Prefect `2 0 4` Hi all I just upgraded from `2 0b8` to `2 0

Question

Prefect `2 0 4` Hi all I just upgraded from `2 0b8` to `2 0 4` In `v2 0b8` errors within flows tasks were caught by Prefect and the flow would continue now in `2 0 4` they are being raised and crashing my run How can I get back to the previous behavior I ll post my code in the thread

Jason Thomas · Answer

Code ```from prefect import flow task from prefect task runners import SequentialTaskRunner task def good task return True task def fail task raise Exception Error raised for testing flow def f1 fail task good task if name == main f1 ```

Jason Thomas · Answer

Logs in 2 0b8 desired behavior ```06 28 28 735 | INFO | prefect engine Created flow run strict cuttlefish for flow f1 06 28 28 735 | INFO | Flow run strict cuttlefish Using task runner ConcurrentTaskRunner 06 28 30 433 | WARNING | Flow run strict cuttlefish No default storage is configured on the server Results from this flow run will be stored in a temporary directory in its runtime environment 06 28 31 470 | INFO | Flow run strict cuttlefish Created task run fail task d8c73196 0 for task fail task 06 28 32 491 | INFO | Flow run strict cuttlefish Created task run good task 2a08f303 0 for task good task 06 28 33 921 | ERROR | Task run fail task d8c73196 0 Encountered exception during execution Traceback most recent call last File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages prefect engine py line 890 in orchestrate task run result = await run sync in interruptible worker thread File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages prefect utilities asyncio py line 116 in run sync in interruptible worker thread tg start soon File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio backends asyncio py line 662 in aexit raise exceptions 0 File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages prefect utilities asyncio py line 96 in capture worker thread and result result = fn args kwargs File test py line 12 in fail task raise Exception Error raised for testing Exception Error raised for testing 06 28 34 943 | ERROR | Task run fail task d8c73196 0 Finished in state Failed Task run encountered an exception 06 28 35 973 | INFO | Task run good task 2a08f303 0 Finished in state Completed 06 28 36 930 | ERROR | Flow run strict cuttlefish Finished in state Failed 1 2 states failed ```

Jason Thomas · Answer

Logs in 2 0 4 undesired behavior ```06 27 00 077 | INFO | prefect engine Created flow run witty hippo for flow f1 06 27 00 219 | INFO | Flow run witty hippo Created task run fail task d8c73196 0 for task fail task 06 27 01 855 | INFO | Flow run witty hippo Executing fail task d8c73196 0 immediately 06 27 02 830 | ERROR | Task run fail task d8c73196 0 Encountered exception during execution Traceback most recent call last File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 1053 in orchestrate task run result = await run sync task fn args kwargs File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 56 in run sync in worker thread return await anyio to thread run sync call cancellable=True File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File test py line 12 in fail task raise Exception Error raised for testing Exception Error raised for testing 06 27 03 837 | ERROR | Task run fail task d8c73196 0 Finished in state Failed Task run encountered an exception 06 27 04 852 | ERROR | Flow run witty hippo Encountered exception during execution Traceback most recent call last File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 557 in orchestrate flow run result = await run sync flow call File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 56 in run sync in worker thread return await anyio to thread run sync call cancellable=True File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File test py line 16 in f1 fail task File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect tasks py line 294 in call return enter task run engine File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 687 in enter task run engine return run async from worker thread begin run File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 136 in run async from worker thread return anyio from thread run call File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio from thread py line 49 in run return asynclib run async from thread func args File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 970 in run async from thread return f result File Library Developer CommandLineTools Library Frameworks Python3 framework Versions 3 8 lib python3 8 concurrent futures base py line 444 in result return self get result File Library Developer CommandLineTools Library Frameworks Python3 framework Versions 3 8 lib python3 8 concurrent futures base py line 389 in get result raise self exception File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 806 in create task run then submit return await future result File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect futures py line 220 in result return final state result raise on failure=raise on failure File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect orion schemas states py line 145 in result raise data File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 1053 in orchestrate task run result = await run sync task fn args kwargs File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 56 in run sync in worker thread return await anyio to thread run sync call cancellable=True File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File test py line 12 in fail task raise Exception Error raised for testing Exception Error raised for testing 06 27 05 831 | ERROR | Flow run witty hippo Finished in state Failed Flow run encountered an exception Traceback most recent call last File test py line 21 in lt module gt f1 File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect flows py line 390 in call return enter flow run engine from flow call File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 152 in enter flow run engine from flow call return anyio run begin run File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio core eventloop py line 70 in run return asynclib run func args backend options File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 292 in run return native run wrapper debug=debug File Library Developer CommandLineTools Library Frameworks Python3 framework Versions 3 8 lib python3 8 asyncio runners py line 44 in run return loop run until complete main File Library Developer CommandLineTools Library Frameworks Python3 framework Versions 3 8 lib python3 8 asyncio base events py line 616 in run until complete return future result File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 287 in wrapper return await func args File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect client py line 104 in with injected client return await fn args kwargs File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 228 in create then begin flow run return state result File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect orion schemas states py line 145 in result raise data File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 557 in orchestrate flow run result = await run sync flow call File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 56 in run sync in worker thread return await anyio to thread run sync call cancellable=True File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File test py line 16 in f1 fail task File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect tasks py line 294 in call return enter task run engine File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 687 in enter task run engine return run async from worker thread begin run File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 136 in run async from worker thread return anyio from thread run call File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio from thread py line 49 in run return asynclib run async from thread func args File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 970 in run async from thread return f result File Library Developer CommandLineTools Library Frameworks Python3 framework Versions 3 8 lib python3 8 concurrent futures base py line 444 in result return self get result File Library Developer CommandLineTools Library Frameworks Python3 framework Versions 3 8 lib python3 8 concurrent futures base py line 389 in get result raise self exception File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 806 in create task run then submit return await future result File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect futures py line 220 in result return final state result raise on failure=raise on failure File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect orion schemas states py line 145 in result raise data File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect engine py line 1053 in orchestrate task run result = await run sync task fn args kwargs File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages prefect utilities asyncutils py line 56 in run sync in worker thread return await anyio to thread run sync call cancellable=True File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv 2 0 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File test py line 12 in fail task raise Exception Error raised for testing Exception Error raised for testing```

Serina · Answer

I can replicate the `1 2 states failed finished` state that I believe you are looking for ```08 56 39 574 | ERROR | Task run fail task d8c73196 0 Finished in state Failed Task run encountered an exception 08 56 39 587 | INFO | Task run good task 2a08f303 0 Finished in state Completed 08 56 39 612 | ERROR | Flow run brown mantis Finished in state Failed 1 2 states failed ``` by modifying the code like so ```from prefect import flow task from prefect task runners import ConcurrentTaskRunner task def good task return True task def fail task raise Exception Error raised for testing flow def f1 fail task submit good task submit if name == main f1 ``` ConcurrentTaskRunner is no longer the default like it was in 2 0b8

Jason Thomas · Answer

Thanks < Serina> that helps a lot It is now running the second task for me and reaching a finished state But it is still raising the error after the flow runs How do I get it to not raise on failure

Serina · Answer

Since your flow finishes in a Failed state and since you are creating an Exception in fail task upon failure it will raise the message you wrote within it where in this case data is Error raised for testing In the UI for the code above I see these logs

Serina · Answer

Is that different than what you would expect to see

Jason Thomas · Answer

I want the error to be caught and logged and execution to continue

Serina · Answer

Then you might consider using the logger instead of raising ```from prefect import flow task from prefect task runners import ConcurrentTaskRunner from prefect logging import get run logger task def good task return True task def fail task logger = get run logger if 2 lt 4 logger error msg= A task failed flow task runner=ConcurrentTaskRunner def f1 fail task submit good task submit if name == main f1 ``` which would give you the following output ```09 32 53 920 | INFO | prefect engine Created flow run cerulean bumblebee for flow f1 09 32 54 030 | INFO | Flow run cerulean bumblebee Created task run fail task d8c73196 0 for task fail task 09 32 54 030 | INFO | Flow run cerulean bumblebee Submitted task run fail task d8c73196 0 for execution 09 32 54 054 | INFO | Flow run cerulean bumblebee Created task run good task 2a08f303 0 for task good task 09 32 54 055 | INFO | Flow run cerulean bumblebee Submitted task run good task 2a08f303 0 for execution 09 32 54 063 | ERROR | Task run fail task d8c73196 0 A task failed 09 32 54 082 | INFO | Task run fail task d8c73196 0 Finished in state Completed 09 32 54 088 | INFO | Task run good task 2a08f303 0 Finished in state Completed 09 32 54 103 | INFO | Flow run cerulean bumblebee Finished in state Completed All states completed ```

Serina · Answer

With the logs in the UI

Jason Thomas · Answer

Here s a modification to my sample code ```from prefect import flow task from prefect task runners import SequentialTaskRunner task def good task return True task def fail task raise Exception Error raised for testing flow def f1 fail task good task flow def f2 good task if name == main f1 f2 print all flows complete ``` And the desired output ```07 33 50 501 | INFO | prefect engine Created flow run purring vole for flow f1 07 33 50 501 | INFO | Flow run purring vole Using task runner ConcurrentTaskRunner 07 33 52 031 | WARNING | Flow run purring vole No default storage is configured on the server Results from this flow run will be stored in a temporary directory in its runtime environment 07 33 53 052 | INFO | Flow run purring vole Created task run fail task d8c73196 0 for task fail task 07 33 54 069 | INFO | Flow run purring vole Created task run good task 2a08f303 0 for task good task 07 33 55 150 | ERROR | Task run fail task d8c73196 0 Encountered exception during execution Traceback most recent call last File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages prefect engine py line 890 in orchestrate task run result = await run sync in interruptible worker thread File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages prefect utilities asyncio py line 116 in run sync in interruptible worker thread tg start soon File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio backends asyncio py line 662 in aexit raise exceptions 0 File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio to thread py line 31 in run sync return await get asynclib run sync in worker thread File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio backends asyncio py line 937 in run sync in worker thread return await future File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages anyio backends asyncio py line 867 in run result = context run func args File Users jason thomas dev sftp sweeper venv b8 lib python3 8 site packages prefect utilities asyncio py line 96 in capture worker thread and result result = fn args kwargs File test py line 10 in fail task raise Exception Error raised for testing Exception Error raised for testing 07 33 56 134 | ERROR | Task run fail task d8c73196 0 Finished in state Failed Task run encountered an exception 07 33 57 167 | INFO | Task run good task 2a08f303 0 Finished in state Completed 07 33 58 164 | ERROR | Flow run purring vole Finished in state Failed 1 2 states failed 07 33 59 380 | INFO | prefect engine Created flow run impartial hummingbird for flow f2 07 33 59 380 | INFO | Flow run impartial hummingbird Using task runner ConcurrentTaskRunner 07 34 00 355 | WARNING | Flow run impartial hummingbird No default storage is configured on the server Results from this flow run will be stored in a temporary directory in its runtime environment 07 34 01 420 | INFO | Flow run impartial hummingbird Created task run good task 2a08f303 0 for task good task 07 34 02 485 | INFO | Task run good task 2a08f303 0 Finished in state Completed 07 34 03 606 | INFO | Flow run impartial hummingbird Finished in state Completed All states completed all flows complete ```

Jason Thomas · Answer

It s not just anticipated errors that I want to catch it s any error I just want my flows to run without crashing

Serina · Answer

Hi < Jason Thomas> can you see if this produces the results you re looking for ```from prefect import flow task from prefect task runners import SequentialTaskRunner task def good task return True task def fail task raise Exception Error raised for testing flow def f1 fail task good task flow def f2 good task if name == main f1 return state=True f2 return state=True print all flows complete ```

Jason Thomas · Answer

That worked on the sample Testing on something more complex

Jason Thomas · Answer

Yes that is working Thank you < Serina>