openapi: 3.0.3
info:
  title: Apptainer Container Runtime Images Instances API
  description: API for the Apptainer container runtime, enabling programmatic management of HPC container images, instances, and execution for scientific computing workloads. Apptainer (formerly Singularity) is optimized for high-performance computing with support for Docker/OCI containers and HPC schedulers.
  version: 1.0.0
  contact:
    name: Apptainer Project
    url: https://apptainer.org/docs/
  license:
    name: BSD 3-Clause
    url: https://opensource.org/licenses/BSD-3-Clause
servers:
- url: https://api.apptainer.org/v1
  description: Apptainer API
security:
- bearerAuth: []
tags:
- name: Instances
  description: Running container instance management
paths:
  /instances:
    get:
      operationId: listInstances
      summary: Apptainer - List Instances
      description: Returns a list of running Apptainer container instances
      tags:
      - Instances
      responses:
        '200':
          description: A list of running instances
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/ContainerInstance'
              examples:
                ListInstancesExample:
                  x-microcks-default: true
                  summary: Example instances list
                  value:
                    data:
                    - instanceId: inst-001
                      name: my-simulation
                      imageId: img-ubuntu-22.04-hpc
                      status: running
                      startedAt: '2026-04-19T09:00:00Z'
        '401':
          description: Unauthorized - invalid or missing authentication token
    post:
      operationId: startInstance
      summary: Apptainer - Start Instance
      description: Starts a new container instance from an Apptainer image
      tags:
      - Instances
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                imageId:
                  type: string
                  description: Image to run as a container instance
                name:
                  type: string
                  description: Name for the container instance
                command:
                  type: string
                  description: Optional command to run in the container
            examples:
              StartInstanceExample:
                x-microcks-default: true
                summary: Example instance start request
                value:
                  imageId: img-ubuntu-22.04-hpc
                  name: my-simulation
                  command: /bin/bash run_simulation.sh
      responses:
        '201':
          description: Instance started successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ContainerInstance'
        '400':
          description: Invalid request body
        '401':
          description: Unauthorized - invalid or missing authentication token
components:
  schemas:
    ContainerInstance:
      title: ContainerInstance
      description: A running Apptainer container instance
      type: object
      properties:
        instanceId:
          type: string
          description: Unique instance identifier
        name:
          type: string
          description: Instance name
        imageId:
          type: string
          description: Container image the instance runs
        status:
          type: string
          enum:
          - running
          - stopped
          - error
          description: Instance status
        startedAt:
          type: string
          format: date-time
          description: Instance start timestamp
        stoppedAt:
          type: string
          format: date-time
          description: Instance stop timestamp
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT