Inline Scripts in Docker – Write Code Directly in Tasks

Writing code directly inside your task.

Write inline scripts inside Docker tasks

To get started with a Script task, paste your custom script inline in your YAML workflow definition along with any other configuration.

id: api_json_to_mongodb
namespace: company.team
tasks:
  - id: extract
    type: io.kestra.plugin.scripts.python.Script
    containerImage: python:3.11-slim
    beforeCommands:
      - pip install requests kestra > /dev/null
    outputFiles:
      - "*.json"
    script: |
      import requests
      import json
      from kestra import Kestra

      response = requests.get("https://api.github.com")
      data = response.json()

      with open("output.json", "w") as output_file:
          json.dump(data, output_file)

      Kestra.outputs({"status": response.status_code})

  - id: load
    type: io.kestra.plugin.mongodb.Load
    connection:
      uri: mongodb://host.docker.internal:27017/
    database: local
    collection: github
    from: "{{ outputs.extract.outputFiles['output.json'] }}"
    description: "you can start MongoDB using: docker run -d mongo"

The example above uses a Python script added as a multiline string into the script property. The script fetches data from an API and stores it as a JSON file in Kestra’s internal storage using the outputFiles property. The Kestra.outputs method captures additional output variables, such as the API response status code.

The image argument of the docker property specifies (optionally) the Docker image to use for the script. If you don’t specify an image, Kestra uses the default image for the language you are using. In the above example, we use the python:3.11-slim image.

You can also optionally use the beforeCommands property to install libraries used in your inline script. Above, the command pip install requests kestra installs pip packages not available in the base image python:3.11-slim.