Enable exemplar export/display support

Ensure the collector's prometheus endpoint produces exemplars
Ensure that prometheus collects and stores exemplar data
Ensure that grafana will display links to exemplars from dashboards/the explore tab

CHANGELOG.md

@@ -202,3 +202,5 @@ significant modifications will be credited to OpenTelemetry Authors.
 ([#700](https://github.com/open-telemetry/opentelemetry-demo/pull/700))
 * Reduce spans generated from quote service
 ([#702](https://github.com/open-telemetry/opentelemetry-demo/pull/702))
+* Enable exemplar support in the metrics exporter, Prometheus, and Grafana
+([#704](https://github.com/open-telemetry/opentelemetry-demo/pull/704))

docker-compose.yml

@@ -625,7 +625,7 @@ services:
 
   # OpenTelemetry Collector
   otelcol:
-    image: otel/opentelemetry-collector-contrib:0.61.0
+    image: otel/opentelemetry-collector-contrib:0.69.0
     container_name: otel-col
     deploy:
       resources:
@@ -657,6 +657,7 @@ services:
       - --storage.tsdb.path=/prometheus
       - --web.enable-lifecycle
       - --web.route-prefix=/
+      - --enable-feature=exemplar-storage
     volumes:
       - ./src/prometheus/prometheus-config.yaml:/etc/prometheus/prometheus-config.yaml
     ports:

docs/demo_features.md

@@ -17,14 +17,14 @@ be added as the relevant SDKs are released.
   Collector](https://opentelemetry.io/docs/collector/getting-started)**: all
   services are instrumented and sending the generated traces and metrics to the
   OpenTelemetry Collector via gRPC. The received traces are then exported to the
-  logs and to Jaeger.
+  logs and to Jaeger; received metrics and exemplars are exported to logs and Prometheus.
 - **[Jaeger](https://www.jaegertracing.io)**: all generated traces are being
   sent to Jaeger.
 - **Synthetic Load Generation**: the application demo comes with a background
   job that creates realistic usage patterns on the website using
   [Locust](https://locust.io/) load generator.
-- **[Prometheus](https://prometheus.io/)**: all generated metrics are scraped by
-  Prometheus.
+- **[Prometheus](https://prometheus.io/)**: all generated metrics and exemplars
+  are scraped by Prometheus.
 - **[Grafana](https://grafana.com/)**: all metric dashboards are stored in
   Grafana.
 - **[Envoy](https://www.envoyproxy.io/)**: Envoy is used as a reverse proxy for

docs/metric_service_features.md

@@ -9,7 +9,7 @@ Emoji Legend
 | Service            | Language        | Instrumentation Libraries | Manual Metric Creation | Multiple Manual Metric Instruments | Metric Attributes | Resource Attributes | Exemplars      | Views          |
 |--------------------|-----------------|---------------------------|------------------------|------------------------------------|-------------------|---------------------|----------------|----------------|
 | Accounting Service | Go              | :construction:            | :construction:         | :construction:                     | :construction:    | :construction:      | :construction: | :construction: |
-| Ad                 | Java            | :100:                     | :100:                  | :construction:                     | :100:             | :100:               | :construction: | :construction: |
+| Ad                 | Java            | :100:                     | :100:                  | :construction:                     | :100:             | :100:               | :100: | :construction: |
 | Cart               | .NET            | :100:                     | :construction:         | :construction:                     | :construction:    | :construction:      | :construction: | :construction: |
 | Checkout           | Go              | :100:                     | :construction:         | :construction:                     | :construction:    | :construction:      | :construction: | :construction: |
 | Currency           | C++             | :no_bell:                 | :construction:         | :construction:                     | :construction:    | :construction:      | :construction: | :construction: |

src/grafana/provisioning/datasources/default.yaml

@@ -7,3 +7,11 @@ datasources:
     url: http://prometheus:9090
     editable: true
     isDefault: true
+    jsonData:
+      exemplarTraceIdDestinations:
+        - datasourceUid: webstore-traces
+          name: trace_id
+
+        - url: http://localhost:8080/jaeger/ui/trace/$${__value.raw}
+          name: trace_id
+          urlDisplayLabel: View in Jaeger UI

src/otelcollector/otelcol-config.yml

@@ -18,6 +18,7 @@ exporters:
     endpoint: "otelcol:9464"
     resource_to_telemetry_conversion:
       enabled: true
+    enable_open_metrics: true
 processors:
   batch:
   spanmetrics: