📘 Student Management API with Custom Metrics (Spring Boot + Micrometer + Prometheus)

This project is a RESTful Student Management System built using Spring Boot, featuring full CRUD operations along with custom application metrics exposed to Prometheus using Spring Boot Actuator + Micrometer.

It demonstrates:

• Java Spring Boot development
• JPA/Hibernate database integration
• REST APIs for student operations
• Custom Micrometer counters and gauges
• Prometheus monitoring setup (Docker-compatible)

---

🚀 Features

✅ Student Management (CRUD)

• Add a new student
• Update a student
• Fetch all students
• Fetch student by ID
• Delete student

📊 Custom Metrics

• Custom Counter: custom.metric.one
• Custom Gauge: custom.metric.two
• Actuator + Micrometer metrics exposed at /actuator/prometheus
• Ready for Prometheus + Grafana dashboards

🐳 Docker-Friendly Monitoring

Prometheus config included for scraping metrics.

---

📂 Project Structure

src/main/java/com/example/demo
│
├── DemoApplication.java
├── entity/
│   └── Student.java
├── repository/
│   └── StudentRepository.java
└── controller/
    └── studentController.java

---

🧩 Entity Model

Student.java

Field	Type	Description
rollNo	int	Primary Key
name	String	Student name
percentage	float	Academic percentage
branch	String	Department
isPassed	Boolean	Passed/Failed flag

---

🔧 Custom Metrics Implemented

1️⃣ Counter — Tracks total students created

this.myStudentCounter = Counter.builder("custom.metric.one")
    .tags("status", "created")
    .description("total number of students created - function one")
    .register(meterRegistry);

Incremented on every student creation:

this.myStudentCounter.increment();

---

2️⃣ Gauge — Tracks total students present in DB

long val = repo.count();
Tags tags = Tags.of("status", "pending");
meterRegistry.gauge("custom.metric.two", tags, val);

---

📡 API Endpoints

➤ Get all students

GET /students

➤ Get student by ID

GET /students/{id}

➤ Add a new student

POST /students/add

Example Body:

{
  "name": "Priya",
  "percentage": 88.5,
  "branch": "CSE",
  "isPassed": true
}

➤ Update an existing student

PUT /students/update/{id}

➤ Delete a student

DELETE /students/delete/{id}

---

📊 Prometheus Configuration

Add this inside prometheus.yml:

global:
 scrape_interval: 15s
 evaluation_interval: 15s
 scrape_timeout: 10s

scrape_configs:
 - job_name: 'prometheus'
   static_configs:
     - targets: ['localhost:9090']

 - job_name: 'todo-api'
   metrics_path: '/actuator/prometheus'
   scrape_interval: 3s
   static_configs:
     - targets: ['host.docker.internal:8080']
       labels:
         application: 'spring-actuator'

---

▶️ Run the Project

1️⃣ Clone the repository

git clone https://github.com/priyagupta20044/Java-API-and-Custom-Metrics-using-Spring-Boot

2️⃣ Build

mvn clean install

3️⃣ Run

mvn spring-boot:run

---

🌐 URLs

Type	URL
Application	http://localhost:8080
Prometheus Metrics	http://localhost:8080/actuator/prometheus

---

📈 Example Prometheus Metrics

custom_metric_one_total{status="created"} 5.0
custom_metric_two{status="pending"} 12.0

👩‍💻 Author

Priya Gupta Java • Spring Boot • Machine Learning • Backend Development