Get started with Flows

Make sure you have a good understanding of the key concepts before you get started with Domino Flows.

Basic flow

This section demonstrates a basic example that:

Takes two integers as an input to a flow.
The first task adds the integers together and passes the result as an input to the second task.
The second task takes the square root of the input and returns the result as the final output of the flow.

This example flow can be visualized as follows:

Simple Math Flow Graph

To create a Domino Flow:

Create a workspace using the Domino Standard Environment (DSE), or a custom environment that is built on top of the DSE.

Create a file named add.py in the root directory. Add the following code to the file to add two integer inputs together:

from pathlib import Path

# Read inputs
a = Path("/workflow/inputs/first_value").read_text()
b = Path("/workflow/inputs/second_value").read_text()

# Calculate sum
sum = int(a) + int(b)
print(f"The sum of {a} + {b} is {sum}")

# Write output
Path("/workflow/outputs/sum").write_text(str(sum))

Create a file named sqrt.py in the root directory. Add the following code to the file to calculate the square root of the input:

from pathlib import Path

# Read input
value = Path("/workflow/inputs/value").read_text()

# Calculate square root
sqrt = int(value) ** 0.5
print(f"The square root of {value} is {sqrt}")

# Write output
Path("/workflow/outputs/sqrt").write_text(str(sqrt))

Create a file named workflow.py in the root directory. Add the following code to the file to define the flow:

from flytekit import workflow
from flytekitplugins.domino.task import DominoJobConfig, DominoJobTask

@workflow
def simple_math_workflow(a: int, b: int) -> float:

    # Create first task
    add_task = DominoJobTask(
        name='Add numbers',
        domino_job_config=DominoJobConfig(Command="python add.py"),
        inputs={'first_value': int, 'second_value': int},
        outputs={'sum': int},
        use_latest=True
    )
    sum = add_task(first_value=a, second_value=b)

    # Create second task
    sqrt_task = DominoJobTask(
        name='Square root',
        domino_job_config=DominoJobConfig(Command="python sqrt.py"),
        inputs={'value': int},
        outputs={'sqrt': float},
        use_latest=True
    )
    sqrt = sqrt_task(value=sum)

    return sqrt

Commit the code and run the following command in the Workspace terminal to register and run the flow:
```
pyflyte run --remote workflow.py simple_math_workflow --a 10 --b 6
```
Once you run the command above, navigate to Flows > Flow name > Run Name in the Domino UI to monitor the results and view the outputs that were produced by the execution.
To visualize the full execution flow, click on the Graph pivot.

AI Hub Flow

Rather than beginning from scratch, you can start from a pre-built ecosystem template from Domino’s AI Hub. This section uses a template that demonstrates a basic training flow example with the following steps:

Data is loaded in from two different sources and a snapshot of the data is taken.
The data is merged together as a single dataset.
Basic preprocessing is done on the dataset.
A model is trained using the cleaned dataset.

The training flow can be visualized as follows:

Training Flow Graph

To create the training flow:

Make a fork of the template GitHub repository.
Create a Workspace using the Domino Standard Environment (DSE), or a custom environment that is built on top of the DSE.

Inspect the flow.py file for the definition of the flow. Note how a helper method, called run_domino_job_task, is used here instead of the DominoJobConfig and DominoJobTask in the basic example above.

task1 = run_domino_job_task(
    flyte_task_name='Load Data A',
    command='python /mnt/code/scripts/load-data-A.py',
    hardware_tier_name='Small',
    inputs=[
        Input(name='data_path', type=str, value=data_path_a)
    ],
    output_specs=[
        Output(name='datasetA', type=FlyteFile[TypeVar('csv')])
    ],
    use_project_defaults_for_omitted=True
)

task2 = run_domino_job_task(
    flyte_task_name='Load Data B',
    command='python /mnt/code/scripts/load-data-B.py',
    hardware_tier_name='Small',
    inputs=[
        Input(name='data_path', type=str, value=data_path_b)
    ],
    output_specs=[
        Output(name='datasetB', type=FlyteFile[TypeVar('csv')])
    ],
    use_project_defaults_for_omitted=True
)

# Additional tasks

Run the following command in the Workspace terminal to register and run the flow:

pyflyte run --remote flow.py model_training --data_path_a /mnt/code/data/datasetA.csv --data_path_b /mnt/code/data/datasetB.csv

Navigate to Flows > Flow name > Run name to monitor the results and view the outputs that were produced by the execution.

Get started with Flows

Basic flow

AI Hub Flow

Next steps