Envoy Simple EDS Flask Server Example

main.py

import logging

from flask import Flask, request


class ServicesDAO(object):
    def __init__(self):
        self.services = {}

    def get(self, service_name):
        if (service_name in self.services):
           return self.services[service_name]
        api.abort(404, "Services {} doesn't exist".format(service_name))

    def create(self, service_name, data):
        if (service_name in self.services):
            api.abort(409, "Serivce {} already exists".format(str(service_name)))
        self.services[service_name] = data
        return data

DAO = ServicesDAO()
app = Flask(__name__)

@api.route('/v2/discovery:endpoints')
def envoy_eds(service_name):
    data = json.loads(request.data)
    print("Inbound v2 request for discovery. POST payload: " + str(data))

    id = data['node']["id"]
    cluster = data['node']["cluster"]
    resource_names = data["resource_names"]
    for r in resource_names:
              if (DAO.services.has_key(r)):
                svc = DAO.services[r]
                endpoints =  []
                for host in svc.get("hosts"):
                   endpoints.append(
                       {"endpoint": {
                        "address":  {
                           "socket_address": {
                               "address": host.get("ip_address"),
                               "port_value":  host.get("port")
                           }
                        }
                       }}
                   )
                resp = {
                  "version_info": _VERSION,
                  "resources": [ 
                      {
                        "@type":"type.googleapis.com/envoy.api.v2.ClusterLoadAssignment",
                        "cluster_name": r,
                        "endpoints": [
                            {
                                "lb_endpoints": endpoints
                            }
                        ]
                      }
                  ]
                }

@app.route('/eds/<string:service_name>', methods=['GET'])
def get_service(service_name):
    try:
        return DAO.services[service_name]
    except KeyError:
        return "Not found"

@app.route('/eds/<string:service_name>', methods=['POST'])
def create_service(service_name):
    data = request.get_json()
    return DAO.create(service_name, data), 201


if __name__ == '__main__':
    log_level = logging.DEBUG
    logging.getLogger('').handlers = []
    logging.basicConfig(format='%(asctime)s %(message)s', level=log_level)
    app.run(debug=True, host='0.0.0.0', port=80)