frontend: Create a Django web frontend

.github/workflows/frontend.yaml

@@ -0,0 +1,17 @@
+name: Frontend build
+
+on:
+  push:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Build
+        shell: bash
+        working-directory: frontend
+        run: |
+          docker build --rm . -t frontend

README.md

@@ -2,7 +2,7 @@
 
 This repo contains step-by-step creationg of low-level Terraform + K8s + other stuff for learning purposes.
 
-### Terraform to create a K8s cluster on EC2
+### Day 1: Set up Terraform with a remote backend
 
 Define the AWS region that will be used for all the commands:
 
@@ -41,15 +41,19 @@ terraform apply \
 
 Use asg_desired_capacity=0 to tear down the cluster.
 
-### Kubernetes single-node cluster on EC2 with kubeadm
+### Day 2: Kubernetes single-node cluster on EC2 with kubeadm
 
-Created a raw low-level simple K8s cluster on EC2 on a single master node. Some interesting facts:
+Commit: https://github.com/lucabrunox/learning/tree/9cc3ac81d7f835a7de5e69c58378381e20351fdd
+
+Using a raw K8s instead of EKS to learn some low-level details. Some interesting facts:
 
 - It takes 2 minutes and 20 second until all containers are in Running state.
 - A t4g.medium is needed to run a cluster. Using a t4g.nano with swap is not enough because the apiserver/etcd will keep timing out.
 - CoreDNS and kube-proxy addons are installed by default.
 - The advertising IP is coming from `ip route` and it coincides with the private IP of the instance rather than the public one.
-- Explanation of flannel networking: https://mvallim.github.io/kubernetes-under-the-hood/documentation/kube-flannel.html
+- Explanations of K8s networking:
+  - https://mvallim.github.io/kubernetes-under-the-hood/documentation/kube-flannel.html
+  - https://www.redhat.com/sysadmin/kubernetes-pods-communicate-nodes
 
 SSH into the EC2 instance and run crictl and kubectl commands to inspect the cluster:
 
@@ -67,3 +71,23 @@ If the cluster is not up check the instance init logs:
 ```bash
 sudo cat /var/log/cloud-init-output.log
 ```
+
+### Day 3: A Django frontend with GH action to build a Docker image, not deployed yet
+
+Set up following https://docs.djangoproject.com/en/5.1/intro/tutorial01/ with `django-admin startproject mysite`.
+
+The Dockerfile is self-explanatory. To try it out:
+
+```bash
+docker run -p 8000:8000 --rm -it $(docker build -q .)
+```
+
+Then open http://localhost:8000
+
+To test GH actions I've set up act to run in a Docker, so that it doesn't need to be installed:
+
+```bash
+./test_gh.sh
+```
+
+Which in turn creates the frontend Docker, yay!

act/Dockerfile

@@ -0,0 +1,5 @@
+FROM alpine:latest
+
+RUN apk add curl sudo bash
+
+RUN curl --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash

frontend/.dockerignore

@@ -0,0 +1,4 @@
+venv
+*.sqlite3
+__pycache__
+.gitignore

frontend/.gitignore

@@ -0,0 +1,3 @@
+venv
+*.sqlite3
+__pycache__

frontend/Dockerfile

@@ -0,0 +1,17 @@
+FROM alpine:latest
+
+WORKDIR /app
+
+RUN set -xe && \
+  apk add python3 py3-pip tini
+
+COPY requirements.txt .
+RUN set -xe && \
+  python3 -m venv venv && \
+  source venv/bin/activate && \
+  pip install -r requirements.txt
+
+COPY . .
+
+ENTRYPOINT ["/sbin/tini", "--"]
+CMD ["/app/venv/bin/python", "/app/manage.py", "runserver", "0.0.0.0:8000"]

frontend/learning/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for learning 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/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'learning.settings')
+
+application = get_asgi_application()

frontend/learning/settings.py

@@ -0,0 +1,123 @@
+"""
+Django settings for learning project.
+
+Generated by 'django-admin startproject' using Django 4.2.16.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.2/ref/settings/
+"""
+
+from pathlib import Path
+
+# 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/4.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-m1-fsy+mc4ow6&u%m=t7a7@b6qn6(95o%f)-m$=l+(=71!_3c0'
+
+# 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',
+]
+
+ROOT_URLCONF = 'learning.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 = 'learning.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/4.2/ref/settings/#databases
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': BASE_DIR / 'db.sqlite3',
+    }
+}
+
+
+# Password validation
+# https://docs.djangoproject.com/en/4.2/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/4.2/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/4.2/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

frontend/learning/urls.py

@@ -0,0 +1,22 @@
+"""
+URL configuration for learning project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.2/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 path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

frontend/learning/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for learning 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/4.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'learning.settings')
+
+application = get_wsgi_application()

frontend/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'learning.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

frontend/requirements.txt

@@ -0,0 +1 @@
+Django==4.2.16

test_gh.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+docker run --privileged -v /var/run/docker.sock:/var/run/docker.sock -v .:/workdir -w /workdir --rm $(docker build --rm -q act) act push -P ubuntu-latest=catthehacker/ubuntu:act-latest