Prev Next

Golang / GoLang Production Patterns and Web Standards Interview Questions

How do you add observability (metrics and distributed tracing) to a Go service?

Production Go services expose Prometheus metrics and OpenTelemetry traces. Both integrate with Go's standard HTTP server and context-based propagation.

// Prometheus metrics with the standard prometheus/client_golang library
import (
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)

var (
    httpRequestsTotal = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Name: "http_requests_total",
            Help: "Total number of HTTP requests",
        },
        []string{"method", "path", "status"},
    )
    httpRequestDuration = prometheus.NewHistogramVec(
        prometheus.HistogramOpts{
            Name:    "http_request_duration_seconds",
            Help:    "HTTP request duration in seconds",
            Buckets: prometheus.DefBuckets,
        },
        []string{"method", "path"},
    )
)

func init() {
    prometheus.MustRegister(httpRequestsTotal, httpRequestDuration)
}

// Metrics middleware
func metricsMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        start := time.Now()
        lrw := &statusResponseWriter{ResponseWriter: w, status: 200}
        next.ServeHTTP(lrw, r)
        dur := time.Since(start).Seconds()
        path := r.URL.Path
        httpRequestsTotal.WithLabelValues(r.Method, path,
            strconv.Itoa(lrw.status)).Inc()
        httpRequestDuration.WithLabelValues(r.Method, path).Observe(dur)
    })
}

// Expose metrics endpoint
mux.Handle("GET /metrics", promhttp.Handler())

// OpenTelemetry tracing (simplified)
// otel.SetTracerProvider(tp)
// tracer := otel.Tracer("myservice")
// ctx, span := tracer.Start(ctx, "operationName")
// defer span.End()
// span.SetAttributes(attribute.String("user.id", userID))

What is the difference between a Counter and a Histogram in Prometheus?
Why should high-cardinality values (like individual user IDs) NOT be used as Prometheus label values?

More Related questions...

Why does Go treat errors as values instead of using exceptions, and what are the advantages? How do you wrap errors in Go 1.13+ and use errors.Is and errors.As for inspection? What are the best practices for defining custom error types in Go? What is context.Context in Go, what does it carry, and how do you create one? How does context propagate through an HTTP request lifecycle in Go? What are the best practices and anti-patterns for using context.WithValue? How do you build a production-ready HTTP server using Go's standard net/http package? What is the standard Go HTTP middleware signature and how do you chain multiple middleware? How has http.ServeMux evolved in Go 1.22 and what routing patterns does it support? How do you encode and decode JSON in Go and what are the common pitfalls? What are the rules for writing HTTP responses correctly in Go handlers? How do you implement dependency injection in Go without a framework? How do you implement structured logging in Go using the slog package? What are the idiomatic Go patterns for managing application configuration? How do you interact with a SQL database in Go using the standard database/sql package? How do you implement graceful shutdown of an HTTP server in Go? How do you test HTTP handlers in Go without starting a real server? What are table-driven tests in Go and why are they the preferred testing pattern? How do you write testable Go code using interfaces and mocks without a framework? How do you implement rate limiting in a Go HTTP server? How do you implement CORS correctly in a Go HTTP server? How and when should you use panic and recover in production Go code? How do you manage environment-specific settings and feature flags in Go? How do you implement health check and readiness endpoints for a Go service? How do you add observability (metrics and distributed tracing) to a Go service? How do build tags work in Go and when do you use them? What are the best practices for using Go's HTTP client in production? What patterns make HTTP error handling consistent and DRY in Go? What are the common API versioning strategies in Go HTTP services? How do Go programs handle OS signals and interact with the operating system? How do you profile a Go service in production using pprof? How does Go's module system work and what are the key commands? How do you validate HTTP request inputs in Go without a framework? How do you implement streaming HTTP responses in Go? How do you write and interpret Go benchmarks? How do you embed static files into a Go binary using go:embed? How do you implement timeouts for non-HTTP operations like database queries and external calls? What are the conventions for returning structured error responses from a Go REST API? How do you implement pagination for list endpoints in a Go REST API? How do you implement JWT authentication middleware in Go? How do you implement HTTP response caching in a Go service? How does gRPC work in Go and when would you choose it over REST/JSON? What linters and static analysis tools are essential for production Go code quality? What is the recommended project structure for a production Go service? How do you implement load shedding and request queue limits in a Go HTTP server? How do you correctly propagate errors from concurrent goroutines in a Go service? How do you document a Go REST API and maintain an OpenAPI specification? What is the production readiness checklist for a Go HTTP service?
Show more question and Answers...

GoLang System Architecture and Testing Interview Questions

Comments & Discussions

Interviews Questions

About Javapedia.net

Javapedia.net is for Java and J2EE developers, technologist and college students who prepare of interview. Also this site includes many practical examples.

This site is developed using J2EE technologies by Steve Antony, a senior Developer/lead at one of the logistics based company.

Follow Javapedia updates

contact: javatutorials2016[at]gmail[dot]com

Kindly consider donating for maintaining this website. Thanks.

Copyright © 2026, javapedia.net, all rights reserved. · .

DMCA.com Protection Status