Rails

Send logs and errors from Rails to LogNorth: a Railtie, request middleware, the Rails error subscriber, and Active Job.

bundle add lognorth

Quick Start

Add credentials:

lognorth:
  url: https://logs.yoursite.com
  api_key: your-api-key

That’s it. The gem auto-configures via Railtie. It sends from every environment except development and test.

Prefer environment variables? Set them in config/application.rb instead of credentials:

config.lognorth.url = ENV["LOGNORTH_URL"]
config.lognorth.api_key = ENV["LOGNORTH_API_KEY"]

Usage

LogNorth.log("User signed up", { user_id: 123 })
LogNorth.error("Checkout failed", exception, { order_id: 42 })

Middleware

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
All LogNorth.log() and LogNorth.error() calls within the request automatically inherit the same trace_id

class UsersController < ApplicationController
  def create
    # This log automatically gets the same trace_id as the middleware request log
    LogNorth.log("User signed up", { user_id: @user.id })
  end
end

Options

# config/application.rb, with the defaults
config.lognorth.enabled = nil            # nil: on everywhere except development and test
config.lognorth.middleware = true        # Log HTTP requests
config.lognorth.error_subscriber = true  # Report exceptions (Rails 7+)
config.lognorth.active_job = true        # One event per job, with the trace of the request that enqueued it

Users and releases

The gem reads Current.user when your app defines it, as the Rails authentication generator does. Otherwise, name the user yourself. Use an ID, never an email:

class ApplicationController < ActionController::Base
  before_action { LogNorth.user = current_user&.id }
end

The issue page then shows how many users an issue hit. Errors also carry the release, from KAMAL_VERSION, LOGNORTH_RELEASE, GIT_SHA, or your host’s commit variable. At boot the gem 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:

config.lognorth.ignored_paths = %w[/healthz /_health /up]

These paths won’t be logged by the middleware. The default is ["/up"]; setting the list replaces it.

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 exit
ErrorSubscriber	Reports exceptions via Rails.error (7+)

error() automatically captures the exception class, file, line, caller method, and backtrace. LogNorth groups errors into issues by them.