Configuration File Formats

Celebi uses YAML files for configuration. This section documents the typical file formats you’ll encounter when working with Celebi projects.

Global Configuration (~/.celebi/config.yaml)

The global configuration file stores user preferences and is located in the user’s home directory under ~/.celebi/.

Example:

editor: code

Common fields:

• editor – Default editor for editing files (e.g., code, vim, nano)

Task Configuration (celebi.yaml)

Each task directory contains a celebi.yaml file that defines the task’s execution environment, parameters, and input aliases.

Minimal example (task with defaults):

alias: []
environment: reanahub/reana-env-root6:6.18.04
kubernetes_memory_limit: 256Mi

Example with parameters:

alias: []
environment: reanahub/reana-env-root6:6.18.04
kubernetes_memory_limit: 256Mi
parameters:
  events: '20000'

Example with input aliases:

alias:
- gen
environment: reanahub/reana-env-root6:6.18.04
kubernetes_memory_limit: 256Mi
parameters: {}

Field descriptions:

• alias – List of short names for input dependencies (empty list if none)

• environment – Docker image or execution environment identifier

• kubernetes_memory_limit – Memory limit for Kubernetes execution (e.g., 256Mi, 1Gi)

• parameters – Dictionary of parameter names and their values (empty {} if none)

Algorithm Configuration (celebi.yaml)

Algorithm directories also use celebi.yaml but with a different structure focused on execution commands rather than parameters.

Example (algorithm with script environment):

environment: script
commands:
  - root -b -q 'code/gendata.C(${events},"outputs/data.root")'

Example (algorithm with Docker environment):

environment: reanahub/reana-env-root6:6.18.04
commands:
  - root -b -q 'code/analysis.C("inputs/data.root","outputs/plot.png")'

Field descriptions:

• environment – Execution environment: script for local execution or Docker image name

• commands – List of shell commands to execute; use ${parameter} syntax for parameter substitution

Project Configuration (.celebi/config.json)

Each project contains a config.json file (note: JSON format, not YAML) in the .celebi/ directory at the project root.

Example:

{
    "object_type": "project",
    "chern_version": "4.0.0",
    "project_uuid": "b50a736ddde44f8cbbcc773b9a075adb"
}

Field descriptions:

• object_type – Always "project" for project configuration

• chern_version – Version of Celebi that created the project

• project_uuid – Unique identifier for the project

Task/Directory Configuration (.celebi/config.json)

Each task and directory also contains a config.json file in its .celebi/ subdirectory.

Example (task):

{
    "object_type": "task",
    "auto_download": true,
    "default_runner": "local"
}

Example (directory):

{
    "object_type": "directory"
}

Common fields:

• object_type – Type of object: "task", "directory", or "algorithm"

• auto_download – Whether to automatically download outputs (tasks only)

• default_runner – Default execution runner (e.g., "local", "reana”)

README Files (README.md)

While not YAML, each object (project, directory, task, algorithm) contains a README.md file for documentation.

Example:

# Fit Task

This task performs a crystal ball fit on the generated J/psi data.

## Inputs

- gen: Generated MC data

## Outputs

- fit_result.png: Fit visualization
- fit_params.json: Fit parameters

Complete Project Example

A typical Celebi project structure with configuration files:

my_project/
├── README.md
├── celebi.yaml              # (if project-level config needed)
├── .celebi/
│   └── config.json          # Project metadata
├── algorithms/
│   ├── gen_data/
│   │   ├── README.md
│   │   ├── celebi.yaml      # Algorithm config with commands
│   │   └── code/
│   └── fit_data/
│       ├── README.md
│       ├── celebi.yaml
│       └── code/
└── tasks/
    ├── generate/
    │   ├── README.md
    │   ├── celebi.yaml      # Task config with parameters
    │   └── .celebi/
    │       └── config.json
    └── fit/
        ├── README.md
        ├── celebi.yaml
        └── .celebi/
            └── config.json