How to Write Custom Actions

Custom Kleinkram actions are implemented as Docker containers. Inside the container, you interact with the Kleinkram platform using the Kleinkram CLI. The Kleinkram CLI is a Python package installable via pip.

Download and List Files inside a Kleinkram Action

The following example shows how to create a simple action that downloads data from a mission and lists the files.

FROM python:latest

# Install Kleinkram CLI
RUN pip install kleinkram --force-reinstall

# Copy entrypoint script and make it executable
COPY ./entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh

ENTRYPOINT ["/entrypoint.sh"]

With the following entrypoint script:

#!/bin/bash

# Exit on error (non-zero exit codes mark action as failed)
set -e

echo "Get Started with Kleinkram Actions 🚀"

# Authenticate with the API key from environment variables
klein login --key "$KLEINKRAM_API_KEY"

echo "Download data from mission with UUID $KLEINKRAM_MISSION_UUID"
mkdir data
klein download -m "$KLEINKRAM_MISSION_UUID" --dest ./data

echo "List files of mission with UUID $KLEINKRAM_MISSION_UUID"
cd ./data || exit 1
ls -la

Environment Variables

The following environment variables are available within the Docker container during action execution:

• KLEINKRAM_API_KEY: API key for Kleinkram API authentication.
• KLEINKRAM_PROJECT_UUID: UUID of the project the action is running within.
• KLEINKRAM_MISSION_UUID: UUID of the mission the action is operating on.
• KLEINKRAM_ACTION_UUID: UUID of the currently running action.
• KLEINKRAM_API_ENDPOINT: Endpoint of the Kleinkram API.
• KLEINKRAM_S3_ENDPOINT: Endpoint of the Kleinkram S3 storage.

Deprecated Environment Variables

The following environment variables are deprecated and will be removed in the future:

• APIKEY (Use KLEINKRAM_API_KEY instead)
• PROJECT_UUID (Use KLEINKRAM_PROJECT_UUID instead)
• MISSION_UUID (Use KLEINKRAM_MISSION_UUID instead)
• ACTION_UUID (Use KLEINKRAM_ACTION_UUID instead)
• ENDPOINT (Use KLEINKRAM_API_ENDPOINT instead)

Push Actions to Docker Hub

Kleinkram actions must be pushed to Docker Hub under the rslethz/*** namespace. To publish your action:

# login to docker hub
docker login

# build the image
docker build -t rslethz/my-action .

# push the image
docker push rslethz/my-action