[SOLVED] Preservice a state in python spyne (like a db connection)

Preservice a state in python spyne (like a db connection)

I am using python v3.5 with the package spyne 2.13 running on a gunicorn server v19.9

I wrote a small SOAP Webservice with python spyne (working well). It takes a string and enqueues it to rabbitmq. It must not neccessarily be rabbitmq, but also a simple DB insert oslt. Right now it works fine, but each time the webservice is called, it

opens a rabbitmq connection (or a DB connection if you'd like)
sends the message
closes the connection again(?)

I'd like to somehow preserve the connection in some sort of 'instance variable' and re-use it everytime the Webservice gets called. So that it connects only once and not everytime i call the ws. Unfortunately spyne does not seem to create any objects, so there are no instance variables.

Generally: How can I preserve a state (DB or RabbitMQ Connection) when using spyne?

Solution

So I tried this Trick with static class properties like so:

class Ws2RabbitMQ(ServiceBase):

    rabbit_connection = pika.BlockingConnection(
        pika.ConnectionParameters(host='localhost'))
    rabbit_channel = rabbit_connection.channel()

    @staticmethod
    def connectRabbit():
        rabbit_cred = pika.PlainCredentials(username='...', password='...')
        Ws2RabbitMQ.rabbit_connection = pika.BlockingConnection(pika.ConnectionParameters(
            host='...', virtual_host='...', credentials=rabbit_cred))
        Ws2RabbitMQ.rabbit_channel = Ws2RabbitMQ.rabbit_connection.channel()
        print('Rabbit connected!')

    @rpc(AnyXml, _returns=Unicode)
    def exportGRID(ctx, payload):
        try:
            if not Ws2RabbitMQ.rabbit_connection.is_open:
                print('RabbitMQ Connection lost - reconnecting...')
                Ws2RabbitMQ.connectRabbit()
        except Exception as e:
            print('RabbitMQ Connection not found - initiating...')
            Ws2RabbitMQ.connectRabbit()

        Ws2RabbitMQ.rabbit_channel.basic_publish(
            exchange='ws2rabbitmq', routing_key="blind", body=payload)

        print(" [x] Sent")
        return 'OK'

When I call the webservice twice, it works. Now, the Connection is created only once and kept in the Singleton Property.

Here is the scripts output:

RabbitMQ Connection not found - initiating...
Rabbit connected!
 [x] Sent
 [x] Sent