CanonicalLog

gem "canonical_log"

use CanonicalLog::Middleware

# Add multiple fields at once
CanonicalLog.add(order_id: 123, checkout_step: "payment")

# Set a single field
CanonicalLog.set(:checkout_step, "payment")

# Increment a counter
CanonicalLog.increment(:external_api_calls)

# Append to an array
CanonicalLog.append(:feature_flags, "new_checkout")

# User context
CanonicalLog.context(:user, id: 42, tier: "premium", account_age_days: 365)

# Business logic context
CanonicalLog.context(:business, endpoint: "create_order", order_id: 123)

# Infrastructure context
CanonicalLog.context(:infra, region: "eu-central-1", k8s_pod: "api-abc123")

# Service metadata
CanonicalLog.context(:service, version: "1.2.3", git_sha: "abc123")

begin
  process_payment
rescue Stripe::CardError => e
  CanonicalLog.add_error(e, code: "card_declined", retriable: false)
  head :unprocessable_entity
end

CanonicalLog.configure do |config|
  # Master on/off switch.
  # Defaults to true in production (or when Rails is not defined), false otherwise.
  # Checked at runtime, so it's toggleable per-request.
  # config.enabled = true

  # Suppress Rails' default ActionController/ActionView log subscribers (default: false).
  # Useful when canonical log replaces the default request logging.
  # config.suppress_rails_logging = true

  # Pretty-print JSON with ANSI colors (default: false).
  # Great for development — cyan keys, green strings, yellow numbers.
  # config.pretty = true

  # Where to write log lines.
  # :auto (default) -> Stdout (JSON to $stdout).
  # Pass any object responding to #write(json_string), or an array of them.
  config.sinks = :auto

  # Output format: :json (default), :pretty, or :logfmt.
  # config.format = :json

  # Parameter keys replaced with [FILTERED] in output.
  config.param_filter_keys = %w[password password_confirmation token secret secret_key api_key access_token credit_card card_number cvv ssn authorization]

  # Filter literal values from SQL in slow_queries (default: true).
  # config.filter_sql_literals = true

  # Filter sensitive params from query strings (default: true).
  # config.filter_query_string = true

  # SQL queries slower than this (ms) are captured individually.
  config.slow_query_threshold_ms = 100.0

  # Paths to skip entirely (no log line emitted).
  # Strings match by prefix, Regexps by pattern.
  config.ignored_paths = ["/health", "/assets", %r{\A/packs}]

  # Fields merged into every event (e.g., app name, environment).
  # config.default_fields = { app: "myapp", env: Rails.env }

  # Number of backtrace lines included in error objects (default: 5, 0 to disable).
  # config.error_backtrace_lines = 5

  # --- Sampling ---

  # Fraction of requests to log (1.0 = everything, 0.05 = 5%).
  # Errors and slow requests are always logged regardless of sample rate.
  config.sample_rate = 1.0

  # Requests slower than this (ms) are always logged, even when sampled out.
  config.slow_request_threshold_ms = 2000.0

  # Custom sampling function (overrides sample_rate).
  # Receives (event_hash, config) -> boolean.
  config.sampling = ->(event, _config) {
    return true if event[:http_status].to_i >= 500
    return true if event[:duration_ms].to_f > 1000
    rand < 0.1  # 10% of the rest
  }

  # --- User context ---

  # Extract user context from each request.
  # Receives the Rack env hash (after the request completes, so Warden is available).
  # When not set and Warden/Devise is detected, user_id and user_email
  # are captured automatically into the :user category.
  config.user_context = ->(env) {
    user = env['warden']&.user
    if user
      { user_id: user.id, role: user.role, org_id: user.organization_id }
    else
      {}
    end
  }

  # --- Log level ---

  # Custom log level resolver (overrides default status-based logic).
  # Default: 5xx/error -> :error, 4xx -> :warn, else -> :info.
  # config.log_level_resolver = ->(event_hash) {
  #   event_hash[:http_status].to_i >= 500 ? :error : :info
  # }

  # Hook called just before the event is serialized and emitted.
  config.before_emit = ->(event) {
    event.set(:app_version, ENV["APP_VERSION"])
    event.context(:infra, region: ENV["AWS_REGION"])
  }
end

CanonicalLog.configure do |config|
  config.sample_rate = 0.05              # Log 5% of normal traffic
  config.slow_request_threshold_ms = 1000 # Always log requests > 1s
end

CanonicalLog.configure do |config|
  # Already defaults to production-only, but you can override:
  config.enabled = true # enable everywhere

  # Suppress Rails' default request logs when canonical log is active:
  config.suppress_rails_logging = Rails.env.production?

  # Pretty-print with colors in development:
  config.pretty = Rails.env.development?
end

Sidekiq.configure_server do |config|
  config.server_middleware do |chain|
    chain.add CanonicalLog::Integrations::Sidekiq
  end
end

class ApplicationController < ActionController::Base
  include CanonicalLog::Integrations::ErrorEnrichment
end

CanonicalLog.configure do |config|
  config.format = :logfmt
end

class DatadogSink < CanonicalLog::Sinks::Base
  def write(json_string)
    # Send to Datadog, Splunk, ClickHouse, BigQuery, etc.
  end
end

CanonicalLog.configure do |config|
  config.sinks = [
    CanonicalLog::Sinks::Stdout.new,
    DatadogSink.new
  ]
end