Installing dependencies

If your policy requires dependencies, you have two options depending on your execution environment:

1. Custom Docker image - Install dependencies at build time in your Dockerfile

2. Native execution - Dependencies are installed automatically at runtime

Your requirements.txt should contain the lunar_policy package at a minimum:

lunar_policy==0.1.6

Custom Docker Image

When running in containers, create a custom Docker image with all dependencies pre-installed. This provides faster startup times, reproducible builds, and eliminates network dependencies at runtime.

Create a Dockerfile that inherits from the official earthly/lunar-scripts image and installs your dependencies at build time:

FROM earthly/lunar-scripts:1.0.0

# Copy and install Python dependencies
COPY requirements.txt /tmp/requirements.txt
RUN pip install --no-cache-dir -r /tmp/requirements.txt && rm /tmp/requirements.txt

Then configure your plugin or lunar-config.yml to use this image:

image: my-org/my-custom-image:v1.0

For more details on image configuration, see Images.

Native Execution

When running with image: native (no container), place your requirements.txt in the same directory as your lunar-config.yml or lunar-policy.yml file. Dependencies are installed automatically before the policy is run, and only once in each environment.

Development convenience with earthly/lunar-scripts

The official earthly/lunar-scripts image automatically installs dependencies from any requirements.txt file found in the plugin directory as part of its entrypoint. This is a convenience feature for quick development iteration, but baking dependencies into your image provides faster startup times in production.

To override this behavior, you can change the ENTRYPOINT in your Dockerfile. For example:

ENTRYPOINT ["/usr/bin/python3"]