Initialize a Streaming Function

Using the CLI

Initialize your Streaming Function with the moose function init CLI command:

npx moose-cli function init --source <SOURCE_DATA_MODEL> --destination <DESTINATION_DATA_MODEL>

moose-cli function init --source <SOURCE_DATA_MODEL> --destination <DESTINATION_DATA_MODEL>

This command generates a new Streaming Function file in the /functions directory of your Moose app according to the file structure described previously.

Manual Initialization

You can alternatively create a new Streaming Function file manually in the /functions directory of your Moose app. The file name should be in the format SourceDataModel__DestinationDataModel.tsSourceDataModel__DestinationDataModel.py. Inside the file, define the function as follows:

import { SourceDataModel } from "../datamodels/path/to/SourceDataModel";
import { DestinationDataModel } from "../datamodels/path/to/DestinationDataModel";
 
export default function functionName(
  source: SourceDataModel,
): DestinationDataModel[] | DestinationDataModel | null {
  // Transformation logic
}

from app.datamodels.path.to.SourceDataModel import SourceDataModel
from app.datamodels.path.to.DestinationDataModel import DestinationDataModel
from moose_lib import StreamingFunction
 
def functionName(source: SourceDataModel) -> DestinationDataModel | list[DestinationDataModel] | None:
  # Transformation logic
 
 
my_streaming_function = StreamingFunction(run=functionName)

Next Steps

With your Streaming Function initialized, you can now start defining the transformation logic to process data from the source Data Model to the destination Data Model. We'll cover this in more detail in the next section.