docs: add docker-compose to run prometheus for the experimental example (#4268)

Co-authored-by: Marc Pichler <[email protected]>

Author: Lp-Francois

experimental/examples/prometheus/README.md

@@ -11,17 +11,28 @@ This is a simple example that demonstrates basic metrics collection and exports
 npm install
 ```
 
-Setup [Prometheus](https://prometheus.io/docs/prometheus/latest/getting_started/)
-
 ## Run the Application
 
-- Run the server
-
 ```sh
 # from this directory
 npm run start
 ```
 
+If you are using the default configurations, the metrics should be available at <http://localhost:9464/metrics>
+
+## Run Prometheus
+
+### With docker
+
+```sh
+# from this directory
+docker compose up
+```
+
+### With binary
+
+Setup [Prometheus](https://prometheus.io/docs/prometheus/latest/getting_started/)
+
 - Replace the `prometheus.yml` provided by the Prometheus installation with the following:
 
 ```yaml
@@ -34,7 +45,6 @@ scrape_configs:
     # scheme defaults to 'http'.
     static_configs:
     - targets: ['localhost:9464']
-
 ```
 
 - Start Prometheus
@@ -44,7 +54,7 @@ scrape_configs:
 prometheus --config.file=prometheus.yml
 ```
 
-### Prometheus UI
+## Prometheus UI
 
 If you are using the default configurations, the prometheus client will be available at <http://localhost:9090>
 

experimental/examples/prometheus/docker-compose.yaml

@@ -0,0 +1,12 @@
+version: '3.7'
+
+services:
+  prometheus:
+    image: prom/prometheus:v2.47.2
+    extra_hosts:
+      - host.docker.internal:host-gateway
+    volumes:
+      - "./prometheus.docker.yml:/etc/prometheus/prometheus.yml"
+    ports:
+      - 9090:9090
+    restart: always

experimental/examples/prometheus/prometheus.docker.yml

@@ -0,0 +1,9 @@
+global:
+  scrape_interval: 15s # Default is every 1 minute.
+
+scrape_configs:
+  - job_name: 'opentelemetry'
+    # metrics_path defaults to '/metrics'
+    # scheme defaults to 'http'.
+    static_configs:
+    - targets: ['host.docker.internal:9464']