# Go

Send Go traces to Kopai with the OpenTelemetry SDK and its OTLP HTTP exporter. Let your coding agent wire it up for you, or follow the manual steps.

Instrument your Go applications to send traces, logs, and metrics to Kopai.

## Installation

```bash
go get go.opentelemetry.io/otel
go get go.opentelemetry.io/otel/sdk
go get go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp
go get go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp
```

## Basic Setup

Initialize OpenTelemetry in your application:

```go
import (
    "context"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/sdk/resource"
    sdktrace "go.opentelemetry.io/otel/sdk/trace"
    semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
)

func initTracer(ctx context.Context) (*sdktrace.TracerProvider, error) {
    exporter, err := otlptracehttp.New(ctx)
    if err != nil {
        return nil, err
    }

    res, _ := resource.New(ctx,
        resource.WithAttributes(semconv.ServiceName("my-service")),
    )

    tp := sdktrace.NewTracerProvider(
        sdktrace.WithBatcher(exporter),
        sdktrace.WithResource(res),
    )
    otel.SetTracerProvider(tp)
    return tp, nil
}
```

The SDK reads the OTLP endpoint from standard OpenTelemetry environment variables.

## Running Your Application

Set the required environment variables and run:

```bash
export OTEL_EXPORTER_OTLP_ENDPOINT="https://otlp-http.kopai.app"
export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Bearer YOUR_TOKEN"
export OTEL_SERVICE_NAME="my-service"
go run main.go
```

| Variable | Description |
|----------|-------------|
| `OTEL_EXPORTER_OTLP_ENDPOINT` | Kopai OTLP endpoint |
| `OTEL_EXPORTER_OTLP_HEADERS` | Auth header with your backend token |
| `OTEL_SERVICE_NAME` | Name shown in Kopai UI |

## Graceful Shutdown

Always shut down the tracer provider to flush remaining spans:

```go
defer func() {
    ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
    defer cancel()
    tp.Shutdown(ctx)
}()
```

## Working Example

For a complete working example:

**[Go Example](https://github.com/kopai-app/kopai-integration-examples/tree/main/go)**