🔣 CCP Method Descriptor: method.json

Every method in CCP is defined by a structured JSON file called method.json. This file fully describes the method’s behavior, interface, and execution context, and is essential for running, sharing, and reproducing the method.

You can download it using the Download button ( Download Icon ) in the method list.

Purpose

The method.json file is the definitive contract for a method’s definition. It:

Specifies inputs, outputs, runtime, and logic
Enables sharing and importing/exporting across VREs
Supports method versioning and provenance tracking

Structure Overview

`id` (required)

"id": "af3e3771-5b1f-402b-89b8-4ecdb121af92"

A globally unique identifier for the method. It must remain consistent to ensure traceability of executions and metadata.

`title`, `description`, `version`

Basic metadata used for display and documentation.

`metadata`

Contains roles like:

author: person or group creating the method
category: classification in the UI
context: VRE or infrastructure where the method is defined

`inputs`

Defines the method’s parameters. Each includes:

id, title, description
schema with type, format, and MIME type
minOccurs / maxOccurs

`ccpimage`: Runtime Docker Image (required)

"ccpimage": {
  "id": "ccpimage",
  "title": "Runtime",
  "description": "The image of the runtime to use for method execution.",
  "schema": {
    "type": "string",
    "format": "url",
    "default": "hub.dev.d4science.org/test/python-gdal:latest"
  }
}

This input defines the Docker image used to run the method logic inside the container. It must be compatible with the target infrastructure.

📦 Output `outputs`

Standard and custom outputs, including stdout, stderr, or generated files.

`additionalParameters`

Includes:

deploy-script: prepares the environment
execute-script: runs the method
undeploy-script: optional cleanup
lifecycle: timestamps and modifications

`links` → `compatibleWith` (required)

"links": [
  {
    "rel": "compatibleWith",
    "title": "D4Science production Infrastructure",
    "href": "infrastructures/d4science-prod-swarm"
  }
]

This field is mandatory and declares which infrastructure(s) the method is compatible with. If not present, the method cannot be scheduled for execution.

It ensures that:

The method can run on the selected infrastructure
The Docker image is accessible from that infrastructure
Runtime features (e.g., network, storage) match execution requirements

`keywords` (optional)

Used for search and discovery in the CCP interface.

💡 Note Notes

The id and compatibleWith fields are mandatory
The method is executed only if the infrastructure matches compatibleWith
The file can be uploaded again to update, clone, or transfer the method across VREs

🔣 CCP Method Descriptor: method.json

Purpose

Structure Overview

id (required)

title, description, version

metadata

inputs

ccpimage: Runtime Docker Image (required)

📦 Output outputs

additionalParameters

links → compatibleWith (required)

keywords (optional)