start_container

Instructions

Implementation Reference

• src/ctfd_mcp/server.py:102-110 (handler)

  MCP tool endpoint for start_container - the async function decorated with @mcp.tool that receives challenge_id and calls client.start_container(challenge_id).

  @mcp.tool(
      description="Unified start: detects plugin (whale/ctfd-owl/k8s) and starts container."
  )
  async def start_container(challenge_id: int):
      client = await _get_client()
      try:
          return await client.start_container(challenge_id)
      except Exception as exc:  # noqa: BLE001
          raise _format_error(exc)

• src/ctfd_mcp/ctfd_client.py:558-579 (handler)

  Unified start_container implementation on CTFdClient - detects the challenge type (dynamic_docker, dynamic_check_docker, k8s) and dispatches to the appropriate backend handler (start_k8s_container, start_dynamic_container, start_owl_container).

  async def start_container(self, challenge_id: int) -> dict[str, Any]:
      """
      Unified start: detects challenge type and calls the appropriate backend.
      - dynamic_docker -> ctfd-whale /api/v1/containers
      - dynamic_check_docker -> ctfd-owl /plugins/ctfd-owl/container
      - k8s-backed -> /api/v1/k8s (form-based)
      """
      details = await self.get_challenge(challenge_id)
      ctype = (details.get("type") or "").lower()
      if self._is_k8s_type(ctype):
          return await self.start_k8s_container(challenge_id)
      if ctype == "dynamic_docker":
          try:
              return await self.start_dynamic_container(challenge_id)
          except NotFoundError:
              # Some events expose dynamic challenges via /api/v1/k8s while keeping the same type.
              return await self.start_k8s_container(challenge_id)
      if ctype == "dynamic_check_docker":
          return await self.start_owl_container(challenge_id)
      raise CTFdClientError(
          f"Unsupported challenge type '{ctype}' for container start."
      )

• src/ctfd_mcp/ctfd_client.py:245-258 (schema)

  Schema/return shape for dynamic_docker container start (start_dynamic_container) - returns connection_info, ip, port, host, container_id, etc.

  return self._trim_none(
      {
          "id": data.get("id"),
          "challenge_id": data.get("challenge_id"),
          "state": data.get("state"),
          "connection_info": connection_info,
          "ip": data.get("ip"),
          "port": port,
          "host": host,
          "container_id": data.get("container_id"),
          "created": data.get("created"),
          "raw": data,
      }
  )

• src/ctfd_mcp/ctfd_client.py:343-354 (schema)

  Schema/return shape for k8s container start (start_k8s_container) - returns connection_info, instance_running, expires_at, etc.

  return {
      "challenge_id": challenge_id,
      "connection_info": connection_info,
      "connection_url": connection_url,
      "connection_port": port,
      "expires_at": expires_at,
      "instance_running": data.get("InstanceRunning"),
      "is_current_instance": data.get("ThisChallengeInstance"),
      "extend_available": data.get("ExtendAvailable"),
      "state": state,
      "raw": data,
  }

• src/ctfd_mcp/ctfd_client.py:491-506 (schema)

  Schema/return shape for ctfd-owl container start (start_owl_container) - returns connection_info, ip, port, remaining_time, container_id, etc.

  return {
      "id": data.get("id") or container_info.get("id"),
      "challenge_id": data.get("challenge_id") or challenge_id,
      "state": data.get("state") or container_info.get("state"),
      "connection_info": connection_info,
      "ip": ip,
      "port": port,
      "host": host,
      "conntype": conntype,
      "remaining_time": container_info.get("remaining_time")
      or data.get("remaining_time"),
      "container_id": container_info.get("container_id")
      or data.get("container_id"),
      "created": data.get("created") or container_info.get("created"),
      "raw": data,
  }

• src/ctfd_mcp/ctfd_client.py:522-527 (helper)

  Helper method _is_k8s_type used by start_container to detect k8s-backed challenges.

  @staticmethod
  def _is_k8s_type(ctype: str | None) -> bool:
      if not ctype:
          return False
      lowered = ctype.lower()
      return "k8s" in lowered or "kube" in lowered

• src/ctfd_mcp/ctfd_client.py:529-532 (helper)

  Helper method _trim_none used by start_container to remove None values from responses.

  @staticmethod
  def _trim_none(values: dict[str, Any]) -> dict[str, Any]:
      """Drop keys with None to keep responses compact."""
      return {k: v for k, v in values.items() if v is not None}

• src/ctfd_mcp/server.py:102-108 (registration)

  Registration of start_container as an MCP tool via @mcp.tool decorator with description.

  @mcp.tool(
      description="Unified start: detects plugin (whale/ctfd-owl/k8s) and starts container."
  )
  async def start_container(challenge_id: int):
      client = await _get_client()
      try:
          return await client.start_container(challenge_id)