osm_lcm/paas_conn.py

#!/usr/bin/python3
#
# Copyright 2022 Canonical Ltd.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
#     Unless required by applicable law or agreed to in writing, software
#     distributed under the License is distributed on an "AS IS" BASIS,
#     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#     See the License for the specific language governing permissions and
#     limitations under the License.

import abc
import asyncio
import logging


def paas_connector_factory(
    uuid: str,
    name: str,
    db: object,
    fs: object,
    loop: object,
    log: object,
    config: dict,
    paas_type="juju",
):
    """Factory Method to create the paas_connector objects according to PaaS Type.
    Args:
        uuid    (str):              Internal id of PaaS account
        name    (str):              name assigned to PaaS account, can be used for logging
        db  (object):               Database object to write current operation status
        fs  (object):               Filesystem object to use during operations
        loop    (object):           Async event loop object
        log (object):               Logger for tracing
        config  (dict):             Dictionary with extra PaaS information.
        paas_type   (str):          Identifier to create paas_connector object using correct PaaS Connector Class

    Returns:
        paas_connector  (object):   paas_connector objects created according to given PaaS Type

    Raises:
        PaasConnException
    """
    connectors = {
        "juju": JujuPaasConnector,
    }
    if paas_type not in connectors.keys():
        raise PaasConnException(f"PaaS type: {paas_type} is not available.")

    return connectors[paas_type](uuid, name, db, fs, loop, log, config)


class PaasConnException(Exception):
    """PaaS Connector Exception Base Class"""

    def __init__(self, message: str = ""):
        """Constructor of PaaS Connector Exception
        Args:
            message (str):  error message to be raised
        """
        Exception.__init__(self, message)
        self.message = message

    def __str__(self):
        return self.message

    def __repr__(self):
        return "{}({})".format(type(self), self.message)


class JujuPaasConnException(PaasConnException):
    """Juju PaaS Connector Exception Class"""


class AbstractPaasConnector(abc.ABC):
    """Abstract PaaS Connector class to perform operations using PaaS Orchestrator."""

    def __init__(
        self,
        uuid=None,
        name=None,
        db=None,
        fs=None,
        logger=None,
        loop=None,
        config=None,
    ):
        """Constructor of PaaS Connector.
        Args:
            uuid    (str):      internal id of PaaS account
            name    (str):      name assigned to this account, can be used for logging
            db  (object):       database object to write current operation status
            fs  (object):       Filesystem object to use during operations
            logger (object):    Logger for tracing
            loop    (object):   Async event loop object
            config  (dict):     Dictionary with extra PaaS information.
        """
        self.id = uuid
        self.name = name
        self.db = db
        self.fs = fs
        self.config = config or {}
        self.logger = logger

    @abc.abstractmethod
    async def connect(self, endpoints: str, user: str = None, secret: str = None):
        """Abstract method to connect PaaS account using endpoints, user and secret.
        Args:
            endpoints   (str):     Endpoint/URL to connect PaaS account
            user    (str):         User which is used to connect PaaS account
            secret  (str):         Used for authentication
        """

    @abc.abstractmethod
    async def instantiate(self, nsr_id: str, nslcmop_id: str):
        """Abstract method to perform PaaS Service instantiation.
        Args:
            nsr_id   (str):     NS service record to be used
            nslcmop_id  (str):  NS LCM operation id
        """

    @abc.abstractmethod
    async def terminate(self, nsr_id: str, nslcmop_id: str):
        """Abstract method to perform PaaS Service termination.
        Args:
            nsr_id   (str):     NS service record to be used
            nslcmop_id  (str):  NS LCM operation id
        """

    @abc.abstractmethod
    async def action(self, nsr_id: str, nslcmop_id: str):
        """Abstract method to perform action on PaaS Service.
        Args:
            nsr_id   (str):     NS service record to be used
            nslcmop_id  (str):  NS LCM operation id
        """


class JujuPaasConnector(AbstractPaasConnector):
    """Concrete PaaS Connector class to perform operations using the Juju PaaS Orchestrator."""

    def __init__(
        self,
        uuid=None,
        name=None,
        db=None,
        fs=None,
        logger=None,
        loop=None,
        config=None,
    ):
        self.logger = logging.getLogger("lcm.juju_paas_connector")
        super(JujuPaasConnector, self).__init__(logger=self.logger)

    async def connect(self, endpoints: str, user: str = None, secret: str = None):
        """Connect Juju PaaS account using endpoints, user and secret.
        Args:
            endpoints   (str):     Endpoint/URL to connect PaaS account
            user    (str):         User which is used to connect PaaS account
            secret  (str):         Used for authentication

        Raises:
            NotImplementedError
        """
        raise NotImplementedError(
            "Juju Paas Connector connect method is not implemented"
        )

    async def instantiate(self, nsr_id: str, nslcmop_id: str):
        """Perform Service instantiation.
        Args:
            nsr_id   (str):     NS service record to be used
            nslcmop_id  (str):  NS LCM operation id

        Raises:
            JujuPaasConnException
        """
        # This is not the real implementation
        # Sample code blocks to validate method execution
        await asyncio.sleep(1)
        self.logger.debug("Juju Paas Connector instantiate method is called")

    async def terminate(self, nsr_id: str, nslcmop_id: str):
        """Perform PaaS Service termination.
        Args:
            nsr_id   (str):     NS service record to be used
            nslcmop_id  (str):  NS LCM operation id

        Raises:
            JujuPaasConnException
        """
        # This is not the real implementation
        # Sample code blocks to validate method execution
        await asyncio.sleep(1)
        self.logger.debug("Juju Paas Connector terminate method is called")

    async def action(self, nsr_id: str, nslcmop_id: str):
        """Perform action on PaaS Service.
        Args:
            nsr_id   (str):     NS service record to be used
            nslcmop_id  (str):  NS LCM operation id

        Raises:
            NotImplementedError
        """
        raise NotImplementedError(
            "Juju Paas Connector instantiate method is not implemented"
        )