capsul-flask/capsulflask/spoke_api.py

import sys
import aiohttp
from flask import Blueprint
from flask import current_app
from flask import request
from flask.json import jsonify
from werkzeug.exceptions import abort

from capsulflask.shared import  my_exec_info_message, authorized_as_hub

bp = Blueprint("spoke", __name__, url_prefix="/spoke")

@bp.route("/heartbeat", methods=("POST",))
def heartbeat():
  if authorized_as_hub(request.headers):
    url = f"{current_app.config['HUB_URL']}/hub/heartbeat/{current_app.config['SPOKE_HOST_ID']}"
    authorization_header = f"Bearer {current_app.config['SPOKE_HOST_TOKEN']}"
    result = current_app.config['HTTP_CLIENT'].post_json_sync(url, body=None, authorization_header=authorization_header)
    if result.status_code == -1:
      current_app.logger.info(f"/hosts/heartbeat returned 503: hub at {url} timed out or cannot be reached")
      return abort(503, "Service Unavailable: hub timed out or cannot be reached")
    if result.status_code == 401:
      current_app.logger.info(f"/hosts/heartbeat returned 502: hub at {url} rejected our token")
      return abort(502, "hub rejected our token")
    if result.status_code != 200:
      current_app.logger.info(f"/hosts/heartbeat returned 502: hub at {url} returned {result.status_code}")
      return abort(502, "Bad Gateway: hub did not return 200")

    return "OK"
  else:
    current_app.logger.info(f"/hosts/heartbeat returned 401: invalid hub token")
    return abort(401, "invalid hub token")

@bp.route("/operation", methods=("POST",))
def operation():
  if authorized_as_hub(request.headers):
    request_body = request.json()
    handlers = {
      "capacity_avaliable": handle_capacity_avaliable,
      "get": handle_get,
      "list_ids": handle_list_ids,
      "create": handle_create,
      "destroy": handle_destroy,
    }

    error_message = ""
    types_csv = ", ".join(handlers.keys())
    if isinstance(request_body, dict) and 'type' in request_body:
      if request_body['type'] in handlers:
        try:
          return handlers[request_body['type']](request_body)
        except:
          error_message = my_exec_info_message(sys.exc_info())
          current_app.logger.error(f"unhandled exception in {request_body['type']} handler: {error_message}")
          return jsonify(dict(error_message=error_message))
      else:
        error_message = f"'type' must be one of {types_csv}"
    else:
      error_message = "'type' json property is required"

    if error_message != "":
      current_app.logger.info(f"/hosts/operation returned 400: {error_message}")
      return abort(400, f"bad request; {error_message}")
  else:
    current_app.logger.info(f"/hosts/operation returned 401: invalid hub token")
    return abort(401, "invalid hub token")

def handle_capacity_avaliable(request_body):
  if 'additional_ram_bytes' not in request_body:
    current_app.logger.info(f"/hosts/operation returned 400: additional_ram_bytes is required for capacity_avaliable")
    return abort(400, f"bad request; additional_ram_bytes is required for capacity_avaliable")

  has_capacity = current_app.config['SPOKE_MODEL'].capacity_avaliable(request_body['additional_ram_bytes'])
  return jsonify(dict(assignment_status="assigned", capacity_avaliable=has_capacity))

def handle_get(request_body):
  if 'id' not in request_body:
    current_app.logger.info(f"/hosts/operation returned 400: id is required for get")
    return abort(400, f"bad request; id is required for get")

  vm = current_app.config['SPOKE_MODEL'].get(request_body['id'])
  
  return jsonify(dict(assignment_status="assigned", id=vm.id, host=vm.host, ipv4=vm.ipv4, ipv6=vm.ipv6))

def handle_list_ids(request_body):
  return jsonify(dict(assignment_status="assigned", ids=current_app.config['SPOKE_MODEL'].list_ids()))

def handle_create(request_body):
  parameters = ["operation_id", "email", "id", "template_image_file_name", "vcpus", "memory_mb", "ssh_public_keys"]
  error_message = ""
  for parameter in parameters:
    if parameter not in request_body:
      error_message = f"{error_message}\n{parameter} is required for create"
  
  if error_message != "":
    current_app.logger.info(f"/hosts/operation returned 400: {error_message}")
    return abort(400, f"bad request; {error_message}")

  # only one host should create the vm, so we first race to assign this create operation to ourselves.
  # only one host will win this race
  authorization_header = f"Bearer {current_app.config['SPOKE_HOST_TOKEN']}"
  url = f"{current_app.config['HUB_URL']}/hub/claim-operation/{request_body['operation_id']}/{current_app.config['SPOKE_HOST_ID']}"
  result = current_app.config['HTTP_CLIENT'].post_json_sync(url, body=None, authorization_header=authorization_header)

  assignment_status = ""
  if result.status_code == 200:
    assignment_status = "assigned"
  elif result.status_code == 409:
    assignment_status = "assigned_to_other_host"
  else:
    current_app.logger.info(f"{url} returned {result.status_code}: {result.body}")
    return abort(503, f"hub did not cleanly handle our request to claim the create operation")
    
  if assignment_status == "assigned":
    try:
      current_app.config['SPOKE_MODEL'].create(
        email=request_body['email'],
        id=request_body['id'],
        template_image_file_name=request_body['template_image_file_name'],
        vcpus=request_body['vcpus'],
        memory_mb=request_body['memory_mb'],
        ssh_public_keys=request_body['ssh_public_keys'],
      )
    except:
      error_message = my_exec_info_message(sys.exc_info())
      params = f"email='{request_body['email']}', id='{request_body['id']}', "
      params = f"{params}, template_image_file_name='{request_body['template_image_file_name']}', vcpus='{request_body['vcpus']}'"
      params = f"{params}, memory_mb='{request_body['memory_mb']}', ssh_public_keys='{request_body['ssh_public_keys']}'"
      current_app.logger.error(f"spoke_model.create({params}) failed: {error_message}")
      return jsonify(dict(assignment_status=assignment_status, error_message=error_message))

  return jsonify(dict(assignment_status=assignment_status))

def handle_destroy(request_body):
  if 'id' not in request_body:
    current_app.logger.info(f"/hosts/operation returned 400: id is required for destroy")
    return abort(400, f"bad request; id is required for destroy")

  if 'email' not in request_body:
    current_app.logger.info(f"/hosts/operation returned 400: email is required for destroy")
    return abort(400, f"bad request; email is required for destroy")

  try:
    current_app.config['SPOKE_MODEL'].destroy(id=request_body['id'], email=request_body['email'])
  except:
    error_message = my_exec_info_message(sys.exc_info())
    current_app.logger.error(f"current_app.config['SPOKE_MODEL'].destroy(id='{request_body['id']}', email='{request_body['email']}') failed: {error_message}")
    return jsonify(dict(assignment_status="assigned", status="error", error_message=error_message))
  
  return jsonify(dict(assignment_status="assigned", status="success"))