OpenTelemetry Middleware

The xotel package provides OpenTelemetry tracing middleware for Kern applications.

Installation

go get github.com/mobentum/kern/extensions/xotel

Basic Usage

import (
    "github.com/mobentum/kern"
    "github.com/mobentum/kern/extensions/xotel"
)

func main() {
    app := kern.New()

    app.Use(xotel.Middleware(xotel.Config{
        ServiceName: "my-api",
    }))

    app.GET("/users/{id}", func(c *kern.Context) {
        _ = c.JSON(200, map[string]string{"id": c.Param("id")})
    })

    app.Run(":8080")
}

Configuration

Option	Type	Default	Description
`TracerProvider`	`trace.TracerProvider`	`otel.GetTracerProvider()`	Custom tracer provider
`Propagator`	`propagation.TextMapPropagator`	`otel.GetTextMapPropagator()`	Trace context propagator
`ServiceName`	`string`	`""`	Service name on every span
`Skip`	`func(*http.Request) bool`	`nil`	Skip tracing for specific requests

Skip Health Checks

app.Use(xotel.Middleware(xotel.Config{
    ServiceName: "my-api",
    Skip: func(r *http.Request) bool {
        return r.URL.Path == "/health"
    },
}))

With Custom Tracer Provider

import (
    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/sdk/trace"
)

func setupOTel() {
    exporter, _ := otlptracehttp.New(ctx)
    tp := trace.NewTracerProvider(trace.WithBatcher(exporter))
    otel.SetTracerProvider(tp)
}

// In main:
app.Use(xotel.Middleware(xotel.Config{
    TracerProvider: otel.GetTracerProvider(),
    ServiceName:    "my-api",
}))

Span Attributes

Each request span includes:

http.request.method — HTTP method (GET, POST, etc.)
url.path — Request path
url.query — Raw query string
network.protocol.version — HTTP version
user_agent.original — User-Agent header
http.response.status_code — Response status code

OpenTelemetry Middleware

OpenTelemetry Middleware

Installation

Basic Usage

Configuration

Skip Health Checks

With Custom Tracer Provider

Span Attributes

See Also

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