🚀 Simple Prometheus Metrics Demo App 📊

What does this demo app do? 🤔

This is a simple PoC application that demonstrates how to implement Prometheus metrics in a Python application. It creates two metrics:

• 🔢 Counter: Tracks the number of requests processed
• ⏱️ Histogram: Measures the processing time of each request

The app simulates processing requests and exposes these metrics for Prometheus to scrape.

Requirements 📋

• 🐍 Python 3.6+
• 📦 prometheus_client==0.21.1

Installation 💻

1. Clone this repository:

git clone https://github.com/sfc-gh-svishnu/simple-python-prometheus-app.git
cd simple-python-prometheus-app

2. Create a virtual environment:

python -m venv prometheus_app_env
source prometheus_app_env/bin/activate

3. Install the dependencies:

pip install -r requirements.txt

Running the App 🏃‍♂️

python simple_metrics_app.py

You'll see output like this:

Metrics server started on port 11501
Simple app with Prometheus metrics running
Visit http://localhost:11501/metrics to see metrics
Request processed in 0.32 seconds
Total requests: 1
Request processed in 0.17 seconds
Total requests: 2
...

Viewing Metrics 👀

Open your browser or use curl to view the metrics:

curl http://localhost:11501/metrics

Sample output:

❯ curl http://localhost:11501/metrics
# HELP simple_app_request_count_total Number of requests received by the application
# TYPE simple_app_request_count_total counter
simple_app_request_count_total 32.0
# HELP simple_app_request_duration_seconds Time spent processing requests
# TYPE simple_app_request_duration_seconds histogram
simple_app_request_duration_seconds_bucket{le="0.005"} 0.0
simple_app_request_duration_seconds_bucket{le="0.01"} 0.0
simple_app_request_duration_seconds_bucket{le="0.025"} 0.0
simple_app_request_duration_seconds_bucket{le="0.05"} 0.0
simple_app_request_duration_seconds_bucket{le="0.075"} 0.0
simple_app_request_duration_seconds_bucket{le="0.1"} 0.0
simple_app_request_duration_seconds_bucket{le="0.25"} 15.0
simple_app_request_duration_seconds_bucket{le="0.5"} 31.0
simple_app_request_duration_seconds_bucket{le="0.75"} 32.0
simple_app_request_duration_seconds_bucket{le="1.0"} 32.0
simple_app_request_duration_seconds_bucket{le="2.5"} 32.0
simple_app_request_duration_seconds_bucket{le="5.0"} 32.0
simple_app_request_duration_seconds_bucket{le="7.5"} 32.0
simple_app_request_duration_seconds_bucket{le="10.0"} 32.0
simple_app_request_duration_seconds_bucket{le="+Inf"} 32.0
simple_app_request_duration_seconds_count 32.0
simple_app_request_duration_seconds_sum 9.58327141427435

How It Works 🧠

1. 🏗️ Creates a custom registry and defines metrics using an Enum
2. 🚦 Starts an HTTP server on port 11501 to expose metrics
3. 🔄 Simulates processing requests in a loop
4. 📝 Records request count and duration as metrics
5. 🌐 Exposes metrics at the /metrics endpoint