Lab1

Lab-1/app_python/.gitignore

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+# Python
+__pycache__/
+*.py[cod]
+venv/
+*.log
+.env
+
+# IDE
+.vscode/
+.idea/
+
+# OS
+.DS_Store

Lab-1/app_python/README.md

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+# DevOps Info Service (Flask)
+
+## Overview
+A small Flask web service that reports service metadata, system information, runtime details, and request context. It also exposes a health check endpoint and Swagger UI.
+
+## Prerequisites
+- Python 3.11+
+- pip
+
+## Installation
+```bash
+python -m venv venv
+# Linux/macOS
+source venv/bin/activate
+# Windows PowerShell
+.\venv\Scripts\Activate.ps1
+
+pip install -r requirements.txt
+```
+
+## Configuration via .env (optional)
+Create a `.env` file in `app_python/`:
+```env
+HOST=0.0.0.0
+PORT=5000
+DEBUG=false
+```
+
+## Running the Application
+```bash
+python app.py
+```
+
+With custom configuration:
+```bash
+PORT=8080 python app.py
+HOST=127.0.0.1 PORT=3000 DEBUG=true python app.py
+```
+
+Windows PowerShell:
+```powershell
+$env:PORT=8080; python app.py
+$env:HOST='127.0.0.1'; $env:PORT=3000; $env:DEBUG='true'; python app.py
+```
+
+## API Endpoints
+- `GET /` - Service and system information
+- `GET /health` - Health check
+- `GET /swagger.json` - OpenAPI spec
+- `GET /docs` - Swagger UI
+
+## Configuration
+| Variable | Default | Description |
+|---|---|---|
+| `HOST` | `0.0.0.0` | Bind address |
+| `PORT` | `5000` | HTTP port |
+| `DEBUG` | `False` | Flask debug mode (`true`/`false`) |

Lab-1/app_python/app.py

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+from __future__ import annotations
+
+import logging
+import os
+import platform
+import socket
+from datetime import datetime, timezone
+
+from dotenv import load_dotenv
+from flask import Flask, jsonify, request
+from flask_swagger_ui import get_swaggerui_blueprint
+
+app = Flask(__name__)
+
+# conf
+load_dotenv()
+HOST = os.getenv('HOST', '0.0.0.0')
+PORT = int(os.getenv('PORT', '5000'))
+DEBUG = os.getenv('DEBUG', 'False').lower() == 'true'
+
+# start time
+START_TIME = datetime.now(timezone.utc)
+
+# Logging
+logging.basicConfig(
+    level=logging.INFO,
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
+)
+logger = logging.getLogger(__name__)
+logger.info('Application starting...')
+
+# swagger info
+SWAGGER_URL = '/docs'
+SWAGGER_API_URL = '/swagger.json'
+
+swaggerui_blueprint = get_swaggerui_blueprint(
+    SWAGGER_URL,
+    SWAGGER_API_URL,
+    config={'app_name': 'DevOps Info Service'}
+)
+app.register_blueprint(swaggerui_blueprint, url_prefix=SWAGGER_URL)
+
+
+def _iso_utc_now() -> str:
+    return datetime.now(timezone.utc).isoformat(timespec='milliseconds').replace('+00:00', 'Z')
+
+
+def get_uptime() -> dict:
+    delta = datetime.now(timezone.utc) - START_TIME
+    seconds = int(delta.total_seconds())
+    hours = seconds // 3600
+    minutes = (seconds % 3600) // 60
+    return {
+        'seconds': seconds,
+        'human': f"{hours} hours, {minutes} minutes"
+    }
+
+
+def get_platform_version() -> str:
+    system = platform.system()
+    if system == 'Linux':
+        try:
+            os_release = platform.freedesktop_os_release()
+            return os_release.get('PRETTY_NAME') or os_release.get('NAME') or platform.release()
+        except (OSError, AttributeError):
+            return platform.release()
+    if system == 'Windows':
+        return platform.version()
+    return platform.release()
+
+
+def get_system_info() -> dict:
+    return {
+        'hostname': socket.gethostname(),
+        'platform': platform.system(),
+        'platform_version': get_platform_version(),
+        'architecture': platform.machine(),
+        'cpu_count': os.cpu_count() or 0,
+        'python_version': platform.python_version()
+    }
+
+
+def get_request_info() -> dict:
+    client_ip = request.headers.get('X-Forwarded-For', request.remote_addr or '')
+    if ',' in client_ip:
+        client_ip = client_ip.split(',')[0].strip()
+
+    return {
+        'client_ip': client_ip,
+        'user_agent': request.headers.get('User-Agent', ''),
+        'method': request.method,
+        'path': request.path
+    }
+
+
+def get_service_info() -> dict:
+    """return metadata"""
+    return {
+        'name': 'devops-info-service',
+        'version': '1.0.0',
+        'description': 'DevOps course info service',
+        'framework': 'Flask'
+    }
+
+
+def get_endpoints() -> list[dict]:
+    """return a list of available endpoints"""
+    return [
+        {'path': '/', 'method': 'GET', 'description': 'Service information'},
+        {'path': '/health', 'method': 'GET', 'description': 'Health check'}
+    ]
+
+#API
+OPENAPI_SPEC = {
+    'openapi': '3.0.3',
+    'info': {
+        'title': 'DevOps Info Service',
+        'version': '1.0.0',
+        'description': 'Service and system information API'
+    },
+    'paths': {
+        '/': {
+            'get': {
+                'summary': 'Service information',
+                'responses': {
+                    '200': {
+                        'description': 'Service and system information'
+                    }
+                }
+            }
+        },
+        '/health': {
+            'get': {
+                'summary': 'Health check',
+                'responses': {
+                    '200': {
+                        'description': 'Health status'
+                    }
+                }
+            }
+        }
+    }
+}
+
+
+@app.before_request
+def log_request() -> None:
+    logger.debug('Request: %s %s', request.method, request.path)
+
+
+@app.route('/')
+def index():
+    """main endpoint"""
+    uptime = get_uptime()
+    payload = {
+        'service': get_service_info(),
+        'system': get_system_info(),
+        'runtime': {
+            'uptime_seconds': uptime['seconds'],
+            'uptime_human': uptime['human'],
+            'current_time': _iso_utc_now(),
+            'timezone': 'UTC'
+        },
+        'request': get_request_info(),
+        'endpoints': get_endpoints()
+    }
+    return jsonify(payload)
+
+
+@app.route('/health')
+def health():
+    """health check endpoint"""
+    uptime = get_uptime()
+    return jsonify({
+        'status': 'healthy',
+        'timestamp': _iso_utc_now(),
+        'uptime_seconds': uptime['seconds']
+    })
+
+
+@app.route('/swagger.json')
+def swagger_json():
+    return jsonify(OPENAPI_SPEC)
+
+
+@app.errorhandler(404)
+def not_found(error):
+    return jsonify({
+        'error': 'Not Found',
+        'message': 'Endpoint does not exist'
+    }), 404
+
+
+@app.errorhandler(500)
+def internal_error(error):
+    return jsonify({
+        'error': 'Internal Server Error',
+        'message': 'An unexpected error occurred'
+    }), 500
+
+
+if __name__ == '__main__':
+    app.run(host=HOST, port=PORT, debug=DEBUG)

Lab-1/app_python/docs/LAB01.md

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+# LAB01 - DevOps Info Service (Python / Flask)
+
+## 1. Framework Selection
+**Chosen framework:** Flask
+
+**Why Flask:**
+- Minimal setup and easy to understand for a first lab
+- Clear request/response handling without extra abstractions)
+- I tried Django, regretted it
+
+**Comparison Table**
+| Framework | Pros | Cons | Why Not Chosen |
+|---|---|---|---|
+| Flask | Lightweight, simple, widely used | Fewer built-in features | Selected due to simplicity |
+| FastAPI | Async, auto-docs, type hints | Slightly more setup | Didn't try it, because of luck of time |
+| Django | Full-featured, includes ORM | Heavy for small API | Too much for the first time|
+
+## 2. Best Practices Applied
+1. **Clean code organization** - helper functions for system, runtime, and request info
+2. **Error handling** - custom 404 and 500 responses
+3. **Logging** - structured logging with timestamp and level
+4. **Configuration via environment variables** - HOST, PORT, DEBUG
+5. **Pinned dependencies** - exact versions in `requirements.txt`
+
+**Code examples (from `app.py`):**
+```python
+HOST = os.getenv('HOST', '0.0.0.0')
+PORT = int(os.getenv('PORT', '5000'))
+DEBUG = os.getenv('DEBUG', 'False').lower() == 'true'
+```
+
+```python
+@app.errorhandler(404)
+def not_found(error):
+    return jsonify({
+        'error': 'Not Found',
+        'message': 'Endpoint does not exist'
+    }), 404
+```
+
+```python
+logging.basicConfig(
+    level=logging.INFO,
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
+)
+```
+
+## 3. API Documentation
+### 3.1 `GET /`
+**Description:** Returns service, system, runtime, request info, and endpoints.
+
+**Example request:**
+```bash
+curl http://127.0.0.1:5000/
+```
+
+**Example response (truncated):**
+```json
+{
+  "service": {
+    "name": "devops-info-service",
+    "version": "1.0.0",
+    "description": "DevOps course info service",
+    "framework": "Flask"
+  }
+}
+```
+
+### 3.2 `GET /health`
+**Description:** Health check endpoint for monitoring.
+
+**Example request:**
+```bash
+curl http://127.0.0.1:5000/health
+```
+
+**Example response:**
+```json
+{
+  "status": "healthy",
+  "timestamp": "2026-01-28T17:31:00.456Z",
+  "uptime_seconds": 180
+}
+```
+
+### 3.3 Swagger UI
+**OpenAPI spec:**
+```
+GET /swagger.json
+```
+
+**Swagger UI:**
+```
+GET /docs
+```
+*it was easier to check app with swagger
+
+## 4. Testing Evidence
+Add screenshots to `docs/screenshots/` and embed them here.
+
+- **Main endpoint:** `screenshots/01-main-endpoint.png`
+- **Health check:** `screenshots/02-health-check.png`
+- **Pretty-printed output:** `screenshots/03-formatted-output.png`
+
+## 5. Challenges & Solutions
+- **Timezone formatting:** Used UTC with ISO 8601 and `Z` suffix for consistency.
+- **Client IP handling:** Added `X-Forwarded-For` fallback for proxy setups.
+
+## 6. GitHub Community
+Starring repositories helps to find useful tools and bookmaer them. Following developers improves collaboration by keeping you aware of classmates' and instructors' work, which supports learning and teamwork.

Lab-1/app_python/requirements.txt

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+# Web Framework
+Flask==3.1.0
+# Swagger UI
+flask-swagger-ui==4.11.1
+# Env support
+python-dotenv==1.0.1