path: root/policyhandler/policy_rest.py

# ================================================================================
# Copyright (c) 2017-2018 AT&T Intellectual Property. All rights reserved.
# ================================================================================
# 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.
# ============LICENSE_END=========================================================
#
# ECOMP is a trademark and service mark of AT&T Intellectual Property.

"""policy-client communicates with policy-engine thru REST API"""

import copy
import json
import logging
import time
from multiprocessing.dummy import Pool as ThreadPool
from threading import Lock

import requests

from .config import Config, Settings
from .onap.audit import (REQUEST_X_ECOMP_REQUESTID, AuditHttpCode,
                         AuditResponseCode, Metrics)
from .policy_consts import (ERRORED_POLICIES, LATEST_POLICIES, POLICY_BODY,
                            POLICY_CONFIG, POLICY_FILTER, POLICY_FILTERS,
                            POLICY_ID, POLICY_NAME)
from .policy_utils import PolicyUtils


class PolicyRest(object):
    """using the http API to policy-engine"""
    _logger = logging.getLogger("policy_handler.policy_rest")
    _lazy_inited = False
    POLICY_GET_CONFIG = 'getConfig'
    PDP_CONFIG_STATUS = "policyConfigStatus"
    PDP_CONFIG_RETRIEVED = "CONFIG_RETRIEVED"
    PDP_CONFIG_NOT_FOUND = "CONFIG_NOT_FOUND"
    PDP_CONFIG_MESSAGE = "policyConfigMessage"
    PDP_NO_RESPONSE_RECEIVED = "No Response Received"
    PDP_STATUS_CODE_ERROR = 400
    PDP_DATA_NOT_FOUND = "PE300 - Data Issue: Incorrect Params passed: Decision not a Permit."

    EXPECTED_VERSIONS = "expected_versions"
    IGNORE_POLICY_NAMES = "ignore_policy_names"

    _lock = Lock()
    _settings = Settings(Config.FIELD_POLICY_ENGINE, Config.POOL_CONNECTIONS,
                         Config.THREAD_POOL_SIZE,
                         Config.POLICY_RETRY_COUNT, Config.POLICY_RETRY_SLEEP)

    _requests_session = None
    _url_get_config = None
    _headers = None
    _target_entity = None
    _thread_pool_size = 4
    _policy_retry_count = 1
    _policy_retry_sleep = 0

    @staticmethod
    def _init():
        """init static config"""
        _, config = PolicyRest._settings.get_by_key(Config.FIELD_POLICY_ENGINE)

        if not PolicyRest._requests_session:
            PolicyRest._requests_session = requests.Session()

        changed, pool_size = PolicyRest._settings.get_by_key(Config.POOL_CONNECTIONS, 20)
        if changed:
            PolicyRest._requests_session.mount(
                'https://', requests.adapters.HTTPAdapter(pool_connections=pool_size,
                                                          pool_maxsize=pool_size))
            PolicyRest._requests_session.mount(
                'http://', requests.adapters.HTTPAdapter(pool_connections=pool_size,
                                                         pool_maxsize=pool_size))

        PolicyRest._url_get_config = (config["url"] + config["path_api"]
                                      + PolicyRest.POLICY_GET_CONFIG)
        PolicyRest._headers = config["headers"]
        PolicyRest._target_entity = config.get("target_entity", Config.FIELD_POLICY_ENGINE)
        _, PolicyRest._thread_pool_size = PolicyRest._settings.get_by_key(
            Config.THREAD_POOL_SIZE, 4)
        if PolicyRest._thread_pool_size < 2:
            PolicyRest._thread_pool_size = 2

        _, PolicyRest._policy_retry_count = PolicyRest._settings.get_by_key(
            Config.POLICY_RETRY_COUNT, 1)
        _, PolicyRest._policy_retry_sleep = PolicyRest._settings.get_by_key(
            Config.POLICY_RETRY_SLEEP, 0)

        PolicyRest._logger.info("PDP url(%s) headers(%s): %s",
                                PolicyRest._url_get_config,
                                Metrics.json_dumps(PolicyRest._headers),
                                PolicyRest._settings)

        PolicyRest._settings.commit_change()
        PolicyRest._lazy_inited = True

    @staticmethod
    def reconfigure():
        """reconfigure"""
        with PolicyRest._lock:
            PolicyRest._settings.set_config(Config.discovered_config)
            if not PolicyRest._settings.is_changed():
                PolicyRest._settings.commit_change()
                return False

            PolicyRest._lazy_inited = False
            PolicyRest._init()
        return True

    @staticmethod
    def _lazy_init():
        """init static config"""
        if PolicyRest._lazy_inited:
            return

        with PolicyRest._lock:
            if PolicyRest._lazy_inited:
                return

            PolicyRest._settings.set_config(Config.discovered_config)
            PolicyRest._init()

    @staticmethod
    def _pdp_get_config(audit, json_body):
        """Communication with the policy-engine"""
        metrics = Metrics(aud_parent=audit, targetEntity=PolicyRest._target_entity,
                          targetServiceName=PolicyRest._url_get_config)

        with PolicyRest._lock:
            session = PolicyRest._requests_session
            url = PolicyRest._url_get_config
            headers = copy.deepcopy(PolicyRest._headers)

        headers[REQUEST_X_ECOMP_REQUESTID] = metrics.request_id
        headers_str = Metrics.json_dumps(headers)

        msg = json.dumps(json_body)
        log_line = "post to PDP {} msg={} headers={}".format(url, msg, headers_str)

        PolicyRest._logger.info(metrics.metrics_start(log_line))

        res = None
        try:
            res = session.post(url, json=json_body, headers=headers)
        except Exception as ex:
            error_code = (AuditHttpCode.SERVICE_UNAVAILABLE_ERROR.value
                          if isinstance(ex, requests.exceptions.RequestException)
                          else AuditHttpCode.SERVER_INTERNAL_ERROR.value)
            error_msg = ("failed {}: {} to {}".format(type(ex).__name__, str(ex), log_line))

            PolicyRest._logger.exception(error_msg)
            metrics.set_http_status_code(error_code)
            audit.set_http_status_code(error_code)
            metrics.metrics(error_msg)
            return (error_code, None)

        log_line = "response {} from post to PDP {}: msg={} text={} headers={}".format(
            res.status_code, url, msg, res.text,
            Metrics.json_dumps(dict(res.request.headers.items())))

        status_code, res_data = PolicyRest._extract_pdp_res_data(audit, metrics, log_line, res)

        if status_code:
            return status_code, res_data

        metrics.set_http_status_code(res.status_code)
        metrics.metrics(log_line)
        PolicyRest._logger.info(log_line)
        return res.status_code, res_data

    @staticmethod
    def _extract_pdp_res_data(audit, metrics, log_line, res):
        """special treatment of pdp response"""
        res_data = None
        if res.status_code == requests.codes.ok:
            res_data = res.json()

            if res_data and isinstance(res_data, list) and len(res_data) == 1:
                rslt = res_data[0]
                if rslt and not rslt.get(POLICY_NAME):
                    res_data = None
                if rslt.get(PolicyRest.PDP_CONFIG_MESSAGE) == PolicyRest.PDP_NO_RESPONSE_RECEIVED:
                    error_code = AuditHttpCode.SERVICE_UNAVAILABLE_ERROR.value
                    error_msg = "unexpected {0}".format(log_line)

                    PolicyRest._logger.error(error_msg)
                    metrics.set_http_status_code(error_code)
                    audit.set_http_status_code(error_code)
                    metrics.metrics(error_msg)
                    return error_code, None
            return None, res_data

        if res.status_code == PolicyRest.PDP_STATUS_CODE_ERROR:
            try:
                res_data = res.json()
            except ValueError:
                return None, None

            if not res_data or not isinstance(res_data, list) or len(res_data) != 1:
                return None, None

            rslt = res_data[0]
            if (rslt and not rslt.get(POLICY_NAME)
                    and rslt.get(PolicyRest.PDP_CONFIG_STATUS) == PolicyRest.PDP_CONFIG_NOT_FOUND
                    and rslt.get(PolicyRest.PDP_CONFIG_MESSAGE) == PolicyRest.PDP_DATA_NOT_FOUND):
                status_code = AuditHttpCode.DATA_NOT_FOUND_ERROR.value
                info_msg = "not found {0}".format(log_line)

                PolicyRest._logger.info(info_msg)
                metrics.set_http_status_code(status_code)
                metrics.metrics(info_msg)
                return status_code, None
        return None, None


    @staticmethod
    def _validate_policy(policy):
        """Validates the config on policy"""
        if not policy:
            return

        policy_body = policy.get(POLICY_BODY)

        return bool(
            policy_body
            and policy_body.get(PolicyRest.PDP_CONFIG_STATUS) == PolicyRest.PDP_CONFIG_RETRIEVED
            and policy_body.get(POLICY_CONFIG)
        )

    @staticmethod
    def get_latest_policy(aud_policy_id):
        """safely try retrieving the latest policy for the policy_id from the policy-engine"""
        audit, policy_id, expected_versions, ignore_policy_names = aud_policy_id
        str_metrics = "policy_id({0}), expected_versions({1}) ignore_policy_names({2})".format(
            policy_id, json.dumps(expected_versions), json.dumps(ignore_policy_names))

        try:
            return PolicyRest._get_latest_policy(
                audit, policy_id, expected_versions, ignore_policy_names, str_metrics)

        except Exception as ex:
            error_msg = ("{0}: crash {1} {2} at {3}: {4}"
                         .format(audit.request_id, type(ex).__name__, str(ex),
                                 "get_latest_policy", str_metrics))

            PolicyRest._logger.exception(error_msg)
            audit.fatal(error_msg, error_code=AuditResponseCode.BUSINESS_PROCESS_ERROR)
            audit.set_http_status_code(AuditHttpCode.SERVER_INTERNAL_ERROR.value)
            return None


    @staticmethod
    def _get_latest_policy(audit, policy_id,
                           expected_versions, ignore_policy_names, str_metrics):
        """retry several times getting the latest policy for the policy_id from the policy-engine"""
        PolicyRest._lazy_init()
        latest_policy = None
        status_code = 0
        retry_get_config = audit.kwargs.get("retry_get_config")
        expect_policy_removed = (ignore_policy_names and not expected_versions)

        for retry in range(1, PolicyRest._policy_retry_count + 1):
            PolicyRest._logger.debug(str_metrics)

            done, latest_policy, status_code = PolicyRest._get_latest_policy_once(
                audit, policy_id, expected_versions, ignore_policy_names,
                expect_policy_removed)

            if done or not retry_get_config or not PolicyRest._policy_retry_sleep:
                break

            if retry == PolicyRest._policy_retry_count:
                audit.warn("gave up retrying {0} from PDP after #{1} for policy_id={2}"
                           .format(PolicyRest._url_get_config, retry, policy_id),
                           error_code=AuditResponseCode.DATA_ERROR)
                break

            audit.warn(
                "retry #{0} {1} from PDP in {2} secs for policy_id={3}".format(
                    retry, PolicyRest._url_get_config,
                    PolicyRest._policy_retry_sleep, policy_id),
                error_code=AuditResponseCode.DATA_ERROR)
            time.sleep(PolicyRest._policy_retry_sleep)

        if (expect_policy_removed and not latest_policy
                and AuditHttpCode.RESPONSE_ERROR.value == status_code):
            audit.set_http_status_code(AuditHttpCode.HTTP_OK.value)
            return None

        audit.set_http_status_code(status_code)
        if not PolicyRest._validate_policy(latest_policy):
            audit.set_http_status_code(AuditHttpCode.DATA_NOT_FOUND_ERROR.value)
            audit.error(
                "received invalid policy from PDP: {0}".format(json.dumps(latest_policy)),
                error_code=AuditResponseCode.DATA_ERROR)

        return latest_policy

    @staticmethod
    def _get_latest_policy_once(audit, policy_id,
                                expected_versions, ignore_policy_names,
                                expect_policy_removed):
        """single attempt to get the latest policy for the policy_id from the policy-engine"""

        status_code, policy_bodies = PolicyRest._pdp_get_config(audit, {POLICY_NAME:policy_id})

        PolicyRest._logger.debug("%s %s policy_bodies: %s",
                                 status_code, policy_id, json.dumps(policy_bodies or []))

        latest_policy = PolicyUtils.select_latest_policy(
            policy_bodies, expected_versions, ignore_policy_names
        )

        if not latest_policy and not expect_policy_removed:
            audit.error("received unexpected policy data from PDP for policy_id={0}: {1}"
                        .format(policy_id, json.dumps(policy_bodies or [])),
                        error_code=AuditResponseCode.DATA_ERROR)

        done = bool(latest_policy
                    or (expect_policy_removed and not policy_bodies)
                    or audit.is_serious_error(status_code))

        return done, latest_policy, status_code

    @staticmethod
    def get_latest_updated_policies(aud_policy_updates):
        """safely try retrieving the latest policies for the list of policy_names"""
        audit, policies_updated, policies_removed = aud_policy_updates
        if not policies_updated and not policies_removed:
            return None, None

        str_metrics = "policies_updated[{0}]: {1} policies_removed[{2}]: {3}".format(
            len(policies_updated), json.dumps(policies_updated),
            len(policies_removed), json.dumps(policies_removed))

        try:
            return PolicyRest._get_latest_updated_policies(
                audit, str_metrics, policies_updated, policies_removed)

        except Exception as ex:
            error_msg = ("{0}: crash {1} {2} at {3}: {4}"
                         .format(audit.request_id, type(ex).__name__, str(ex),
                                 "get_latest_updated_policies", str_metrics))

            PolicyRest._logger.exception(error_msg)
            audit.fatal(error_msg, error_code=AuditResponseCode.BUSINESS_PROCESS_ERROR)
            audit.set_http_status_code(AuditHttpCode.SERVER_INTERNAL_ERROR.value)
            return None, None

    @staticmethod
    def _get_latest_updated_policies(audit, str_metrics, policies_updated, policies_removed):
        """Get the latest policies of the list of policy_names from the policy-engine"""
        PolicyRest._lazy_init()
        metrics_total = Metrics(
            aud_parent=audit,
            targetEntity="{0} total get_latest_updated_policies".format(PolicyRest._target_entity),
            targetServiceName=PolicyRest._url_get_config)

        metrics_total.metrics_start("get_latest_updated_policies {0}".format(str_metrics))
        PolicyRest._logger.debug(str_metrics)

        policies_to_find = {}
        for (policy_id, policy_version) in policies_updated:
            if not policy_id or not policy_version or not policy_version.isdigit():
                continue
            policy = policies_to_find.get(policy_id)
            if not policy:
                policies_to_find[policy_id] = {
                    POLICY_ID: policy_id,
                    PolicyRest.EXPECTED_VERSIONS: {policy_version: True},
                    PolicyRest.IGNORE_POLICY_NAMES: {}
                }
                continue
            policy[PolicyRest.EXPECTED_VERSIONS][policy_version] = True

        for (policy_id, policy_names) in policies_removed:
            if not policy_id:
                continue
            policy = policies_to_find.get(policy_id)
            if not policy:
                policies_to_find[policy_id] = {
                    POLICY_ID: policy_id,
                    PolicyRest.IGNORE_POLICY_NAMES: policy_names
                }
                continue
            policy[PolicyRest.IGNORE_POLICY_NAMES].update(policy_names)

        apns = [(audit, policy_id,
                 policy_to_find.get(PolicyRest.EXPECTED_VERSIONS),
                 policy_to_find.get(PolicyRest.IGNORE_POLICY_NAMES))
                for (policy_id, policy_to_find) in policies_to_find.items()]

        policies = None
        apns_length = len(apns)
        if apns_length == 1:
            policies = [PolicyRest.get_latest_policy(apns[0])]
        else:
            pool = ThreadPool(min(PolicyRest._thread_pool_size, apns_length))
            policies = pool.map(PolicyRest.get_latest_policy, apns)
            pool.close()
            pool.join()

        metrics_total.metrics("result get_latest_updated_policies {0}: {1} {2}"
                              .format(str_metrics, len(policies), json.dumps(policies)))

        updated_policies = dict((policy[POLICY_ID], policy)
                                for policy in policies
                                if policy and policy.get(POLICY_ID))

        removed_policies = dict((policy_id, True)
                                for (policy_id, policy_to_find) in policies_to_find.items()
                                if not policy_to_find.get(PolicyRest.EXPECTED_VERSIONS)
                                and policy_to_find.get(PolicyRest.IGNORE_POLICY_NAMES)
                                and policy_id not in updated_policies)

        errored_policies = dict((policy_id, policy_to_find)
                                for (policy_id, policy_to_find) in policies_to_find.items()
                                if policy_id not in updated_policies
                                and policy_id not in removed_policies)

        PolicyRest._logger.debug(
            "result updated_policies %s, removed_policies %s, errored_policies %s",
            json.dumps(updated_policies), json.dumps(removed_policies),
            json.dumps(errored_policies))

        if errored_policies:
            audit.set_http_status_code(AuditHttpCode.DATA_NOT_FOUND_ERROR.value)
            audit.error(
                "errored_policies in PDP: {0}".format(json.dumps(errored_policies)),
                error_code=AuditResponseCode.DATA_ERROR)

        return updated_policies, removed_policies


    @staticmethod
    def _get_latest_policies(aud_policy_filter):
        """get the latest policies by policy_filter from the policy-engine"""
        audit, policy_filter = aud_policy_filter
        try:
            str_policy_filter = json.dumps(policy_filter)
            PolicyRest._logger.debug("%s", str_policy_filter)

            status_code, policy_bodies = PolicyRest._pdp_get_config(audit, policy_filter)

            PolicyRest._logger.debug("%s policy_bodies: %s %s", status_code,
                                     str_policy_filter, json.dumps(policy_bodies or []))

            latest_policies = PolicyUtils.select_latest_policies(policy_bodies)

            if not latest_policies:
                audit.set_http_status_code(AuditHttpCode.DATA_NOT_FOUND_ERROR.value)
                audit.warn(
                    "received no policies from PDP for policy_filter {0}: {1}"
                    .format(str_policy_filter, json.dumps(policy_bodies or [])),
                    error_code=AuditResponseCode.DATA_ERROR)
                return None, latest_policies

            audit.set_http_status_code(status_code)
            valid_policies = {}
            errored_policies = {}
            for (policy_id, policy) in latest_policies.items():
                if PolicyRest._validate_policy(policy):
                    valid_policies[policy_id] = policy
                else:
                    errored_policies[policy_id] = policy
            return valid_policies, errored_policies

        except Exception as ex:
            error_msg = ("{0}: crash {1} {2} at {3}: policy_filter({4})"
                         .format(audit.request_id, type(ex).__name__, str(ex),
                                 "_get_latest_policies", json.dumps(policy_filter)))

            PolicyRest._logger.exception(error_msg)
            audit.fatal(error_msg, error_code=AuditResponseCode.BUSINESS_PROCESS_ERROR)
            audit.set_http_status_code(AuditHttpCode.SERVER_INTERNAL_ERROR.value)
            return None, None


    @staticmethod
    def get_latest_policies(audit, policy_filter=None, policy_filters=None):
        """Get the latest policies by policy-filter(s) from the policy-engine"""
        result = {}
        aud_policy_filters = None
        str_policy_filters = None
        str_metrics = None
        target_entity = None

        try:
            PolicyRest._lazy_init()
            if policy_filter:
                aud_policy_filters = [(audit, policy_filter)]
                str_policy_filters = json.dumps(policy_filter)
                str_metrics = "get_latest_policies for policy_filter {0}".format(
                    str_policy_filters)
                target_entity = ("{0} total get_latest_policies by policy_filter"
                                 .format(PolicyRest._target_entity))
                result[POLICY_FILTER] = copy.deepcopy(policy_filter)
            elif policy_filters:
                aud_policy_filters = [
                    (audit, policy_filter)
                    for policy_filter in policy_filters
                ]
                str_policy_filters = json.dumps(policy_filters)
                str_metrics = "get_latest_policies for policy_filters {0}".format(
                    str_policy_filters)
                target_entity = ("{0} total get_latest_policies by policy_filters"
                                 .format(PolicyRest._target_entity))
                result[POLICY_FILTERS] = copy.deepcopy(policy_filters)
            else:
                return result

            PolicyRest._logger.debug("%s", str_policy_filters)
            metrics_total = Metrics(aud_parent=audit, targetEntity=target_entity,
                                    targetServiceName=PolicyRest._url_get_config)

            metrics_total.metrics_start(str_metrics)

            latest_policies = None
            apfs_length = len(aud_policy_filters)
            if apfs_length == 1:
                latest_policies = [PolicyRest._get_latest_policies(aud_policy_filters[0])]
            else:
                pool = ThreadPool(min(PolicyRest._thread_pool_size, apfs_length))
                latest_policies = pool.map(PolicyRest._get_latest_policies, aud_policy_filters)
                pool.close()
                pool.join()

            metrics_total.metrics("total result {0}: {1} {2}".format(
                str_metrics, len(latest_policies), json.dumps(latest_policies)))

            # latest_policies == [(valid_policies, errored_policies), ...]
            result[LATEST_POLICIES] = dict(
                pair for (vps, _) in latest_policies if vps for pair in vps.items())

            result[ERRORED_POLICIES] = dict(
                pair for (_, eps) in latest_policies if eps for pair in eps.items())

            PolicyRest._logger.debug("got policies for policy_filters: %s. result: %s",
                                     str_policy_filters, json.dumps(result))
            return result

        except Exception as ex:
            error_msg = ("{0}: crash {1} {2} at {3}: {4}"
                         .format(audit.request_id, type(ex).__name__, str(ex),
                                 "get_latest_policies", str_metrics))

            PolicyRest._logger.exception(error_msg)
            audit.fatal(error_msg, error_code=AuditResponseCode.BUSINESS_PROCESS_ERROR)
            audit.set_http_status_code(AuditHttpCode.SERVER_INTERNAL_ERROR.value)
            return None