docs: add django example (#282)

## Which problem is this PR solving?

- Lack of django example; while the repo is maintenance mode and we are
focusing efforts on OpenTelemetry, it is still helpful to have examples

## Short description of the changes

- Add django example app
- Remove `poetry.lock` files for example apps
- Make examples more consistent, including trace context and details on
`beeline.init()`
- Also update the dataset for classic users to match service name, as
they should be the same

Author: JamieDanielson

.gitignore

@@ -13,3 +13,4 @@ bin
 .vscode
 .coverage
 htmlcov
+examples/**/poetry.lock

examples/django/README.md

@@ -0,0 +1,40 @@
+# example django app
+
+This simple django app uses auto-instrumentation and adds a manual span with trace context including the message of "Hello World".
+
+## Prerequisites
+
+First set an environment variable `HONEYCOMB_API_KEY`, available from your account page.
+This will configure the server to send instrumentation events to Honeycomb in a dataset called my-django-app.
+
+You'll also need [Poetry](https://python-poetry.org/) installed to run the example.
+Poetry automatically creates a virtual environment to run the example in so you don't need to manage one yourself.
+
+## Running the example
+
+Install the dependencies:
+
+```bash
+poetry install
+```
+
+Navigate into the app directory:
+
+```bash
+cd app
+```
+
+Run the application:
+
+```bash
+poetry run python3 manage.py runserver
+```
+
+Now you can `curl` the app:
+
+```bash
+$ curl localhost:8000/hello/
+Hello World
+```
+
+Check out the results in Honeycomb!

examples/django/app/app/__init__.py

@@ -0,0 +1,122 @@
+"""
+Django settings for app project.
+
+Generated by 'django-admin startproject' using Django 2.1.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/2.1/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/2.1/ref/settings/
+"""
+
+import os
+
+# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/2.1/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'd)3c35#-ay3a(6=lss#em#!t91x#7m+4h8m-uza6csew&9%ajn'
+
+# 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',
+    'hello'
+]
+
+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',
+    'beeline.middleware.django.HoneyMiddleware',
+]
+
+ROOT_URLCONF = 'app.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 = 'app.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/2.1/ref/settings/#databases
+
+DATABASES = {
+    # 'default': {
+    #     'ENGINE': 'django.db.backends.sqlite3',
+    #     'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
+    # }
+}
+
+
+# Password validation
+# https://docs.djangoproject.com/en/2.1/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/2.1/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_L10N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/2.1/howto/static-files/
+
+STATIC_URL = '/static/'

examples/django/app/app/settings.py

@@ -0,0 +1,22 @@
+"""app URL Configuration
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/2.1/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'))
+"""
+from django.contrib import admin
+from django.urls import include, path
+
+urlpatterns = [
+    path("hello/", include("hello.urls")),
+    path("admin/", admin.site.urls),
+]

examples/django/app/app/urls.py

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+"""
+WSGI config for app project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/2.1/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'app.settings')
+
+application = get_wsgi_application()

examples/django/app/app/wsgi.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

examples/django/app/hello/__init__.py

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+import beeline
+import os
+
+from django.apps import AppConfig
+
+class HelloConfig(AppConfig):
+    name = 'hello'
+
+    def ready(self):
+        beeline.init(
+            # Get this via https://ui.honeycomb.io/account after signing up for Honeycomb
+            writekey=os.environ.get("HONEYCOMB_API_KEY"),
+            api_host=os.environ.get('HONEYCOMB_API_ENDPOINT', 'https://api.honeycomb.io:443'),
+            # The name of your app is a good choice to start with
+            # dataset='my-django-app', # only needed for classic
+            service_name=os.environ.get('SERVICE_NAME', 'my-django-app'),
+            debug=True, # enable to see telemetry in console
+        )