The plugin-based framework of the Nextline backend API server
Table of Contents
- Introduction
- Citation
- Packages
- How to run the Nextline backend API server
- Configuration
- Check out code for development
Nextline is a DAQ sequencer of the Observatory Control System (OCS). Nextline allows line-by-line execution of concurrent Python scripts, which control telescopes, by multiple users simultaneously from web browsers.
Nextline consists of multiple packages. This package, nextline-graphql, provides the framework for the backend API server. It is a plugin-based framework. Features are added by plugins.
Please use the following DOI for the core package to cite Nextline in general unless you need to refer to a specific package.
- nextline: The core functionality of Nextline. It controls the execution of the Python scripts. It is used by the plugin ctrl.
The plugin system of nextline-graphql is apluggy.
These plugins are included in this package.
- graphql: The entry point of the GraphQL API, implemented with strawberry-graphql.
- ctrl: The core plugin that controls the execution of the Python scripts. It uses the package nextline.
These plugins are not included in this package. They can be installed separately.
- nextline-rdb: A relational database for nextline. It stores configuration, execution history, and other information. It is implemented with SQLAlchemy 2.
- nextline-schedule: The auto mode. The queue system. An interface to the SO scheduler.
- nextline-alert: An interface to the alert system campana.
- nextline-test-utils: A collection of test utilities for backend development
The front-end web app is currently in a single package. The development of a plugin-based system is planned.
- nextline-web: (TypeScript) The front-end web app of Nextline. It is a Vue.js app.
The section shows how to run the Nextline backend API server. How to run the front-end web app is described elsewhere.
Docker images of the Nextline backend API server are created as ghcr.io/simonsobs/nextline-graphql. These images are created by the Dockerfile. No external plugins are included in the images.
Use, for example, the following command to run as a Docker container.
docker run -p 8080:8000 ghcr.io/simonsobs/nextline-graphqlIf you access to the API server with a web browser, you will see the GraphQL IDE: http://localhost:8080/.
To include external plugins, you can create a new Docker image with ghcr.io/simonsobs/nextline-graphql as the base image. For example, nextline-rdb shows how to create a new Docker image with nextline-rdb as an external plugin.
You can create a virtual environment, install packages, and run the API server as follows.
python -m venv venv
source venv/bin/activate
pip install nextline-graphql
pip install uvicorn
uvicorn --lifespan on --factory --port 8080 nextlinegraphql:create_appCheck with a web browser at http://localhost:8080/.
If you check out external plugins, nextline-graphql automatically detects them as plugins. An example can be described in nextline-rdb.
nextline-graphql uses dynaconf for configuration management. nextline-graphql itself does not have any configuration except for logging. External plugins have configurations.
This section shows an example way to check out code from GitHub for development.
python -m venv venv
source venv/bin/activate
git clone [email protected]:simonsobs/nextline.git
git clone [email protected]:simonsobs/nextline-graphql.git
pip install -e ./nextline/"[tests,dev]"
pip install -e ./nextline-graphql/"[tests,dev]"To run
uvicorn --port 8080 --lifespan on --factory --reload --reload-dir nextline-graphql --reload-dir nextline nextlinegraphql:create_app