Send Metrics from .NET Application using OpenTelemetry

The automatic instrumentation collects .NET runtime and process metrics automatically. No additional configuration is needed.

Exported Metrics

Garbage Collection Metrics:

• process.runtime.dotnet.gc.collections.count - Number of garbage collections by generation
• process.runtime.dotnet.gc.objects.size - Bytes in use by GC heap objects
• process.runtime.dotnet.gc.allocations.size - Total bytes allocated on managed heap
• process.runtime.dotnet.gc.duration - Total time paused in GC

JIT Compilation Metrics:

• process.runtime.dotnet.jit.il_compiled.size - IL bytes compiled by JIT
• process.runtime.dotnet.jit.methods_compiled.count - Number of methods JIT compiled
• process.runtime.dotnet.jit.compilation_time - Time spent in JIT compilation

Threading Metrics:

• process.runtime.dotnet.thread_pool.threads.count - Number of thread pool threads
• process.runtime.dotnet.thread_pool.completed_items.count - Work items completed
• process.runtime.dotnet.thread_pool.queue.length - Thread pool queue length
• process.runtime.dotnet.monitor.lock_contention.count - Monitor lock contentions
• process.runtime.dotnet.timer.count - Active timer count

Assembly Metrics:

• process.runtime.dotnet.assemblies.count - Number of loaded assemblies

Process Metrics:

• process.cpu.time - CPU time by state (user/system)
• process.cpu.count - Number of available processors
• process.memory.usage - Physical memory in use
• process.memory.virtual - Committed virtual memory
• process.thread.count - Process thread count

OpenTelemetry provides four metric instrument types. Each example shows how to create and use the instrument.

Counter

A value that only increases (e.g., total requests, orders processed).

using System.Diagnostics.Metrics;
 
var meter = new Meter("MyApp.Metrics", "1.0.0");
 
var requestCounter = meter.CreateCounter<long>(
    "http.requests.total",
    description: "Total number of HTTP requests");
 
// Increment the counter
requestCounter.Add(1);

UpDownCounter

A value that can increase or decrease (e.g., queue size, active connections).

using System.Diagnostics.Metrics;
 
var meter = new Meter("MyApp.Metrics", "1.0.0");
 
var activeRequests = meter.CreateUpDownCounter<int>(
    "http.requests.active",
    description: "Number of active requests");
 
// Increment when request starts
activeRequests.Add(1);
 
// Decrement when request ends
activeRequests.Add(-1);

Histogram

A distribution of values (e.g., request duration, response size).

using System.Diagnostics.Metrics;
 
var meter = new Meter("MyApp.Metrics", "1.0.0");
 
var requestDuration = meter.CreateHistogram<double>(
    "http.request.duration",
    unit: "ms",
    description: "HTTP request duration");
 
// Record a duration value
var stopwatch = System.Diagnostics.Stopwatch.StartNew();
// ... process request ...
requestDuration.Record(stopwatch.ElapsedMilliseconds);

ObservableGauge

A point-in-time value via callback (e.g., temperature, memory usage).

using System.Diagnostics.Metrics;
 
var meter = new Meter("MyApp.Metrics", "1.0.0");
 
meter.CreateObservableGauge(
    "app.memory.usage",
    () => GC.GetTotalMemory(false),
    unit: "By",
    description: "Current memory usage");

Metrics not appearing?

Check environment variables:

echo $OTEL_EXPORTER_OTLP_ENDPOINT
echo $OTEL_METRICS_EXPORTER
echo $OTEL_DOTNET_AUTO_METRICS_ADDITIONAL_SOURCES

Verify instrumentation is active: Look for OpenTelemetry startup messages in the application logs.

Check meter name registration: Ensure OTEL_DOTNET_AUTO_METRICS_ADDITIONAL_SOURCES matches your meter name (e.g., MyApp.Metrics). You can use wildcards like MyApp.*.

Metrics delayed or not updating?

OTEL_METRIC_EXPORT_INTERVAL controls how often metrics are exported in milliseconds. The default is 60000 (60 seconds), so metrics may take up to a minute to appear.

To reduce the interval for testing:

export OTEL_METRIC_EXPORT_INTERVAL=10000  # 10 seconds

Authentication errors

If you see "Unauthorized" or "403 Forbidden":

• Verify your ingestion key is correct in OTEL_EXPORTER_OTLP_HEADERS
• Ensure the header format is exactly: signoz-ingestion-key=<your-key> (no extra spaces)

What is the OpenTelemetry Collector?

Think of the OTel Collector as a middleman between your app and SigNoz. Instead of your application sending data directly to SigNoz, it sends everything to the Collector first, which then forwards it along.

Why use it?

• Cleaning up data - Filter out noisy metrics you don't care about, or remove sensitive info before it leaves your servers.
• Keeping your app lightweight - Let the Collector handle batching, retries, and compression instead of your application code.
• Adding context automatically - The Collector can tag your data with useful info like which Kubernetes pod or cloud region it came from.
• Future flexibility - Want to send data to multiple backends later? The Collector makes that easy without changing your app.

See Switch from direct export to Collector for step-by-step instructions to convert your setup.

For more details, see Why use the OpenTelemetry Collector? and the Collector configuration guide.