feat: redact sensitive feed data in structured logs

app/web/boot/setup.rb

@@ -13,6 +13,7 @@ class << self
           def call!
             validate_environment!
             configure_request_service!
+            configure_runtime_logging!
           end
 
           private
@@ -28,6 +29,13 @@ def validate_environment!
           def configure_request_service!
             nil
           end
+
+          # @return [void]
+          def configure_runtime_logging!
+            return unless defined?(Rack::Timeout::Logger)
+
+            Rack::Timeout::Logger.logger = AppLogger.logger
+          end
         end
       end
     end

app/web/request/request_context_middleware.rb

@@ -57,7 +57,7 @@ def build_context(request)
         path = request.path_info.to_s
         RequestContext::Context.new(
           request_id: request_id_for(request),
-          path: path,
+          path: LogSanitizer.sanitize_path(path),
           http_method: request.request_method.to_s.upcase,
           route_group: route_group_for(path),
           actor: nil,

app/web/security/security_logger.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require 'logger'
 require 'json'
 require 'digest'
 require 'time'
@@ -11,16 +10,10 @@ module Web
     # Provides structured logging for security events to stdout
     module SecurityLogger
       class << self
-        # Initialize logger to stdout with structured JSON output
-        # @return [Logger]
-        def logger
-          Thread.current[:security_logger] ||= create_logger
-        end
-
-        # Reset logger (for testing)
+        # Reset shared logger state for tests.
         # @return [void]
         def reset_logger!
-          Thread.current[:security_logger] = nil
+          AppLogger.reset_logger!
         end
 
         ##
@@ -134,32 +127,18 @@ def log_cache_lifecycle(component, event, details = {})
 
         private
 
-        def create_logger
-          Logger.new($stdout).tap do |log|
-            log.formatter = proc do |severity, datetime, _progname, msg|
-              "#{{
-                timestamp: datetime.iso8601,
-                level: severity,
-                service: 'html2rss-web',
-                **JSON.parse(msg, symbolize_names: true)
-              }.to_json}\n"
-            end
-          end
-        end
-
         ##
         # Log a security event
         # @param event_type [String] type of security event
         # @param data [Hash] event data
         def log_event(event_type, data, severity: :warn)
-          context_data = RequestContext.current_h
-          payload = {
-            security_event: event_type,
-            **context_data,
-            **data
-          }.to_json
-
-          logger.public_send(severity, payload)
+          LogEvent.emit(
+            level: severity,
+            payload: {
+              security_event: event_type,
+              **data
+            }
+          )
         rescue StandardError => error
           handle_logging_error(error, event_type, data)
         end

app/web/telemetry/app_logger.rb

@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require 'json'
+require 'logger'
+require 'time'
+require 'uri'
+
+module Html2rss
+  module Web
+    ##
+    # Shared structured logger for application and middleware runtime events.
+    module AppLogger
+      class << self
+        # @return [Logger]
+        def logger
+          Thread.current[:app_logger] ||= build_logger
+        end
+
+        # @return [void]
+        def reset_logger!
+          Thread.current[:app_logger] = nil
+        end
+
+        private
+
+        # @return [Logger]
+        def build_logger
+          Logger.new($stdout).tap do |log|
+            log.formatter = method(:format_entry)
+          end
+        end
+
+        # @param severity [String]
+        # @param datetime [Time]
+        # @param _progname [String, nil]
+        # @param message [String]
+        # @return [String]
+        def format_entry(severity, datetime, _progname, message)
+          "#{base_payload(severity, datetime).merge(normalize_message(message)).to_json}\n"
+        end
+
+        # @param severity [String]
+        # @param datetime [Time]
+        # @return [Hash{Symbol=>Object}]
+        def base_payload(severity, datetime)
+          {
+            timestamp: datetime.iso8601,
+            level: severity,
+            service: 'html2rss-web'
+          }
+        end
+
+        # @param message [Object]
+        # @return [Hash{Symbol=>Object}]
+        def normalize_message(message)
+          parsed_json(message) || parse_logfmt(message.to_s) || { message: message.to_s }
+        end
+
+        # @param message [Object]
+        # @return [Hash{Symbol=>Object}, nil]
+        def parsed_json(message)
+          JSON.parse(message.to_s, symbolize_names: true)
+        rescue JSON::ParserError, TypeError
+          nil
+        end
+
+        # @param message [String]
+        # @return [Hash{Symbol=>Object}, nil]
+        def parse_logfmt(message)
+          pairs = message.scan(/([a-zA-Z0-9_.-]+)=("[^"]*"|\S+)/)
+          return nil if pairs.empty?
+
+          pairs.to_h do |key, raw_value|
+            [key.to_sym, normalize_logfmt_value(raw_value)]
+          end
+        end
+
+        # @param raw_value [String]
+        # @return [String, Integer, Float, TrueClass, FalseClass]
+        def normalize_logfmt_value(raw_value)
+          value = raw_value.delete_prefix('"').delete_suffix('"')
+          return true if value == 'true'
+          return false if value == 'false'
+          return value.to_i if value.match?(/\A-?\d+\z/)
+          return value.to_f if value.match?(/\A-?\d+\.\d+\z/)
+
+          value
+        end
+      end
+    end
+  end
+end

app/web/telemetry/log_event.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Html2rss
+  module Web
+    ##
+    # Shared structured log emitter for request-scoped application events.
+    module LogEvent
+      class << self
+        # @param payload [Hash{Symbol=>Object}]
+        # @param level [Symbol]
+        # @return [void]
+        def emit(payload:, level: :info)
+          logger.public_send(level, build_payload(payload).to_json)
+        end
+
+        private
+
+        # @return [Logger]
+        def logger
+          AppLogger.logger
+        end
+
+        # @param payload [Hash{Symbol=>Object}]
+        # @return [Hash{Symbol=>Object}]
+        def build_payload(payload)
+          RequestContext.current_h.merge(LogSanitizer.sanitize_details(payload))
+        end
+      end
+    end
+  end
+end

app/web/telemetry/log_sanitizer.rb

@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require 'digest'
+require 'uri'
+
+module Html2rss
+  module Web
+    ##
+    # Sanitizes request and detail payloads before structured logging.
+    module LogSanitizer
+      FEED_TOKEN_ROUTE = %r{\A(/api/v1/feeds/)([^/.?]+)(\.(?:json|xml|rss))?\z}
+
+      class << self
+        # @param path [String, nil]
+        # @return [String, nil]
+        def sanitize_path(path)
+          return if path.nil?
+
+          path.to_s.gsub(FEED_TOKEN_ROUTE, '\1[REDACTED]\3')
+        end
+
+        # @param details [Hash]
+        # @return [Hash]
+        def sanitize_details(details)
+          details.each_with_object({}) do |(key, value), sanitized|
+            sanitized[key] = sanitize_value(key, value)
+          end
+        end
+
+        private
+
+        # @param key [Object]
+        # @param value [Object]
+        # @return [Object]
+        def sanitize_value(key, value)
+          return sanitize_url(value) if key.to_sym == :url
+          return sanitize_details(value) if value.is_a?(Hash)
+          return value.map { |entry| sanitize_value(key, entry) } if value.is_a?(Array)
+
+          value
+        end
+
+        # @param value [Object]
+        # @return [Hash{Symbol=>Object}, Object]
+        def sanitize_url(value)
+          url = value.to_s
+          return value if url.empty?
+
+          uri = URI.parse(url)
+          {
+            host: uri.host,
+            scheme: uri.scheme,
+            hash: Digest::SHA256.hexdigest(url)[0..11]
+          }.compact
+        rescue URI::InvalidURIError
+          { hash: Digest::SHA256.hexdigest(url)[0..11] }
+        end
+      end
+    end
+  end
+end

app/web/telemetry/observability.rb

@@ -1,9 +1,5 @@
 # frozen_string_literal: true
 
-require 'json'
-require 'logger'
-require 'time'
-
 module Html2rss
   module Web
     ##
@@ -18,27 +14,13 @@ class << self
         # @param level [Symbol]
         # @return [void]
         def emit(event_name:, outcome:, details: {}, level: :info)
-          logger.public_send(level, build_payload(event_name, outcome, details).to_json)
+          LogEvent.emit(payload: build_payload(event_name, outcome, details), level: level)
         rescue StandardError => error
           handle_emit_error(error, event_name, outcome)
         end
 
         private
 
-        # @return [Logger]
-        def logger
-          Thread.current[:observability_logger] ||= Logger.new($stdout).tap do |log|
-            log.formatter = proc do |severity, datetime, _progname, msg|
-              "#{{
-                timestamp: datetime.iso8601,
-                level: severity,
-                service: 'html2rss-web',
-                **JSON.parse(msg, symbolize_names: true)
-              }.to_json}\n"
-            end
-          end
-        end
-
         # @param error [StandardError]
         # @param event_name [String]
         # @param outcome [String]