From 333e1f3f33f7ed9031e91d0d8b5ee157f2b00f23 Mon Sep 17 00:00:00 2001
From: Theo Felippe <git@theocodes.com>
Date: Sat, 5 Oct 2024 21:26:41 +0100
Subject: [PATCH] Logger local named tags

Adds the ability to set named tags on the logger instance via the new
`#named_tags=` instance method. Once set, subsequent calls to the logger
that would normally emit a log entry will contain the local named tags,
in addition to global ones or those added with `#tagged`.

Within a `#tagged` block, logs generated by the instance will already
contain the local named tags, but any other logger's entries will not.
---
 lib/semantic_logger/base.rb | 14 +++++++++-
 test/logger_test.rb         | 56 +++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/lib/semantic_logger/base.rb b/lib/semantic_logger/base.rb
index 8fa26a0..155e692 100644
--- a/lib/semantic_logger/base.rb
+++ b/lib/semantic_logger/base.rb
@@ -211,7 +211,15 @@ def tags
     end
 
     def named_tags
-      SemanticLogger.named_tags
+      SemanticLogger.named_tags.merge(@named_tags || {})
+    end
+
+    # Sets named tags which are local to the logger instance.
+    #
+    # Local named tags are merged into the log entry along with the thread-level ones
+    # and those set via `#tagged` or `#with_tags`.
+    def named_tags=(tags)
+      (@named_tags ||= {}).merge!(tags)
     end
 
     # Returns the list of tags pushed after flattening them out and removing blanks
@@ -327,6 +335,10 @@ def log_internal(level, index, message = nil, payload = nil, exception = nil)
       end
 
       log = Log.new(name, level, index)
+
+      # Apply the named tags to the log entry
+      log.named_tags = named_tags
+
       should_log =
         if exception.nil? && payload.nil? && message.is_a?(Hash)
           # All arguments as a hash in the message.
diff --git a/test/logger_test.rb b/test/logger_test.rb
index 8c6e224..06701f5 100644
--- a/test/logger_test.rb
+++ b/test/logger_test.rb
@@ -50,6 +50,14 @@ def self.call(log)
       end
     end
 
+    describe "#named_tags=" do
+      it "adds local named tags to logger" do
+        logger.named_tags = {test: "123"}
+        assert_equal({test: "123"}, logger.named_tags)
+        assert_equal({}, SemanticLogger.named_tags)
+      end
+    end
+
     describe "Compatibility" do
       # Ensure that any log level can be logged
       Logger::Severity.constants.each do |level|
@@ -152,6 +160,54 @@ def self.call(log)
           assert_equal logger.object_id, yielded_logger.object_id
         end
       end
+
+      it "adds logger-local named tags to log entries" do
+        logger.named_tags = {test: "123"}
+
+        logger.tagged do
+          logger.info("test")
+        end
+
+        assert log = logger.events.first
+        assert_equal({test: "123"}, log.named_tags)
+      end
+
+      it "does not change local tags" do
+        logger.named_tags = {test: "123"}
+
+        logger.tagged(foo: "bar") do
+          logger.info("test")
+        end
+
+        assert_equal({test: "123"}, logger.named_tags)
+        assert_equal({}, SemanticLogger.named_tags)
+        assert_equal({test: "123", foo: "bar"}, logger.events.first.named_tags)
+      end
+
+      it "does not override global tags" do
+        SemanticLogger.push_named_tags(global: true)
+        logger.named_tags = {test: "123"}
+
+        logger.info("test")
+
+        assert_equal({global: true, test: "123"}, logger.events.first.named_tags)
+        assert_equal({global: true}, SemanticLogger.named_tags)
+
+        SemanticLogger.pop_named_tags
+      end
+
+      it "does no add local named tags to other loggers in block" do
+        another_logger = SemanticLogger::Test::CaptureLogEvents.new
+        logger.named_tags = {test: "123"}
+
+        logger.tagged(foo: "bar") do
+          logger.info("has local tags")
+          another_logger.info("does not have local tags")
+        end
+
+        assert_equal({test: "123", foo: "bar"}, logger.events.first.named_tags)
+        assert_equal({foo: "bar"}, another_logger.events.first.named_tags)
+      end
     end
   end
 end