appetiser

Replacement for jp2iser/tizer. Converts various image resources into JPEG2000 and a collection of thumbnails.

Dependencies

Kakadu

Appetiser is dependent on being able to access the compiled binaries for Kakadu as a tarball. In production it is expected that this will be an S3 file location that appetiser has access to at run-time, set with the environment variable:

KDU_BINARIES=s3://bucket/path-/to/kdu/binaries.tar

This is downloaded to the location /kdu_src/kdu.tar within the running container. convert

For local development using docker compose, the ./local_data/kdu_src directory is mapped to /kdu_src within the appetiser container. A copy of the Kakadu binaries should be placed in the ./local_data/kdu_src/ directory, and symlinked to ./local_data/kdu_src/kdu.tar

Python

Python dependencies for appetiser are managed using uv. This is the case both for app dependencies, that are installed by uv in the docker image, and development dependencies, that are used for testing and tooling.

Development and testing dependencies should be added using the --dev flag, e.g.

uv add --dev httpx

Although the app is containerised, it will be necessary to install the project dependencies for local development via:

uv sync

OS

Pillow has a number of OS level dependencies for dealing with various image formats that are installed in the Docker image. As we're installing Pillow through uv (previously pip) rather than apt this is required to ensure support for the required image formats. These seem to correspond with the External libraries in the Pillow docs.

Running locally

A docker-compose.yml file is provided for local development. This contains a number of volume mappings for local files, so the following must exist in the local directory:

• ./local_data/kdu_src: Directory containing the Kakadu binaries as described above. gitingored.
• ./local_data/output: Output directory mapped to /test_output and used in API examples and tests. gitignored.

Running tests

Integration tests can be found in ./tests and should be run with:

uv run pytest

These tests are dependent on pytest-docker, and use the ./tests/docker-compose.test.yml file.

API Documentation

OpenAPI docs for the appetiser API can be found at http://localhost:8000/docs on a locally running instance of appetiser. These provide documentation and examples for the convert/ endpoint, along with expected types.

Customising

The following environment variables can be used to configure the service

EnvVar	Description	Default
JPEG_QUALITY	Integer, 0-100, controls thumbnail jpeg quality	90