Reuse the Logger instead of reopening the log file on every call when saving to a file

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ### Unreleased
 
+* (patch) Fix `KnapsackPro.logger` building a new logger and reopening the log file on every call when `KNAPSACK_PRO_LOG_DIR` is set.
+
 ### 10.0.1
 
 * Add support for [File Paths Encryption](https://docs.knapsackpro.com/ruby/encryption/) to [Retry only Failures](https://docs.knapsackpro.com/ruby/retry-only-failures/).

lib/knapsack_pro.rb

@@ -110,17 +110,17 @@ def root
     end
 
     def logger
-      if KnapsackPro::Config::Env.log_dir
-        default_logger = Logger.new("#{KnapsackPro::Config::Env.log_dir}/knapsack_pro_node_#{KnapsackPro::Config::Env.ci_node_index}.log")
-        default_logger.level = KnapsackPro::Config::Env.log_level
-        self.logger = default_logger
-      end
+      return @logger if @logger
 
-      unless @logger
-        default_logger = ::Logger.new(stdout)
-        default_logger.level = KnapsackPro::Config::Env.log_level
-        self.logger = default_logger
-      end
+      log_dir = KnapsackPro::Config::Env.log_dir
+      default_logger =
+        if log_dir
+          ::Logger.new("#{log_dir}/knapsack_pro_node_#{KnapsackPro::Config::Env.ci_node_index}.log")
+        else
+          ::Logger.new(stdout)
+        end
+      default_logger.level = KnapsackPro::Config::Env.log_level
+      self.logger = default_logger
 
       @logger
     end

spec/knapsack_pro_spec.rb

@@ -51,6 +51,19 @@
           end
         end
       end
+
+      it 'reuses the logger instead of reopening the log file on every call' do
+        Dir.mktmpdir do |dir|
+          stub_const('ENV', 'KNAPSACK_PRO_LOG_DIR' => dir)
+
+          expect(::Logger).to receive(:new).once.and_call_original
+
+          logger = described_class.logger
+
+          expect(described_class.logger).to be(logger)
+          expect(described_class.logger).to be(logger)
+        end
+      end
     end
 
     context 'with the default logger' do