run python script supports debugging, code bundling, output dir by cosmicBboy · Pull Request #789 · flyteorg/flyte-sdk

cosmicBboy · 2026-03-13T02:35:33Z

This pull request introduces support for running plain Python scripts as Flyte tasks without pickling, by bundling the script and using a new ScriptTaskResolver. It also adds a new copy style (python_script) for code bundles, updates the task and environment APIs to support custom resolvers, and improves the developer experience for remote script execution and debugging. Additional minor changes update dependencies and resource specifications in example files.

Python script task support and code bundling:

Added ScriptTaskResolver (src/flyte/_internal/resolvers/script.py) to enable bundling and execution of plain Python scripts as Flyte tasks, avoiding pickling and enabling proper remote debugging.
Updated run_python_script (src/flyte/_run_python_script.py) to use the new resolver, bundle scripts with the new python_script copy style, and support VS Code debugging. [1] [2] [3] [4]
Introduced build_code_bundle_from_relative_paths and added "python_script" to the CopyFiles literal for selective script bundling. [1] [2]
Modified _Runner and remote/hybrid run logic to support the new copy style and script bundling parameters. [1] [2] [3] [4] [5]

Task and environment API enhancements:

Added task_resolver argument to TaskEnvironment.task and AsyncFunctionTaskTemplate, and ensured it is used during serialization and container argument construction. [1] [2] [3] [4] [5]

Developer experience and examples:

Added a new hello.py script example demonstrating running a plain Python script with Flyte.
Updated example resource specifications and dependency versions for better compatibility and GPU support. [1] [2] [3]
Added more arguments to VS Code debug launch configuration for improved debugging.

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

kumare3 · 2026-03-13T04:22:47Z

src/flyte/_run_python_script.py

+@dataclass
+class PythonScriptOutput:
+    exit_code: int
+    stdout: str


I dont think we should capture the stdout, this is already in the logs. This can be a lot!

note here that I'm only getting the last 1000 characters: https://github.com/flyteorg/flyte-sdk/pull/789/changes#diff-bc180013a121c671af8420075855a9a12efdcd6a01b24e90c07a6322a09001ceR75-R76

This is still useful for local debugging... user (or agent) gets stderr and stdout in the CLI, we have to think LLM-first!

kumare3 · 2026-03-13T04:22:53Z

src/flyte/_run_python_script.py

+class PythonScriptOutput:
+    exit_code: int
+    stdout: str
+    stderr: str


same for stderr

note here that I'm only getting the last 1000 characters: https://github.com/flyteorg/flyte-sdk/pull/789/changes#diff-bc180013a121c671af8420075855a9a12efdcd6a01b24e90c07a6322a09001ceR75-R76

This is still useful for local debugging... user (or agent) gets stderr and stdout in the CLI, we have to think LLM-first!

src/flyte/_run_python_script.py

src/flyte/_task_environment.py

kumare3 · 2026-03-13T04:26:15Z

src/flyte/_code_bundle/__init__.py

+__all__ = [
+    "CopyFiles",
+    "build_code_bundle",
+    "build_code_bundle_from_relative_paths",


is this an existing function, is it used for apps?

src/flyte/cli/_run.py

kumare3 · 2026-03-13T04:30:10Z

I think we should also add support for additional files regex (as a follow up us ok), so i like the include files thing

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

cosmicBboy · 2026-03-13T15:13:16Z

I think we should also add support for additional files regex (as a follow up us ok), so i like the include files thing

yep, gonna do that in a separate PR

kumare3 · 2026-03-14T01:53:47Z

src/flyte/_run_python_script.py

-        }
+        return PythonScriptOutput(
+            exit_code=result.returncode,
+            stdout=result.stdout[-1000:],


I dont know if this is ok, this will still blow up memory i feel. this will buffer everything in memory

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

wild-endeavor · 2026-03-16T19:03:36Z

src/flyte/_code_bundle/_utils.py

 from ._ignore import Ignore, IgnoreGroup, StandardIgnore

-CopyFiles = Literal["loaded_modules", "all", "none"]
+CopyFiles = Literal["loaded_modules", "all", "none", "custom"]


I don't follow this... what does this do? Are we adding this to the public API now? how will users specify this on the command line?

eventually yes, but for now it raises an error in the CLI: https://github.com/flyteorg/flyte-sdk/pull/789/changes/BASE..930891aee1134516f04b3d53807e83d116de98e3#diff-2cf224e2941b042aea27fbca293952e864aced9d4fae51de65eb9961a8aa6482R231-R232

cosmicBboy added 5 commits March 12, 2026 15:25

implement ScriptTaskResolver for better debugging

828ea0b

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

implement python_script code bundling with ScriptTaskResolver

c9493a1

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

lint

49d3b75

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

clean up

d44bae3

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

fix vscode debugger args

3e9fba9

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

kumare3 reviewed Mar 13, 2026

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src/flyte/_run_python_script.py Show resolved Hide resolved

kumare3 reviewed Mar 13, 2026

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src/flyte/_task_environment.py Show resolved Hide resolved

kumare3 reviewed Mar 13, 2026

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refactor: copy_style "custom" and create InternalTaskResolver

a7efecc

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

kumare3 reviewed Mar 14, 2026

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kumare3 previously approved these changes Mar 14, 2026

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write stdout and stderr to disk, read tail

930891a

Signed-off-by: Niels Bantilan <niels.bantilan@gmail.com>

cosmicBboy dismissed kumare3’s stale review via 930891a March 15, 2026 22:28

kumare3 approved these changes Mar 16, 2026

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cosmicBboy merged commit 0c2eec5 into main Mar 16, 2026
29 checks passed

cosmicBboy deleted the nielsb/run-python-script-bundle branch March 16, 2026 03:47

wild-endeavor reviewed Mar 16, 2026

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kumare3 commented Mar 13, 2026

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