holger-utils 0.7.12

utils for developing web application

Holger Utils

Sentry

settings.py

from holger import sentry
...
SENTRY_KEY = '<your sentry key>'
SENTRY_ORGANIZATION = '<your sentry organization name>'
SENTRY_PROJECT = '<your sentry project name>'
SENTRY_ALLOWED_ALL = 'if true all status captured' # default False
SENTRY_ALLOWED_STATUS = 'list of status that should capture' # default []
sentry.init()

or

from holger import sentry
...
SENTRY_URL = '<your sentry url>'
SENTRY_ALLOWED_ALL = 'if true all status captured' # default False
SENTRY_ALLOWED_STATUS = 'list of status that should capture' # default []
sentry.init()

Elastic search

settings.py

ELASTIC_PROTOCOL = '<http or https>' # default 'http'
ELASTIC_HOST = '<host that elastic run>' # default 'localhost'
ELASTIC_PORT = '<listen port>' # default 9200
ELASTIC_USE_SSL = '' # default False
TIME_ZONE = '<elastic timezone>' # default 'UTC'
ELASTIC_ALLOWED_STATUS = ['<allowed status>'] # default []
ELASTIC_USER = '<elastic username>' # default ''
ELASTIC_PASSWORD = '<elastic secret>' # default ''

Firebase

settings.py

FIREBASE_APP_OPTIONS = '<app dict options>' # default {}
FIREBASE_APP_NAME = 'your app name' # default 'FIRESTORE_DEFAULT'

Log

for use log, you must config elastic search and sentry before

JWT Authentication

in your root urls.py file (or any other url config), include routes for Holger’s TokenObtainPairView and TokenRefreshView views:

from django.urls import path
from holger.rest.authorization import (
    HolgerTokenObtainPairView,
    HolgerRefreshView
)
urlpatterns = [
    ...,
    path('apiv1/accounts/token/', HolgerTokenObtainPairView.as_view(), name='token_obtain_pair'),
    path('apiv1/accounts/refresh/', HolgerRefreshView.as_view(), name='token_refresh'),
    ...
]

Settings

Some of Holger’s authentication behavior can be customized through settings variables in settings.py

from datetime import timedelta

SIMPLE_JWT = {
    'ACCESS_TOKEN_LIFETIME': timedelta(minutes=5),
    'REFRESH_TOKEN_LIFETIME': timedelta(days=1),
    'ROTATE_REFRESH_TOKENS': False,
    'BLACKLIST_AFTER_ROTATION': True,

    'ALGORITHM': 'HS256',
    'SIGNING_KEY': SECRET_KEY,
    'VERIFYING_KEY': None,
    'AUDIENCE': None,
    'ISSUER': None,

    'AUTH_HEADER_TYPES': ('Bearer',),
    'USER_ID_FIELD': 'id',
    'USER_ID_CLAIM': 'user_id',

    'AUTH_TOKEN_CLASSES': ('Holger.rest.authorization.AccessToken',),
    'TOKEN_TYPE_CLAIM': 'token_type',

    'JTI_CLAIM': 'jti',

    'SLIDING_TOKEN_REFRESH_EXP_CLAIM': 'refresh_exp',
    'SLIDING_TOKEN_LIFETIME': timedelta(minutes=5),
    'SLIDING_TOKEN_REFRESH_LIFETIME': timedelta(days=1),
}

Database replica router

With database.router.ReplicaRouter all read queries will go to a replica database; all inserts, updates, and deletes will do to the default database. First, define REPLICA_DATABASES in your settings. It should be a list of database aliases that can be found in DATABASES:

DATABASES = {
    'default': {...},
    'replica-1': {...},
    'replica-2': {...},
}
REPLICA_DATABASES = ['replica-1', 'replica-2']

Then put database.router.ReplicaRouter into DATABASE_ROUTERS:

DATABASE_ROUTERS = ('database.router.ReplicaRouter',)

The replica databases will be chosen in round-robin fashion. If you want to get a connection to a replica in your app, use database.router.ReplicaRouter

from django.db import connections
from holger.database import router
connection = connections[router.get_replica()]

Database PinningReplicaRouter

In some applications, the lag between the primary database receiving a write and its replication to the replicas is enough to cause inconsistency for the end user. For example, imagine a scenario with 1 second of replication lag. If a user makes a forum post (to the primary) and then is redirected to a fully-rendered view of it (from a replica) 500ms later, the view will fail. If this is a problem in your application, consider using multidb.PinningReplicaRouter. This router works in combination with multidb.middleware.PinningRouterMiddleware to assure that, after writing to the default database, future reads from the same user agent are directed to the default database for a configurable length of time.

PinningRouterMiddleware identifies database writes primarily by request type, assuming that requests with HTTP methods that are not GET, TRACE, HEAD, or OPTIONS are writes. You can indicate that any view writes to the database by using the holger.database.router.db_write decorator. This will cause the same result as if the request were, e.g., a POST.

To use PinningReplicaRouter, put it into DATABASE_ROUTERS in your settings:

DATABASE_ROUTERS = ('database.router.PinningReplicaRouter',)

Then, install the middleware. It must be listed before any other middleware which performs database writes:

MIDDLEWARE_CLASSES = (
    'multidb.middleware.PinningRouterMiddleware',
    ...more middleware here...
)

PinningRouterMiddleware attaches a cookie to any user agent who has just written. The cookie should be set to expire at a time longer than your replication lag. By default, its value is a conservative 15 seconds, but it can be adjusted like so:

HOLGER_PINNING_SECONDS = 5

If you need to change the name of the cookie, use the HOLGER_PINNING_COOKIE setting:

HOLGER_PINNING_COOKIE = 'holger_pin_writes'