Docs: Modify Prometheus exporters section under Language APIs & SDKs

content/en/docs/languages/_includes/exporters/prometheus-setup.md

@@ -1,43 +1,64 @@
 ## Prometheus
 
-To send your metric data to [Prometheus](https://prometheus.io/), you can either
-[enable Prometheus' OTLP Receiver](https://prometheus.io/docs/guides/opentelemetry/#enable-the-otlp-receiver)
-and use the [OTLP exporter](#otlp) or you can use the Prometheus exporter, a
-`MetricReader` that starts an HTTP server that collects metrics and serialize to
-Prometheus text format on request.
+To send your metric data to [Prometheus](https://prometheus.io/), you can either:
+- [Enable Prometheus' OTLP Receiver](https://prometheus.io/docs/guides/opentelemetry/#enable-the-otlp-receiver)
+and use the [OTLP exporter](#otlp) (best practice),
+- [Enable Prometheus' OTLP Receiver](https://prometheus.io/docs/guides/opentelemetry/#enable-the-otlp-receiver)
+and [push Prometheus to the metrics endpoint directly](#push-metrics-directly) (for development or testing purposes), or
+- Use the Prometheus exporter, a `MetricReader` that starts an HTTP server that collects metrics and serializes to Prometheus text format on request.
 
-### Backend Setup {#prometheus-setup}
+### Backend setup {#prometheus-setup}
 
-> [!NOTE]
->
-> If you have Prometheus or a Prometheus-compatible backend already set up, you
-> can skip this section and setup the [Prometheus](#prometheus-dependencies) or
-> [OTLP](#otlp-dependencies) exporter dependencies for your application.
-
-You can run [Prometheus](https://prometheus.io) in a docker container,
-accessible on port `9090` by following these instructions:
-
-Create a file called `prometheus.yml` with the following content:
-
-```yaml
-scrape_configs:
-  - job_name: dice-service
-    scrape_interval: 5s
-    static_configs:
-      - targets: [host.docker.internal:9464]
+For [OTLP Exporter](#otlp-dependencies) or [Prometheus exporter](#prometheus-dependencies):
+
+  To run a Prometheus server backend and begin scraping metrics, see the [Prometheus getting started guide](https://prometheus.io/docs/prometheus/latest/getting_started/). To enable the OTLP Receiver, see the [Prometheus guide for enabling the OTLP Receiver](https://prometheus.io/docs/guides/opentelemetry/#enable-the-otlp-receiver).
+
+For pushing to a metrics endpoint directly:
+
+  Follow the [example prometheus.yml configuration in this Prometheus guide](https://prometheus.io/docs/guides/opentelemetry/#configuring-prometheus).
+
+Once you have Prometheus set up, you can set up the OTLP Exporter, Prometheus exporter, or push to a metrics endpoint directly.
+
+### Push to metrics endpoint {#push-metrics-directly}
+This section explains how to configure your application to send metrics directly to a Prometheus endpoint.
+
+#### Use environment variables
+You can configure OpenTelemetry SDKs and instrumentation libraries with [standard environment variables](/docs/languages/sdk-configuration/). Set the environment variables before starting your application. Below are the OpenTelemetry variables needed to send OpenTelemetry metrics to a Prometheus server on localhost:
+
+```bash
+export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
+export OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=http://localhost:9090/api/v1/otlp
 ```
+Note:
+
+- The [OpenTelemetry specification](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.50.0/specification/protocol/exporter.md#endpoint-urls-for-otlphttp) states that the OTEL_EXPORTER_OTLP_METRICS_ENDPOINT env var must be used as a base URL. The signal `/v1/metrics` is automatically appended
+- See also: [opentelemetry-python #2443](https://github.com/open-telemetry/opentelemetry-python/issues/2443) 
 
-Run Prometheus in a docker container with the UI accessible on port `9090`:
+Turn off traces and logs:
 
-```shell
-docker run --rm -v ${PWD}/prometheus.yml:/prometheus/prometheus.yml -p 9090:9090 prom/prometheus --web.enable-otlp-receiver
+```bash
+export OTEL_TRACES_EXPORTER=none
+export OTEL_LOGS_EXPORTER=none
+```
+
+The default push interval for OpenTelemetry metrics is 60 seconds. The following will set a 15-second push interval:
+
+```bash
+export OTEL_METRIC_EXPORT_INTERVAL=15000
+```
+
+If your instrumentation library does not provide `service.name` and `service.instance.id` out-of-the-box, it is highly recommended to set them. The example below assumes that the `uuidgen` command is available on your system.
+
+```bash
+export OTEL_SERVICE_NAME="my-example-service"
+export OTEL_RESOURCE_ATTRIBUTES="service.instance.id=$(uuidgen)"
 ```
 
 > [!NOTE]
->
-> When using Prometheus' OTLP Receiver, make sure that you set the OTLP endpoint
-> for metrics in your application to `http://localhost:9090/api/v1/otlp`.
->
-> Not all docker environments support `host.docker.internal`. In some cases you
-> may need to replace `host.docker.internal` with `localhost` or the IP address
-> of your machine.
+> Make sure that `service.instance.id` is unique for each instance, 
+> and that a new `service.instance.id` is generated whenever a resource attribute changes.
+> The [recommended way](https://github.com/open-telemetry/semantic-conventions/tree/main/docs/resource) 
+> is to generate a new UUID on each startup of an instance.
+
+#### Configure telemetry
+Update your OpenTelemetry Configuration to use the same `exporter` and `reader` from the [OTLP](#otlp-dependencies) setup. If the environment variables are set up and loaded correctly, the OpenTelemetry SDK reads them automatically.