flyte-migrate-tasks-workflows

Flyte 1 to 2 Migration: Tasks and Workflows

The biggest structural change in Flyte 2 is that everything is a task. The Flyte 1 @task, @workflow, and @dynamic decorators all collapse into a single @env.task on a flyte.TaskEnvironment, and a "workflow" is now just a task that calls other tasks. This skill covers the structural shift, sequential ordering without the >> operator, nested subworkflows, TaskEnvironment configuration basics, and the full @task parameter mapping.

Grounding References

Resource	URL
Migration guide	https://www.union.ai/docs/v2/flyte/user-guide/migration/flyte-2/tasks-and-workflows/
Official docs	https://www.union.ai/docs/v2/flyte
Docs index (LLMs)	https://www.union.ai/docs/v2/flyte/llms.txt
SDK API reference	https://www.union.ai/docs/v2/union/api-reference/flyte-sdk/
Example code	https://github.com/unionai/unionai-examples
Flyte MCP tools	Available via flyte-mcp server

The Structural Shift

In Flyte 1 you decorated units of work with @task, composed them with @workflow, and used @dynamic for runtime-generated graphs. In Flyte 2 you create one flyte.TaskEnvironment that carries the configuration, then decorate every function — leaf tasks and orchestrating "workflows" alike — with @env.task. There is no separate @workflow decorator: the entrypoint is just a task that calls other tasks.

Hello World: Tasks and Workflows

A @task plus @workflow becomes two @env.tasks, where the entrypoint task calls the others. Sequential calls are naturally ordered — no >> operator required.

Flyte 1

import flytekit

@flytekit.task
def say_hello(name: str) -> str:
    return f"Hello, {name}!"

@flytekit.task
def to_upper(greeting: str) -> str:
    return greeting.upper()

@flytekit.workflow
def main(name: str) -> str:
    greeting = say_hello(name=name)
    return to_upper(greeting=greeting)

Flyte 2

import flyte

env = flyte.TaskEnvironment(name="hello_world")

@env.task
def say_hello(name: str) -> str:
    return f"Hello, {name}!"

@env.task
def to_upper(greeting: str) -> str:
    return greeting.upper()

# The "workflow" is now just a task that calls other tasks.
@env.task
def main(name: str) -> str:
    greeting = say_hello(name)
    return to_upper(greeting)