Initial app setup (#1)

Author: Laura

.env.sample

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+## DevCycle SDK Key ##
+# This can be found in the DevCycle dashboard Settings under "Environments & Keys"
+DEVCYCLE_SERVER_SDK_KEY="<YOUR_SDK_KEY>"

README.md

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-# example-python
-An example app built using the DevCycle Python SDK
+# DevCycle Python Server SDK Example App
+An example app built using the [DevCycle Python Server SDK](https://docs.devcycle.com/sdk/server-side-sdks/python/)
+
+## Requirements.
+
+Python 3.7+ and Django 4.2+
+
+## Running the Example
+### Setup
+
+* Create a `.env` file and set `DEVCYCLE_SERVER_SDK_KEY` to your Environment's SDK Key.\
+You can find this under [Settings > Environments](https://app.devcycle.com/r/environments) on the DevCycle dashboard.
+[Learn more about environments](https://docs.devcycle.com/essentials/environments).
+* Run `python3 -m pip install -r requirements.txt` in the project directory to install dependencies. You may need to run `pip` with root permission: `sudo pip install -r requirements.txt`
+* Run `python3 manage.py migrate` to apply migrations
+
+### Development
+
+`python3 manage.py runserver`
+
+The server will start on port 8000. You can access the example app at http://localhost:8000.
+
+## Documentation
+For more information about using the DevCycle Python Server SDK, see [the documentation](https://docs.devcycle.com/sdk/server-side-sdks/python/)
+

hello_togglebot/__init__.py

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+"""
+ASGI config for hello_togglebot project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/5.0/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'hello_togglebot.settings')
+
+application = get_asgi_application()

hello_togglebot/asgi.py

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+from django.conf import settings
+from django.core.exceptions import ImproperlyConfigured
+from devcycle_python_sdk import (
+    DevCycleLocalClient,
+    DevCycleLocalOptions,
+)
+
+try:
+    devcycle_sdk_key = settings.DEVCYCLE_SERVER_SDK_KEY
+except AttributeError:
+    raise ImproperlyConfigured("Please set DEVCYCLE_SERVER_SDK_KEY in .env")
+
+# Create an options object to do custom configurations, or use the defaults
+options = DevCycleLocalOptions()
+
+# Initialize the SDK singleton once here - it will be captured in the closure below
+devcycle_client = DevCycleLocalClient(devcycle_sdk_key, options)
+
+def get_devcycle_client():
+    return devcycle_client

hello_togglebot/devcycle.py

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+from devcycle_python_sdk.models.user import DevCycleUser
+from .devcycle import get_devcycle_client
+
+def devcycle_middleware(get_response):
+    """
+    This middleware adds the DevCycle client to the request object passed to
+    all views as `request.devcycle`.
+    """
+    def middleware(request):
+        # all client functions require user data to be an instance of the DevCycleUser class
+        request.user = DevCycleUser(
+            user_id='user123',
+            email='jane.doe@example.ca',
+            country='CA'
+        )
+        request.devcycle = get_devcycle_client()
+        return get_response(request)
+
+    return middleware

hello_togglebot/middleware.py

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+"""
+Django settings for hello_togglebot project.
+
+Generated by 'django-admin startproject' using Django 5.0.1.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/5.0/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/5.0/ref/settings/
+"""
+
+from os import environ
+from pathlib import Path
+from dotenv import load_dotenv
+
+load_dotenv()
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/5.0/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-$sc_)$u!8^ryitgtejjf&-y3nwz2grovp88m8h-(c73m=2g!q%'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+    # Initialize the DevCycle client in the middleware
+    'hello_togglebot.middleware.devcycle_middleware',
+]
+
+ROOT_URLCONF = 'hello_togglebot.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [],
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'hello_togglebot.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/5.0/ref/settings/#databases
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': BASE_DIR / 'db.sqlite3',
+    }
+}
+
+
+# Password validation
+# https://docs.djangoproject.com/en/5.0/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/5.0/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/5.0/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/5.0/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'
+
+# DevCycle Settings
+DEVCYCLE_SERVER_SDK_KEY = environ["DEVCYCLE_SERVER_SDK_KEY"]

hello_togglebot/settings.py

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+"""
+URL configuration for hello_togglebot project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/5.0/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+import sys
+from django.urls import path
+from .views import home_page, get_variables
+from .utils import log_variation
+
+urlpatterns = [
+    path("", home_page, name="home"),
+    path("variables", get_variables, name="variables"),
+]
+
+is_runserver = any(arg.casefold() == "runserver" for arg in sys.argv)
+if (is_runserver):
+    print('Starting development server at http://127.0.0.1:8000/')
+    print('Quit the server with CONTROL-C.')
+    log_variation()
+

hello_togglebot/urls.py

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+import sys
+import time
+from devcycle_python_sdk.models.user import DevCycleUser
+from .devcycle import get_devcycle_client
+
+"""
+Since this is used outside of a request context, we define a service user.
+This can contian properties unique to this service, and allows you to target
+services in the same way you would target app users.
+"""
+SERVICE_USER = DevCycleUser(
+    user_id='api-service'
+)
+
+"""
+Log the current DevCycle variation to the console.
+"""
+def log_variation():
+    devcycle_client = get_devcycle_client()
+
+    def render_frame(idx=0):
+        timeout = 500
+
+        if devcycle_client.is_initialized():
+            features = devcycle_client.all_features(SERVICE_USER)
+            variation_name = features['hello-togglebot'].variationName if 'hello-togglebot' in features else 'Default'
+
+            wink = devcycle_client.variable_value(SERVICE_USER, 'togglebot-wink', False)
+            speed = devcycle_client.variable_value(SERVICE_USER, 'togglebot-speed', 'off')
+
+            spin_chars = "◟◜◝◞" if speed == 'slow' else "◜◠◝◞◡◟"
+            spinner = '○' if speed == 'off' else spin_chars[idx]
+            idx = (idx + 1) % len(spin_chars)
+
+            face = '(- ‿ ○)' if wink else '(○ ‿ ○)'
+
+            frame = '{} Serving variation: {} {}'.format(spinner, variation_name, face)
+            color = 'rainbow' if speed == 'surprise' else 'blue'
+
+            write_to_console(frame, color)
+
+            timeout = 100 if speed in ['fast', 'surprise', 'off-axis'] else 500
+            
+        time.sleep(timeout / 1000)
+        render_frame(idx)
+
+    try:
+        print('{}------------------------------------------{}'.format(COLORS['blue'], END_CHAR))
+        render_frame()
+    except KeyboardInterrupt:
+        sys.stdout.write('\n')
+        sys.exit(0)
+
+COLORS = {}
+COLORS['red'] = '\033[91m'
+COLORS['green'] = '\033[92m'
+COLORS['yellow'] = '\033[93m'
+COLORS['blue'] = '\033[94m'
+COLORS['magenta'] = '\033[95m'
+END_CHAR = '\033[0m'
+
+def add_color(text, color):
+    colors = {}
+    colors.update(COLORS)
+    colors['rainbow'] = '\033[38;5;{}m'.format(int(time.time() * 1000) % 230)
+
+    if color in colors:
+        return colors[color] + text + END_CHAR
+    else:
+        return text
+
+def write_to_console(frame, color):
+    frame = add_color(frame, color)
+    sys.stdout.write('\r\x1b[K' + frame)

hello_togglebot/utils.py

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+from django.http import HttpResponse
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+def home_page(request):
+    step = request.devcycle.variable_value(request.user, "example-text", "default")
+
+    header = ""
+    body = ""
+    if step == "step-1":
+        header = "Welcome to DevCycle's example app."
+        body = "If you got here through the onboarding flow, just follow the instructions to change and create new Variations and see how the app reacts to new Variable values."
+    elif step == "step-2":
+        header = "Great! You've taken the first step in exploring DevCycle."
+        body = "You've successfully toggled your very first Variation. You are now serving a different value to your users and you can see how the example app has reacted to this change. Next, go ahead and create a whole new Variation to see what else is possible in this app."
+    elif step == "step-3":
+        header = "You're getting the hang of things."
+        body = "By creating a new Variation with new Variable values and toggling it on for all users, you've already explored the fundamental concepts within DevCycle. There's still so much more to the platform, so go ahead and complete the onboarding flow and play around with the feature that controls this example in your dashboard."
+    else:
+        header = "Welcome to DevCycle's example app."
+        body = "If you got to the example app on your own, follow our README guide to create the Feature and Variables you need to control this app in DevCycle."
+    
+    response = '<h2>{header}</h2><p>{body}</p><p><a href="/variables">All Variables</a></p>'.format(header=header, body=body)
+    return HttpResponse(response)
+
+def get_variables(request):
+    variables = request.devcycle.all_variables(request.user)
+    response = ''
+    for key, variable in variables.items():
+        response += '<li><strong>{key}</strong>: {value}</li>'.format(key=key, value=variable.value)
+    return HttpResponse('<h2>Variables</h2><ul>' + response + '</ul><p><a href="/">Home</a></p>')