update documentation

Author: herin049

docs/exporter/prometheus/prometheus.rst

@@ -16,7 +16,7 @@ The OpenTelemetry Prometheus Exporter package is available on PyPI::
 Usage
 -----
 
-The Prometheus exporter starts an HTTP server that collects metrics and serializes them to 
+The Prometheus exporter starts an HTTP server that collects metrics and serializes them to
 Prometheus text format on request::
 
     from prometheus_client import start_http_server
@@ -39,6 +39,47 @@ Prometheus text format on request::
     provider = MeterProvider(resource=resource, metric_readers=[reader])
     metrics.set_meter_provider(provider)
 
+Resource attributes
+-------------------
+
+By default, resource attributes are exported on the ``target_info`` metric. To
+also add selected resource attributes as Prometheus labels on every exported
+metric, pass a ``resource_attr_filter`` callback to ``PrometheusMetricReader``.
+The callback receives the original resource attribute key and returns ``True``
+for attributes that should be copied to metric labels::
+
+    from prometheus_client import start_http_server
+
+    from opentelemetry import metrics
+    from opentelemetry.exporter.prometheus import PrometheusMetricReader
+    from opentelemetry.sdk.metrics import MeterProvider
+    from opentelemetry.sdk.resources import SERVICE_NAME, Resource
+
+    resource = Resource.create(
+        attributes={
+            SERVICE_NAME: "checkout-service",
+            "service.namespace": "shop",
+            "deployment.environment": "production",
+        }
+    )
+
+    start_http_server(port=9464, addr="localhost")
+    included_resource_attrs = {SERVICE_NAME, "service.namespace"}
+    reader = PrometheusMetricReader(
+        resource_attr_filter=lambda key: key in included_resource_attrs
+    )
+    provider = MeterProvider(resource=resource, metric_readers=[reader])
+    metrics.set_meter_provider(provider)
+
+    meter = metrics.get_meter(__name__)
+    counter = meter.create_counter("orders")
+    counter.add(1)
+
+The exported metric includes ``service_name="checkout-service"`` and
+``service_namespace="shop"`` labels. Resource attribute keys are sanitized to
+valid Prometheus label names, and metric attributes with the same sanitized name
+take precedence over copied resource attributes.
+
 Configuration
 -------------
 
@@ -56,4 +97,4 @@ References
 ----------
 
 * `Prometheus <https://prometheus.io/>`_
-* `OpenTelemetry Project <https://opentelemetry.io/>`_ 
+* `OpenTelemetry Project <https://opentelemetry.io/>`_

exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/__init__.py

@@ -132,7 +132,16 @@ def _convert_buckets(
 
 
 class PrometheusMetricReader(MetricReader):
-    """Prometheus metric exporter for OpenTelemetry."""
+    """Prometheus metric exporter for OpenTelemetry.
+
+    Args:
+        disable_target_info: Whether to disable the ``target_info`` metric.
+        prefix: Prefix added to exported Prometheus metric names.
+        resource_attr_filter: Optional callback to select resource attributes
+            that are copied as labels on exported metrics. The callback receives
+            the original resource attribute key. Selected keys are sanitized to
+            valid Prometheus label names.
+    """
 
     def __init__(
         self,