Why Open telemetry metrics are not getting exported to console and OTLP in .net core API ?

[manu-balakrishnan]

Open telemetry metrics are not getting exported to console and OTLP in .net core API. here is my configurations.

Startup.cs

var serviceName = "SampleAPI.Metrics";

services.AddOpenTelemetryMetrics((builder) =>
{
    builder
    .AddMeter(serviceName)
    .AddConsoleExporter()
    .AddOtlpExporter(options => {
        options.Endpoint = new Uri("http://localhost:4317");
    });
});

docker-compose

version: "2"
services:


  prometheus:
    container_name: prometheus
    image: prom/prometheus:latest
    volumes:
      - ./prometheus.yaml:/etc/prometheus/prometheus.yml
    ports:
      - "9090:9090"

  otel-collector:
    image: otel/opentelemetry-collector:latest
    command: ["--config=/etc/otel-collector-config.yaml"]
    volumes:
      - ./otel-collector-config.yaml:/etc/otel-collector-config.yaml
      - ./output:/etc/output:rw # Store the logs
    ports:
      - "8888:8888"   # Prometheus metrics exposed by the collector
      - "8889:8889"   # Prometheus exporter metrics
      - "4317:4317"   # OTLP gRPC receiver
    depends_on:
      - jaeger-all-in-one
      - prometheus
      
  jaeger-all-in-one:
    image: jaegertracing/all-in-one:latest
    ports:
      - "16686:16686"
      - "14268"
      - "14250"

otel-collector-config

receivers:
  otlp:
    protocols:
      grpc:

exporters:
  jaeger:
    endpoint: jaeger-all-in-one:14250
    insecure: true
  prometheus:
    endpoint: "0.0.0.0:8889"

processors:
  batch:

service:
  pipelines:
    traces:
      receivers: [otlp]
      exporters: [jaeger]
      processors: [batch]
    metrics:
      receivers: [otlp]
      exporters: [prometheus]
      processors: [batch]

Prometheus

scrape_configs:
- job_name: 'otel-collector'
  scrape_interval: 10s
  static_configs:
  - targets: ['otel-collector:8889']
  - targets: ['otel-collector:8888']

I have added few counters and incremented its value in one of the controller. however while triggering the API, metrics are not getting exported to neither console nor OTLP. Please help to resolve the issue.

[cijothomas]

Without seeing a minimal repro app, its not possible to tell what is going on.
I'd suggest to get started with https://github.com/open-telemetry/opentelemetry-dotnet/tree/main/docs/metrics/getting-started
or use the example application provided : https://github.com/open-telemetry/opentelemetry-dotnet/tree/main/examples/AspNetCore

[manu-balakrishnan]

@cijothomas I've followed the same sample applications that you mentioned above. For console application, metrics are exporting as expected however in case of .net core, even though traces and logs exporting, metrics failed to export.

here is the repro app that that you can refer.
repro app

[cijothomas]

https://github.com/open-telemetry/opentelemetry-dotnet/tree/main/src/OpenTelemetry#self-diagnostics - run with self-diagnostics and paste the log file, which will tell us why it is not working.

[cijothomas]

https://github.com/manu-balakrishnan/Dotnet_OpenTelemetry/blob/main/Controllers/WeatherForecastController.cs#L49-L51 -- This is not correct. Please create Meter, Instruments only once (eg: static Meter).