )
Key Recommendations:
1. Create deployments outside of flows when possible 2. If creating within flows, implement proper checks and controls 3. Use event triggers for flow dependencies instead of creating deployments dynamically 4. Always check for existing deployments before creating new ones 5. Avoid automatic scheduling in dynamically created deployments 6. Use proper versioning and naming conventions Would you like me to elaborate on any of these approaches or provide more specific examples for your use case?
r
@Marvin can i limit the run count of a flow
m
thought for 101.0 seconds
Here are several ways to limit flow runs: 1. Using a Counter in the Flow:
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python
from prefect import flow
from prefect import get_client
from prefect.artifacts import create_markdown_artifact

@flow
def limited_flow():
    client = get_client(sync_client=True)
    
    # Get count of previous runs
    flow_runs = client.read_flow_runs(
        flow_name="limited_flow",
        sort="-start_time"
    )
    
    max_runs = 5  # Set your desired limit
    current_runs = len(flow_runs)
    
    if current_runs >= max_runs:
        message = f"Flow has reached maximum runs ({max_runs})"
        create_markdown_artifact(
            key="max_runs_reached",
            markdown=message,
            description="Maximum run limit reached"
        )
        raise Exception(message)
    
    # Your flow logic here
    return "Flow executed successfully"
2. Using Global Concurrency Limits:
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python
from prefect import flow
from prefect.client.schemas.objects import ConcurrencyLimit

@flow
def flow_with_concurrency():
    client = get_client(sync_client=True)
    
    # Create or update concurrency limit
    client.create_concurrency_limit(
        tag="my-flow-limit",
        concurrency_limit=5
    )
    
    # Your flow logic here
3. Using Work Queue Limits:
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python
from prefect import flow

@flow
def flow_with_queue_limit():
    client = get_client(sync_client=True)
    
    # Set work queue concurrency limit
    client.update_work_queue(
        name="your-work-queue",
        concurrency_limit=5
    )
4. Using a Persistent Counter:
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python
from prefect import flow
from prefect.blocks.system import JSON

@flow
def flow_with_persistent_counter():
    try:
        counter_block = JSON.load("run-counter")
        count = counter_block.value.get("count", 0)
    except:
        counter_block = JSON(value={"count": 0})
        count = 0
    
    max_runs = 5
    if count >= max_runs:
        raise Exception(f"Maximum runs ({max_runs}) reached")
    
    # Increment counter
    counter_block.value["count"] = count + 1
    counter_block.save("run-counter")
    
    # Your flow logic here
5. Using Deployment Configuration:
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python
from datetime import timedelta
from prefect.deployments import Deployment
from prefect.server.schemas.schedules import CronSchedule

# Limit runs by scheduling window
deployment = Deployment.build_from_flow(
    flow=your_flow,
    name="limited-deployment",
    schedule=CronSchedule(
        cron="0 0 * * *",  # Daily at midnight
        timezone="UTC",
        end_date=datetime.utcnow() + timedelta(days=5)  # Run for 5 days only
    )
)
6. Using Tags and Concurrency Limits:
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python
from prefect import flow, tags

@flow
def flow_with_tag_limit():
    with tags("limited-flow"):
        client = get_client(sync_client=True)
        
        # Set concurrency limit for tag
        client.create_concurrency_limit(
            tag="limited-flow",
            concurrency_limit=5
        )
        
        # Your flow logic here
7. Monitoring and Stopping Programmatically:
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python
from prefect import flow
from prefect.states import Cancelled

@flow
def monitored_flow():
    client = get_client(sync_client=True)
    
    flow_runs = client.read_flow_runs(
        flow_name="monitored_flow",
        state={"type": "COMPLETED"}
    )
    
    if len(flow_runs) >= 5:
        # Cancel any future runs
        client.set_flow_run_state(
            flow_run_id=flow_run_id,
            state=Cancelled(message="Maximum run limit reached")
        )
        return
    
    # Your flow logic here
Best Practices: 1. Document the Limits:
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python
@flow(description="This flow is limited to 5 runs")
def limited_flow():
    # Add documentation about limits
    pass
2. Handle Limit Gracefully: ```python @flow def graceful_limited_flow(): try: # Check limits if limit_reached(): # Create notification or log
create_markdown_artifact( key="limit-reached", markdown="Flow has reached its run limit" ) return except Exception as e: # Handle errors pass
Copy code
3. *Monitor Limits*:
```python
@flow
def monitored_limited_flow():
    client = get_client(sync_client=True)
    
    # Track run counts
    runs = client.read_flow_runs(
        flow_name="monitored_limited_flow"
    )
    
    # Create monitoring artifact
    create_markdown_artifact(
        key="run-count",
        markdown=f"Current run count: {len(runs)}"
    )
Would you like me to explain any of these approaches in more detail or provide more specific examples for your use case?