Base OTEL docker-compose

Creates basic docker-compose that could be used for the local
running/testing opentelemetry output.

It contains Grafana, Grafana Alloy (which has OTEL receivers) and
Prometheus as metric backend.

docker-compose.yml

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+version: '3.8'
+
+networks:
+  k6:
+
+services:
+  prometheus:
+    image: prom/prometheus:v2.52.0
+    command:
+      - --web.enable-remote-write-receiver
+      - --enable-feature=native-histograms
+      - --config.file=/etc/prometheus/prometheus.yml
+    networks:
+      - k6
+    ports:
+      - "9090:9090"
+
+  alloy:
+    image: grafana/alloy:v1.0.0
+    networks:
+      - k6
+    volumes:
+      - ./grafana/alloy:/etc/alloy
+    environment:
+      REMOTE_WRITE_HOST: prometheus:9090
+    depends_on:
+      - prometheus
+    command:
+      - run
+      - /etc/alloy/config.alloy
+      - --storage.path=/var/lib/alloy/data
+      - --server.http.listen-addr=0.0.0.0:12345
+      - --stability.level=experimental # Enable all functionality
+    ports:
+      - "12345:12345" # Alloy UI
+      - "4317:4317" # gRPC receiver
+      - "4318:4318" # HTTP receiver
+
+  grafana:
+    image: grafana/grafana:10.1.2
+    networks:
+      - k6
+    ports:
+      - "3000:3000"
+    environment:
+      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
+      - GF_AUTH_ANONYMOUS_ENABLED=true
+      - GF_AUTH_BASIC_ENABLED=false
+    volumes:
+      - ./grafana:/etc/grafana/provisioning/

grafana/alloy/config.alloy

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+// expose OTEL receivers
+// https://grafana.com/docs/alloy/latest/reference/components/otelcol.receiver.otlp/
+otelcol.receiver.otlp "default" {
+	// configures the default gRPC receiver endpoint "0.0.0.0:4317"
+	// https://grafana.com/docs/alloy/latest/reference/components/otelcol.receiver.otlp/#grpc-block
+	grpc {}
+
+	// configures the default HTTP receiver endpoint "0.0.0.0:4318"
+	// https://grafana.com/docs/alloy/latest/reference/components/otelcol.receiver.otlp/#http-block
+	http {}
+
+	output {
+		metrics = [otelcol.processor.batch.default.input]
+	}
+}
+
+otelcol.processor.batch "default" {
+	// https://grafana.com/docs/alloy/latest/reference/components/otelcol.processor.batch/
+	output {
+		metrics = [otelcol.exporter.prometheus.default.input]		
+	}
+}
+
+otelcol.exporter.prometheus "default" {
+	add_metric_suffixes = false
+	forward_to          = [prometheus.remote_write.default.receiver]
+}
+
+// Collect metrics from the local running Alloy instance and forward to
+// Prometheus.
+prometheus.exporter.self "alloy" {}
+prometheus.scrape "alloy" {
+	targets    = prometheus.exporter.self.alloy.targets
+	forward_to = [prometheus.remote_write.default.receiver]
+}
+
+prometheus.remote_write "default" {
+	endpoint {
+		url = format(
+			"http://%s/api/v1/write",
+			coalesce(env("REMOTE_WRITE_HOST"), "localhost:9090"),
+		)
+	}
+}

grafana/dashboards/dashboards.yaml

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+# For configuration options, see
+#   https://grafana.com/docs/grafana/latest/administration/provisioning/#dashboards
+
+apiVersion: 1
+
+providers:
+  # We're defining a directory from which to load file-based dashboards
+  - name: 'prometheus'
+    type: file
+    disableDeletion: false
+    updateIntervalSeconds: 10
+    editable: true
+    options:
+      path: /etc/grafana/provisioning/dashboards