Add SIGUSR1 trap to dump settings and help debug

config/initializers/sidekiq.rb

@@ -1,4 +1,5 @@
 require "sidekiq/web"
+require Rails.root.join("lib/settings_signal_dumper")
 
 if Rails.env.production?
   Sidekiq::Web.use(Rack::Auth::Basic) do |username, password|
@@ -14,3 +15,7 @@
   # 10 min "catch-up" window in case worker process is re-deploying when cron tick occurs
   config.reschedule_grace_period = 600
 end
+
+Sidekiq.configure_server do |_config|
+  SettingsLogDump.install_usr1_trap(process_label: "Sidekiq worker")
+end

config/initializers/signal_handlers.rb

@@ -0,0 +1,81 @@
+# Signal handlers for worker processes (Sidekiq)
+#
+# SIGUSR1: Dump current settings array values (masked) to Rails.log
+#
+# Note: For web processes (Puma), the signal handler is configured in config/puma.rb
+# using on_worker_boot to avoid conflicts with Puma's master process signal handling
+Rails.application.config.after_initialize do
+  # Only set up signal handler for Sidekiq worker processes
+  # Puma workers get their handler set up in config/puma.rb
+  if defined?(Sidekiq) && Sidekiq.server?
+    Signal.trap("USR1") do
+      Thread.new do
+        begin
+          Rails.logger.info "=" * 80
+          Rails.logger.info "SIGUSR1 received in Sidekiq worker - Dumping application settings"
+          Rails.logger.info "Process: #{$PROGRAM_NAME} (PID: #{Process.pid})"
+          Rails.logger.info "=" * 80
+
+          # Get all declared fields from Setting model
+          declared_fields = Setting.singleton_class.instance_methods(false)
+            .map(&:to_s)
+            .reject { |m| m.end_with?("=") || m.start_with?("raw_") || %w[[] []= key? delete dynamic_keys validate_onboarding_state! validate_openai_config!].include?(m) }
+            .sort
+
+          # Get all dynamic fields
+          dynamic_fields = Setting.dynamic_keys.sort
+
+          # Helper to mask sensitive values
+          mask_value = lambda do |field_name, value|
+            return nil if value.nil?
+
+            sensitive = [ /key/i, /token/i, /secret/i, /password/i, /api/i, /credentials?/i, /auth/i ]
+            is_sensitive = sensitive.any? { |pattern| field_name.match?(pattern) }
+
+            if is_sensitive && value.present?
+              case value
+              when String
+                value.length <= 4 ? "[MASKED]" : "#{value[0..3]}#{'*' * [ value.length - 4, 8 ].min}"
+              when TrueClass, FalseClass
+                value
+              else
+                "[MASKED]"
+              end
+            else
+              value
+            end
+          end
+
+          # Dump declared fields
+          unless declared_fields.empty?
+            Rails.logger.info "\n--- Declared Settings ---"
+            declared_fields.each do |field|
+              value = Setting.public_send(field)
+              masked_value = mask_value.call(field, value)
+              Rails.logger.info "  #{field}: #{masked_value.inspect}"
+            end
+          end
+
+          # Dump dynamic fields
+          unless dynamic_fields.empty?
+            Rails.logger.info "\n--- Dynamic Settings ---"
+            dynamic_fields.each do |field|
+              value = Setting[field]
+              masked_value = mask_value.call(field, value)
+              Rails.logger.info "  #{field}: #{masked_value.inspect}"
+            end
+          end
+
+          Rails.logger.info "\n" + "=" * 80
+          Rails.logger.info "Settings dump complete (#{declared_fields.size} declared, #{dynamic_fields.size} dynamic)"
+          Rails.logger.info "=" * 80
+        rescue => e
+          Rails.logger.error "Error dumping settings: #{e.class} - #{e.message}"
+          Rails.logger.error e.backtrace.join("\n")
+        end
+      end
+    end
+
+    Rails.logger.info "Signal handlers initialized for Sidekiq worker (SIGUSR1 -> dump settings)"
+  end
+end

config/puma.rb

@@ -2,6 +2,8 @@
 # are invoked here are part of Puma's configuration DSL. For more information
 # about methods provided by the DSL, see https://puma.io/puma/Puma/DSL.html.
 
+require_relative "../lib/settings_log_dump"
+
 rails_env = ENV.fetch("RAILS_ENV", "development")
 
 # Puma starts a configurable number of processes (workers) and each process
@@ -54,3 +56,10 @@
   # isn't killed by Puma when suspended by a debugger.
   worker_timeout 3600
 end
+
+# Set up SIGUSR1 handler in worker processes to dump settings
+# This runs after Puma sets up its worker, so it only affects individual workers
+# The master process can still use SIGUSR1 for phased restarts
+on_worker_boot do
+  SettingsLogDump.install_usr1_trap(process_label: "Puma worker")
+end

lib/settings_log_dump.rb

@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require "timeout"
+
+module SettingsSignalDumper
+  SENSITIVE_PATTERNS = [
+    /key/i,
+    /token/i,
+    /secret/i,
+    /password/i,
+    /api/i,
+    /credentials?/i,
+    /auth/i
+  ].freeze
+
+  SETTINGS_QUERY_TIMEOUT = 5
+
+  def self.install_usr1_trap(process_label:, logger: nil)
+    logger ||= Rails.logger
+
+    Signal.trap("USR1") do
+      Thread.new do
+        dump_settings(process_label: process_label, logger: logger)
+      end
+    end
+
+    logger.info "Signal handler initialized for #{process_label} (SIGUSR1 -> dump settings)"
+  end
+
+  def self.dump_settings(process_label:, logger: nil)
+    logger ||= Rails.logger
+
+    declared_fields = declared_setting_fields
+    dynamic_fields = dynamic_setting_fields(logger: logger)
+
+    logger.info "=" * 80
+    logger.info "SIGUSR1 received in #{process_label} - Dumping application settings"
+    logger.info "Process: #{$PROGRAM_NAME} (PID: #{Process.pid})"
+    logger.info "=" * 80
+
+    unless declared_fields.empty?
+      logger.info "\n--- Declared Settings ---"
+      declared_fields.each do |field|
+        value = Setting.public_send(field)
+        masked_value = mask_value(field, value)
+        logger.info "  #{field}: #{masked_value.inspect}"
+      end
+    end
+
+    unless dynamic_fields.empty?
+      logger.info "\n--- Dynamic Settings ---"
+      dynamic_fields.each do |field|
+        value = Setting[field]
+        masked_value = mask_value(field, value)
+        logger.info "  #{field}: #{masked_value.inspect}"
+      end
+    end
+
+    logger.info "\n" + "=" * 80
+    logger.info "Settings dump complete (#{declared_fields.size} declared, #{dynamic_fields.size} dynamic)"
+    logger.info "=" * 80
+  rescue => e
+    logger.error "Error dumping settings: #{e.class} - #{e.message}"
+    logger.error e.backtrace.join("\n")
+  end
+
+  def self.declared_setting_fields
+    Setting.singleton_class.instance_methods(false)
+      .map(&:to_s)
+      .reject do |method_name|
+        method_name.end_with?("=") ||
+          method_name.start_with?("raw_") ||
+          %w[[] []= key? delete dynamic_keys validate_onboarding_state! validate_openai_config!].include?(method_name)
+      end
+      .sort
+  end
+
+  def self.dynamic_setting_fields(logger: nil)
+    logger ||= Rails.logger
+
+    Timeout.timeout(SETTINGS_QUERY_TIMEOUT) do
+      Setting.dynamic_keys.sort
+    end
+  rescue Timeout::Error
+    logger.error "Timed out fetching dynamic settings after #{SETTINGS_QUERY_TIMEOUT} seconds"
+    []
+  end
+
+  def self.mask_value(field_name, value)
+    return nil if value.nil?
+
+    is_sensitive = SENSITIVE_PATTERNS.any? { |pattern| field_name.match?(pattern) }
+
+    if is_sensitive
+      case value
+      when String
+        if value.empty?
+          "[EMPTY]"
+        elsif value.length <= 4
+          "[MASKED]"
+        else
+          "#{value[0..3]}#{'*' * [ value.length - 4, 8 ].min}"
+        end
+      when TrueClass, FalseClass
+        value
+      else
+        "[MASKED]"
+      end
+    else
+      value
+    end
+  end
+end