Eine WebPage die den Status vom Netzwerk und Docker-Containern angeben soll.

==
NodeJS: Server.js
==========================

const express = require("express");
const pool = require("./db");
const scheduleChecks = require("./scheduler");

const runCheck = require("./checkRunner");

const app = express();
app.set("view engine", "ejs");
app.use(express.static("public"));

app.get("/", async (req, res) => {
  const { rows } = await pool.query("SELECT * FROM checks ORDER BY id");
  res.render("index", { checks: rows });
});

app.post("/run/:id", async (req, res) => {
  const checkId = req.params.id;

  const { rows } = await pool.query("SELECT * FROM checks WHERE id = $1", [checkId]);
  if (rows.length === 0) {
    return res.status(404).send("Check not found");
  }

  const check = rows[0];
  const result = await runCheck(check);

  await pool.query(
    `INSERT INTO results (check_id, status, message, duration_ms)
     VALUES ($1,$2,$3,$4)`,
    [check.id, result.status, result.message, result.duration]
  );

  await pool.query(
    `UPDATE checks SET last_run = NOW(), last_status = $1 WHERE id = $2`,
    [result.status, check.id]
  );

  res.redirect("/");
});


app.listen(3000, async () => {
  console.log("Server läuft auf Port 3000");
  await scheduleChecks();
});


==
NodeJS: scheduler.js
=============================================
const cron = require("node-cron");
const pool = require("./db");
const runCheck = require("./checkRunner");

async function scheduleChecks() {
  const { rows } = await pool.query("SELECT * FROM checks WHERE active = true");

  rows.forEach(check => {
    cron.schedule(`*/${check.schedule_seconds} * * * * *`, async () => {
      const result = await runCheck(check);

      await pool.query(
        `INSERT INTO results (check_id, status, message, duration_ms)
         VALUES ($1,$2,$3,$4)`,
        [check.id, result.status, result.message, result.duration]
      );

      await pool.query(
        `UPDATE checks SET last_run = NOW(), last_status = $1 WHERE id = $2`,
        [result.status, check.id]
      );
    });
  });
}

module.exports = scheduleChecks;


==
nodeJS: db.js
====================================================
const { Pool } = require("pg");

module.exports = new Pool({
  host: process.env.DB_HOST,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
  port: process.env.DB_PORT
});


==
nodeJS: dockerApi.js
===============================================================
const http = require("http");

function dockerRequest(path) {
  return new Promise((resolve, reject) => {
    const options = {
      socketPath: "/var/run/docker.sock",
      path,
      method: "GET"
    };

    const req = http.request(options, (res) => {
      let data = "";
      res.on("data", chunk => data += chunk);
      res.on("end", () => {
        try {
          resolve(JSON.parse(data));
        } catch {
          resolve(data);
        }
      });
    });

    req.on("error", reject);
    req.end();
  });
}

async function isContainerRunning(name) {
  try {
    const data = await dockerRequest(`/containers/${name}/json`);
    return data.State?.Running === true;
  } catch {
    return false;
  }
}

async function networkContainsContainer(networkName, containerName) {
  try {
    const data = await dockerRequest(`/networks/${networkName}`);
    if (!data.Containers) return false;
    return Object.values(data.Containers)
      .some(c => c.Name === containerName);
  } catch {
    return false;
  }
}

module.exports = { isContainerRunning, networkContainsContainer };


==
NodeJS: checkRunner
====================================================

const { spawn } = require("child_process");
const path = require("path");
const dockerApi = require("./dockerApi");

const CHECKS_DIR = path.join(__dirname, "checks");

async function runCheck(check) {
  const start = Date.now();

  if (check.type === "docker_container") {
    const result = await dockerApi.isContainerRunning(check.target);
    return {
      status: result ? "OK" : "FAIL",
      message: `Container ${check.target} running: ${result}`,
      duration: Date.now() - start
    };
  }

  if (check.type === "docker_network") {
    const [network, container] = check.target.split(",");
    const result = await dockerApi.networkContainsContainer(network, container);
    return {
      status: result ? "OK" : "FAIL",
      message: `Container ${container} in network ${network}: ${result}`,
      duration: Date.now() - start
    };
  }

  if (check.type === "script") {

    if (!check.script_name) {
      return {
        status: "FAIL",
        message: "No script_name defined",
        duration: Date.now() - start
      };
    }

    return new Promise((resolve) => {
      const scriptPath = path.join(CHECKS_DIR, check.script_name);

      const child = spawn("sh", [scriptPath], {
        timeout: (check.timeout_seconds || 10) * 1000
      });

      child.on("close", (code) => {
        resolve({
          status: code === 0 ? "OK" : "FAIL",
          message: `Exit code: ${code}`,
          duration: Date.now() - start
        });
      });
    });
  }
}

module.exports = runCheck;


==
index.ejs
============================

<!DOCTYPE html>
<html>
<head>
  <title>Docker Info Dashboard</title>
  <link rel="stylesheet" href="/style.css">
</head>
<body>
<h1>System Status</h1>
<table>
<tr>
<th>ID</th>
<th>Name</th>
<th>Status</th>
<th>Last Run</th>
<th>Action</th>
</tr>

<% checks.forEach(c => { %>
<tr>
<td><%= c.id %></td>
<td><%= c.name %></td>
<td class="<%= c.last_status === 'OK' ? 'ok' : 'fail' %>">
<%= c.last_status || 'N/A' %>
</td>
<td><%= c.last_run || 'N/A' %></td>
 <td>
    <form method="POST" action="/run/<%= c.id %>" style="margin:0;">
      <button type="submit">Run-Test</button>
    </form>
  </td>
</tr>
<% }) %>

</table>
</body>
</html>

==
checks/check_http_google.sh
=============================
#!/bin/sh
wget -q --spider https://google.com
exit $?


==
DB
===================================
CREATE TABLE checks (
    id SERIAL PRIMARY KEY,
    name TEXT NOT NULL,
    type TEXT NOT NULL, -- script | docker_container | docker_network
    description TEXT,
    target TEXT,
    script_name TEXT,
    schedule_seconds INTEGER DEFAULT 60,
    timeout_seconds INTEGER DEFAULT 20,
    active BOOLEAN DEFAULT TRUE,
    last_run TIMESTAMP,
    last_status TEXT
);

CREATE TABLE results (
    id SERIAL PRIMARY KEY,
    check_id INTEGER REFERENCES checks(id) ON DELETE CASCADE,
    run_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    status TEXT,
    message TEXT,
    duration_ms INTEGER
);

INSERT INTO checks (name, type, description, target)
VALUES
('Google HTTP', 'script', 'Prüft google.com', NULL),
('Postgres Container Running', 'docker_container', 'Ist Postgres Container aktiv?', 'info-postgres'),
('Default Network contains Postgres', 'docker_network', 'Ist Postgres im default Netzwerk?', 'bridge');


==
Docker-compose.yaml
=========================================


services:
  app:
    image: node:20-alpine
    container_name: info-node-app
    working_dir: /app
    command: sh -c "npm install && node server.js"
    volumes:
      - ./app:/app
      - ./checks:/app/checks
      - /var/run/docker.sock:/var/run/docker.sock
    ports:
      - "3000:3000"
    depends_on:
      - db
    environment:
      DB_HOST: db
      DB_USER: postgres
      DB_PASSWORD: postgres
      DB_NAME: infodb
      DB_PORT: 5432
    restart: unless-stopped

  db:
    image: postgres:16-alpine
    container_name: info-postgres
    restart: unless-stopped
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: infodb
    volumes:
      - ./pgdata:/var/lib/postgresql/data
      - ./db/init.sql:/docker-entrypoint-initdb.d/init.sql
    ports:
      - "5432:5432"


====================================
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====================================