Added a test

By added the notification_type to the filter we get a better performance on the query. Especially when selecting for NotificationHistory.

app/__init__.py

@@ -1,19 +1,23 @@
+import time
 import os
 import random
 import string
 import uuid
 
-from flask import _request_ctx_stack, request, g, jsonify, make_response
+from celery import current_task
+from flask import _request_ctx_stack, request, g, jsonify, make_response, current_app, has_request_context
 from flask_sqlalchemy import SQLAlchemy as _SQLAlchemy
 from flask_marshmallow import Marshmallow
 from flask_migrate import Migrate
 from gds_metrics import GDSMetrics
+from gds_metrics.metrics import Gauge, Histogram
 from time import monotonic
 from notifications_utils.clients.zendesk.zendesk_client import ZendeskClient
 from notifications_utils.clients.statsd.statsd_client import StatsdClient
 from notifications_utils.clients.redis.redis_client import RedisClient
 from notifications_utils.clients.encryption.encryption_client import Encryption
 from notifications_utils import logging, request_helper
+from sqlalchemy import event
 from werkzeug.exceptions import HTTPException as WerkzeugHTTPException
 from werkzeug.local import LocalProxy
 
@@ -64,6 +68,11 @@ clients = Clients()
 api_user = LocalProxy(lambda: _request_ctx_stack.top.api_user)
 authenticated_service = LocalProxy(lambda: _request_ctx_stack.top.authenticated_service)
 
+CONCURRENT_REQUESTS = Gauge(
+    'concurrent_web_request_count',
+    'How many concurrent requests are currently being served',
+)
+
 
 def create_app(application):
     from app.config import configs
@@ -108,6 +117,9 @@ def create_app(application):
     from app.commands import setup_commands
     setup_commands(application)
 
+    # set up sqlalchemy events
+    setup_sqlalchemy_events(application)
+
     return application
 
 
@@ -255,17 +267,22 @@ def register_v2_blueprints(application):
 
 
 def init_app(app):
+
     @app.before_request
     def record_user_agent():
         statsd_client.incr("user-agent.{}".format(process_user_agent(request.headers.get('User-Agent', None))))
 
     @app.before_request
     def record_request_details():
+        CONCURRENT_REQUESTS.inc()
+
         g.start = monotonic()
         g.endpoint = request.endpoint
 
     @app.after_request
     def after_request(response):
+        CONCURRENT_REQUESTS.dec()
+
         response.headers.add('Access-Control-Allow-Origin', '*')
         response.headers.add('Access-Control-Allow-Headers', 'Content-Type,Authorization')
         response.headers.add('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE')
@@ -311,3 +328,83 @@ def process_user_agent(user_agent_string):
         return "non-notify-user-agent"
     else:
         return "unknown"
+
+
+def setup_sqlalchemy_events(app):
+
+    TOTAL_DB_CONNECTIONS = Gauge(
+        'db_connection_total_connected',
+        'How many db connections are currently held (potentially idle) by the server',
+    )
+
+    TOTAL_CHECKED_OUT_DB_CONNECTIONS = Gauge(
+        'db_connection_total_checked_out',
+        'How many db connections are currently checked out by web requests',
+    )
+
+    DB_CONNECTION_OPEN_DURATION_SECONDS = Histogram(
+        'db_connection_open_duration_seconds',
+        'How long db connections are held open for in seconds',
+        ['method', 'host', 'path']
+    )
+
+    # need this or db.engine isn't accessible
+    with app.app_context():
+        @event.listens_for(db.engine, 'connect')
+        def connect(dbapi_connection, connection_record):
+            # connection first opened with db
+            TOTAL_DB_CONNECTIONS.inc()
+
+        @event.listens_for(db.engine, 'close')
+        def close(dbapi_connection, connection_record):
+            # connection closed (probably only happens with overflow connections)
+            TOTAL_DB_CONNECTIONS.dec()
+
+        @event.listens_for(db.engine, 'checkout')
+        def checkout(dbapi_connection, connection_record, connection_proxy):
+            # connection given to a web worker
+            TOTAL_CHECKED_OUT_DB_CONNECTIONS.inc()
+
+            # this will overwrite any previous checkout_at timestamp
+            connection_record.info['checkout_at'] = time.monotonic()
+
+            # checkin runs after the request is already torn down, therefore we add the request_data onto the
+            # connection_record as otherwise it won't have that information when checkin actually runs.
+            # Note: this is not a problem for checkouts as the checkout always happens within a web request or task
+
+            # web requests
+            if has_request_context():
+                connection_record.info['request_data'] = {
+                    'method': request.method,
+                    'host': request.host,
+                    'url_rule': request.url_rule.rule if request.url_rule else 'No endpoint'
+                }
+            # celery apps
+            elif current_task:
+                connection_record.info['request_data'] = {
+                    'method': 'celery',
+                    'host': current_app.config['NOTIFY_APP_NAME'],  # worker name
+                    'url_rule': current_task.name,  # task name
+                }
+            # anything else. migrations possibly.
+            else:
+                current_app.logger.warning('Checked out sqlalchemy connection from outside of request/task')
+                connection_record.info['request_data'] = {
+                    'method': 'unknown',
+                    'host': 'unknown',
+                    'url_rule': 'unknown',
+                }
+
+        @event.listens_for(db.engine, 'checkin')
+        def checkin(dbapi_connection, connection_record):
+            # connection returned by a web worker
+            TOTAL_CHECKED_OUT_DB_CONNECTIONS.dec()
+
+            # duration that connection was held by a single web request
+            duration = time.monotonic() - connection_record.info['checkout_at']
+
+            DB_CONNECTION_OPEN_DURATION_SECONDS.labels(
+                connection_record.info['request_data']['method'],
+                connection_record.info['request_data']['host'],
+                connection_record.info['request_data']['url_rule']
+            ).observe(duration)

app/authentication/auth.py

@@ -6,12 +6,18 @@ from notifications_python_client.errors import (
 from notifications_utils import request_helper
 from sqlalchemy.exc import DataError
 from sqlalchemy.orm.exc import NoResultFound
+from gds_metrics import Histogram
 
 from app.dao.services_dao import dao_fetch_service_by_id_with_api_keys
 
 
 GENERAL_TOKEN_ERROR_MESSAGE = 'Invalid token: make sure your API token matches the example at https://docs.notifications.service.gov.uk/rest-api.html#authorisation-header'  # noqa
 
+AUTH_DB_CONNECTION_DURATION_SECONDS = Histogram(
+    'auth_db_connection_duration_seconds',
+    'Time taken to get DB connection and fetch service from database',
+)
+
 
 class AuthError(Exception):
     def __init__(self, message, code, service_id=None, api_key_id=None):
@@ -87,7 +93,8 @@ def requires_auth():
     issuer = __get_token_issuer(auth_token)  # ie the `iss` claim which should be a service ID
 
     try:
-        service = dao_fetch_service_by_id_with_api_keys(issuer)
+        with AUTH_DB_CONNECTION_DURATION_SECONDS.time():
+            service = dao_fetch_service_by_id_with_api_keys(issuer)
     except DataError:
         raise AuthError("Invalid token: service id is not the right data type", 403)
     except NoResultFound:

app/celery/celery.py

@@ -1,5 +1,6 @@
 import time
 
+from gds_metrics.metrics import Histogram
 from celery import Celery, Task
 from celery.signals import worker_process_shutdown
 from flask import g, request
@@ -19,6 +20,12 @@ def log_on_worker_shutdown(sender, signal, pid, exitcode, **kwargs):
 
 
 def make_task(app):
+    SQS_APPLY_ASYNC_DURATION_SECONDS = Histogram(
+        'sqs_apply_async_duration_seconds',
+        'Time taken to put task on queue',
+        ['task_name']
+    )
+
     class NotifyTask(Task):
         abstract = True
         start = None
@@ -52,7 +59,8 @@ def make_task(app):
             if has_request_context() and hasattr(request, 'request_id'):
                 kwargs['request_id'] = request.request_id
 
-            return super().apply_async(args, kwargs, task_id, producer, link, link_error, **options)
+            with SQS_APPLY_ASYNC_DURATION_SECONDS.labels(self.name).time():
+                return super().apply_async(args, kwargs, task_id, producer, link, link_error, **options)
 
     return NotifyTask
 

app/celery/letters_pdf_tasks.py

@@ -42,6 +42,7 @@ from app.models import (
     NOTIFICATION_TECHNICAL_FAILURE,
     NOTIFICATION_VALIDATION_FAILED,
     NOTIFICATION_VIRUS_SCAN_FAILED,
+    LETTER_TYPE
 )
 from app.cronitor import cronitor
 
@@ -216,7 +217,7 @@ def group_letters(letter_pdfs):
 def sanitise_letter(self, filename):
     try:
         reference = get_reference_from_filename(filename)
-        notification = dao_get_notification_by_reference(reference)
+        notification = dao_get_notification_by_reference(reference=reference, notification_type=LETTER_TYPE)
 
         current_app.logger.info('Notification ID {} Virus scan passed: {}'.format(notification.id, filename))
 
@@ -352,7 +353,7 @@ def _move_invalid_letter_and_update_status(
 def process_virus_scan_failed(filename):
     move_failed_pdf(filename, ScanErrorType.FAILURE)
     reference = get_reference_from_filename(filename)
-    notification = dao_get_notification_by_reference(reference)
+    notification = dao_get_notification_by_reference(reference=reference, notification_type=LETTER_TYPE)
     updated_count = update_letter_pdf_status(reference, NOTIFICATION_VIRUS_SCAN_FAILED, billable_units=0)
 
     if updated_count != 1:
@@ -371,7 +372,7 @@ def process_virus_scan_failed(filename):
 def process_virus_scan_error(filename):
     move_failed_pdf(filename, ScanErrorType.ERROR)
     reference = get_reference_from_filename(filename)
-    notification = dao_get_notification_by_reference(reference)
+    notification = dao_get_notification_by_reference(reference=reference, notification_type=LETTER_TYPE)
     updated_count = update_letter_pdf_status(reference, NOTIFICATION_TECHNICAL_FAILURE, billable_units=0)
 
     if updated_count != 1:

app/celery/process_ses_receipts_tasks.py

@@ -10,7 +10,7 @@ from app import notify_celery, statsd_client
 from app.config import QueueNames
 from app.clients.email.aws_ses import get_aws_responses
 from app.dao import notifications_dao
-from app.models import NOTIFICATION_SENDING, NOTIFICATION_PENDING
+from app.models import NOTIFICATION_SENDING, NOTIFICATION_PENDING, EMAIL_TYPE
 
 from app.notifications.notifications_ses_callback import (
     determine_notification_bounce_type,
@@ -39,7 +39,9 @@ def process_ses_results(self, response):
         reference = ses_message['mail']['messageId']
 
         try:
-            notification = notifications_dao.dao_get_notification_or_history_by_reference(reference=reference)
+            notification = notifications_dao.dao_get_notification_or_history_by_reference(
+                reference=reference, notification_type=EMAIL_TYPE
+            )
         except NoResultFound:
             message_time = iso8601.parse_date(ses_message['mail']['timestamp']).replace(tzinfo=None)
             if datetime.utcnow() - message_time < timedelta(minutes=5):

app/celery/tasks.py

@@ -536,7 +536,7 @@ def update_letter_notification(filename, temporary_failures, update):
 
 
 def check_billable_units(notification_update):
-    notification = dao_get_notification_or_history_by_reference(notification_update.reference)
+    notification = dao_get_notification_or_history_by_reference(notification_update.reference, LETTER_TYPE)
 
     if int(notification_update.page_count) != notification.billable_units:
         msg = 'Notification with id {} has {} billable_units but DVLA says page count is {}'.format(

app/dao/notifications_dao.py

@@ -650,33 +650,29 @@ def dao_get_notifications_by_recipient_or_reference(
 
 
 @statsd(namespace="dao")
-def dao_get_notification_by_reference(reference):
+def dao_get_notification_by_reference(reference, notification_type):
     return Notification.query.filter(
-        Notification.reference == reference
+        Notification.reference == reference,
+        Notification.notification_type == notification_type
     ).one()
 
 
 @statsd(namespace="dao")
-def dao_get_notification_or_history_by_reference(reference):
+def dao_get_notification_or_history_by_reference(reference, notification_type):
     try:
         # This try except is necessary because in test keys and research mode does not create notification history.
         # Otherwise we could just search for the NotificationHistory object
         return Notification.query.filter(
-            Notification.reference == reference
+            Notification.reference == reference,
+            Notification.notification_type == notification_type
         ).one()
     except NoResultFound:
         return NotificationHistory.query.filter(
-            NotificationHistory.reference == reference
+            NotificationHistory.reference == reference,
+            NotificationHistory.notification_type == notification_type
         ).one()
 
 
-@statsd(namespace="dao")
-def dao_get_notifications_by_references(references):
-    return Notification.query.filter(
-        Notification.reference.in_(references)
-    ).all()
-
-
 @statsd(namespace="dao")
 def dao_created_scheduled_notification(scheduled_notification):
     db.session.add(scheduled_notification)

app/delivery/send_to_providers.py

@@ -72,8 +72,8 @@ def send_sms_to_provider(notification):
                 notification.billable_units = template.fragment_count
                 update_notification_to_sending(notification, provider)
 
-        delta_milliseconds = (datetime.utcnow() - notification.created_at).total_seconds() * 1000
-        statsd_client.timing("sms.total-time", delta_milliseconds)
+        delta_seconds = (datetime.utcnow() - notification.created_at).total_seconds()
+        statsd_client.timing("sms.total-time", delta_seconds)
 
 
 def send_email_to_provider(notification):
@@ -118,8 +118,8 @@ def send_email_to_provider(notification):
             notification.reference = reference
             update_notification_to_sending(notification, provider)
 
-        delta_milliseconds = (datetime.utcnow() - notification.created_at).total_seconds() * 1000
-        statsd_client.timing("email.total-time", delta_milliseconds)
+        delta_seconds = (datetime.utcnow() - notification.created_at).total_seconds()
+        statsd_client.timing("email.total-time", delta_seconds)
 
 
 def update_notification_to_sending(notification, provider):

app/notifications/notifications_ses_callback.py

@@ -5,7 +5,7 @@ from app.dao.notifications_dao import dao_get_notification_or_history_by_referen
 from app.dao.service_callback_api_dao import (
     get_service_delivery_status_callback_api_for_service, get_service_complaint_callback_api_for_service
 )
-from app.models import Complaint
+from app.models import Complaint, EMAIL_TYPE
 from app.celery.service_callback_tasks import (
     send_delivery_status_to_service,
     send_complaint_to_service,
@@ -33,7 +33,7 @@ def handle_complaint(ses_message):
     except KeyError as e:
         current_app.logger.exception("Complaint from SES failed to get reference from message", e)
         return
-    notification = dao_get_notification_or_history_by_reference(reference)
+    notification = dao_get_notification_or_history_by_reference(reference, EMAIL_TYPE)
     ses_complaint = ses_message.get('complaint', None)
 
     complaint = Complaint(

app/notifications/process_notifications.py

@@ -34,6 +34,15 @@ from app.dao.notifications_dao import (
 from app.v2.errors import BadRequestError
 
 
+from gds_metrics import Histogram
+
+
+REDIS_GET_AND_INCR_DAILY_LIMIT_DURATION_SECONDS = Histogram(
+    'redis_get_and_incr_daily_limit_duration_seconds',
+    'Time taken to get and possibly incremement the daily limit cache key',
+)
+
+
 def create_content_for_notification(template, personalisation):
     template_object = template._as_utils_template_with_personalisation(personalisation)
     check_placeholders(template_object)
@@ -115,8 +124,9 @@ def persist_notification(
     if not simulated:
         dao_create_notification(notification)
         if key_type != KEY_TYPE_TEST:
-            if redis_store.get(redis.daily_limit_cache_key(service.id)):
-                redis_store.incr(redis.daily_limit_cache_key(service.id))
+            with REDIS_GET_AND_INCR_DAILY_LIMIT_DURATION_SECONDS.time():
+                if redis_store.get(redis.daily_limit_cache_key(service.id)):
+                    redis_store.incr(redis.daily_limit_cache_key(service.id))
 
         current_app.logger.info(
             "{} {} created at {}".format(notification_type, notification_id, notification_created_at)

app/notifications/validators.py

@@ -22,15 +22,24 @@ from app.utils import get_public_notify_type_text
 from app.dao.service_email_reply_to_dao import dao_get_reply_to_by_id
 from app.dao.service_letter_contact_dao import dao_get_letter_contact_by_id
 
+from gds_metrics.metrics import Histogram
+
+
+REDIS_EXCEEDED_RATE_LIMIT_DURATION_SECONDS = Histogram(
+    'redis_exceeded_rate_limit_duration_seconds',
+    'Time taken to check rate limit',
+)
+
 
 def check_service_over_api_rate_limit(service, api_key):
     if current_app.config['API_RATE_LIMIT_ENABLED'] and current_app.config['REDIS_ENABLED']:
         cache_key = rate_limit_cache_key(service.id, api_key.key_type)
         rate_limit = service.rate_limit
         interval = 60
-        if redis_store.exceeded_rate_limit(cache_key, rate_limit, interval):
-            current_app.logger.info("service {} has been rate limited for throughput".format(service.id))
-            raise RateLimitError(rate_limit, interval, api_key.key_type)
+        with REDIS_EXCEEDED_RATE_LIMIT_DURATION_SECONDS.time():
+            if redis_store.exceeded_rate_limit(cache_key, rate_limit, interval):
+                current_app.logger.info("service {} has been rate limited for throughput".format(service.id))
+                raise RateLimitError(rate_limit, interval, api_key.key_type)
 
 
 def check_service_over_daily_message_limit(key_type, service):

app/v2/notifications/post_notifications.py

@@ -7,6 +7,7 @@ from boto.exception import SQSError
 from flask import request, jsonify, current_app, abort
 from notifications_utils.postal_address import PostalAddress
 from notifications_utils.recipients import try_validate_and_format_phone_number
+from gds_metrics import Histogram
 
 from app import (
     api_user,
@@ -74,6 +75,12 @@ from app.v2.notifications.notification_schemas import (
 from app.v2.utils import get_valid_json
 
 
+POST_NOTIFICATION_JSON_PARSE_DURATION_SECONDS = Histogram(
+    'post_notification_json_parse_duration_seconds',
+    'Time taken to parse and validate post request json',
+)
+
+
 @v2_notification_blueprint.route('/{}'.format(LETTER_TYPE), methods=['POST'])
 def post_precompiled_letter_notification():
     request_json = get_valid_json()
@@ -116,16 +123,17 @@ def post_precompiled_letter_notification():
 
 @v2_notification_blueprint.route('/<notification_type>', methods=['POST'])
 def post_notification(notification_type):
-    request_json = get_valid_json()
+    with POST_NOTIFICATION_JSON_PARSE_DURATION_SECONDS.time():
+        request_json = get_valid_json()
 
-    if notification_type == EMAIL_TYPE:
-        form = validate(request_json, post_email_request)
-    elif notification_type == SMS_TYPE:
-        form = validate(request_json, post_sms_request)
-    elif notification_type == LETTER_TYPE:
-        form = validate(request_json, post_letter_request)
-    else:
-        abort(404)
+        if notification_type == EMAIL_TYPE:
+            form = validate(request_json, post_email_request)
+        elif notification_type == SMS_TYPE:
+            form = validate(request_json, post_sms_request)
+        elif notification_type == LETTER_TYPE:
+            form = validate(request_json, post_letter_request)
+        else:
+            abort(404)
 
     check_service_has_permission(notification_type, authenticated_service.permissions)
 

requirements-app.txt

@@ -26,6 +26,8 @@ notifications-python-client==5.5.1
 # PaaS
 awscli-cwlogs>=1.4,<1.5
 
-git+https://github.com/alphagov/notifications-utils.git@39.4.3#egg=notifications-utils==39.4.3
+git+https://github.com/alphagov/notifications-utils.git@39.4.4#egg=notifications-utils==39.4.4
 
+# gds-metrics requires prometheseus 0.2.0, override that requirement as 0.7.1 brings significant performance gains
+prometheus-client==0.7.1
 gds-metrics==0.2.0

requirements.txt

@@ -28,8 +28,10 @@ notifications-python-client==5.5.1
 # PaaS
 awscli-cwlogs>=1.4,<1.5
 
-git+https://github.com/alphagov/notifications-utils.git@39.4.3#egg=notifications-utils==39.4.3
+git+https://github.com/alphagov/notifications-utils.git@39.4.4#egg=notifications-utils==39.4.4
 
+# gds-metrics requires prometheseus 0.2.0, override that requirement as 0.7.1 brings significant performance gains
+prometheus-client==0.7.1
 gds-metrics==0.2.0
 
 ## The following requirements were added by pip freeze:
@@ -66,7 +68,6 @@ mistune==0.8.4
 monotonic==1.5
 orderedset==2.0.1
 phonenumbers==8.11.2
-prometheus-client==0.2.0
 pyasn1==0.4.8
 pycparser==2.20
 PyPDF2==1.26.0

tests/app/dao/notification_dao/test_notification_dao.py

@@ -28,7 +28,6 @@ from app.dao.notifications_dao import (
     update_notification_status_by_id,
     update_notification_status_by_reference,
     dao_get_notification_by_reference,
-    dao_get_notifications_by_references,
     dao_get_notification_or_history_by_reference,
     notifications_not_yet_sent,
 )
@@ -1613,7 +1612,7 @@ def test_dao_update_notifications_by_reference_updates_history_when_one_of_two_n
 
 def test_dao_get_notification_by_reference_with_one_match_returns_notification(sample_letter_template, notify_db):
     create_notification(template=sample_letter_template, reference='REF1')
-    notification = dao_get_notification_by_reference('REF1')
+    notification = dao_get_notification_by_reference('REF1', 'letter')
 
     assert notification.reference == 'REF1'
 
@@ -1623,30 +1622,25 @@ def test_dao_get_notification_by_reference_with_multiple_matches_raises_error(sa
     create_notification(template=sample_letter_template, reference='REF1')
 
     with pytest.raises(SQLAlchemyError):
-        dao_get_notification_by_reference('REF1')
+        dao_get_notification_by_reference('REF1', 'letter')
 
 
 def test_dao_get_notification_by_reference_with_no_matches_raises_error(notify_db):
     with pytest.raises(SQLAlchemyError):
-        dao_get_notification_by_reference('REF1')
+        dao_get_notification_by_reference('REF1', 'email')
 
 
-def test_dao_get_notifications_by_references(sample_template):
-    create_notification(template=sample_template, reference='noref')
-    notification_1 = create_notification(template=sample_template, reference='ref')
-    notification_2 = create_notification(template=sample_template, reference='ref')
-
-    notifications = dao_get_notifications_by_references(['ref'])
-    assert len(notifications) == 2
-    assert notifications[0].id in [notification_1.id, notification_2.id]
-    assert notifications[1].id in [notification_1.id, notification_2.id]
+def test_dao_get_notification_by_reference_with_no_matches_for_type_raises_error(sample_email_template):
+    create_notification(template=sample_email_template, reference='REF1')
+    with pytest.raises(SQLAlchemyError):
+        dao_get_notification_by_reference('REF1', 'letter')
 
 
 def test_dao_get_notification_or_history_by_reference_with_one_match_returns_notification(
         sample_letter_template
 ):
     create_notification(template=sample_letter_template, reference='REF1')
-    notification = dao_get_notification_or_history_by_reference('REF1')
+    notification = dao_get_notification_or_history_by_reference('REF1', 'letter')
 
     assert notification.reference == 'REF1'
 
@@ -1658,12 +1652,18 @@ def test_dao_get_notification_or_history_by_reference_with_multiple_matches_rais
     create_notification(template=sample_letter_template, reference='REF1')
 
     with pytest.raises(SQLAlchemyError):
-        dao_get_notification_or_history_by_reference('REF1')
+        dao_get_notification_or_history_by_reference('REF1', 'letter')
 
 
-def test_dao_get_notification_or_history_by_reference_with_no_matches_raises_error(notify_db):
+def test_dao_get_notification_or_history_by_reference_with_no_matches_raises_error(sample_letter_template):
+    create_notification(template=sample_letter_template, reference='REF1')
     with pytest.raises(SQLAlchemyError):
-        dao_get_notification_or_history_by_reference('REF1')
+        dao_get_notification_or_history_by_reference('REF1', 'email')
+
+
+def test_dao_get_notification_or_history_by_reference_with_no_matches_for_type_raises_error(notify_db):
+    with pytest.raises(SQLAlchemyError):
+        dao_get_notification_or_history_by_reference('REF1', 'email')
 
 
 @pytest.mark.parametrize("notification_type",

tests/app/v2/test_errors.py

@@ -4,7 +4,7 @@ from sqlalchemy.exc import DataError
 
 
 @pytest.fixture(scope='function')
-def app_for_test(mocker):
+def app_for_test():
     import flask
     from flask import Blueprint
     from app.authentication.auth import AuthError