Merge pull request #14 from Cdeth567/lab12

Add ConfigMaps and PVC support for lab 12

Author: Cdeth567

app-policy.hcl

@@ -0,0 +1,11 @@
+path "secret/data/devops-info-service/config" {
+  capabilities = ["read"]
+}
+
+path "secret/metadata/devops-info-service/config" {
+  capabilities = ["read", "list"]
+}
+
+path "sys/internal/ui/mounts/secret/data/devops-info-service/config" {
+  capabilities = ["read"]
+}

app_python/README.md

@@ -4,10 +4,13 @@
 
 ## Overview
 DevOps Info Service is a small Flask web application that exposes:
-- `GET /` — service metadata, system/runtime info, and request details
+- `GET /` — service metadata, system/runtime info, request details, and visit counter increment
+- `GET /visits` — current persisted visit count
 - `GET /health` — simple health check endpoint
+- `GET /ready` — readiness probe endpoint
+- `GET /metrics` — Prometheus metrics
 
-This project is the foundation for future DevOps labs (Docker, CI/CD, monitoring, Kubernetes).
+The application stores visit statistics in a file (default: `/data/visits`) so the counter survives container restarts when a volume is mounted.
 
 ## Prerequisites
 - Python 3.11+
@@ -59,14 +62,15 @@ Custom config:
 
 **Linux/Mac:**
 ```bash
-HOST=127.0.0.1 PORT=3000 DEBUG=True python app.py
+HOST=127.0.0.1 PORT=3000 DEBUG=True VISITS_FILE=./data/visits python app.py
 ```
 
 **Windows (PowerShell):**
 ```powershell
 $env:HOST="127.0.0.1"
 $env:PORT="3000"
 $env:DEBUG="True"
+$env:VISITS_FILE=".\data\visits"
 python app.py
 ```
 
@@ -75,16 +79,21 @@ python app.py
 set HOST=127.0.0.1
 set PORT=3000
 set DEBUG=True
+set VISITS_FILE=.\data\visits
 python app.py
 ```
 
 ## API Endpoints
-- `GET /` — service and system information
+- `GET /` — service and system information, increments the counter
+- `GET /visits` — current visit counter value from persisted storage
 - `GET /health` — health check
+- `GET /ready` — readiness check
+- `GET /metrics` — Prometheus metrics
 
 Examples:
 ```bash
 curl http://127.0.0.1:5000/
+curl http://127.0.0.1:5000/visits
 curl http://127.0.0.1:5000/health
 ```
 
@@ -97,46 +106,88 @@ curl http://127.0.0.1:5000/ | python -m json.tool
 
 | Variable | Default | Description |
 |----------|---------|-------------|
-| HOST     | 0.0.0.0 | Bind address |
-| PORT     | 5000    | HTTP port |
-| DEBUG    | False   | Flask debug mode |
+| HOST | 0.0.0.0 | Bind address |
+| PORT | 5000 | HTTP port |
+| DEBUG | False | Flask debug mode |
+| VISITS_FILE | /data/visits | Path to the persisted visits counter |
+| SERVICE_NAME | devops-info-service | Service name shown in the API |
+| SERVICE_VERSION | 1.0.0 | Service version shown in the API |
+| SERVICE_DESCRIPTION | DevOps course info service | Service description shown in the API |
 
 ## Docker
 
 This application can also be built and run as a Docker container.
 
 ### Build (local)
-Pattern:
 ```bash
-docker build -t <image_name>:<tag> .
+docker build -t devops-info-service:lab12 .
 ```
 
-### Run
-Pattern:
+### Run with a bind mount
 ```bash
-docker run --rm -p <host_port>:5000 --name <container_name> <image_name>:<tag>
+mkdir -p data
+docker run --rm -p 5000:5000 \
+  -e VISITS_FILE=/data/visits \
+  -v "$(pwd)/data:/data" \
+  --name devops-info-service \
+  devops-info-service:lab12
 ```
 
 Then test:
 ```bash
-curl http://127.0.0.1:<host_port>/
-curl http://127.0.0.1:<host_port>/health
+curl http://127.0.0.1:5000/
+curl http://127.0.0.1:5000/
+curl http://127.0.0.1:5000/visits
+cat ./data/visits
+```
+
+### Docker Compose
+`docker-compose.yml` is included for local persistence testing.
+
+Start the application:
+```bash
+mkdir -p data
+docker compose up -d --build
+```
+
+Verify persistence:
+```bash
+curl http://127.0.0.1:5000/
+curl http://127.0.0.1:5000/
+curl http://127.0.0.1:5000/visits
+cat ./data/visits
+docker compose restart
+curl http://127.0.0.1:5000/visits
+cat ./data/visits
+```
+
+Stop it:
+```bash
+docker compose down
 ```
 
+Expected persistence flow:
+1. First request to `/` creates `./data/visits` with value `1`
+2. Additional requests keep incrementing the file
+3. After container restart, `/visits` returns the previously saved value instead of resetting to `0`
+
 ### Pull from Docker Hub
 Pattern:
 ```bash
 docker pull <dockerhub_username>/<repo_name>:<tag>
 docker run --rm -p <host_port>:5000 <dockerhub_username>/<repo_name>:<tag>
 ```
 
-> Note (Windows PowerShell): `curl` is an alias for `Invoke-WebRequest`.  
+> Note (Windows PowerShell): `curl` is an alias for `Invoke-WebRequest`.
 > For classic curl behavior, use `curl.exe`.
 
 ## Testing
 Install dev dependencies:
-- python -m pip install -r requirements-dev.txt
+```bash
+python -m pip install -r requirements-dev.txt
+```
 
 Run tests:
-- pytest
-
+```bash
+pytest
+```

app_python/app.py

@@ -4,8 +4,10 @@
 import platform
 import socket
 import sys
+import threading
 import time
 from datetime import datetime, timezone
+from pathlib import Path
 
 from flask import Flask, Response, g, has_request_context, jsonify, request
 from prometheus_client import CONTENT_TYPE_LATEST, Counter, Gauge, Histogram, generate_latest
@@ -18,6 +20,7 @@
 PORT = int(os.getenv("PORT", 5000))
 DEBUG = os.getenv("DEBUG", "False").lower() == "true"
 START_TIME = datetime.now(timezone.utc)
+DEFAULT_VISITS_FILE = "/data/visits"
 
 REQUEST_LATENCY_BUCKETS = (
     0.005,
@@ -101,6 +104,58 @@ def format(self, record: logging.LogRecord) -> str:
         return json.dumps(payload, ensure_ascii=False)
 
 
+class VisitCounter:
+    """File-backed counter used to persist the number of root endpoint visits."""
+
+    def __init__(self, path_getter):
+        self._path_getter = path_getter
+        self._lock = threading.Lock()
+        self._value = 0
+        self.reload()
+
+    def _path(self) -> Path:
+        return Path(self._path_getter())
+
+    def _read_from_disk(self) -> int:
+        path = self._path()
+        try:
+            return int(path.read_text(encoding="utf-8").strip() or "0")
+        except FileNotFoundError:
+            return 0
+        except ValueError:
+            logger.warning(
+                "Visits file contained invalid data, resetting counter to 0",
+                extra={
+                    "event": "visits.invalid_data",
+                    "service": SERVICE_NAME,
+                },
+            )
+            return 0
+
+    def _write_to_disk(self, value: int) -> None:
+        path = self._path()
+        path.parent.mkdir(parents=True, exist_ok=True)
+        tmp_path = path.with_suffix(f"{path.suffix}.tmp")
+        tmp_path.write_text(str(value), encoding="utf-8")
+        os.replace(tmp_path, path)
+
+    def reload(self) -> int:
+        with self._lock:
+            self._value = self._read_from_disk()
+            return self._value
+
+    def get_value(self) -> int:
+        with self._lock:
+            return self._value
+
+    def increment(self) -> int:
+        with self._lock:
+            self._value += 1
+            self._write_to_disk(self._value)
+            return self._value
+
+
+
 def configure_logging() -> logging.Logger:
     """Configure application logging to stdout in JSON format."""
     handler = logging.StreamHandler(sys.stdout)
@@ -121,6 +176,15 @@ def configure_logging() -> logging.Logger:
 
 logger = configure_logging()
 app = Flask(__name__)
+app.config.setdefault("VISITS_FILE", os.getenv("VISITS_FILE", DEFAULT_VISITS_FILE))
+
+
+def get_visits_file_path() -> str:
+    """Return the configured path to the visits counter file."""
+    return app.config.get("VISITS_FILE", DEFAULT_VISITS_FILE)
+
+
+visit_counter = VisitCounter(get_visits_file_path)
 
 
 def get_platform_version() -> str:
@@ -135,6 +199,7 @@ def get_platform_version() -> str:
     return platform.platform()
 
 
+
 def get_uptime() -> dict:
     """Calculate the application's uptime."""
     delta = datetime.now(timezone.utc) - START_TIME
@@ -147,6 +212,7 @@ def get_uptime() -> dict:
     }
 
 
+
 def get_system_info() -> dict:
     """Collect system information."""
     with system_info_collection_seconds.time():
@@ -160,6 +226,7 @@ def get_system_info() -> dict:
         }
 
 
+
 def get_client_ip() -> str | None:
     """Return the client IP, preferring X-Forwarded-For when present."""
     if not has_request_context():
@@ -171,17 +238,19 @@ def get_client_ip() -> str | None:
     return request.remote_addr
 
 
+
 def normalize_endpoint() -> str:
     """Return a low-cardinality endpoint label for Prometheus metrics."""
     if not has_request_context():
         return "unknown"
     if request.url_rule and request.url_rule.rule:
         return request.url_rule.rule
-    if request.path in {"/", "/health", "/metrics"}:
+    if request.path in {"/", "/health", "/metrics", "/ready", "/visits"}:
         return request.path
     return "unmatched"
 
 
+
 def build_request_log_context(status_code: int | None = None) -> dict:
     """Build structured context for request-related logs."""
     context: dict[str, object] = {"event": "http.request", "service": SERVICE_NAME}
@@ -209,6 +278,7 @@ def build_request_log_context(status_code: int | None = None) -> dict:
     return context
 
 
+
 def finalize_request_metrics(status_code: int) -> None:
     """Record Prometheus metrics for the current request exactly once."""
     if not has_request_context() or not getattr(g, "metrics_tracked", False):
@@ -280,6 +350,7 @@ def cleanup_request_metrics(exc) -> None:
 @app.route("/")
 def index():
     """Main endpoint - service and system information."""
+    current_visits = visit_counter.increment()
     uptime = get_uptime()
 
     response = {
@@ -304,8 +375,13 @@ def index():
             "method": request.method,
             "path": request.path,
         },
+        "visits": {
+            "count": current_visits,
+            "storage": get_visits_file_path(),
+        },
         "endpoints": [
             {"path": "/", "method": "GET", "description": "Service information"},
+            {"path": "/visits", "method": "GET", "description": "Visit counter"},
             {"path": "/health", "method": "GET", "description": "Health check"},
             {"path": "/ready", "method": "GET", "description": "Readiness check"},
             {"path": "/metrics", "method": "GET", "description": "Prometheus metrics"},
@@ -315,6 +391,17 @@ def index():
     return jsonify(response)
 
 
+@app.route("/visits")
+def visits():
+    """Return the current persisted visit count."""
+    return jsonify(
+        {
+            "visits": visit_counter.get_value(),
+            "storage": get_visits_file_path(),
+        }
+    )
+
+
 @app.route("/health")
 def health():
     """Health check endpoint for monitoring."""
@@ -397,6 +484,7 @@ def handle_unexpected_error(error):
 
 
 if __name__ == "__main__":
+    visit_counter.reload()
     logger.info(
         "Application startup",
         extra={

app_python/data/.gitkeep

@@ -0,0 +1 @@
+7

app_python/data/visits

@@ -0,0 +1,16 @@
+services:
+  devops-info-service:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    container_name: devops-info-service
+    environment:
+      HOST: 0.0.0.0
+      PORT: 5000
+      DEBUG: "False"
+      VISITS_FILE: /data/visits
+    ports:
+      - "5000:5000"
+    volumes:
+      - ./data:/data
+    restart: unless-stopped