📊 Telegram Alerts Monitoring Stack

class-prometheus-grafana-telegram-alerts

A complete, containerized monitoring environment designed to simulate real-world application metrics, visualize them, and automatically send alerts to a Telegram chat.

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🚀 Architecture Overview

Our stack is built on four core pillars:

1. 🟢 Node.js App (Port 8081)
   A minimal Express backend using prom-client to expose metrics. Includes a dedicated /simulate-error endpoint to manually trigger issue scenarios for testing.
2. 🔥 Prometheus (Port 9090)
   A powerful time-series database configured to continuously scrape metrics exposed by the Node.js application and cAdvisor.
3. 🐳 cAdvisor (Port 8082)
   Exposes real, system-level CPU and Memory metrics for the Docker containers, providing true resource consumption data.
4. 📈 Grafana (Port 4000)
   The visualization and alerting engine, completely pre-provisioned via code:
   • Data Source: Pre-linked to Prometheus.
   • Custom Dashboard: Live tracking of errors, error rates, real container CPU/RAM usage, and HTTP response times (p95 & p50).
   • Alerting: Pre-configured Notification Policies & Contact Points pointing directly to a custom Telegram channel.
   • Smart Rules: Instantly triggers notifications when the Node.js error counter spikes.

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⚙️ Prerequisites

Before you begin, ensure you have the following installed:

• Docker
• Docker Compose

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🛠️ How to Run Locally

1. Clone the repository (or navigate to this environment folder):

git clone git@github.com:fdhhhdjd/class-prometheus-grafana-telegram-alerts.git
cd class-prometheus-grafana-telegram-alerts

2. Start the monitoring stack in detached mode:

docker compose up -d

Note: Wait a few moments for the containers to fully start and for Grafana to provision its plugins and modules.

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🔍 Accessing the Services

Once the stack is up and running, you can access the following interfaces:

Service	Local URL	Network IP	Default Credentials
Node.js App	http://localhost:8081	http://<ip>:8081	-
Prometheus	http://localhost:9090	http://<ip>:9090	-
Grafana	http://localhost:4000/dashboards	http://<ip>:4000/dashboards	admin / admin

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🚨 How to Test Telegram Alerts

The stack comes fully prepared with your Telegram Bot credentials and Channel ID. Here's how to trigger an alert:

1. Open Grafana: Go to the Node.js Application Dashboard in your browser.
2. Trigger an Error: In a new tab, purposefully trigger a backend error by visiting the /simulate-error endpoint:

   http://localhost:8081/simulate-error
   

3. Spike the Counter: Refresh the simulation page multiple times to simulate a surge in errors.
4. Test Latency (Optional): Open another tab and hit the /slow endpoint to test HTTP response times:

   http://localhost:8081/slow
   

5. Watch the Metrics: Return to the Grafana dashboard. Within 10 to 30 seconds, you will observe the graphs spiking.
6. Check Telegram: Grafana will automatically evaluate the threshold rule, mark it as Firing, and dispatch an HTML-formatted alert securely via your bot to the Telegram chat! 📲