Go

Send logs and errors from Go to LogNorth: an slog handler, HTTP middleware with trace IDs, and stack traces on errors.

go get github.com/karloscodes/lognorth-sdk-go

Quick Start

package main

import lognorth "github.com/karloscodes/lognorth-sdk-go"

func main() {
  lognorth.Config("https://logs.yoursite.com", "your-api-key")

  lognorth.Log("User signed up", map[string]any{"user_id": 123})
  lognorth.Error("Checkout failed", err, map[string]any{"order_id": 42})
}

Environments

Config sends from every environment. To label events and keep development and test quiet, use Configure:

lognorth.Configure(lognorth.Options{
  URL:         os.Getenv("LOGNORTH_URL"),
  APIKey:      os.Getenv("LOGNORTH_API_KEY"),
  Environment: os.Getenv("APP_ENV"), // stamped on every event as context.environment
})

With Configure, LogNorth sends nothing when Environment is development or test. Set Enabled to decide yourself.

With slog

slog.SetDefault(slog.New(lognorth.NewHandler()))

slog.Info("User signed up", "user_id", 123)
slog.Error("Checkout failed", "error", err)

Middleware

http.HandleFunc("/", homeHandler)
http.HandleFunc("/users", usersHandler)

http.ListenAndServe(":8080", lognorth.Middleware(http.DefaultServeMux))

The middleware automatically:

Generates a trace_id per request (or uses X-Trace-ID from the incoming header)
Sets X-Trace-ID on the response
Logs the request with duration_ms and trace_id as top-level fields

Users and releases

Name the signed-in user inside a handler. Use an ID, never an email:

lognorth.SetUser(r.Context(), strconv.Itoa(user.ID))

The issue page then shows how many users an issue hit. Errors also carry the release, from Options.Release or from LOGNORTH_RELEASE, GIT_SHA, KAMAL_VERSION, or your host’s commit variable. At startup the SDK logs Release <version> started, and LogNorth draws each deploy as a dashed line on its charts.

Ignoring Routes

Skip health checks and other noisy endpoints:

lognorth.IgnorePaths("/healthz", "/_health", "/metrics")

These paths won’t be logged by the middleware.

How It Works

Method	Behavior
`Log()`	Batched (10 events or 5s)
`Error()`	Sent immediately with stack trace
Middleware	Logs requests with `trace_id` + `duration_ms`
Shutdown	Auto-flush on SIGINT/SIGTERM

Error() automatically captures the error class, file, line, caller function, and full stack trace. LogNorth groups errors into issues by them.