app.py

#!/usr/bin/env python3
from flask import Flask, jsonify
import psutil
import datetime
import os
from version import VERSION

app = Flask(__name__)

def get_metrics():
    """Collect system metrics and return a dict ready for JSON serialisation."""
    # ---------- CPU ----------
    cpu_percent = psutil.cpu_percent(interval=0.5)   # short measurement

    # ---------- Memory ----------
    mem = psutil.virtual_memory()
    mem_info = {
        "total_mb": round(mem.total / (1024 ** 2), 2),
        "used_mb": round(mem.used / (1024 ** 2), 2),
        "available_mb": round(mem.available / (1024 ** 2), 2),
        "percent_used": mem.percent,
    }

    # ---------- Disk ----------
    # By default use the root mount. You can override with env var DISK_MOUNT.
    # This is useful in containers where the host root may be mounted elsewhere.
    disk_mount = os.environ.get("DISK_MOUNT", "/")
    disk = psutil.disk_usage(disk_mount)
    disk_info = {
        "total_gb": round(disk.total / (1024 ** 3), 2),
        "used_gb": round(disk.used / (1024 ** 3), 2),
        "free_gb": round(disk.free / (1024 ** 3), 2),
        "percent_used": disk.percent,
    }

    # ---------- Timestamp ----------
    ts = datetime.datetime.utcnow().replace(microsecond=0).isoformat() + "Z"

    return {
        "cpu_percent": cpu_percent,
        "memory": mem_info,
        "disk": disk_info,
        "timestamp": ts,
    }

@app.route("/", methods=["GET"])
def entrypage():
    """REST endpoint – returns the JSON payload."""
    details = {
        "service": "monitoring-api",
        "version": VERSION,
        "routes": [
            "/api/metrics",
            "/api/healthcheck"
        ]
    }
    return jsonify(details)

@app.route("/api/healthcheck")
def healthcheck():
    return jsonify({"status": "ok"})

@app.route("/api/metrics", methods=["GET"])
def metrics():
    """REST endpoint – returns the JSON payload."""
    return jsonify(get_metrics())

# ----------------------------------------------------------------------
# Running the app directly (python app.py) will start the Flask server.
# ----------------------------------------------------------------------
if __name__ == "__main__":
    # host='0.0.0.0' → listen on *all* network interfaces
    # port=3003      → the port you asked for
    # debug=False   → production‑ready (no auto‑reload)
    app.run(host="0.0.0.0", port=3003, debug=False)