<@ULVA73B9P>: If I create a more sophisticated wor...
# ask-marvin
b
@Marvin: If I create a more sophisticated workflow and connect the flows using automations, what is the recommended way to share data between the flows? Let's assume all my flows work with a "project_name" that is set in the first flow, how should this data be injected into the subsequent flows in the automation?
m
To share data between flows using automations in Prefect, especially when each flow relies on a common parameter like "project_name," you have a few options: 1. Result Storage: You can use Prefect's result storage to persist the output of one flow and then retrieve it in another. This involves configuring your flows to store results in a shared storage backend. Check the
result_storage
and
result_serializer
options when creating a flow to ensure that results are stored and serialized correctly. 2. Parameter Passing: When triggering subsequent flows, you can pass parameters directly. If you're using automations, you might be able to configure them to pass specific parameters from one flow to another. 3. Environment Variables: For a more manual approach, you could use environment variables or a configuration file that all flows read from and write to, ensuring the "project_name" is available to each flow. For more details on configuring automations and handling data between flows, refer to the Prefect Automations Documentation. If you want to explore more about how to configure flows and their parameters, you might find the Prefect source code for flows helpful: Prefect Flows Source. Given your preference for imperative programming, you might find it straightforward to directly manipulate these configurations programmatically in your flow definitions.
b
@Marvin: Show me an example of parameter passing
m
To pass parameters between flows in Prefect, you can use the Prefect API to specify parameters for each flow run. Here’s a simple example of how you might define and pass parameters to a flow:
Copy code
python
from prefect import flow

@flow
def first_flow(project_name: str):
    # Do something with project_name
    print(f"Running first flow with project: {project_name}")
    return project_name

@flow
def second_flow(project_name: str):
    # Use the project_name parameter
    print(f"Running second flow with project: {project_name}")

# Run the first flow and capture its output
project_name = first_flow(project_name="MyProject")

# Pass the output to the second flow
second_flow(project_name=project_name)
### Key Points: - Parameters: When defining a flow, you can specify parameters by including them as function arguments. - Passing Data: The output from
first_flow
is passed as an argument to
second_flow
. - API Usage: When using the Prefect API, ensure you specify parameter names as keyword arguments, as positional arguments are not supported. For more information, you can refer to the Prefect Flow Documentation. This example assumes you are working within an environment where you can invoke flows directly. If you are using Prefect Cloud or an API, you would configure these parameters in your deployment settings.