Testing with Kelvin Publisher¶

kelvin-publisher is a CLI tool for testing applications during development. It's not meant to be imported in your code, but used as a standalone testing utility.

The publisher has three modes for simulating data:

1. Simulator - Random Data¶

Generate random data to your application's inputs:

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kelvin-publisher simulator --help
kelvin-publisher simulator

This automatically discovers your application's inputs and publishes random data.

2. CSV - File-based Data¶

Publish data from a CSV file:

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kelvin-publisher csv --help
kelvin-publisher csv --csv data.csv

Replays test data from CSV files.

3. Generator - Custom Data¶

Use a custom Python class to generate data:

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kelvin-publisher generator --help
kelvin-publisher generator --entrypoint action_generator.py:CustomActionGenerator

Example generator script:

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import asyncio
from typing import AsyncGenerator

from kelvin.message import Number
from kelvin.krn import KRNAssetDataStream
from kelvin.publisher import DataGenerator

class OtherGenerator(DataGenerator):
    def __init__(self) -> None:
        print("Hello from OtherGenerator")

    async def run(self) -> AsyncGenerator[Number, None]:
        print("Running OtherGenerator")
        for i in range(20, 30):
            yield Number(
                resource=KRNAssetDataStream("test-asset-1", "input-number"),
                payload=i,
            )
            await asyncio.sleep(1)

This mode allows you to implement sophisticated test scenarios with custom logic.