Customize presets and images

Override the framework presets and Docker images used for building and deploying your apps.

Presets and images

File format

Presets

The presets file (/opt/devpush/app/settings/presets.json) is a list of objects, each one describing a possible preset that you can select in your project settings.

Example:

[
  {
    "slug": "python",
    "name": "Python",
    "category": "Python",
    "image": "python-3.12",
    "build_command": "pip install -r requirements.txt",
    "pre_deploy_command": "",
    "start_command": "gunicorn -w 3 -b 0.0.0.0:8000 main:app",
    "logo": "<svg>...</svg>",
    "detection": {
      "priority": 30,
      "any_files": ["requirements.txt", "pyproject.toml"]
    }
  }
]

Each preset has the following fields:

Field Type Required Description
slug string Yes Unique identifier used in URLs and config overrides.
name string Yes Display name shown in the UI.
category string No UI grouping for the preset list.
image string No Default runner image slug (must exist in images list).
root_directory string No Working directory for commands (e.g. ./ or apps/api).
build_command string Yes Install/build step run during deployment.
pre_deploy_command string Yes Optional step run before starting the app.
start_command string Yes Command used to start the app.
beta boolean No Marks the preset as beta in the UI.
logo string Yes SVG markup used as the preset icon.
detection object No Auto-detection rules for this preset.

Detection

The detection object enables automatic preset detection when creating a new project. When a user selects a repository, DevPush scans its file tree and matches against detection rules to suggest the appropriate preset.

Field Type Description
priority number Higher values win when multiple presets match (default: 0).
any_files array At least one file must exist. Supports globs (e.g. */settings.py).
all_files array All files must exist. Supports globs.
any_paths array Alias for any_files (supports globs).
none_files array None of these files should exist. Used for exclusions.
package_check string Dependency name to find in requirements.txt, pyproject.toml, or package.json.

Example detection rules:

{
  "slug": "django",
  "detection": {
    "priority": 100,
    "any_files": ["manage.py", "*/manage.py"],
    "any_paths": ["*/settings.py", "*/wsgi.py"]
  }
}

{
  "slug": "fastapi",
  "detection": {
    "priority": 95,
    "any_files": ["requirements.txt", "pyproject.toml"],
    "none_files": ["manage.py"],
    "package_check": "fastapi"
  }
}

Images

The images file (/opt/devpush/app/settings/images.json) is a list of runner images. Each entry describes what the user can select in the project settings.

Example:

[
  {
    "slug": "python-3.12",
    "name": "Python 3.12",
    "category": "Python"
  }
]

Fields:

Field Type Required Description
slug string Yes Image identifier (maps to a Dockerfile name).
name string Yes Display name shown in the UI.
category string Yes UI grouping for the image list.

Dockerfiles

Runner Dockerfiles live in docker/runner/ inside the DevPush app source. Each file is named Dockerfile.<slug> and is used to build the runner image for that slug (for example, Dockerfile.python-3.12).

Overriding

To override presets and/or images, place JSON files in the data directory with the correct ownership and permissions. You can override only one file or both.

sudo install -m 0644 -o devpush -g devpush ./presets.json /var/lib/devpush/presets.json
sudo install -m 0644 -o devpush -g devpush ./images.json /var/lib/devpush/images.json

Runner images are built from Dockerfiles based on the slug provided in the images.json file. This means you can override a runner without changing images.json.

sudo install -d -m 0755 -o devpush -g devpush /var/lib/devpush/runner
sudo install -m 0644 -o devpush -g devpush ./Dockerfile.python-3.12 \
  /var/lib/devpush/runner/Dockerfile.python-3.12