Replace puts with injectable Logger instance

lib/jsonrpc/configuration.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'logger'
+
 module JSONRPC
   # Configuration class for JSON-RPC procedure management and validation.
   #
@@ -49,6 +51,20 @@ class Configuration
     #
     Procedure = Data.define(:allow_positional_arguments, :contract, :parameter_name)
 
+    # Logger instance used to emit log messages
+    #
+    # @api public
+    #
+    # @example Using the default logger
+    #   config.logger # => #<Logger:...>
+    #
+    # @example Setting a custom logger
+    #   config.logger = Logger.new($stderr)
+    #
+    # @return [Logger] the logger instance
+    #
+    attr_accessor :logger
+
     # Whether to log detailed internal error information in the terminal
     #
     # @api public
@@ -129,14 +145,16 @@ def json_adapter=(adapter)
     # @example With custom options
     #   config = JSONRPC::Configuration.new(
     #     log_request_validation_errors: true,
-    #     render_internal_errors: true
+    #     render_internal_errors: true,
+    #     logger: Logger.new($stderr)
     #   )
     #
     # @param log_internal_errors [Boolean] whether to log detailed internal error information in the terminal
     # @param log_request_validation_errors [Boolean] whether to log validation errors during JSON-RPC request processing
     # @param rescue_internal_errors [Boolean] whether internal errors should be rescued and converted to JSON-RPC errors
     # @param render_internal_errors [Boolean] whether to render detailed internal error information in responses
     # @param validate_procedure_signatures [Boolean] whether procedure signatures are validated
+    # @param logger [Logger] the logger instance used to emit log messages
     #
     # @return [Configuration] a new configuration instance
     #
@@ -145,14 +163,16 @@ def initialize(
       log_request_validation_errors: false,
       rescue_internal_errors: true,
       render_internal_errors: false,
-      validate_procedure_signatures: true
+      validate_procedure_signatures: true,
+      logger: Logger.new($stdout)
     )
       @procedures = {}
       @log_internal_errors = log_internal_errors
       @log_request_validation_errors = log_request_validation_errors
       @rescue_internal_errors = rescue_internal_errors
       @render_internal_errors = render_internal_errors
       @validate_procedure_signatures = validate_procedure_signatures
+      @logger = logger
     end
 
     # Returns the singleton instance of the Configuration class

lib/jsonrpc/middleware.rb

@@ -41,13 +41,15 @@ class Middleware
     # @option options [String] :path ('/') The path to handle JSON-RPC requests on
     # @option options [Boolean] :rescue_internal_errors (nil) Override config rescue_internal_errors
     # @option options [Boolean] :log_internal_errors (true) Override config log_internal_errors
+    # @option options [Logger] :logger Override the logger used for internal error reporting
     #
     def initialize(app, options = {})
       @app = app
-      @parser = Parser.new
-      @validator = Validator.new
       @path = options.fetch(:path, DEFAULT_PATH)
       @config = JSONRPC.configuration
+      @logger = options.fetch(:logger, @config.logger)
+      @parser = Parser.new
+      @validator = Validator.new(logger: @logger)
       @log_internal_errors = options.fetch(:log_internal_errors, @config.log_internal_errors)
       @rescue_internal_errors = options.fetch(:rescue_internal_errors, @config.rescue_internal_errors)
     end
@@ -377,7 +379,7 @@ def read_request_body
       body_content
     end
 
-    # Logs internal errors to stdout with full backtrace
+    # Logs internal errors using the configured logger
     #
     # @api private
     #
@@ -389,8 +391,8 @@ def read_request_body
     # @return [void]
     #
     def log_internal_error(error)
-      puts "Internal error: #{error.message}"
-      puts error.backtrace.join("\n")
+      @logger.error("Internal error: #{error.message}")
+      @logger.error(error.backtrace.join("\n"))
     end
   end
 end

lib/jsonrpc/validator.rb

@@ -13,6 +13,24 @@ module JSONRPC
   #   error = validator.validate(request)
   #
   class Validator
+    # Initializes a new Validator
+    #
+    # @api public
+    #
+    # @example Default initialization
+    #   validator = JSONRPC::Validator.new
+    #
+    # @example With a custom logger
+    #   validator = JSONRPC::Validator.new(logger: Logger.new($stderr))
+    #
+    # @param logger [Logger] Logger instance for logging validation errors
+    #
+    # @return [Validator] a new validator instance
+    #
+    def initialize(logger: JSONRPC.configuration.logger)
+      @logger = logger
+    end
+
     # Validates a single request, notification or a batch
     #
     # @api public
@@ -100,8 +118,8 @@ def validate_request_params(request_or_notification)
       nil
     rescue StandardError => e
       if JSONRPC.configuration.log_request_validation_errors
-        puts "Validation error: #{e.message}"
-        puts e.backtrace.join("\n")
+        @logger.error("Validation error: #{e.message}")
+        @logger.error(e.backtrace.join("\n"))
       end
 
       InternalError.new(request_id: extract_request_id(request_or_notification))

spec/jsonrpc/middleware_spec.rb

@@ -389,12 +389,20 @@
   end
 
   context 'when processing a JSON-RPC request that causes an unexpected exception' do
-    it 'returns HTTP 200 OK with a JSON-RPC internal error' do
-      # TODO: Remove this in the next iteration
-      # rubocop:disable RSpec/AnyInstance
-      allow_any_instance_of(described_class).to receive(:log_internal_error)
-      # rubocop:enable RSpec/AnyInstance
+    let(:logger) { instance_double(Logger) }
+
+    let(:app) do
+      test_logger = logger
+      middleware = described_class
+      Rack::Builder.new do
+        use middleware, path: '/jsonrpc', logger: test_logger
+        run TestApp.new
+      end
+    end
+
+    before { allow(logger).to receive(:error) }
 
+    it 'returns HTTP 200 OK with a JSON-RPC internal error' do
       post_jsonrpc_request(
         jsonrpc: '2.0',
         method: 'explode',
@@ -413,14 +421,14 @@
       )
     end
 
-    it 'logs the internal error to stdout' do
-      expect do
-        post_jsonrpc_request(
-          jsonrpc: '2.0',
-          method: 'explode',
-          id: 'req-internal-error'
-        )
-      end.to output(/Internal error: Internal JSON-RPC error\./).to_stdout
+    it 'logs the internal error using the configured logger' do
+      post_jsonrpc_request(
+        jsonrpc: '2.0',
+        method: 'explode',
+        id: 'req-internal-error'
+      )
+
+      expect(logger).to have_received(:error).with(/Internal error: Internal JSON-RPC error\./)
     end
   end